Astronomers capture most detailed thousand-colour image of a galaxy

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MUSE view of the Sculptor Galaxy

PR Image eso2510b
MUSE view of ionised gas in the Sculptor Galaxy

PR Image eso2510c
Digitized Sky Survey image of NGC 253

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The galaxy NGC 253 in the constellation of Sculptor

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Videos

PR Video eso2510a
Astronomers capture galaxy in thousands of colours | ESO News


PR Video eso2510b
Zooming into a thousand-colour image of the Sculptor Galaxy


PR Video eso2510c
The Sculptor Galaxy in a myriad of colours


PR Video eso2510d
Animation of the rotation of the Sculptor Galaxy

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Datacube

Datacube Visualisation

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Astronomers have created a galactic masterpiece: an ultra-detailed image that reveals previously unseen features in the Sculptor Galaxy. Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), they observed this nearby galaxy in thousands of colours simultaneously. By capturing vast amounts of data at every single location, they created a galaxy-wide snapshot of the lives of stars within Sculptor.

"Galaxies are incredibly complex systems that we are still struggling to understand," says ESO researcher Enrico Congiu, who led a new Astronomy & Astrophysics study on Sculptor. Reaching hundreds of thousands of light-years across, galaxies are extremely large, but their evolution depends on what’s happening at much smaller scales. “The Sculptor Galaxy is in a sweet spot,” says Congiu. “It is close enough that we can resolve its internal structure and study its building blocks with incredible detail, but at the same time, big enough that we can still see it as a whole system.”

A galaxy’s building blocks — stars, gas and dust — emit light at different colours. Therefore, the more shades of colour there are in an image of a galaxy, the more we can learn about its inner workings. While conventional images contain only a handful of colours, this new Sculptor map comprises thousands. This tells astronomers everything they need to know about the stars, gas and dust within, such as their age, composition, and motion.

To create this map of the Sculptor Galaxy, which is 11 million light-years away and is also known as NGC 253, the researchers observed it for over 50 hours with the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s VLT. The team had to stitch together over 100 exposures to cover an area of the galaxy about 65 000 light-years wide.

According to co-author Kathryn Kreckel from Heidelberg University, Germany, this makes the map a potent tool: “We can zoom in to study individual regions where stars form at nearly the scale of individual stars, but we can also zoom out to study the galaxy as a whole.”
In their first analysis of the data, the team uncovered around 500 planetary nebulae, regions of gas and dust cast off from dying Sun-like stars, in the Sculptor Galaxy. Co-author Fabian Scheuermann, a doctoral student at Heidelberg University, puts this number into context: “Beyond our galactic neighbourhood, we usually deal with fewer than 100 detections per galaxy.”

Because of the properties of planetary nebulae, they can be used as distance markers to their host galaxies. “Finding the planetary nebulae allows us to verify the distance to the galaxy — a critical piece of information on which the rest of the studies of the galaxy depend,” says Adam Leroy, a professor at The Ohio State University, USA, and study co-author.

Future projects using the map will explore how gas flows, changes its composition, and forms stars all across this galaxy. “How such small processes can have such a big impact on a galaxy whose entire size is thousands of times bigger is still a mystery,” says Congiu.

Source: ESO/News

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More information

This research was presented in a paper accepted for publication in Astronomy & Astrophysics.

The team is composed of E. Congiu (European Southern Observatory, Chile [ESO Chile]), F. Scheuermann (Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Germany [ARI-ZAH]), K. Kreckel (ARI-ZAH), A. Leroy (Department of Astronomy and Center for Cosmology and Astroparticle Physics, The Ohio State University [OSU], USA), E. Emsellem (European Southern Observatory, Germany [ESO Garching] and Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, France), F. Belfiore (INAF – Osservatorio Astrofisico di Arcetri, Italy), J. Hartke (Finnish Centre for Astronomy with ESO [FINCA] and Tuorla Observatory, Department of Physics and Astronomy [Tuorla], University of Turku, Finland), G. Anand (Space Telescope Science Institute, USA), O. V. Egorov (ARI-ZAH), B. Groves (International Centre for Radio Astronomy Research, University of Western Australia, Australia), T. Kravtsov (Tuorla and FINCA), D. Thilker (Department of Physics and Astronomy, The Johns Hopkins University, USA), C. Tovo (Dipartimento di Fisica e Astronomia ‘G. Galilei’, Universit‘a di Padova, Italy), F. Bigiel (Argelander-Institut für Astronomie, Universität Bonn, Germany), G. A. Blanc (Observatories of the Carnegie Institution for Science, USA, and Departamento de Astronomía, Universidad de Chile, Chile), A. D. Bolatto and S. A. Cronin (Department of Astronomy, University of Maryland, USA), D. A. Dale (Department of Physics and Astronomy, University of Wyoming, USA), R. McClain (OSU), J. E. Méndez-Delgado (Instituto de Astronomía, Universidad Nacional Autónoma de México, Mexico), E. K. Oakes (Department of Physics, University of Connecticut, USA), R. S. Klessen (Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik and Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Germany, Center for Astrophysics Harvard & Smithsonian, USA, and Elizabeth S. and Richard M. Cashin Fellow at the Radcliffe Institute for Advanced Studies at Harvard University, USA) E. Schinnerer (Max-Planck-Institut für Astronomie, Germany), T. G. Williams (Sub-department of Astrophysics, Department of Physics, University of Oxford, UK).

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.

