Friday, October 04, 2024

Scientists discover planet orbiting closest single star to our Sun

PR Image eso2414a
Artist’s impression of a sub-Earth-mass planet orbiting Barnard’s star

PR Image eso2414b
The nearest stars to the Sun (infographic)

PR Image eso2414c
Barnard’s Star in the constellation Ophiuchus

PR Image eso2414d
Widefield image of the sky around Barnard’s Star showing its motion


Videos

New planet discovered orbiting closest single star to our Sun | ESO News
PR Video eso2414a
New planet discovered orbiting closest single star to our Sun | ESO News

Animation of a sub-Earth-mass planet orbiting Barnard’s star
PR Video eso2414b
Animation of a sub-Earth-mass planet orbiting Barnard’s star

Animation of a sub-Earth-mass planet orbiting Barnard’s star
PR Video eso2414c
Animation of a sub-Earth-mass planet orbiting Barnard’s star

Barnard’s Star in the Solar neighborhood
PR Video eso2414d
Barnard’s Star in the Solar neighborhood

The radial velocity method for finding exoplanets
PR Video eso2414e
The radial velocity method for finding exoplanets


Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered an exoplanet orbiting Barnard’s star, the closest single star to our Sun. On this newly discovered exoplanet, which has at least half the mass of Venus, a year lasts just over three Earth days. The team’s observations also hint at the existence of three more exoplanet candidates, in various orbits around the star.

Located just six light-years away, Barnard’s star is the second-closest stellar system — after Alpha Centauri’s three-star group — and the closest individual star to us. Owing to its proximity, it is a primary target in the search for Earth-like exoplanets. Despite a promising detection back in 2018, no planet orbiting Barnard's star had been confirmed until now.

The discovery of this new exoplanet — announced in a paper published today in the journal Astronomy & Astrophysics — is the result of observations made over the last five years with ESO’s VLT, located at Paranal Observatory in Chile. “Even if it took a long time, we were always confident that we could find something,” says Jonay González Hernández, a researcher at the Instituto de Astrofísica de Canarias in Spain, and lead author of the paper. The team were looking for signals from possible exoplanets within the habitable or temperate zone of Barnard’s star — the range where liquid water can exist on the planet’s surface. Red dwarfs like Barnard’s star are often targeted by astronomers since low-mass rocky planets are easier to detect there than around larger Sun-like stars. [1]

Barnard b [2], as the newly discovered exoplanet is called, is twenty times closer to Barnard’s star than Mercury is to the Sun. It orbits its star in 3.15 Earth days and has a surface temperature around 125 °C. “Barnard b is one of the lowest-mass exoplanets known and one of the few known with a mass less than that of Earth. But the planet is too close to the host star, closer than the habitable zone,” explains González Hernández. “Even if the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface.”

For their observations, the team used ESPRESSO, a highly precise instrument designed to measure the wobble of a star caused by the gravitational pull of one or more orbiting planets. The results obtained from these observations were confirmed by data from other instruments also specialised in exoplanet hunting: HARPS at ESO’s La Silla Observatory, HARPS-N and CARMENES. The new data do not, however, support the existence of the exoplanet reported in 2018. 

In addition to the confirmed planet, the international team also found hints of three more exoplanet candidates orbiting the same star. These candidates, however, will require additional observations with ESPRESSO to be confirmed. “We now need to continue observing this star to confirm the other candidate signals,” says Alejandro Suárez Mascareño, a researcher also at the Instituto de Astrofísica de Canarias and co-author of the study. “But the discovery of this planet, along with other previous discoveries such as Proxima b and d, shows that our cosmic backyard is full of low-mass planets.”

ESO’s Extremely Large Telescope (ELT), currently under construction, is set to transform the field of exoplanet research. The ELT’s ANDES instrument will allow researchers to detect more of these small, rocky planets in the temperate zone around nearby stars, beyond the reach of current telescopes, and enable them to study the composition of their atmospheres.

Source: ESO/News


Notes

[1] Astronomers target cool stars, like red dwarfs, because their temperate zone is much closer to the star than that of hotter stars, like the Sun. This means that the planets orbiting within their temperate zone have shorter orbital periods, allowing astronomers to monitor them over several days or weeks, rather than years. In addition, red dwarfs are much less massive than the Sun, so they are more easily disturbed by the gravitational pull of the planets around them and thus they wobble more strongly.

[2] It’s common practice in science to name exoplanets by the name of their host star with a lowercase letter added to it, ‘b’ indicating the first known planet, ’c’ the next one, and so on. The name Barnard b was therefore also given to a previously suspected planet candidate around Barnard's star, which scientists were unable to confirm.


More information

This research was presented in the paper “A sub-Earth-mass planet orbiting Barnard’s star” to appear in Astronomy & Astrophysics. (https://www.aanda.org/10.1051/0004-6361/202451311)

The team is composed of J. I. González Hernández (Instituto de Astrofísica de Canarias, Spain [IAC] and Departamento de Astrofísica, Universidad de La Laguna, Spain [IAC-ULL]), A. Suárez Mascareño (IAC and IAC-ULL), A. M. Silva (Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Portugal [IA-CAUP] and Departamento de Física e Astronomia Faculdade de Ciências, Universidade do Porto, Portugal [FCUP]), A. K. Stefanov (IAC and IAC-ULL), J. P. Faria (Observatoire de Genève, Université de Genève, Switzerland [UNIGE]; IA-CAUP and FCUP), H. M. Tabernero (Departamento de Física de la Tierra y Astrofísica & Instituto de Física de Partículas y del Cosmos, Universidad Complutense de Madrid, Spain), A. Sozzetti (INAF - Osservatorio Astrofisico di Torino [INAF-OATo] and Istituto Nazionale di Astrofisica, Torino, Italy), R. Rebolo (IAC; IAC-ULL and Consejo Superior de Investigaciones Científicas, Spain [CSIC]), F. Pepe (UNIGE), N. C. Santos (IA-CAUP; FCUP), S. Cristiani (INAF - Osservatorio Astronomico di Trieste, Italy [INAF-OAT] and Institute for Fundamental Physics of the Universe, Trieste, Italy [IFPU]), C. Lovis (UNIGE), X. Dumusque (UNIGE), P. Figueira (UNIGE and IA-CAUP), J. Lillo-Box (Centro de Astrobiología, CSIC-INTA, Madrid, Spain [CAB]), N. Nari (IAC; Light Bridges S. L., Canarias, Spain and IAC-ULL), S. Benatti (INAF - Osservatorio Astronomico di Palermo, Italy [INAF-OAPa]), M. J. Hobson (UNIGE), A. Castro-González (CAB), R. Allart (Institut Trottier de Recherche sur les Exoplanètes, Université de Montréal, Canada and UNIGE), V. M. Passegger (National Astronomical Observatory of Japan, Hilo, USA; IAC; IAC-ULL and Hamburger Sternwarte, Hamburg, Germany), M.-R. Zapatero Osorio (CAB), V. Adibekyan (IA-CAUP and FCUP), Y. Alibert (Center for Space and Habitability, University of Bern, Switzerland and Weltraumforschung und Planetologie, Physikalisches Institut, University of Bern, Switzerland), C. Allende Prieto (IAC and IAC-ULL), F. Bouchy (UNIGE), M. Damasso (INAF-OATo), V. D’Odorico (INAF-OAT and IFPU), P. Di Marcantonio (INAF-OAT), D. Ehrenreich (UNIGE), G. Lo Curto (European Southern Observatory, Santiago, Chile [ESO Chile]), R. Génova Santos (IAC and IAC-ULL), C. J. A. P. Martins (IA-CAUP and Centro de Astrofísica da Universidade do Porto, Portugal), A. Mehner (ESO Chile), G. Micela (INAF-OAPa), P. Molaro (INAF-OAT), N. Nunes (Instituto de Astrofísica e Ciências do Espaço, Universidade de Lisboa), E. Palle (IAC and IAC-ULL), S. G. Sousa (IA-CAUP and FCUP), and S. Udry (UNIGE).

