ESO telescope uncovers closest pair of supermassive black holes yet

PR Image eso2117a

Close-up and wide views of the nearest pair of supermassive black holes 

 

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Close-up view of the nearest pair of supermassive black holes 

 

PR Image eso2117c

Bumps in the heavens 

 

PR Image eso2117d

Wide-field view of the region of the sky hosting NGC 7727

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Videos

PR Video eso2117a

Supermassive Black Holes on a Collision Course (ESOcast 246 Light)

 

PR Video eso2117b

Journey to the closest pair of supermassive black holes 

 

PR Video eso2117c

How MUSE uncovered the closest pair of supermassive black holes

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Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have revealed the closest pair of supermassive black holes to Earth ever observed. The two objects also have a much smaller separation than any other previously spotted pair of supermassive black holes and will eventually merge into one giant black hole.

Located in the galaxy NGC 7727 in the constellation Aquarius, the supermassive black hole pair is about 89 million light-years away from Earth. Although this may seem distant, it beats the previous record of 470 million light-years by quite some margin, making the newfound supermassive black hole pair the closest to us yet.  

Supermassive black holes lurk at the centre of massive galaxies and when two such galaxies merge, the black holes end up on a collision course. The pair in NGC 7727 beat the record for the smallest separation between two supermassive black holes, as they are observed to be just 1600 light-years apart in the sky. “It is the first time we find two supermassive black holes that are this close to each other, less than half the separation of the previous record holder,” says Karina Voggel, an astronomer at the Strasbourg Observatory in France and lead author of the study published online today in Astronomy & Astrophysics.

“The small separation and velocity of the two black holes indicate that they will merge into one monster black hole, probably within the next 250 million years,” adds co-author Holger Baumgardt, a professor at the University of Queensland, Australia. The merging of black holes like these could explain how the most massive black holes in the Universe come to be.

Voggel and her team were able to determine the masses of the two objects by looking at how the gravitational pull of the black holes influences the motion of the stars around them. The bigger black hole, located right at the core of NGC 7727, was found to have a mass almost 154 million times that of the Sun, while its companion is 6.3 million solar masses.

It is the first time the masses have been measured in this way for a supermassive black hole pair. This feat was made possible thanks to the close proximity of the system to Earth and the detailed observations the team obtained at the Paranal Observatory in Chile using the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s VLT, an instrument Voggel learnt to work with during her time as a student at ESO. Measuring the masses with MUSE, and using additional data from the NASA/ESA Hubble Space Telescope, allowed the team to confirm that the objects in NGC 7727 were indeed supermassive black holes.

Astronomers suspected that the galaxy hosted the two black holes, but they had not been able to confirm their presence until now since we do not see large amounts of high-energy radiation coming from their immediate surroundings, which would otherwise give them away. “Our finding implies that there might be many more of these relics of galaxy mergers out there and they may contain many hidden massive black holes that still wait to be found,” says Voggel. “It could increase the total number of supermassive black holes known in the local Universe by 30 percent.”

The search for similarly hidden supermassive black hole pairs is expected to make a great leap forward with ESO’s Extremely Large Telescope (ELT), set to start operating later this decade in Chile’s Atacama Desert. “This detection of a supermassive black hole pair is just the beginning,” says co-author Steffen Mieske, an astronomer at ESO in Chile and Head of ESO Paranal Science Operations. “With the HARMONI instrument on the ELT we will be able to make detections like this considerably further than currently possible. ESO’s ELT will be integral to understanding these objects.”

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More Information

This research was presented in a paper titled "First Direct Dynamical Detection of a Dual Super-Massive Black Hole System at sub-kpc Separation" to appear in Astronomy & Astrophysics (doi: 10.1051/0004-6361/202140827).

The team is composed of Karina T. Voggel (Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, France), Anil C. Seth (University of Utah, Salt Lake City, USA [UofU]), Holger Baumgardt (School of Mathematics and Physics, University of Queensland, St. Lucia, Australia), Bernd Husemann (Max-Planck-Institut für Astronomie, Heidelberg, Germany [MPIA]), Nadine Neumayer (MPIA), Michael Hilker (European Southern Observatory, Garching bei München, Germany), Renuka Pechetti (Astrophysics Research Institute, Liverpool John Moores University, Liverpool, UK), Steffen Mieske (European Southern Observatory, Santiago de Chile, Chile), Antoine Dumont (UofU), and Iskren Georgiev (MPIA).