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Contacts:

Enrico Congiu
European Southern Observatory (ESO)
Santiago, Chile
Email: econgiu@eso.org

Kathryn Kreckel
Heidelberg University
Heidelberg, Germany
Tel: +49 6221 54-1859
Email: kathryn.kreckel@uni-heidelberg.de

Adam Leroy
The Ohio State University
Columbus, Ohio, USA
Tel: +1 614 292-1765
Email: leroy.42@osu.edu

Fabian Scheuermann
Heidelberg University
Heidelberg, Germany
Email: f.scheuermann@uni-heidelberg.de

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

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Stellar Explosions and Cosmic Chemistry

Excerpts from the ALCHEMI atlas of the center of NGC 253. The different colors represent the distribution of molecular gas (blue), shocked regions (red), relatively high-density regions (orange), young starbursts (yellow), developed starbursts (magenta), and molecular gas affected by cosmic-ray ionization (cyan). Credit: ALMA (ESO/NAOJ/NRAO), N. Harada et al. Hi-Res File

(Top) Spectra from the ALCHEMI survey. (Bottom) A schematic image of the center of the starburst galaxy, NGC 253, describing locations where various tracer molecular species are enhanced according to the ALCHEMI survey. Credit: ALMA (ESO/NAOJ/NRAO), N. Harada et al. Hi-Res File

Artist’s impression of the center of the starburst galaxy NGC 253

Credit: NRAO/AUI/NSF. Hi-Res File

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Unveiling the Secrets of Starburst Galaxies with ALMA

Astronomers have discovered the secrets of a starburst galaxy producing new stars at a rate much faster than our Milk Way. This research revealed many different molecules, more than ever seen before in a galaxy like this.

This international research team used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the center of starburst galaxy NGC 253. Through ALMA’s high sensitivity and angular resolution, the team detected over one hundred molecular species in NGC 253, far more than previously observed in galaxies beyond the Milky Way.

This research was assembled from several papers from the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI),a large program led by Sergio Martín of the European Southern Observatory/Joint ALMA Observatory, Nanase Harada of the National Astronomical Observatory of Japan, and Jeff Mangum of the National Radio Astronomy Observatory.

The astronomers found that the center of NGC 253 has a lot of dense gas, which helps make stars. This molecular gas is more than ten times as dense as the gas found in the center of our own Milky Way galaxy. Astronomers also discovered an abundance of complex organic molecules around regions of active star formation. When clouds of gas collide, they create shock waves that make certain molecules easier to see with telescopes like ALMA. The ALCHEMI survey expanded the molecular species atlas outside the Milky Way, doubling the number of identified species.

By employing machine learning, astronomers identified molecules effectively tracing various stages of star formation. This research also observed enhanced species like H3O+ and HOC+ in developed starburst regions, indicating energy output from massive stars, which could inhibit future star formation. NGC 253 has had a lot of stars explode as supernovae, and these powerful bursts of energy make it harder for gas to come together to form new stars.

The ALCHEMI survey provided an atlas of 44 molecular species. By applying a machine-learning technique to this atlas, the researchers were able to identify which molecules are present at specific stages of star formation. Identifying tracers can help guide future ALMA observations, particularly with the anticipated wideband sensitivity upgrade. This upgrade, outlined in the ALMA 2030 Development roadmap, will allow for the simultaneous tracking of multiple tracer molecules, further advancing astronomers understanding of how stars form.

Links

• Read more at ALMA

Source: National Radio Astronomy Observatory (NRAO)/News

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Can You Spot It?

Image description: A black, mostly empty field with a variety of stars and galaxies spread across it. Most are very small. A couple of galaxies and stars are larger with visible details. In the centre is a relatively small, irregularly-shaped galaxy; it is formed of many very small stars and a few slightly larger, bright stars, all surrounded by a very faint glow that marks the borders of the galaxy. Credit: ESA/Hubble & NASA, B. Mutlu-Pakdil | Acknowledgement: G. Donatiello

Right in the middle of this image, nestled amongst a smattering of distant stars and even more distant galaxies, lies the newly discovered dwarf galaxy known as Donatiello II. If you cannot quite distinguish the clump of faint stars that is all we can see of Donatiello II in this image, then you are in good company. Donatiello II is one of three newly discovered galaxies that were so difficult to spot that they were all missed by an algorithm designed to search astronomical data for potential galaxy candidates. Even the best algorithms have their limitations when it comes to distinguishing very faint galaxies from individual stars and background noise. In these most challenging identification cases, discovery has to be done the old-fashioned way — by a dedicated human trawling through the data themselves.

The data that enabled these discoveries was collected by the Dark Energy Survey (DES), an intense observation effort that spanned six years, and was carried out using the Dark Energy Camera (DECam), which is mounted on the Víctor M. Blanco 4-metre Telescope at Cerro Tololo Inter-American Observatory, a Program of NSF’s NOIRLab. As is the case for most major telescopes that receive public funding, the DES data were made available to the public. That is when the experienced amateur astronomer Giuseppe Donatiello stepped in. He laboriously processed and analysed chunks of the DES data, and made his discovery — three very faint galaxies, now named Donatiello II, III and IV respectively. All three are satellites of the well known Sculptor galaxy (otherwise known as NGC 253), meaning that they are all bound gravitationally to their much more massive companion.

This image comes from an observing programme from the NASA/ESA Hubble Space Telescope. Based on their own independent search, a team led by Burçin Mutlu-Pakdil used Hubble to obtain long-exposure images of several faint galaxies, including Donatiello II. With the Hubble images, they were able to confirm their target galaxies’ association with NGC 253 — thereby providing both an independent confirmation of Donatiello’s discovery, and this new Picture of the Week.

Links

• Hubble paper in the Astrophysical Journal
• Video of Can You Spot It?

Source: ESA/Hubble/potw

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Featured Image: Outflows from the Silver Coin Galaxy

NGC 253

The Silver Coin Galaxy, also known as NGC 253, is one of the nearest examples of a starburst galaxy — one that forms new stars faster than typical galaxies. In visible light, the nearly edge-on Silver Coin looks like a bright, narrow ellipse mottled with dark dust clouds. X-ray data tell a different story, though, as the image above shows. While the optical emission (H-alpha; green) is confined to the galaxy’s tilted disk, the X-ray emission (blue) extends perpendicular to the disk, tracing immense outflows powered by the galaxy’s fervent star formation. Millimeter emission (red) rounds out the three-color image. Using images and spectra from the Chandra X-ray Observatory, Sebastian Lopez (The Ohio State University) and collaborators investigated the physical properties of the galaxy’s outflows, finding that the galactic winds expel roughly 6 solar masses of gas each year. Spectral analysis revealed that the innermost region of the outflows are chemically enriched, providing a potential source for the metals found in the sparse gas between the Milky Way and its galactic neighbors. For more details about this windy starburst galaxy, be sure to check out the full article linked below!