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.


Links


Contacts:

Jonay I. González Hernández
Instituto de Astrofísica de Canarias
Tenerife, Spain
Tel: +34 922 605 751 or +34 922 605 200
Email: jonay.gonzalez@iac.es Alejandro Suárez Mascareño
Instituto de Astrofísica de Canarias
Tenerife, Spain
Tel: +34 658 778 954
Email: alejandro.suarez.mascareno@iac.es

Serena Benatti
INAF - Osservatorio Astronomico di Palermo
Palermo, Italy
Tel: +39 091 233270
Email: serena.benatti@inaf.it

João Faria
Département d’astronomie de l’Université de Genève
Geneve, Switzerland
Tel: +41 22 379 22 76
Email: joao.faria@unige.ch

André M. Silva
Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto
Porto, Portugal
Tel: +351 226 089 830
Email: Andre.Silva@astro.up.pt

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: press@eso.org

Posted by at
Labels: , , , , , ,

Thursday, October 03, 2024

The cosmic-ray ionization rate in the local Milky Way is ten times lower than previously thought

This figure illustrates the spatial distribution of gas density obtained from the high-resolution 3D dust extinction map. Shown is the cross section of one of molecular clouds where the CRIR was measured, the line of sight toward a background star is indicated by the dashed line. The individual pixels reflect the 1-parsec spatial resolution provided by the map. © M. Obolontseva et al.

Shown are re-evaluated values of the CRIR (ζH2 , blue bullets) obtained from the analysis of observations toward different stars (indicated by their HD catalogue numbers), and earlier results for these sight lines. The gray curve represents the CRIR derived from the Voyager data. The horizontal axis indicates the gas column density of molecular clouds where the CRIR was measured. © M. Obolontseva et al.


An international group of astrophysicists, led by MPE scientists Marta Obolentseva, Alexei Ivlev, Kedron Silsbee, and Paola Caselli, have revisited the long-standing problem of evaluating the rate at which cosmic rays ionize gas in the interstellar medium. By combining available observational data for diffuse molecular clouds with novel developments in understanding the dust and gas distribution in these regions and applying numerical modeling, the scientists were able to compute the cosmic-ray ionization rate (or its upper limit) for a dozen nearby clouds. They showed that earlier estimates were a factor of ten too high.

Galactic cosmic rays (CRs) play a crucial role in the evolution of molecular clouds, governing multiple physical and chemical processes that accompany practically all stages of star formation. The impact of CRs on these processes is quantified in terms of the CR ionization rate (CRIR), which is the number of ionization events produced by CRs per gas molecule in unit time. The value of this fundamentally important parameter has been debated by the star formation community for over half a century. The principal difficulty here originates from the fact that the CRIR in the interstellar medium is determined by a relatively small population of non-relativistic CRs. In contrast to the well-constrained ultra-relativistic population, there are no robust direct methods to detect such “low-energy” particles in space – nor can they be measured on Earth, because of their efficient exclusion from the heliosphere by the Solar wind.

The only direct method to measure the CR energy spectra and thus to derive the CRIR would be to use spacecraft that are able to reach beyond the heliosphere. Such measurements have indeed been performed a decade ago by the Voyager probes 1 and 2 when they crossed the outmost edge of the heliosphere – the heliopause. Nevertheless, this unique direct sampling of CRs still represents the very local interstellar medium in the immediate proximity of the Sun, at a distance of only about 120 au.

For this reason, indirect methods have been widely used to estimate the CRIR in numerous molecular clouds surrounding us in the Milky Way. Such methods typically rely on measuring light absorption due to specific ions produced by CRs, accumulated along the line of sight that connects the observer to the background star (acting as the emission source). Much attention has been given to absorption observations of H3+ ions (molecular hydrogen, H2, with an extra proton attached), often considered the most reliable method to measure the CRIR in diffuse molecular clouds – thanks to the particularly simple formation and destruction routes of these ions and the fact that they involve the most abundant molecule in the universe, H2. It turned out, however, that typical CRIR values inferred from these measurements are more than a factor of ten higher than those derived from the Voyager data!

This dramatic discrepancy has been a major puzzle in the cosmic-ray community over the last decade. At the same time, the so-called 3D dust extinction maps have changed our understanding of the three-dimensional dust and gas distribution in the surrounding molecular clouds. These maps have been constructed using distances to over a billion stars, based on parallax measurements by the Gaia satellite. Recently, the high-resolution maps developed by our neighbors at MPA in the group of Dr. Torsten Enßlin reached sufficient accuracy to allow a reconstruction of the gas distribution down to parsec scales. This breakthrough made it possible to identify the individual clouds where H3+ absorption actually occurred in each observation, and thus to pinpoint precisely the positions of individual CRIR measurements in 3D space.

Motivated by this staggering development, the scientists revisited the analysis of available H3+ observations. They performed 3D simulations of the identified clouds, with the CRIR being the only unconstrained parameter of the model. By comparing their results with observations, this made it possible for the first time to self-consistently reconstruct the physical structure of the individual clouds and derive the respective CRIR.

“One of the astonishing outcomes of our analysis is that the re-evaluated values of CRIR are an order of magnitude lower than the previous estimates, which actually brings our results into agreement with the CR spectrum measured by the Voyager probes”, says Alexei Ivlev, one of the main authors of the study. “While we of course cannot claim the very local Voyager spectrum to be representative of a typical Galactic spectrum of CRs, it is certainly no longer an outlier – as it has been considered for many years.”

“In addition to the impressive results on the CRIR, this work represents a major step forward in the realism of astrochemical modeling. These are the first simulations to incorporate the actual gas density distribution. I anticipate that combining astrochemical simulations with accurate determinations of the density structure and the radiation field will result in many more exciting advances in the coming years”, Kedron Silsbee adds.

The work that has discovered the drastic reduction in the CRIR also led to a remarkable “byproduct” discovery: it was found that all earlier estimates of the gas density in diffuse molecular clouds, where the H3+ measurements are typically conducted, strongly exceed the values derived from the extinction maps. In order to identify the origin of this discrepancy, one of the group’s collaborators, Prof. David Neufeld from the Johns Hopkins University, has revisited the method commonly used to estimate gas densities. This method is based on observations of excited rotational states of molecular carbon (C2) and therefore depends on the rates of C2 excitation in collisions with gas molecules. It turned out that the rates assumed for the earlier estimates were considerably lower than the accurate values obtained recently, with the result that the inferred densities were too high. In the companion paper led by David Neufeld, the scientists presented revised gas densities that are now in good agreement with those from the extinction maps.

“Initially, I had been quite skeptical of the lower density estimates that emerged from the dust extinction maps, because they were inconsistent with what we thought we knew. But when I looked more closely at the methods used previously to evaluate the gas density from observations of C2, I found that they had yielded density estimates that were far too high”, says Neufeld.