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 in astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, the Czech Republic, 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 two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. 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 APEX and ALMA on Chajnantor, two facilities that observe 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 

Karina Voggel
Strasbourg Observatory, University of Strasbourg
Strasbourg, France
Email: karina.voggel@astro.unistra.fr

Holger Baumgardt
School of Mathematics and Physics, University of Queensland
St. Lucia, Queensland, Australia
Tel: +61 (0)7 3365 3430
Email: h.baumgardt@uq.edu.au

Steffen Mieske
European Southern Observatory
Vitacura, Santiago, Chile
Tel: +56 22 463 3060
Email: smieske@eso.org

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

Source: ESO/News

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Black Hole Collision May Have Exploded With Light

Image Credit: Caltech/R. Hurt (IPAC)

In a first, astronomers may have seen light from the merger of two black holes, providing opportunities to learn about these mysterious dark objects.

This artist's concept shows a supermassive black hole surrounded by a disk of gas. Embedded in this disk are two smaller black holes that may have merged together to form a new black hole.

When two black holes spiral around each other and ultimately collide, they send out gravitational waves - ripples in space and time that can be detected with extremely sensitive instruments on Earth. Since black holes and black hole mergers are completely dark, these events are invisible to telescopes and other light-detecting instruments used by astronomers. However, theorists have come up with ideas about how a black hole merger could produce a light signal by causing nearby material to radiate.

Now, scientists using Caltech's Zwicky Transient Facility (ZTF) located at Palomar Observatory near San Diego may have spotted what could be just such a scenario. If confirmed, it would be the first known light flare from a pair of colliding black holes.

The merger was identified on May 21, 2019, by two gravitational wave detectors – the National Science Foundation's Laser Interferometer Gravitational-wave Observatory, or LIGO, and the European Virgo detector – in an event called GW190521g. That detection allowed the ZTF scientists to look for light signals from the location where the gravitational wave signal originated. These gravitational wave detectors have also spotted mergers between dense cosmic objects called neutron stars, and astronomers have identified light emissions from those collisions.

Learn more: What Is a Black Hole?
Black Hole Image Makes History; NASA Telescopes Coordinated Observations

Editor: Yvette Smith

Source: NASA/Black Holes

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NASA’s Webb Will Join Forces with the Event Horizon Telescope to Reveal the Milky Way’s Supermassive Black Hole

An enormous swirling vortex of hot gas glows with infrared light, marking the approximate location of the supermassive black hole at the heart of our Milky Way galaxy. This multiwavelength composite image includes near-infrared light captured by NASA’s Hubble Space Telescope, and was the sharpest infrared image ever made of the galactic center region when it was released in 2009. Dynamic flickering flares in the region immediately surrounding the black hole, named Sagittarius A*, have complicated the efforts of the Event Horizon Telescope (EHT) collaboration to create a closer, more detailed image. While the black hole itself does not emit light and so cannot be detected by a telescope, the EHT team is working to capture it by getting a clear image of the hot glowing gas and dust directly surrounding it. NASA’s upcoming James Webb Space Telescope, scheduled to launch in December 2021, will combine Hubble’s resolution with even more infrared light detection. In its first year of science operations, Webb will join with EHT in observing Sagittarius A*, lending its infrared data for comparison to EHT’s radio data, making it easier to determine when bright flares are present, producing a sharper overall image of the region. In the composite image shown here, colors represent different wavelengths of light. Hubble’s near-infrared observations are shown in yellow, revealing hundreds of thousands of stars, stellar nurseries, and heated gas. The deeper infrared observations of NASA’s Spitzer Space Telescope are shown in red, revealing even more stars and gas clouds. Light detected by NASA’s Chandra X-ray Observatory is shown in blue and violet, indicating where gas is heated to millions of degrees by stellar explosions and by outflows from the supermassive black hole. Credits: NASA, ESA, SSC, CXC, STScI.  Hi-res image

On isolated mountaintops across the planet, scientists await word that tonight is the night: The complex coordination between dozens of telescopes on the ground and in space is complete, the weather is clear, tech issues have been addressed—the metaphorical stars are aligned. It is time to look at the supermassive black hole at the heart of our Milky Way galaxy.