By Kerry Hensley

Citation

“X-Ray Properties of NGC 253’s Starburst-Driven Outflow,” Sebastian Lopez et al 2023 ApJ 942 108. doi:10.3847/1538-4357/aca65e

Source: American Astronomical Society - AAS Nova

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Galactic Space Oddity Discovered

An international team of researchers led by Aaron Romanowsky of San José State University has used the Subaru Telescope to identify a faint dwarf galaxy disrupting around a nearby giant spiral galaxy. The observations provide a valuable glimpse of a process that is fleeting but important in shaping galaxies.

"The outer regions of giant galaxies like our own Milky Way appear to be a jumble of debris from hundreds of smaller galaxies that fell in over time and splashed into smithereens," said Romanowsky. "These dwarfs are considered building blocks of the giants, but the evidence for giants absorbing dwarfs has been largely circumstantial. Now we have caught a pair of galaxies in the act of a deadly embrace." (Figure 1)

Figure 1: The giant spiral galaxy NGC 253 (shown in color) is accompanied by a newly discovered dwarf galaxy, NGC 253-dw2 (at upper left). The peculiar, elongated shape of the dwarf implies it is being torn apart by the gravity of the bigger galaxy – which in turn shows irregularities on its periphery that may be caused by the mutual interaction. Click here for the original tiff file. (Image credit: Copyright © 2015 R. Jay GaBany (Cosmotography.com) & Michael Sidonio. Insert image: R. Jay GaBany & Johannes Schedler.)

The two objects in the study are NGC 253, also called the Silver Dollar galaxy, and the newly discovered dwarf NGC 253-dw2. They are located in the Southern constellation of Sculptor at a distance of 11 million light years from Earth, and are separated from each other by about 160 thousand light years. The dwarf has an elongated appearance that is the hallmark of being stretched apart by the gravity of a larger galaxy.

The dwarf has been trapped by its giant host and will not survive intact for much longer," said team member Nicolas Martin, of the Strasbourg Observatory. "The next time it plunges closer to its host, it could be shredded into oblivion. However, the host may suffer some damage too, if the dwarf is heavy enough."

The interplay between the two galaxies may resolve an outstanding mystery about NGC 253, as the giant spiral shows signs of being disturbed by a dwarf. The disturber was previously unseen and presumed to have perished, but now the likely culprit has been found. "This looks like a case of galactic stealth attack," said Gustavo Morales of Heidelberg University. "The dwarf galaxy has dived in from the depths of space and barraged the giant, while remaining undetected by virtue of its extreme faintness."

The discovery of NGC 253-dw2 has an unusual pedigree. It began with a digital image of the giant galaxy taken by astrophotographer Michael Sidonio using a 30 centimeter (12 inch) diameter amateur telescope in Australia. Other members of the international team noticed a faint smudge in the image and followed it up with a larger, 80 centimeter (30 inch) amateur telescope in Chile, led by Johannes Schedler. The identity of the object was still not clear, and it was observed with the 8 meter (27 foot) Subaru Telescope on the summit of Mauna Kea in Hawaii, in December 2014. "In the first image, we weren't sure if there was really a faint galaxy or if it was some kind of stray reflection," said David Martínez-Delgado, also from Heidelberg University. "With the high-quality imaging of the Suprime-Cam instrument on the Subaru Telescope, we can now see that the smudge is composed of individual stars and is a bona fide dwarf galaxy. This discovery is a wonderful example of fruitful collaboration between amateur and professional astronomers." (Figure 2)

Figure 2: Close-up view of the dwarf galaxy NGC 253-dw2. The closely packed red dots show that it is composed of individual stars. Click here for the original tiff file. (Image credit: Copyright © 2015 R. Jay GaBany (Cosmotography.com), Zachary Jennings (University of California, Santa Cruz), and National Astronomical Observatory of Japan (NAOJ)).

The findings are in research paper published in the Monthly Notices of the Royal Astronomical Society Letters by Oxford University Press, as "Satellite accretion in action: a tidally disrupting dwarf spheroidal around the nearby spiral galaxy NGC 253" by Romanowsky et al., first online on January 23, 2016 (http://mnrasl.oxfordjournals.org/lookup/doi/10.1093/mnrasl/slv207).

The research team:

• Aaron J. Romanowsky (San José State University and University of California Observatories, USA)
• David Martínez-Delgado (Zentrum für Astronomie der Universität Heidelberg, Germany)
• Nicolas F. Martin (Université de Strasbourg, France and Max-Planck-Institut für Astronomie, Germany)
• Gustavo Morales (Zentrum für Astronomie der Universität Heidelberg, Germany)
• Zachary G. Jennings (University of California, USA)
• R. Jay GaBany (Black Bird Observatory II, USA)
• Jean P. Brodie (University of California Observatories and University of California, USA)
• Eva K. Grebel (Zentrum für Astronomie der Universität Heidelberg, Germany)
• Johannes Schedler (Cerro Tololo Inter-American Observatory, Chile)
• Michael Sidonio (Terroux Observatory, Australia)

Links:

• http://subarutelescope.org/Pressrelease/2014/07/01/index.html
• http://subarutelescope.org/Pressrelease/2012/02/08/index.htmll

Source: Subaru Telescope

Mysterious Starburst Unshrouded in Nearby Galaxy

Figure 1. Color composite image of the central region of NGC 253, from Flamingos 2 images using the filters J (blue), H (green) and Ks (red). This region of the edge-on viewed galaxy appears completely veiled in optical images due to the presence of large amounts of dust (so dense that it is still obscuring some regions at the near-infrared spectral range). The wavelength range covered by F-2 goes from 1 to 2.5 μm. The field of view is 420 x 144 arcseconds.

Figure 2. Color composite image of the core region of NGC 253, from T-ReCS images using the filters Si-2 (blue), [NeII] (green) and Qa (red). The nucleus candidate IRC appears as the brightest object in the infrared. The wavelength range covered by T-ReCS images goes from 8 to 20 μm. The field of view is 32 x 23 arcseconds.