Ultimately, the dramatically reduced gas densities as well as the reduction in the CRIR have profound and diverse implications. Not only does this affect the chemical composition of diffuse and translucent molecular clouds, but also changes the evolution of their physical structure, which finally has a broad impact on the initial stages of star formation.

“CRs are fundamental ingredients for the dynamical evolution of interstellar molecular clouds, where stars and planets form, and for chemical evolution in space, where the precursors of pre-biotic molecules form. It is thus crucial for astrophysics and astrochemistry to know the CRIR, making this one of our long-standing scientific goals”, says Paola Caselli, director at the Center for Astrochemical studies at MPE. “I am very proud that our study, also involving scientists from MPA and international colleagues in a truly interdisciplinary effort, has achieved this goal”, she adds.

These studies also have important consequences for all available CRIR measurements utilizing various ionization tracers. The presented results show that a careful re-evaluation of previously published estimates of CRIR in molecular clouds would be useful, in particular by considering the recent revolutionary changes in our understanding of the diffuse gas distribution in the Milky Way.



Contact:

Priv. Doz. Dr. habil. Alexei Ivlev
scientist in CAS group
Tel:++49 89 30000-3356
ivlev@mpe.mpg.de
Max Planck Institute for extraterrestrial Physics , Garching

Marta Obolentseva
PhD-student CAS group
marta@mpe.mpg.de
Max Planck Institute for extraterrestrial Physics

Prof. Dr. Paola Caselli
Director of the CAS group at MPE
Tel:+49 89 30000-3400
Fax:+49 89 30000-3399
caselli@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching


Original Publications
1. M. Obolentseva, A. Ivlev et al.
Re-evaluation of the cosmic-ray ionization rate in diffuse clouds
The Astrophysical Journal (2024), Vol. 973, A142

DOI

2. D. Neufeld, D. Welty, A. Ivlev et al.
The densities in diffuse and translucent molecular clouds: estimates from observations of C2 and from 3-dimensional extinction maps
The Astrophysical Journal 2024, Vol. 973, A143

DOI


Further Information

Cosmic rays in molecular gas
One of the principal aims of the CAS-Theory group is to understand the physics of low-energy CRs in molecular gas, by combining advanced methods of the kinetic theory and plasma physics and applying available observational constraints. More

3. Edenhofer, C. Zucker, P. Fran et al.
A parsec-scale Galactic 3D dust map out to 1.25 kpc from the Sun★
A&A, Vol. 685, A82 (2024)

Source | DOI

JWST sheds Light on the Journey of Cosmic Icy Grains
July 04, 2024
Using the JWST, a team of researchers including Paola Caselli and Michela Giuliano from MPE, have probed deep into dense cloud cores, revealing details of interstellar ice that were previously unobservable. The study focuses on the Chamaeleon I region, using JWST’s NIRCam to measure spectroscopic lines towards hundreds of stars behind the cloud. More

Posted by at
Labels: , ,

Wednesday, October 02, 2024

ESO telescope captures the most detailed infrared map ever of our Milky Way

PR Image eso2413a
Highlights of the most detailed infrared map of the Milky Way

PR Image eso2413b
An infrared view of the Messier 17 nebula

PR Image eso2413c
An infrared view of the NGC 6188 nebula and the NGC 6193 cluster

PR Image eso2413d
An infrared view of the Messier 22 globular cluster

PR Image eso2413e
The Lobster Nebula seen with ESO’s VISTA telescope

PR Image eso2413f
VISTA’s view on stellar births

PR Image eso2413g
Area of the Milky Way mapped by the VVV and VVVX surveys


Videos

Comparison of VISTA image of NGC 6357 with a visible light image
PR Video eso2413a
Comparison of VISTA image of NGC 6357 with a visible light image


Astronomers have published a gigantic infrared map of the Milky Way containing more than 1.5 billion objects ― the most detailed one ever made. Using the European Southern Observatory’s VISTA telescope, the team monitored the central regions of our Galaxy over more than 13 years. At 500 terabytes of data, this is the largest observational project ever carried out with an ESO telescope.

“We made so many discoveries, we have changed the view of our Galaxy forever,” says Dante Minniti, an astrophysicist at Universidad Andrés Bello in Chile who led the overall project.

This record-breaking map comprises 200 000 images taken by ESO’s VISTA ― the Visible and Infrared Survey Telescope for Astronomy. Located at ESO’s Paranal Observatory in Chile, the telescope’s main purpose is to map large areas of the sky. The team used VISTA’s infrared camera VIRCAM, which can peer through the dust and gas that permeates our galaxy. It is therefore able to see the radiation from the Milky Way’s most hidden places, opening a unique window onto our galactic surroundings.

This gigantic dataset [1] covers an area of the sky equivalent to 8600 full moons, and contains about 10 times more objects than a previous map released by the same team back in 2012. It includes newborn stars, which are often embedded in dusty cocoons, and globular clusters –– dense groups of millions of the oldest stars in the Milky Way. Observing infrared light means VISTA can also spot very cold objects, which glow at these wavelengths, like brown dwarfs (‘failed’ stars that do not have sustained nuclear fusion) or free-floating planets that don’t orbit a star.

The observations began in 2010 and ended in the first half of 2023, spanning a total of 420 nights. By observing each patch of the sky many times, the team was able to not only determine the locations of these objects, but also track how they move and whether their brightness changes. They charted stars whose luminosity changes periodically that can be used as cosmic rulers for measuring distances [2]. This has given us an accurate 3D view of the inner regions of the Milky Way, which were previously hidden by dust. The researchers also tracked hypervelocity stars — fast-moving stars catapulted from the central region of the Milky Way after a close encounter with the supermassive black hole lurking there.

The new map contains data gathered as part of the VISTA Variables in the Vía Láctea (VVV) survey [3] and its companion project, the VVV eXtended (VVVX) survey. “The project was a monumental effort, made possible because we were surrounded by a great team,” says Roberto Saito, an astrophysicist at the Universidade Federal de Santa Catarina in Brazil and lead author of the paper published today in Astronomy & Astrophysics on the completion of the project.

The VVV and VVVX surveys have already led to more than 300 scientific articles. With the surveys now complete, the scientific exploration of the gathered data will continue for decades to come. Meanwhile, ESO’s Paranal Observatory is being prepared for the future: VISTA will be updated with its new instrument 4MOST and ESO's Very Large Telescope (VLT) will receive its MOONS instrument. Together, they will provide spectra of millions of the objects surveyed here, with countless discoveries to be expected.

Source: ESO/News


Notes
[1] The dataset is too large to release as a single image, but the processed data and objects catalogue can be accessed in the ESO Science Portal.

[2] One way to measure the distance to a star is by comparing how bright it appears as seen from Earth to how intrinsically bright it is; but the latter is often unknown. Certain types of stars change their brightness periodically, and there is a very strong connection between how quickly they do this and how intrinsically luminous they are. Measuring these fluctuations allows astronomers to work out how luminous these stars are, and therefore how far away they lie.

[3] Vía Láctea is the Latin name for the Milky Way.



More information
This research was presented in a paper entitled “The VISTA Variables in the Vía Láctea eXtended (VVVX) ESO public survey: Completion of the observations and legacy” published in Astronomy & Astrophysics (https://doi.org/10.1051/0004-6361/202450584). Data DOI: VVV, VVVX.