This “scheduling Sudoku,” as the astronomers call it, happens each day of an observing campaign by the Event Horizon Telescope (EHT) collaboration, and they will soon have a new player to factor in; NASA’s James Webb Space Telescope will be joining the effort. During Webb’s first slate of observations, astronomers will use its infrared imaging power to address some of the unique and persistent challenges presented by the Milky Way’s black hole, named Sagittarius A* (Sgr A*; the asterisk is pronounced as “star”).

In 2017, EHT used the combined imaging power of eight radio telescope facilities across the planet to capture the historic first view of the region immediately surrounding a supermassive black hole, in the galaxy M87. Sgr A* is closer but dimmer than M87’s black hole, and unique flickering flares in the material surrounding it alter the pattern of light on an hourly basis, presenting challenges for astronomers.

“Our galaxy’s supermassive black hole is the only one known to have this kind of flaring, and while that has made capturing an image of the region very difficult, it also makes Sagittarius A* even more scientifically interesting,” said astronomer Farhad Yusef-Zadeh, a professor at Northwestern University and principal investigator on the Webb program to observe Sgr A*.

The flares are due to the temporary but intense acceleration of particles around the black hole to much higher energies, with corresponding light emission. A huge advantage to observing Sgr A* with Webb is the capability of capturing data in two infrared wavelengths (F210M and F480M) simultaneously and continuously, from the telescope’s location beyond the Moon. Webb will have an uninterrupted view, observing cycles of flaring and calm that the EHT team can use for reference with their own data, resulting in a cleaner image.

The source or mechanism that causes Sgr A*’s flares is highly debated. Answers as to how Sgr A*’s flares begin, peak, and dissipate could have far-reaching implications for the future study of black holes, as well as particle and plasma physics, and even flares from the Sun.

“Black holes are just cool,” said Sera Markoff, an astronomer on the Webb Sgr A* research team and currently vice chairperson of EHT’s Science Council. “The reason that scientists and space agencies across the world put so much effort into studying black holes is because they are the most extreme environments in the known universe, where we can put our fundamental theories, like general relativity, to a practical test.”

Heated gas swirls around the region of the Milky Way galaxy’s supermassive black hole, illuminated in near-infrared light captured by NASA’s Hubble Space Telescope. Released in 2009 to celebrate the International Year of Astronomy, this was the sharpest infrared image ever made of the galactic center region. NASA’s upcoming James Webb Space Telescope, scheduled to launch in December 2021, will continue this research, pairing Hubble-strength resolution with even more infrared-detecting capability. Of particular interest for astronomers will be Webb’s observations of flares in the area, which have not been observed around any other supermassive black hole and the cause of which is unknown. The flares have complicated the Event Horizon Telescope (EHT) collaboration’s quest to capture an image of the area immediately surrounding the black hole, and Webb’s infrared data is expected to help greatly in producing a clean image.Credits: NASA, ESA, STScI, Q. Daniel Wang (UMass). Hi-res image

Black holes, predicted by Albert Einstein as part of his general theory of relativity, are in a sense the opposite of what their name implies—rather than an empty hole in space, black holes are the most dense, tightly-packed regions of matter known. A black hole’s gravitational field is so strong that it warps the fabric of space around itself, and any material that gets too close is bound there forever, along with any light the material emits. This is why black holes appear “black.” Any light detected by telescopes is not actually from the black hole itself, but the area surrounding it. Scientists call the ultimate inner edge of that light the event horizon, which is where the EHT collaboration gets its name.

The EHT image of M87 was the first direct visual proof that Einstein’s black hole prediction was correct. Black holes continue to be a proving ground for Einstein’s theory, and scientists hope carefully scheduled multi-wavelength observations of Sgr A* by EHT, Webb, X-ray, and other observatories will narrow the margin of error on general relativity calculations, or perhaps point to new realms of physics we don’t currently understand.