The nearest spiral galaxy with a nuclear starburst (greatly enhanced star formation near a galaxy’s center) is also the site of a long-standing astronomical mystery. Designated NGC 253, or by amateurs as the Silver Dollar Galaxy, the core of this galaxy is so shrouded by gas and dust that the exact location of its core has remained unresolved for years. Now, thanks to research by Guillermo Günthardt of the National University of Cordoba (Argentina), Gemini South infrared data appear to have unambiguously pinpointed the galaxy’s core. In the process, evidence for a lowish-mass, but rapidly growing, black hole as the starburst’s trigger is painting a new picture of this enigmatic galaxy (Figure 1).

NGC 253 is the nearest spiral galaxy with a nuclear starburst. The nuclear region is so veiled by large amounts of dust associated to the star formation process that it has been unclear, until now, where this galaxy’s true galactic nucleus lies. Guillermo Günthardt, from the National University of Cordoba (Argentina), and an international team suggest that the brightest near- and mid-infrared source in the central region, named the IRC (Infrared Core) by the authors, is the galaxy’s core. Long considered just a large young star cluster, Günthardt et al. present several features leading to the conclusion this source is the genuine galactic nucleus. This contradicts the previous idea that a source called TH2 (a bright fuzzy radio source catalogued by Turner and Ho in 1985) is the best candidate for the nucleus.

In the team’s paper, to appear in the next issue of The Astronomical Journal the team presents kinematic, spectrophotometric, and morphological evidence that support the hypothesis that the IRC is NGC 253's galactic nucleus. This includes the fact that the IRC is the most massive object in NGC 253's central region, the major source of the nuclear starburst outflow, the molecular gas rotation center, and it is almost coincident with the galactic bar symmetry center.

Günthardt’s team obtained near-infrared observations with Flamingos 2 (F2) on the Gemini South telescope, including spectroscopy and images in four bands. In order to penetrate the veil of dust deeper, F2 observations were complemented by mid-infrared images obtained at Gemini South with T-ReCS (Thermal-Region Camera Spectrograph) in 2011, again, using four filters. At near- and mid-infrared wavelengths the IRC, TH7 in the radio source catalogue, appears an order of magnitude brighter than any other objects in the central region of NGC 253, moreover, there is no infrared source detected at the previous candidate position (TH2). The T-ReCS high-spatial-resolution images show a shell-like structure around the IRC, and F2 spectra show the largest turbulence motions in the ionized gas at this location, with expanding velocities over 500 km per second. This observation reveals that the IRC is also the main present source of the galaxy-wide gaseous winds detected in 2013 with ALMA by Bolatto et al.

The innermost radial velocity measures of the molecular gas do not exclude the possible presence of a few million solar masses black hole at the center of the IRC. Considering that NGC 253 is a large spiral galaxy with a mass of more than 7 x 10¹¹ times the mass of our Sun, the IRC is an unexpectedly lightweight core, but which might be growing rapidly as it co-evolves with the violent star-formation process taking place in the galaxy’s nuclear region.

The off-center position of the IRC and of the nuclear disk, with respect to the galaxy’s bulge of stars, also contributed to the historic uncertainty in the nucleus location and implies a decoupling of the central gas and nuclear cluster from the older galactic structure. In 2015 Emsellem et al. theorized just such a decoupling using numerical simulation models in which a small nuclear core oscillates around the center of symmetry of a barred galaxy. In such a scenario, the small black hole in NGC 253 would not only grow rapidly while it accretes the dense nuclear gas, but also would efficiently trigger star formation due to its dance around the galaxy’s geometrical center.

This work is available on Astro-ph at: http://arxiv.org/abs/1509.00330

Paper Abstract:

NGC253 is the nearest spiral galaxy with a nuclear starburst, which becomes the best candidate to study the relationship between starburst and AGN activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus. The near infrared spectroscopy could be advantageous in order to shed light on the true nucleus identity. Using Flamingos 2 at Gemini South we have taken deep K-band spectra along the major axis and through the brightest infrared source. We present evidence showing that the brightest near infrared and mid infrared source in the central region, already known as radio source TH7 and so far considered just a stellar supercluster, in fact, presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. It is the most massive compact infrared object in the central region, located at 2.0 arcseconds of the symmetry center of the galactic bar. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H2 rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 parsecs from TH7, which is consistent with the radius of a shell detected around the nucleus candidate observed at 18.3 μm (Qa) and 12.8 μm ([NeII]) with T-ReCS. Also, the Brγ emission line profile is blue-shifted and this emission line has also the highest equivalent width at this position. All these evidences point out TH7 as the best candidate to be the galactic nucleus of NGC 253. 

Source: Gemini Observatory

Why Do Starburst Galaxies 'Burst'? ALMA Sees Super Stellar Nurseries at Heart of Sculptor Galaxy

What is the recipe for starburst? Astronomers studied NGC 253 with ALMA to find out. These new ALMA data reveal a diffuse envelope of carbon monoxide gas (shown in red), which surrounds stellar nurseries -- regions of active star formation (in yellow). By dissecting these regions with ALMA, astronomers are uncovering clues to the processes and conditions that drive furious star formation. The ALMA data are superimposed on a Hubble image that covers part of the same region. Credit: B. Saxton (NRAO/AUI/NSF); ALMA (NRAO/ESO/NAOJ); A. Leroy; STScI/NASA, ST-ECF/ESA, CADC/NRC/CSA

NGC253 -- Why Starburst Galaxies "Burst" from NRAO Outreach on Vimeo.