The team is composed of R. K. Saito (Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Brazil [UFSC]), M. Hempel (Instituto de Astrofísica, Dep. de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Providencia, Chile [ASTROUNAB] and Max Planck Institute for Astronomy, Heidelberg, Germany), J. Alonso-García (Centro de Astronomía, Universidad de Antofagasta, Antofagasta, Chile [CITEVA] and Millennium Institute of Astrophysics, Providencia, Chile [MAS]), P. W. Lucas (Centre for Astrophysics Research, University of Hertfordshire, Hatfield, United Kingdom [CAR]), D. Minniti (ASTROUNAB; Vatican Observatory, Vatican City, Vatican City State [VO] and UFSC), S. Alonso (Departamento de Geofísica y Astronomía, CONICET, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, Rivadavia, Argentina [UNSJ-CONICET]), L. Baravalle (Instituto de Astronomía Teórica y Experimental, Córdoba, Argentina [IATE-CONICET]; Observatorio Astronómico de Córdoba, Universidad Nacional de Córdoba, Argentina [OAC]), J. Borissova (Instituto de Física y Astronomía, Universidad de Valparaíso, Valparaíso, Chile [IFA-UV] and MAS), C. Caceres (ASTROUNAB), A. N. Chené (Gemini Observatory, Northern Operations Center, Hilo, USA), N. J. G. Cross (Wide-Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, United Kingdom), F. Duplancic (UNSJ-CONICET), E. R. Garro (European Southern Observatory, Vitacura, Chile [ESO Chile]), M. Gómez (ASTROUNAB), V. D. Ivanov (European Southern Observatory, Garching bei München [ESO Germany]), R. Kurtev (IFA-UV and MAS), A. Luna (INAF – Osservatorio Astronomico di Capodimonte, Napoli, Italy [INAF- OACN]), D. Majaess (Mount Saint Vincent University, Halifax, Canada), M. G. Navarro (INAF – Osservatorio Astronomico di Roma, Italy [INAF-OAR]), J. B. Pullen (ASTROUNAB), M. Rejkuba (ESO Germany), J. L. Sanders (Department of Physics and Astronomy, University College London, London, United Kingdom), L. C. Smith (Institute of Astronomy, University of Cambridge, Cambridge, United Kingdom), P. H. C. Albino (UFSC), M. V. Alonso (IATE-CONICET and OAC), E. B. Amôres (Departamento de Física, Universidade Estadual de Feira de Santana, Feira de Santana, Brazil), E. B. R. Angeloni (Gemini Observatory/NSF’s NOIRLab, La Serena, Chile [NOIRLab]), J. I. Arias (Departamento de Astronomía, Universidad de La Serena, La Serena, Chile [ULS]), M. Arnaboldi (ESO Germany), B. Barbuy (Universidade de São Paulo, São Paulo, Brazil), A. Bayo (ESO Germany), J. C. Beamin (ASTROUNAB and Fundación Chilena de Astronomía, Santiago, Chile), L. R. Bedin (Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, Padova, Italy [INAF-OAPd]), A. Bellini (Space Telescope Science Institute, Baltimore, USA [STScI]), R. A. Benjamin (Department of Physics, University of Wisconsin-Whitewater, Whitewater, USA), E. Bica (Departamento de Astronomia, Instituto de Física, Porto Alegre, Brazil [IF – UFRGS]), C. J. Bonatto (IF – UFRGS), E. Botan (Instituto de Ciências Naturais, Humanas e Sociais, Universidade Federal de Mato Grosso, Sinop, Brazil), V. F. Braga (INAF-OAR), D. A. Brown (Vatican Observatory, Tucson, USA), J. B. Cabral (IATE-CONICET and Gerencia De Vinculación Tecnológica, Comisión Nacional de Actividades Espaciales, Córdoba, Argentina), D. Camargo (Colégio Militar de Porto Alegre, Ministério da Defesa, Exército Brasileiro, Brazil), A. Caratti o Garatti (INAF- OACN), J. A. Carballo-Bello (Instituto de Alta Investigación, Universidad de Tarapacá, Arica, Chile [IAI-UTA]), M.Catelan (Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Santiago, Chile [Instituto de Astrofísica UC]; MAS and Centro de Astro-Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile [AIUC]), C. Chavero (OAC and Consejo Nacional de Investigaciones Científica y Técnicas, Ciudad Autónoma de buenos Aires, Argentina [CONICET]), M. A. Chijani (ASTROUNAB), J. J. Clariá (OAC and CONICET), G. V. Coldwell (UNSJ-CONICET), C. Contreras Peña (Department of Physics and Astronomy, Seoul National University, Seoul, Republic of Korea and Research Institute of Basic Sciences, Seoul National University, Seoul, Republic of Korea), C. R. Contreras Ramos (Instituto de Astrofísica UC and MAS), J. M. Corral-Santana (ESO Chile), C. C. Cortés (Departamento de Tecnologías Industriales, Faculty of Engineering, Universidad de Talca, Curicó, Chile), M. Cortés-Contreras (Departamento de Física de la Tierra y Astrofísica & Instituto de Física de Partículas y del Cosmos de la UCM, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid, Spain), P. Cruz (Centro de Astrobiología, CSIC-INTA, Madrid, Spain [CAB]), I. V. Daza-Perilla (CONICET; IATE-CONICET and Facultad de Matemática, Astronomía, Física y Computación, Universidad Nacional de Córdoba, Córdoba, Argentina), V. P. Debattista (University of Central Lancashire, Preston, United Kingdom), B. Dias (ASTROUNAB), L. Donoso (Instituto de Ciencias Astronómicas, de la Tierra y del Espacio, San Juan, Argentina), R. D’Souza (VO), J. P. Emerson (Astronomy Unit, School of Physical and Chemical Sciences, Queen Mary University of London, London, United Kingdom), S. Federle (ESO Chile and ASTROUNAB), V. Fermiano (UFSC), J. Fernandez (UNSJ-CONICET), J. G. Fernández-Trincado (Instituto de Astronomía, Universidad Católica del Norte, Antofagasta, Chile [IA-UCN]), T. Ferreira (Department of Astronomy, Yale University, New Haven, USA), C. E. Ferreira Lopes (Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama, Copiapó, Chile [INCT] and MAS), V. Firpo (NOIRLab), C. Flores-Quintana (ASTROUNAB and MAS), L. Fraga (Laboratorio Nacional de Astrofísica, Itajubá, Brazil), D.Froebrich (Centre for Astrophysics and Planetary Science, School of Physics and Astronomy, University of Kent, Canterbury, United Kingdom), D. Galdeano (UNSJ-CONICET), I. Gavignaud (ASTROUNAB), D. Geisler (Departamento de Astronomía, Universidad de Concepción, Chile [UdeC]; Instituto Multidisciplinario de Investigación y Postgrado, Universidad de La Serena, Chile [IMIP-ULS] and ULS), O. E.Gerhard (Max Planck Institute for Extraterrestrial Physics, Germany [MPE]), W. Gieren (UdeC), O. A. Gonzalez (UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, United Kingdom), L. V. Gramajo (OAC and CONICET), F. Gran (Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France [Lagrange]), P. M. Granitto (Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas, Rosario, Argentina), M. Griggio (INAF-OAPd; Dipartimento di Fisica, Università di Ferrara, Ferrara, Italy and STScI), Z. Guo (IFA-UV and MAS), S. Gurovich (IATE-CONICET and Western Sydney University, Kingswood, Australia), M. Hilker (ESO Germany), H. R. A. Jones (CAR), R. Kammers (UFSC), M. A. Kuhn (CAR), M. S. N. Kumar (Centro de Astrofísica da Universidade do Porto, Porto, Portugal), R. Kundu (Miranda House, University of Delhi, India and Inter University centre for Astronomy and Astrophysics, Pune, India), M. Lares (IATE-CONICET), M. Libralato (INAF-OAPd), E. Lima (Universidade Federal do Pampa, Uruguaiana, Brazil), T. J. Maccarone (Department of Physics & Astronomy, Texas Tech University, Lubbock, USA), P. Marchant Cortés (ULS), E. L. Martin (Instituto de Astrofisica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, San Cristóbal de la Laguna, Spain), N. Masetti (Istituto Nazionale di Astrofisica, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Bologna, Italy and ASTROUNAB), N. Matsunaga (Department of Astronomy, Graduate School of Science, The University of Tokyo, Japan), F. Mauro (IA-UCN), I. McDonald (Jodrell Bank Centre for Astrophysics, The University of Manchester, UK [JBCA]), A. Mejías (Departamento de Astronomía, Universidad de Chile, Las Condes, Chile), V. Mesa (IMIP-ULS; Association of Universities for Research in Astronomy, Chile, Grupo de Astrofísica Extragaláctica-IANIGLA; CONICET, and Universidad Nacional de Cuyo, Mendoza, Argentina), F. P. Milla-Castro (ULS), J. H. Minniti (Department of Physics and Astronomy, Johns Hopkins University, Baltimore, USA), C. Moni Bidin (IA-UCN), K. Montenegro (Clínica Universidad de los Andes, Santiago, Chile), C. Morris (CAR), V. Motta (OAC), F. Navarete (SOAR Telescope/NSF’s NOIRLab, La Serena, Chile), C. Navarro Molina (Centro de Docencia Superior en Ciencias Básicas, Universidad Austral de Chile, Puerto Montt, Chile), F. Nikzat (Instituto de Astrofísica UC and MAS), J. L. NiloCastellón (IMIP-ULS and ULS), C. Obasi (IA-UCN and Centre for Basic Space Science, University of Nigeria, Nsukka, Nigeria), M. Ortigoza-Urdaneta (Departamento de Matemática, Universidad de Atacama, Copiapó, Chile), T. Palma (OAC), C. Parisi (OAC and IATE-CONICET), K. Pena Ramírez (NSF NOIRLab/Vera C. Rubin Observatory, La Serena, Chile), L. Pereyra (IATE-CONICET), N. Perez (UNSJ-CONICET), I. Petralia (ASTROUNAB), A. Pichel (Instituto de Astronomía y Física del Espacio, Ciudad Autónoma de Buenos Aires, Argentina [IAFE-CONICET]), G. Pignata (IAI-UTA), S. Ramírez Alegría (CITEVA), A. F. Rojas (Instituto de Astrofísica UC, Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Santiago, Chile and CITEVA), D. Rojas (ASTROUNAB), A. Roman-Lopes (ULS), A. C. Rovero (IAFE-CONICET), S. Saroon (ASTROUNAB), E. O. Schmidt (OAC and IATE-CONICET), A. C. Schröder (MPE), M. Schultheis (Lagrange), M. A. Sgró (OAC), E. Solano (CAB), M. Soto (INCT), B. Stecklum (Thüringer Landessternwarte, Tautenburg, Germany), D. Steeghs (Department of Physics, University of Warwick, UK), M. Tamura (Department of Astronomy, Graduate School of Science, University of Tokyo; Astrobiology Center, Tokyo, Japan, and National Astronomical Observatory of Japan, Tokyo, Japan), P. Tissera (Instituto de Astrofísica UC and AIUC), A. A. R. Valcarce (Departamento de Física, Universidad de Tarapacá, Chile), C. A. Valotto (IATE-CONICET and OAC), S. Vasquez (Museo Interactivo de la Astronomía, La Granja, Chile), C. Villalon (IATE-CONICET and OAC), S. Villanova (UdeC), F. Vivanco Cádiz (ASTROUNAB), R. Zelada Bacigalupo (North Optics, La Serena, Chile), A. Zijlstra (JBCA and School of Mathematical and Physical Sciences, Macquarie University, Sydney, Australia), and M. Zoccali (Instituto de Astrofísica UC and MAS).