As exciting as the prospect of new understanding and/or new physics may be, both Markoff and Zadeh noted that this is only the beginning. “It’s a process. We will likely have more questions than answers at first,” Markoff said. The Sgr A* research team plans to apply for more time with Webb in future years, to witness additional flaring events and build up a knowledge base, determining patterns from seemingly random flares. Knowledge gained from studying Sgr A* will then be applied to other black holes, to learn what is fundamental to their nature versus what makes one black hole unique.

So the stressful scheduling Sudoku will continue for some time, but the astronomers agree it’s worth the effort. “It’s the noblest thing humans can do, searching for truth,” Zadeh said. “It’s in our nature. We want to know how the universe works, because we are part of the universe. Black holes could hold clues to some of these big questions.”

NASA’s Webb telescope will serve as the premier space science observatory for the next decade and explore every phase of cosmic history—from within our solar system to the most distant observable galaxies in the early universe, and everything in between. Webb will reveal new and unexpected discoveries, and help humanity understand the origins of the universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

By Leah Ramsay
Space Telescope Science Institute, Baltimore, Md.

Editor: Lynn Jenner

Source: NASA/Blacks Holes

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Dense Molecular Clouds in the Center of Milky Way are Unable to Form Stars

Composite image of Hubble Space Telescope (red) mapping hot ionized gas, and ALMA (blue and purple) detail of the much colder molecular gas of Sgr A* circumnuclear disk. Credit: Dong, H. et al 2011 – ESA/Hubble | Hsieh, P.-Y. et al. – N. Lira – ALMA (EOS/NAOJ/NRAO)

Composite animation of Hubble Space Telescope (red) mapping hot ionized gas, and ALMA (blue and purple) detail of the much colder molecular gas of Sgr A* circumnuclear disk. Credit:Dong, H. et al 2011 – ESA/Hubble | Hsieh, P.-Y. et al. – N. Lira – ALMA (EOS/NAOJ/NRAO)

Clumps of molecular gas overlaid on Sgr A* circumnuclear disk as seen by ALMA in the CS(7-6) line. Yellow circles are thin clumps that are going to be shredded by the gravitational force of supermassive black hole Sgr A*. Green circles are dense enough to survive the tidal shredding but are not able to form stars. Purple/pink circles have the needed density to form stars, but no star formation has been observed. Credit: Hsieh, P.-Y. et al. – ALMA (EOS/NAOJ/NRAO)

New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) allowed astronomers to map in exquisite detail the ring of dense molecular gas rotating around the supermassive black hole in Sgr A* at the center of our galaxy. In that ring, also known as a circumnuclear disk, they found thousands of dense gas clumps but, surprisingly, no active star formation: either the tidal stress of the black hole or some other mechanism prevents the clumps from collapsing into new stars.

Every large galaxy has a central supermassive black hole that dominates and is fed by nearby molecular gas. In many galaxies, there are also bright nuclear star clusters. Since molecular gas is the material that supplies black holes and forms stars, the research team wanted to know how much gas is available to form stars and how much is going to feed the supermassive black hole. Sgr A* is the closest supermassive black hole to us. The first challenge of star formation in the vicinity of the Galactic Center is avoiding the high tidal shear that can easily tear apart the nearby molecular clouds, preventing them from accumulating enough mass for fragmentation and core-collapse to proceed.

“The circumnuclear disk can be imagined as a factory of many doughs rotating around the supermassive black hole,” explains Pei-Ying Hsieh, principal investigator of this study and fellow astronomer at ALMA. “If the dough is too thin, it will be stretched like spaghetti by the black hole and so feed it; if the dough is dense enough, it has a chance to overcome the tidal shear and become ‘bread’, and so a star.”

The astronomers used ALMA to observe the carbon monosulfide molecule lines in the circumnuclear disk to achieve this image. Carbon monosulfide is a dense gas tracer that better samples the circumnuclear disk than carbon monoxide, a commonly used molecule to observe interstellar gas. This method provided a better way to constrain the gas densities and better understand what is going on in it.

The research team found that while a significant amount of gas is available to form stars, there is no clear evidence of star formation. The seemingly unstable clumps of molecular gas should then be marginally stabilized by other forces such as magnetic fields.