Animation of ALMA data reveals a diffuse envelope of carbon monoxide gas (shown in red), which surrounds stellar nurseries -- regions of active star formation (in yellow). By dissecting these regions with ALMA, astronomers are uncovering clues to the processes and conditions that drive furious star formation. The ALMA data are superimposed on a Hubble image that covers part of the same region. Credit: B. Saxton (NRAO/AUI/NSF); ALMA (NRAO/ESO/NAOJ); A. Leroy; STScI/NASA, ST-ECF/ESA, CADC/NRC/CSA

ALMA image of starbursting clouds inside NGC 253. The red region is the lower density CO gas surrounding higher density star-forming regions in yellow.Credit: B. Saxton (NRAO/AUI/NSF); ALMA (NRAO/ESO/NAOJ); A. Leroy;

ALMA antennas at night. Credit: NRAO/AUI/NSF

Starburst galaxies transmute gas into new stars at a dizzying pace – up to 1,000 times faster than typical spiral galaxies like the Milky Way. To help understand why some galaxies "burst" while others do not, an international team of astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to dissect a cluster of star-forming clouds at the heart of NGC 253, one of the nearest starburst galaxies to the Milky Way.

"All stars form in dense clouds of dust and gas," said Adam Leroy, an astronomer formerly with the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, and now with The Ohio State University in Columbus. "Until now, however, scientists struggled to see exactly what was going on inside starburst galaxies that distinguished them from other star-forming regions."

ALMA changes that by offering the power to resolve individual star-forming structures, even in distant systems. As an early demonstration of this capability, Leroy and his colleagues mapped the distributions and motions of multiple molecules in clouds at the core of NGC 253, also known as the Sculptor Galaxy.

Sculptor, a disk-shape galaxy currently undergoing intense starburst, is located approximately 11.5 million light-years from Earth, which is remarkably nearby for such an energetic star factory. This proximity makes Sculptor an excellent target for detailed study.

“There is a class of galaxies and parts of galaxies, we call them starbursts, where we know that gas is just plain better at forming stars,” noted Leroy. “To understand why, we took one of the nearest such regions and pulled it apart – layer by layer – to see what makes the gas in these places so much more efficient at star formation.”

ALMA’s exceptional resolution and sensitivity allowed the researchers to first identify ten distinct stellar nurseries inside the heart of Sculptor, something that was remarkably hard to accomplish with earlier telescopes, which blurred the different regions together.

The team then mapped the distribution of about 40 millimeter-wavelength “signatures” from different molecules inside the center of the galaxy. This was critically important since different molecules correspond to different conditions in and around star-forming clouds. For example, carbon monoxide (CO) corresponds to massive envelopes of less dense gas that surround stellar nurseries. Other molecules, like hydrogen cyanide (HCN), reveal dense areas of active star formation. Still rarer molecules, like H13CN and H13CO+, indicate even denser regions.

By comparing the concentration, distribution, and motion of these molecules, the researchers were able to peel apart the star-forming clouds in Sculptor, revealing that they are much more massive, ten times denser, and far more turbulent than similar clouds in normal spiral galaxies.

These stark differences suggest that it’s not just the number of stellar nurseries that sets the throttle for a galaxy to create new stars, but also what kind of stellar nurseries are present. Because the star-forming clouds in Sculptor pack so much material into such a small space, they are simply better at forming stars than the clouds in a galaxy like the Milky Way. Starburst galaxies, therefore, show real physical changes in the star-formation process, not just a one-to-one scaling of star formation with the available reservoir of material.

“These differences have wide-ranging implications for how galaxies grow and evolve,” concluded Leroy. “What we would ultimately like to know is whether a starburst like Sculptor produces not just more stars, but different types of stars than a galaxy like the Milky Way. ALMA is bringing us much closer to that goal.”

These results are accepted for publication in the Astrophysical Journal and are being presented February 15, 2015, at a news conference at the American Association for the Advancement of Science (AAAS) meeting in San Jose, California.

                                                       

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The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

Contact: 

Charles E. Blue, 
NRAO Public Information Officer
434-296-0314; 
Email: cblue@nrao.edu

Source:  National Radio Astronomy Observatory (NRAO)

Poised for Discovery: Gemini’s Much-anticipated Infrared Instrument Goes On-sky

This FLAMINGOS-2 near-infrared image details part of the magnificent Swan Nebula (M17), where ultraviolet radiation streaming from young hot stars sculpts a dense region of dust and gas into myriad fanciful forms. M17 lies some 5,200 light-years distant in the constellation Sagittarius and is one of the most massive and luminous star-forming region's in our Galaxy. It is also one of the most studied. Field of view: 5.5 x 4.0 arcmin. Credit: Gemini Observatory/AURA.  Full Resolution TIF (4MB) | Full Resolution JPG (2MB) | Med Resolution JPG (280KB) 

NGC 6300 is an intriguing barred spiral galaxy in the constellation of Ara. This near-infrared image with FLAMINGOS-2 shows the galaxy’s complex arm structure forming a spectacular ring of star formation. The galaxy’s bar also has a strong vein of dust that almost obscures its bright active nucleus –– whose prodigious energy is the result of matter accreting onto a black hole with an estimated mass of 280,000 Suns. Field of view: 3.1 x 2.9 arcmin. Credit: Gemini Observatory/AURA. Full Resolution TIF (2.3MB) | Full Resolution JPG (1.2MB) | Med Resolution JPG (153KB) 

In this near-infrared image, FLAMINGOS-2 peered deep into the heart of spiral galaxy NGC 253, which lies about 11.5 million light-years nearby in the constellation of Sculptor. The new instrument captured an intricate whirlpool of dust spiraling in to a diffuse nuclear region, where violent star formation may be occurring around a supermassive black hole. The instrument also imaged a dusting of star forming sites in its spiral arms. Field of view: 4.8 x 4.1 arcmin. Credit: Gemini Observatory/AURA.   Full Resolution TIF (4MB) | Full Resolution JPG (2MB) | Med Resolution JPG (141KB) 

 

Spiral galaxy NGC 7582 is the brightest member of the Grus Quartet of galaxies, some 60 million light-years distant traveling together through space. In this near-infrared image, FLAMINGOS-2 resolved its high quantity of dust that line NGC 7582’s arms as well as regions rich in star formation. Field of view: 2.5 x 1.7 arcmin. Credit: Gemini Observatory/AURA.  Full Resolution TIF (836KB) | Med Resolution JPG (425KB)

Gemini Observatory’s latest instrument, a powerful infrared camera and spectrograph at Gemini South, reveals its potential in a series of striking on-sky commissioning images released today. 