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.



Links


Contacts

Roberto K. Saito
Universidade Federal de Santa Catarina
Florianópolis, Brazil
Email: roberto.saito@ufsc.br

Dante Minniti
Universidad Andrés Bello
Santiago, Chile
Email: vvvdante@gmail.com

Phil Lucas
University of Hertfordshire
Hartfield, United Kingdom
Email: p.w.lucas@herts.ac.uk

Juan Carlos Muñoz-Mateos
ESO Media Officer
Garching bei München, Germany
Tel: +49 89 3200 6176
Email: press@eso.org

Posted by at
Labels: , , , , ,

Tuesday, October 01, 2024

NASA's Hubble Finds that a Black Hole Beam Promotes Stellar Eruptions

This is an artist's concept looking down into the core of the giant elliptical galaxy M87. A supermassive black hole ejects a 3,000-light-year-long jet of plasma, traveling at nearly the speed of light. In the foreground, to the right is a binary star system. The system is far from the black hole, but in the vicinity of the jet. In the system an aging, swelled-up, normal star spills hydrogen onto a burned-out white dwarf companion star. As the hydrogen accumulates on the surface of the dwarf, it reaches a tipping point where it explodes like a hydrogen bomb. Novae frequently pop-off throughout the giant galaxy of 1 trillion stars, but those near the jet seem to explode more frequently. So far, it's anybody's guess why black hole jets enhance the rate of nova eruptions. Credits: Artwork: NASA, ESA, Joseph Olmsted (STScI) 

A Hubble Space Telescope image of the giant galaxy M87 shows a 3,000-light-year-long jet of plasma blasting from the galaxy's 6.5-billion-solar-mass central black hole. The blowtorch-like jet seems to cause stars to erupt along its trajectory. These novae are not caught inside the jet, but are apparently in a dangerous neighborhood nearby. During a recent 9-month survey, astronomers using Hubble found twice as many of these novae going off near the jet as elsewhere in the galaxy. The galaxy is the home of several trillion stars and thousands of star-like globular star clusters. Credits: Science: NASA, ESA, STScI, Alec Lessing (Stanford University), Mike Shara (AMNH) Acknowledgment: Edward Baltz (Stanford University) - Image Processing: Joseph DePasquale (STScI)


In a surprise finding, astronomers using NASA's Hubble Space Telescope have discovered that the blowtorch-like jet from a supermassive black hole at the core of a huge galaxy seems to cause stars to erupt along its trajectory. The stars, called novae, are not caught inside the jet, but apparently in a dangerous neighborhood nearby.

The finding is confounding researchers searching for an explanation. "We don't know what's going on, but it's just a very exciting finding," said Alec Lessing of Stanford University, lead author of the paper accepted for publication in The Astrophysical Journal. "This means there's something missing from our understanding of how black hole jets interact with their surroundings."

A nova erupts in a double-star system where an aging, swelled-up, normal star spills hydrogen onto a burned-out white dwarf companion star. When the dwarf has tanked up a mile-deep surface layer of hydrogen that layer explodes like a giant nuclear bomb. The white dwarf isn't destroyed by the nova eruption, which ejects its surface layer and then goes back to siphoning fuel from its companion, and the nova-outburst cycle starts over again.