“Because the polarized signal generated by the magnetic field from dust emission is weak and difficult to measure, the magnetic field of the circumnuclear disk has not yet been probed at clump-scale (8000 AU),” explains Hsieh. “Thanks to the high resolution and sensitivity of ALMA, we have been granted the ALMA time to mosaic the magnetic field of the circumnuclear disk in future observations with ALMA. We will then continue to explore the role of magnetic fields in star formation in this region.”

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

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

Contacts

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago - Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Source: Atacama Large Millimeter/submillimeter Array (ALMA)

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Northern Clump: Galaxy Cluster Travels Down an Intergalactic Highway

NGC 330

Credit X-ray: (Chandra: NASA/CXC/Univ. Bonn/A. Veronica et al; XMM-Newton: ESA/XMM-Newton); 

Optical: DES/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA; Radio: CSIRO/ASKAP/EMU

JPEG (280.7 kb) - Large JPEG (4.9 MB) - Tiff (102.9 MB) - More Images

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Researchers have found a galaxy cluster acting like a passenger on what astronomers are calling an "intergalactic highway." The cluster is known as the "Northern Clump" and it is located about 690 million light years from Earth. Previously, scientists discovered an enormous filament, a thin strip of very hot gas that stretched for at least 50 million light years. A new study found evidence that the Northern Clump is traveling along this filament, similar to how a car moves along the interstate.

A composite with ESA's XMM-Newton (blue), Chandra data (purple), optical and infrared data (orange, green, blue), plus radio data from the Evolutionary Map of the Universe survey made by the Australian Square Kilometer Array Pathfinder telescope (red) is shown with an inset with the Chandra data.

Also included is a side-by-side graphic. On the left side of this panel is an optical and infrared image from the Dark Energy Camera in Chile. The right side contains an X-ray image from ESA's XMM-Newton (blue), with high-precision X-ray data from NASA's Chandra X-ray Observatory are in the inset (purple).

Credit: X-ray: (Chandra: NASA/CXC/Univ. Bonn/A. Veronica et al; XMM-Newton: ESA/XMM-Newton); Optical: DES/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA; Radio: CSIRO/ASKAP/EMU

Each telescope gives important information about this system. For example, the optical data provides a view of the galaxies in the cluster, while the XMM-Newton data reveal hot gas in the cluster with temperatures of millions of degrees. The Chandra data show hot gas around a supermassive black hole in the middle of a galaxy in the cluster's center.

Previous observations from the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) have shown that the Northern Clump and a pair of galaxy clusters to the south all lie along an enormous filament of gas. The Northern Clump is moving towards the other clusters and all three will eventually merge with each other. The other two clusters, Abell 3391 and Abell 3395, are not shown in this image.

In the radio data, astronomers found a pair of jets of particles being ejected from regions close to the black hole that point backwards like the braids of a runner. The X-ray shows evidence of a bow shock, like the sonic boom from a supersonic plane, towards the south and a tail of hot gas towards the north that is likely being dragged off the cluster as it moves. The bend in the radio jet and both of these X-ray features are consistent with the cluster traveling south along the filament towards the other two clusters. These results agree with simulations showing that galaxy clusters grow by traveling towards each other along enormous filaments of gas, before colliding and merging.

These results, led by Angie Veronica of the University of Bonn in Germany, were presented at the recent European Astronomical Society meeting. A paper describing this study has been submitted to Astronomy & Astrophysics journal and is available online. NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts.

Source: Chandra X-Ray Observatory

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Fast Facts for Northern Clump:

Scale: Image is about 8.75 arcmin (1.7 million light years) across.
Category: Groups & Clusters of Galaxies, Black Holes
Coordinates (J2000): RA 06h 21m 43.30s | Dec -52° 41´ 33.3
Constellation: Carina
Observation Date: 4 observations between Oct 3, 2010 and May 21, 2020
Observation Time: 30 hours 15 minutes (1 day 6 hours and 15 minutes)
Obs. ID: 11499, 22723-22725
Instrument: ACIS
References: Veronica, A., et al, 2021, A&A (submitted); arXiv:2012.08491
Color Code: X-ray: Chandra, purple; XMM-Newton, blue; Radio: red, Optical: orange, green, blue
Distance Estimate: About 690 million light years (z=0.0511) 

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