 

Gemini Observatory’s latest tool for astronomers, a second-generation infrared instrument called FLAMINGOS-2, has “traveled a long road” to begin science observations for the Gemini scientific community. Recent images taken by FLAMINGOS-2 during its last commissioning phase dramatically illustrate that the instrument was worth the wait for astronomers around the world who are anxious to begin using it. 

“It’s already one of our most requested instruments at the Gemini telescopes,” remarks Nancy Levenson, Gemini’s Deputy Director and Head of Science. “We see a long and productive life ahead for FLAMINGOS-2 once astronomers really start using it later this year.” 

“It has not been an easy journey,” says Percy Gomez Gemini’s FLAMINGOS-2 Instrument Scientist, “but thanks to the dedicated work of Gemini engineers and scientists very soon astronomers will be able to use a reliable and robust instrument.” After significant redesign and rebuilds for optimal performance on the Gemini South telescope, FLAMINGOS-2 has proven that it will provide astronomers with a powerful mix of capabilities. These include extreme sensitivity to infrared (heat) radiation from the universe, high-resolution wide-field imaging, and a combination of spectroscopic capabilities that will allow cutting-edge research in topics spanning from the exploration of our Solar System, to the most distant and energetic explosions in our universe. 

While work still remains on some of its spectroscopic features, as well as refining imaging at the edge of its large field of view, Gemini’s team of engineers and scientists has mitigated its most severe risk – potential damage to a large collimator lens that catastrophically cracked during a planned final commissioning in early 2012 (it was later replaced). The thermal environment surrounding this lens – located where the temperature changes periodically for routine switching of masks for multi-object spectroscopy - creates special challenges. It was these temperature changes that initially caused the crack, but a year later procedures and design modifications are now in place to significantly reduce risks to the lens’s integrity and functionality. 

“The Gemini team has done a remarkable job in optimizing this instrument for Gemini and it will soon be everything, and more, that we had envisioned years ago when the project began,” says Steve Eikenberry, who led the team who built FLAMINGOS-2 at the University of Florida. “Like a lot of scientists, I’m anxious to use FLAMINGOS-2 to collect data – specifically, I want to look toward the center of our Galaxy and study binary black holes as well as the mass evolution of the super-massive black hole that lurks at the heart of our Galaxy.” Eikenberry and collaborators are eager to make the most of FLAMINGOS-2’s power as soon as the instrument’s multi-object spectroscopy capability is fully functional. “With most of the challenges behind us, now the fun begins!” Eikenberry said. 

Kevin Stevenson of the University of Chicago already has plans to use FLAMINGOS-2 later this year to study the intriguing exoplanet WASP-18b. This well-known exoplanet is being strongly heated by its ultra-nearby host star and according to Stevenson, “It's even hotter than some of the coolest, low-mass stars known.” Stevenson and his team hope to determine the abundances of water vapor and methane when the planet is eclipsed by its host star. “Our plan is to compare the system's light immediately before and during an eclipse to measure the contribution from the planet. When we do this over several parts of the infrared part of the light spectrum, we can piece together the planet's spectrum and learn about its temperature and composition.” 

The quality and usefulness of FLAMINGOS-2 for these and future projects is reflected in the images released today. They cover a wide range of targets which are representative of the types of science in which FLAMINGOS-2 is expected to excel. In addition, the instrument may later accept an adaptive optics (AO) feed for extremely high-resolution imaging from GeMS (Gemini Multi-conjugate adaptive optics System). 

It is expected that most of these systems, including multi-object spectroscopy, will be fully integrated in 2014 with imaging and long-slit spectroscopy available now. The next round of observations with FLAMINGOS-2 are slated to begin on September 1st.

Contacts:

• Percy Gomez
  Gemini Observatory, La Serena, Chile
  Phone (Desk): 56-51-2-205696
  Email: pgomez@gemini.edu


• Peter Michaud
  Gemini Observatory, Hilo, Hawai‘i
  Office: +1 (808) 974-2510
  Cell: +1 (808) 936-6643
  pmichaud@gemini.edu


• Antonieta Garcia
  Gemini Observatory, La Serena, Chile
  Phone (Desk): 56-51-2-205628
  Cell: 09-69198294
  Email: agarcia@gemini.edu

Starburst to Star Bust

PR Image eso1334a

Three-dimensional view of ALMA observations 
of the outflows from NGC 253

PR Image eso1334b

The starburst galaxy NGC 253 seen with the VISTA and ALMA

PR Image eso1334c

The galaxy NGC 253 in the constellation of Sculptor

PR Image eso1334d

Wide-field view of NGC 253 from the VLT Survey Telescope

   

Videos

PR Video eso1334a

Three-dimensional view of ALMA observations  o
f the outflows from NGC 253 

PR Video eso1334b

Three-dimensional view of ALMA observations 
of the outflows from NGC 253

ALMA Sheds Light on Mystery of Missing Massive Galaxies

New observations from the ALMA telescope in Chile have given astronomers the best view yet of how vigorous star formation can blast gas out of a galaxy and starve future generations of stars of the fuel they need to form and grow. The dramatic images show enormous outflows of molecular gas ejected by star-forming regions in the nearby Sculptor Galaxy. These new results help to explain the strange paucity of very massive galaxies in the Universe. The study is published in the journal Nature on 25 July 2013.

Galaxies — systems like our own Milky Way that contain up to hundreds of billions of stars — are the basic building blocks of the cosmos. One ambitious goal of contemporary astronomy is to understand the ways in which galaxies grow and evolve, a key question being star formation: what determines the number of new stars that will form in a galaxy?

The Sculptor Galaxy, also known as NGC 253, is a spiral galaxy located in the southern constellation of Sculptor. At a distance of around 11.5 million light-years from our Solar System it is one of our closer intergalactic neighbours, and one of the closest starburst galaxies [1] visible from the southern hemisphere. 

Using the Atacama Large Millimeter/submillimeter Array (ALMA) astronomers have discovered billowing columns of cold, dense gas fleeing from the centre of the galactic disc.