Hubble found twice as many novae going off near the jet as elsewhere in the giant galaxy during the surveyed time period. The jet is launched by a 6.5-billion-solar-mass central black hole surrounded by a disk of swirling matter. The black hole, engorged with infalling matter, launches a 3,000-light-year-long jet of plasma blazing through space at nearly the speed of light. Anything caught in the energetic beam would be sizzled. But being near its blistering outflow is apparently also risky, according to the new Hubble findings.

The finding of twice as many novae near the jet implies that there are twice as many nova-forming double-star systems near the jet or that these systems erupt twice as often as similar systems elsewhere in the galaxy.

"There's something that the jet is doing to the star systems that wander into the surrounding neighborhood. Maybe the jet somehow snowplows hydrogen fuel onto the white dwarfs, causing them to erupt more frequently," said Lessing. "But it's not clear that it's a physical pushing. It could be the effect of the pressure of the light emanating from the jet. When you deliver hydrogen faster, you get eruptions faster. Something might be doubling the mass transfer rate onto the white dwarfs near the jet." Another idea the researchers considered is that the jet is heating the dwarf's companion star, causing it to overflow further and dump more hydrogen onto the dwarf. However, the researchers calculated that this heating is not nearly large enough to have this effect.

"We're not the first people who've said that it looks like there's more activity going on around the M87 jet," said co-investigator Michael Shara of the American Museum of Natural History in New York City. "But Hubble has shown this enhanced activity with far more examples and statistical significance than we ever had before."

Shortly after Hubble's launch in 1990, astronomers used its first-generation Faint Object Camera (FOC) to peer into the center of M87 where the monster black hole lurks. They noted that unusual things were happening around the black hole. Almost every time Hubble looked, astronomers saw bluish "transient events" that could be evidence for novae popping off like camera flashes from nearby paparazzi. But the FOC's view was so narrow that Hubble astronomers couldn't look away from the jet to compare with the near-jet region. For over two decades, the results remained mysteriously tantalizing.

Compelling evidence for the jet's influence on the stars of the host galaxy was collected over a nine-month interval of Hubble observing with newer, wider-view cameras to count the erupting novae. This was a challenge for the telescope's observing schedule because it required revisiting M87 precisely every five days for another snapshot. Adding up all of the M87 images led to the deepest images of M87 that have ever been taken.

Hubble found 94 novae in the one-third of M87 that its camera can encompass. "The jet was not the only thing that we were looking at — we were looking at the entire inner galaxy. Once you plotted all known novae on top of M87 you didn't need statistics to convince yourself that there is an excess of novae along the jet. This is not rocket science. We made the discovery simply by looking at the images. And while we were really surprised, our statistical analyses of the data confirmed what we clearly saw," said Shara.

This accomplishment is entirely due to Hubble's unique capabilities. Ground-based telescope images do not have the clarity to see novae deep inside M87. They cannot resolve stars or stellar eruptions close to the galaxy's core because the black hole's surroundings are far too bright. Only Hubble can detect novae against the bright M87 background.

Novae are remarkably common in the universe. One nova erupts somewhere in M87 every day. But since there are at least 100 billion galaxies throughout the visible universe, around 1 million novae erupt every second somewhere out there.

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.



About This Release

Credits:

Media Contact:

Ray Villard Space Telescope Science Institute, Baltimore, Maryland

Science Contact:

Alec Lessing
Stanford University, Stanford, California

Michael Shara
American Museum of Natural History, New York, New York

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents

Posted by at
Labels: , , , ,

Monday, September 30, 2024

DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered

PR Image noirlab2422a
Artist Illustration of Early-Universe Quasar Cosmic Neighborhood


Videos

Cosmoview Episode 86: DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered
PR Video noirlab2422a
Cosmoview Episode 86: DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered

Cosmoview Episodio 86: DECam confirma que los vecindarios de los cuásares del Universo primitivo están realmente abarrotados


New finding with the expansive Dark Energy Camera offers a clear explanation to quasar ‘urban density’-conundrum

Observations using the Dark Energy Camera (DECam) confirm astronomers’ expectation that early-Universe quasars formed in regions of space densely populated with companion galaxies. DECam’s exceptionally wide field of view and special filters played a crucial role in reaching this conclusion, and the observations reveal why previous studies seeking to characterize the density of early-Universe quasar neighborhoods have yielded conflicting results.

Quasars are the most luminous objects in the Universe and are powered by material accreting onto supermassive black holes at the centers of galaxies. Studies have shown that early-Universe quasars have black holes so massive that they must have been swallowing gas at very high rates, leading most astronomers to believe that these quasars formed in some of the densest environments in the Universe where gas was most available. However, observational measurements seeking to confirm this conclusion have thus far yielded conflicting results. Now, a new study using the Dark Energy Camera (DECam) points the way to both an explanation for these disparate observations and also a logical framework to connect observation with theory.

DECam was fabricated by the Department of Energy and is mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF NOIRLab.

The study was led by Trystan Lambert, who completed this work as a PhD student at Diego Portales University’s Institute of Astrophysical Studies in Chile [1] and is now a postdoc at the University of Western Australia node at the International Centre for Radio Astronomy Research (ICRAR). Utilizing DECam’s massive field of view, the team conducted the largest on-sky area search ever around an early-Universe quasar in an effort to measure the density of its environment by counting the number of surrounding companion galaxies.

For their investigation, the team needed a quasar with a well-defined distance. Luckily, quasar VIK 2348–3054 has a known distance, determined by previous observations with the Atacama Large Millimeter/submillimeter Array (ALMA), and DECam’s three-square-degree field of view provided an expansive look at its cosmic neighborhood. Serendipitously, DECam is also equipped with a narrowband filter perfectly matched for detecting its companion galaxies. “This quasar study really was the perfect storm,” says Lambert. “We had a quasar with a well-known distance, and DECam on the Blanco telescope offered the massive field of view and exact filter that we needed.”

DECam’s specialized filter allowed the team to count the number of companion galaxies around the quasar by detecting a very specific type of light they emit, known as Lyman-alpha radiation. Lyman alpha radiation is a specific energy signature of hydrogen, produced when it is ionized and then recombined during the process of star formation. Lyman-alpha emitters are typically younger, smaller galaxies, and their Lyman-alpha emission can be used as a way to reliably measure their distances. Distance measurements for multiple Lyman-alpha emitters can then be used to construct a 3D map of a quasar’s neighborhood.

After systematically mapping the region of space around quasar VIK J2348-3054, Lambert and his team found 38 companion galaxies in the wider environment around the quasar — out to a distance of 60 million light-years — which is consistent with what is expected for quasars residing in dense regions. However, they were surprised to find that within 15 million light-years of the quasar, there were no companions at all.

This finding illuminates the reality of past studies aimed at classifying early-Universe quasar environments and proposes a possible explanation for why they have turned out conflicting results. No other survey of this kind has used a search area as large as the one provided by DECam, so to smaller-area searches a quasar’s environment can appear deceptively empty.

“DECam’s extremely wide view is necessary for studying quasar neighborhoods thoroughly. You really have to open up to a larger area,” says Lambert. “This suggests a reasonable explanation as to why previous observations are in conflict with one another.”

The team also suggests an explanation for the lack of companion galaxies in the immediate vicinity of the quasar. They postulate that the intensity of the radiation from the quasar may be large enough to affect, or potentially stop, the formation of stars in these galaxies, making them invisible to our observations.

“Some quasars are not quiet neighbors,” says Lambert. “Stars in galaxies form from gas that is cold enough to collapse under its own gravity. Luminous quasars can potentially be so bright as to illuminate this gas in nearby galaxies and heat it up, preventing this collapse.”

Lambert’s team is currently following up with additional observations to obtain spectra and confirm star formation suppression. They also plan to observe other quasars to build a more robust sample size.

“These findings show the value of the National Science Foundation’s productive partnership with the Department of Energy,” says Chris Davis, NSF program director for NSF NOIRLab. “We expect that productivity will be amplified enormously with the upcoming NSF–DOE Vera C. Rubin Observatory, a next-generation facility that will reveal even more about the early Universe and these remarkable objects.”



Notes

[1] This study was made possible through a collaboration between researchers at Diego Portales University and the Max Planck Institute of Astronomy. A portion of this work was funded through a grant by Chile’s National Research and Development Agency (ANID) for collaborations with the Max Planck Institutes.


More information
This research was presented in a paper entitled “A lack of LAEs within 5 Mpc of a luminous quasar in an overdensity at z=6.9: potential evidence of quasar negative feedback at protocluster scales” to appear in Astronomy & Astrophysics. DOI: 10.1051/0004-6361/202449566

The team is composed of Trystan S. Lambert (Universidad Diego Portales, Chile/University of Western Australia, Australia), R.J. Assef (Universidad Diego Portales, Chile), C. Mazzucchelli (Universidad Diego Portales, Chile), E. Bañados (Max Planck Institute of Astronomy, Germany), M. Aravena (Universidad Diego Portales, Chile), F. Barrientos (Pontificia Universidad Católica de Chile, Chile), J. González-López (Las Campanas Observatory, Chile/Universidad Diego Portales, Chile), W. Hu (George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, USA), L. Infante (Pontificia Universidad Católica de Chile, Chile), S. Malhotra (NASA Goddard Space Flight Center, USA), C. Moya-Sierralta (Pontificia Universidad Católica de Chile, Chile), J. Rhoads (NASA Goddard Space Flight Center, USA), F. Valdes (NSF NOIRLab), J. Wang (University of Science and Technology of China, People’s Republic of China), I.G.B. Wold (Center for Research and Exploration in Space Science and Technology, NASA Goddard Space Flight Center, USA/Catholic University of America, USA), and Z. Zheng (Shanghai Astronomical Observatory, People’s Republic of China).

NSF NOIRLab (U.S. National Science Foundation National Optical-Infrared Astronomy Research Laboratory), the U.S. center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.



Links


 Contacts

Trystan Lambert
Postdoc Scholar
University of Western Australia
Email: trystanscottlambert@gmail.com

Josie Fenske
Jr. Public Information Officer
NSF NOIRLab
Email: josie.fenske@noirlab.edu

Posted by at
Labels: , , , , ,

Sunday, September 29, 2024

In Odd Galaxy, NASA's Webb Finds Potential Missing Link to First Stars

Caption: The galaxy GS-NDG-9422 may easily have gone unnoticed. However, what appears as a faint blur in this James Webb Space Telescope NIRCam (Near-Infrared Camera) image may actually be a groundbreaking discovery that points astronomers on a new path of understanding galaxy evolution in the early universe.

Detailed information on the galaxy’s chemical makeup, captured by Webb’s NIRSpec (Near-Infrared Spectrograph) instrument, indicates that the light we see in this image is coming from the galaxy’s hot gas, rather than its stars. That is the best explanation astronomers have discovered so far to explain the unexpected features in the light spectrum. They think that the galaxy’s stars are so extremely hot (more than 140,000 degrees Fahrenheit, or 80,000 degrees Celsius) that they are heating up the nebular gas, allowing it to shine even brighter than the stars themselves.

The authors of a new study on Webb’s observations of the galaxy think GS-NDG-9422 may represent a never-before-seen phase of galaxy evolution in the early universe, within the first billion years after the big bang. Their task now is to see if they can find more galaxies displaying the same features. Credits: Image: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)


Looking deep into the early universe with NASA’s James Webb Space Telescope, astronomers have found something unprecedented: a galaxy with an odd light signature, which they attribute to its gas outshining its stars. Found approximately one billion years after the big bang, galaxy GS-NDG-9422 (9422) may be a missing-link phase of galactic evolution between the universe’s first stars and familiar, well-established galaxies.

“My first thought in looking at the galaxy’s spectrum was, ‘that’s weird,’ which is exactly what the Webb telescope was designed to reveal: totally new phenomena in the early universe that will help us understand how the cosmic story began,” said lead researcher Alex Cameron of the University of Oxford.

Cameron reached out to colleague Harley Katz, a theorist, to discuss the strange data. Working together, their team found that computer models of cosmic gas clouds heated by very hot, massive stars, to an extent that the gas shone brighter than the stars, was nearly a perfect match to Webb’s observations.

“It looks like these stars must be much hotter and more massive than what we see in the local universe, which makes sense because the early universe was a very different environment,” said Katz, of Oxford and the University of Chicago.

In the local universe, typical hot, massive stars have a temperature ranging between 70,000 to 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius). According to the team, galaxy 9422 has stars hotter than 140,000 degrees Fahrenheit (80,000 degrees Celsius).

The research team suspects that the galaxy is in the midst of a brief phase of intense star formation inside a cloud of dense gas that is producing a large number of massive, hot stars. The gas cloud is being hit with so many photons of light from the stars that it is shining extremely brightly.

In addition to its novelty, nebular gas outshining stars is intriguing because it is something predicted in the environments of the universe’s first generation of stars, which astronomers classify as Population III stars.

“We know that this galaxy does not have Population III stars, because the Webb data shows too much chemical complexity. However, its stars are different than what we are familiar with – the exotic stars in this galaxy could be a guide for understanding how galaxies transitioned from primordial stars to the types of galaxies we already know,” said Katz. At this point, galaxy 9422 is one example of this phase of galaxy development, so there are still many questions to be answered. Are these conditions common in galaxies at this time period, or a rare occurrence? What more can they tell us about even earlier phases of galaxy evolution? Cameron, Katz, and their research colleagues are actively identifying more galaxies to add to this population to better understand what was happening in the universe within the first billion years after the big bang.

“It’s a very exciting time, to be able to use the Webb telescope to explore this time in the universe that was once inaccessible,” Cameron said. “We are just at the beginning of new discoveries and understanding.”

The research paper is published in Monthly Notices of the Royal Astronomical Society.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

About This Release

Credits:

Media Contact:

Leah Ramsay
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents

Posted by at
Labels: , , , ,

Saturday, September 28, 2024

The new and improved IC 1954

A spiral galaxy seen tilted diagonally. It has two large, curling arms that extend from the centre and wrap around. The arms are followed by thick strands of dark reddish dust. The arms and rest of the galaxy’s disc are speckled with glowing patches; some are blue in colour, others are pink, showing gas illuminated by new stars. A faint glow surrounds the galaxy, which lies on a dark, nearly empty background. Credit: ESA/Hubble & NASA, D. Thilker, J. Lee and the PHANGS-HST Team

The spiral galaxy IC 1954, located 45 million light-years from Earth in the constellation Horologium, is the star of this Picture of the Week from the Hubble Space Telescope. It sports a glowing bar in its core, two main majestically winding spiral arms and clouds of dark dust across it. An image of this galaxy was previously released in 2021; this week’s image is entirely new and now includes H-alpha data. The improved coverage of star-forming nebulae, which are prominent emitters of the red H-alpha light, can be seen in the numerous glowing, pink spots across the disc of the galaxy. Interestingly, some astronomers posit that the galaxy’s ‘bar’ is actually an energetic star-forming region that just happens to lie over the galactic centre.