“With ALMA’s superb resolution and sensitivity, we can clearly see for the first time massive concentrations of cold gas being jettisoned by expanding shells of intense pressure created by young stars,” said Alberto Bolatto of the University of Maryland, USA lead author of the paper. “The amount of gas we measure gives us very good evidence that some growing galaxies spew out more gas than they take in. We may be seeing a present-day example of a very common occurrence in the early Universe.”

These results may help to explain why astronomers have found surprisingly few high-mass galaxies throughout the cosmos. Computer models show that older, redder galaxies should have considerably more mass and a larger number of stars than we currently observe. It seems that the galactic winds or outflow of gas are so strong that they deprive the galaxy of the fuel for the formation of the next generation of stars [2].

“These features trace an arc that is almost perfectly aligned with the edges of the previously observed hot, ionised gas outflow,” noted Fabian Walter, a lead investigator at the Max Planck Institute for Astronomy in Heidelberg, Germany, and a co-author of the paper. “We can now see the step-by-step progression of starburst to outflow.”

The researchers determined that vast quantities of molecular gas — nearly ten times the mass of our Sun each year and possibly much more — were being ejected from the galaxy at velocities between 150 000 and almost 1 000 000 kilometres per hour [3]. The total amount of gas ejected would add up to more gas than actually went into forming the galaxy’s stars in the same time. At this rate, the galaxy could run out of gas in as few as 60 million years.

“For me, this is a prime example of how new instruments shape the future of astronomy. We have been studying the starburst region of NGC 253 and other nearby starburst galaxies for almost ten years. But before ALMA, we had no chance to see such details,” says Walter. The study used an early configuration of ALMA with only 16 antennas. “It’s exciting to think what the complete ALMA with 66 antennas will show for this kind of outflow!” Walter adds.

More studies with the full ALMA array will help determine the ultimate fate of the gas carried away by the wind, which will reveal whether the starburst-driven winds are recycling or truly removing star forming material.

Notes

[1] Starburst galaxies are producing stars at an exceptionally high rate. As NGC 253 is one of the closest such extreme objects it is an ideal target to study the effect of such growth frenzy on the galaxy hosting it.

[2] Previous observations had shown hotter, but much less dense, gas streaming away from NGC 253’s star-forming regions, but alone this would have little, if any, impact on the fate of the galaxy and its ability to form future generations of stars. This new ALMA data show the much more dense molecular gas getting its initial “kick” from the formation of new stars and then being swept along with the thin, hot gas on its way to the galactic halo.

[3] Although the velocities are high, they may not be high enough for the gas to be ejected from the galaxy. It would get trapped in the galactic halo for many millions of years, and could eventually rain back on the disk, causing new episodes of star formation.

More information

This research was presented in a paper “The Starburst-Driven Molecular Wind in NGC 253 and the Suppression of Star Formation”, by Alberto D. Bolatto et al., to appear in Nature on 25 July 2013.

The team is composed of A. D. Bolatto (Department of Astronomy, Laboratory for Millimeter-wave Astronomy, and Joint Space Institute, University of Maryland, USA), S. R. Warren (University of Maryland), A. K. Leroy (National Radio Astronomy Observatory, Charlottesville, USA), F. Walter (Max-Planck Institut für Astronomie, Heidelberg, Germany), S. Veilleux (University of Maryland), E. C. Ostriker (Department of Astrophysical Sciences, Princeton University, USA), J. Ott (National Radio Astronomy Observatory, New Mexico, USA), M. Zwaan (European Southern Observatory, Garching, Germany), D. B. Fisher (University of Maryland), A. Weiss (Max-Planck-Institut für Radioastronomie, Bonn, Germany), E. Rosolowsky (Department of Physics, University of Alberta, Canada) and J. Hodge (Max-Planck Institut für Astronomie, Heidelberg, Germany).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

• Research paper
• More about ALMA
• Photos of ALMA
• Press release at NRAO
• Press release at MPIA

Contacts

Alberto Bolatto
University of Maryland
USA
Tel: +49 6221 528 493
Email: bolatto@astro.umd.edu

Martin Zwaan
ESO
Garching bei München, Germany
Tel: +49 89 3200 6834
Email: mzwaan@eso.org

Fabian Walter
Max-Planck Institut für Astronomie
Heidelberg, Germany
Tel: +49 6221 528 225
Email: walter@mpia.de

Richard Hook
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org

Black Hole Naps Amidst Stellar Chaos

The Sculptor galaxy (NGC253) is seen in a new light, in this composite image from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Southern Observatory in Chile. Image credit: NASA/JPL-Caltech/JHU.  › Full image and caption  -  › NuSTAR view only

Nearly a decade ago, NASA's Chandra X-ray Observatory caught signs of what appeared to be a black hole snacking on gas at the middle of the nearby Sculptor galaxy. Now, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), which sees higher-energy X-ray light, has taken a peek and found the black hole asleep. 

"Our results imply that the black hole went dormant in the past 10 years," said Bret Lehmer of the Johns Hopkins University, Baltimore, and NASA's Goddard Space Flight Center, Greenbelt, Md. "Periodic observations with both Chandra and NuSTAR should tell us unambiguously if the black hole wakes up again. If this happens in the next few years, we hope to be watching." Lehmer is lead author of a new study detailing the findings in the Astrophysical Journal. 

The slumbering black hole is about 5 million times the mass of our sun. It lies at the center of the Sculptor galaxy, also known as NGC 253, a so-called starburst galaxy actively giving birth to new stars. At 13 million light-years away, this is one of the closest starbursts to our own galaxy, the Milky Way. 

The Milky Way is all around more quiet than the Sculptor galaxy. It makes far fewer new stars, and its behemoth black hole, about 4 million times the mass of our sun, is also snoozing. 

"Black holes feed off surrounding accretion disks of material. When they run out of this fuel, they go dormant," said co-author Ann Hornschemeier of Goddard. "NGC 253 is somewhat unusual because the giant black hole is asleep in the midst of tremendous star-forming activity all around it." 

The findings are teaching astronomers how galaxies grow over time. Nearly all galaxies are suspected to harbor supermassive black holes at their hearts. In the most massive of these, the black holes are thought to grow at the same rate that new stars form, until blasting radiation from the black holes ultimately shuts down star formation. In the case of the Sculptor galaxy, astronomers do not know if star formation is winding down or ramping up. 

"Black hole growth and star formation often go hand-in-hand in distant galaxies," said Daniel Stern, a co-author and NuSTAR project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It's a bit surprising as to what's going on here, but we've got two powerful complementary X-ray telescopes on the case." 

Chandra first observed signs of what appeared to be a feeding supermassive black hole at the heart of the Sculptor galaxy in 2003. As material spirals into a black hole, it heats up to tens of millions of degrees and glows in X-ray light that telescopes like Chandra and NuSTAR can see. 

Then, in September and November of 2012, Chandra and NuSTAR observed the same region simultaneously. The NuSTAR observations -- the first-ever to detect focused, high-energy X-ray light from the region -- allowed the researchers to say conclusively that the black hole is not accreting material. NuSTAR launched into space in June of 2012. 

In other words, the black hole seems to have fallen asleep. Another possibility is that the black hole was not actually awake 10 years ago, and Chandra observed a different source of X-rays. Future observations with both telescopes may solve the puzzle. 

"The combination of coordinated Chandra and NuSTAR observations is extremely powerful for answering questions like this," said Lou Kaluzienski, NuSTAR Program Scientist at NASA Headquarters in Washington. "Now, we can get all sides of the story." 

The observations also revealed a smaller, flaring object that the researchers were able to identify as an "ultraluminous X-ray source," or ULX. ULXs are black holes feeding off material from a partner star. They shine more brightly than typical stellar-mass black holes generated from dying stars, but are fainter and more randomly distributed than the supermassive black holes at the centers of massive galaxies. Astronomers are still working to understand the size, origins and physics of ULXs. 

"These stellar-mass black holes are bumping along near the center of this galaxy," said Hornschemeier. "They tend to be more numerous in areas where there is more star-formation activity." 

If and when the Sculptor's slumbering giant does wake up in the next few years amidst all the commotion, NuSTAR and Chandra will monitor the situation. The team plans to check back on the system periodically.

NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA's Jet Propulsion Laboratory, also in Pasadena, for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley; Columbia University, New York; NASA's Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center. 

NuSTAR's mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Rohnert Park, Calif. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA. 

For more information, visit: http://www.nasa.gov/nustar and http://www.nustar.caltech.edu/ . Follow the mission on Twitter via http://www.twitter.com/NASANuSTAR . 

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

A Galaxy Blooming with New Stars

PR Image eso1152a
Wide-field view of NGC 253 from the VLT Survey Telescope

PR Image eso1152b
The galaxy NGC 253 in the constellation of Sculptor

PR Image eso1152c
Wide-field view of the sky around NGC 253

PR Video eso1152a
Zooming in on NGC 253

VLT Survey Telescope snaps wide-field view of NGC 253

The VLT Survey Telescope (VST) has captured the beauty of the nearby spiral galaxy NGC 253. The new portrait is probably the most detailed wide-field view of this object and its surroundings ever taken. It demonstrates that the VST, the newest telescope at ESO's Paranal Observatory, provides broad views of the sky while also offering impressive image sharpness.

NGC 253 gleams about eleven and a half million light-years away in the southern constellation of Sculptor. It is often just called the Sculptor Galaxy, although other descriptive names include the Silver Coin or Silver Dollar Galaxy. It is easy to get a good look at NGC 253 through binoculars as it is one of the brightest galaxies in the sky after the Milky Way's closest, big galactic neighbour, the Andromeda Galaxy.

Astronomers have noted the widespread active star formation in NGC 253 and labelled it a "starburst" galaxy [1]. The many bright clumps dotting the galaxy are stellar nurseries where hot young stars have just ignited. The radiation streaming from these giant blue-white babies makes the surrounding hydrogen gas clouds glow brightly (green in this image).

This nearby spiral galaxy was discovered by the German–British astronomer Caroline Herschel, the sister of the famed astronomer William Herschel, as she searched for comets in 1783. The Herschels would have been delighted by the crisp, richly detailed view of NGC 253 that the VST can provide.

This latest image of NGC 253 was taken during VST’s science verification phase — when the telescope’s scientific performance is assessed before it enters operations. The VST data are being combined with infrared images from VISTA (eso0949) to identify the younger generations of stars in NGC 253. This picture is more than 12 000 pixels across and the superb sky conditions at ESO’s Paranal Observatory, combined with the fine telescope optics, result in sharp star images over the entire image.

The VST is a 2.6-metre wide-field survey telescope with a one-degree field of view — twice as broad as the full Moon [2]. The VST programme is a joint venture between the INAF–Osservatorio Astronomico di Capodimonte, Naples, Italy and ESO (eso1119). The 268-megapixel camera OmegaCAM at its heart is designed to map the sky both quickly and with very fine image quality. VST is the largest telescope in the world designed to exclusively survey the sky in visible light, complementing ESO's VISTA infrared survey telescope, also located at Paranal.

Zooming into this new picture not only allows a very detailed inspection of the star-forming spiral arms of the galaxy to be made, but also reveals a very rich tapestry of much more distant galaxies far beyond NGC 253.

Notes

[1] Further details about NGC 253 have been revealed by ESO's Very Large Telescope (VLT) along with the NASA/ESA Hubble Space Telescope. These instruments showed in 2009 that, at its centre, NGC 253 harbours a supermassive black hole with very similar properties to those of the black hole lurking in the Milky Way's core (see ESO Press Release eso0902).

[2] The image presented here has been cropped and is slightly smaller than the full VST field of view.

More information

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links
Photos of the VST
VST public web pages

Contacts

Massimo Capaccioli
University of Naples Federico II and INAF-Capodimonte Astronomical Observatory
Naples, Italy
Tel: +39 081 557 5601
Cell: +39 335 677 6940
Email: capaccioli@na.infn.it

Richard Hook
ESO, La Silla, Paranal, E-ELT and Survey Telescopes Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org