The new data featured in this image come from a programme to extend the cooperation between multiple observatories: Hubble, the infrared James Webb Space Telescope, and the Atacama Large Millimeter/submillimeter Array, a ground-based radio telescope. By surveying IC 1954 and over fifty other nearby galaxies in radio, infrared, optical, and ultraviolet light, astronomers aim to fully trace and reconstruct the path matter takes through stars and the interstellar gas and dust in each galaxy. Hubble’s observing capabilities form an important part of this survey: it can capture younger stars and star clusters when they are brightest at ultraviolet and optical wavelengths, and its H-alpha filter effectively tracks emission from nebulae. The resulting dataset will form a treasure trove of research on the evolution of stars in galaxies, which Webb will build upon as it continues its science operations into the future.


Posted by at
Labels: , , ,

Friday, September 27, 2024

Gargantuan Black Hole Jets Are Biggest Seen Yet

An artist’s illustration of the longest black hole jet system ever observed. Nicknamed Porphyrion after a mythological Greek giant, these jets span roughly 7 megaparsecs, or 23 million light-years. That is equivalent to lining up 140 Milky Way galaxies back-to-back. Porphyrion dates back to a time when our universe was less than half its present age. During this early epoch, the wispy filaments that connect and feed galaxies, known as the cosmic web, were closer together than they are now. Consequently, this colossal jet pair extended across a larger portion of the cosmic web compared to similar jets in our nearby universe. Porphyrion’s discovery thus implies that jets in the early universe may have influenced the formation of galaxies to a greater extent than previously believed. Image credit: E. Wernquist / D. Nelson (IllustrisTNG Collaboration) / M. Oei


The jumbo jets blast hot plasma well beyond their own host galaxy

Maunakea, Hawaiʻi – Astronomers have spotted the biggest pair of black hole jets ever seen, spanning 23 million light-years in total length. That’s equivalent to lining up 140 Milky Way galaxies back to back.

“This pair is not just the size of a solar system, or a Milky Way; we are talking about 140 Milky Way diameters in total,” says Martijn Oei, a Caltech postdoctoral scholar and lead author of the new study. “The Milky Way would be a little dot in these two giant eruptions.”

The study, which includes data from W. M. Keck Observatory on Maunakea, Hawaiʻi, published online today in the journal Nature and will be featured on the cover of the print issue tomorrow, September 19.

The jet megastructure, nicknamed Porphyrion after a giant in Greek mythology, dates to a time when our universe was 6.3 billion years old, or less than half its present age of 13.8 billion years. These fierce outflows—with a total power output equivalent to trillions of suns—shoot out from above and below a supermassive black hole at the heart of a remote galaxy.

Prior to Porphyrion’s discovery, the largest confirmed jet system was Alcyoneus, also named after a giant in Greek mythology. Alcyoneus, which was discovered in 2022 by the same team that found Porphyrion, spans the equivalent of around 100 Milky Ways. For comparison, the well-known Centaurus A jets, the closest major jet system to Earth, spans 10 Milky Ways.

The latest finding suggests that these giant jet systems may have had a larger influence on the formation of galaxies in the young universe than previously believed. Porphyrion existed during an early epoch when the wispy filaments that connect and feed galaxies, known as the cosmic web, were closer together than they are now. That means enormous jets like Porphyrion reached across a greater portion of the cosmic web compared to jets in the local universe.

“Astronomers believe that galaxies and their central black holes co-evolve, and one key aspect of this is that jets can spread huge amounts of energy that affect the growth of their host galaxies and other galaxies near them,” says co-author George Djorgovski, professor of astronomy and data science at Caltech. “This discovery shows that their effects can extend much farther out than we thought.”

Lurking in the Past

To find the galaxy from which Porphyrion originated, the team used the Giant Metrewave Radio Telescope in India along with ancillary data from a project called Dark Energy Spectroscopic Instrument, which operates from Kitt Peak National Observatory in Arizona. The observations pinpointed the home of the jets to a hefty galaxy about 10 times more massive than our Milky Way.

The team then used the Keck Observatory to show that Porphyrion is 7.5 billion light-years from Earth.

“Up until now, these giant jet systems appeared to be a phenomenon of the recent universe,” Oei says. “If distant jets like these can reach the scale of the cosmic web, then every place in the universe may have been affected by black hole activity at some point in cosmic time,” Oei says.

Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS) also revealed that Porphyrion emerged from what is called a radiative-mode active black hole, as opposed to one that is in a jet-mode state. When supermassive black holes become active—in other words, when their immense forces of gravity tug on and heat up surrounding material—they are thought to either emit energy in the form of radiation or jets. Radiative-mode black holes were more common in the young, or distant, universe, while jet-mode ones are more common in the present-day universe.

The fact that Porphyrion came from a radiative-mode black hole came as a surprise because astronomers did not know this mode could produce such huge and powerful jets. What is more, because Porphyrion lies in the distant universe where radiative-mode black holes abound, the finding implies there may be a lot more colossal jets left to be found.


Ongoing Mysteries

How the jets can extend so far beyond their host galaxies without destabilizing is still unclear.

“Martijn’s work has shown us that there isn’t anything particularly special about the environments of these giant sources that causes them to reach those large sizes,” says Hardcastle, who is an expert in the physics of black hole jets. “My interpretation is that we need an unusually long-lived and stable accretion event around the central, supermassive black hole to allow it to be active for so long—about a billion years—and to ensure that the jets keep pointing in the same direction over all of that time. What we’re learning from the large number of giants is that this must be a relatively common occurrence.”

As a next step, Oei wants to better understand how these megastructures influence their surroundings. The jets spread cosmic rays, heat, heavy atoms, and magnetic fields throughout the space between galaxies.

Oei is specifically interested in finding out the extent to which giant jets spread magnetism.

“The magnetism on our planet allows life to thrive, so we want to understand how it came to be,” he says. “We know magnetism pervades the cosmic web, then makes its way into galaxies and stars, and eventually to planets, but the question is: Where does it start? Have these giant jets spread magnetism through the cosmos?”



About LRIS
The Low Resolution Imaging Spectrometer (LRIS) is a very versatile and ultra-sensitive visible-wavelength imager and spectrograph built at the California Institute of Technology by a team led by Prof. Bev Oke and Prof. Judy Cohen and commissioned in 1993. Since then it has seen two major upgrades to further enhance its capabilities: the addition of a second, blue arm optimized for shorter wavelengths of light and the installation of detectors that are much more sensitive at the longest (red) wavelengths. Each arm is optimized for the wavelengths it covers. This large range of wavelength coverage, combined with the instrument’s high sensitivity, allows the study of everything from comets (which have interesting features in the ultraviolet part of the spectrum), to the blue light from star formation, to the red light of very distant objects. LRIS also records the spectra of up to 50 objects simultaneously, especially useful for studies of clusters of galaxies in the most distant reaches, and earliest times, of the universe. LRIS was used in observing distant supernovae by astronomers who received the Nobel Prize in Physics in 2011 for research determining that the universe was speeding up in its expansion.

 About W. M. Keck Observatory
The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two 10-meter optical/infrared telescopes atop Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

Posted by at
Labels: , ,
Subscribe to: Posts (Atom)