3
|
Abstract
Fast Radio Bursts (FRBs) represent a novel tool for probing the properties of the universe at cosmological distances. The dispersion measures of FRBs, combined with the redshifts of their host galaxies, has very recently yielded a direct measurement of the baryon content of the universe, and has the potential to directly constrain the location of the “missing baryons”. The first results are consistent with the expectations of ΛCDM for the cosmic density of baryons, and have provided the first constraints on the properties of the very diffuse intergalactic medium (IGM) and circumgalactic medium (CGM) around galaxies. FRBs are the only known extragalactic sources that are compact enough to exhibit diffractive scintillation in addition to showing exponential tails which are typical of scattering in turbulent media. This will allow us to probe the turbulent properties of the circumburst medium, the host galaxy ISM/halo, and intervening halos along the path, as well as the IGM. Measurement of the Hubble constant and the dark energy parameter w can be made with FRBs, but require very large samples of localised FRBs (>103) to be effective on their own—they are best combined with other independent surveys to improve the constraints. Ionisation events, such as for He ii, leave a signature in the dispersion measure—redshift relation, and if FRBs exist prior to these times, they can be used to probe the reionisation era, although more than 103 localised FRBs are required.
Collapse
|
7
|
Emonts BHC, Lehnert MD, Villar-Martín M, Norris RP, Ekers RD, van Moorsel GA, Dannerbauer H, Pentericci L, Miley GK, Allison JR, Sadler EM, Guillard P, Carilli CL, Mao MY, Röttgering HJA, De Breuck C, Seymour N, Gullberg B, Ceverino D, Jagannathan P, Vernet J, Indermuehle BT. Molecular gas in the halo fuels the growth of a massive cluster galaxy at high redshift. Science 2016; 354:1128-1130. [PMID: 27934760 DOI: 10.1126/science.aag0512] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/21/2016] [Indexed: 11/02/2022]
Abstract
The largest galaxies in the universe reside in galaxy clusters. Using sensitive observations of carbon monoxide, we show that the Spiderweb galaxy-a massive galaxy in a distant protocluster-is forming from a large reservoir of molecular gas. Most of this molecular gas lies between the protocluster galaxies and has low velocity dispersion, indicating that it is part of an enriched intergalactic medium. This may constitute the reservoir of gas that fuels the widespread star formation seen in earlier ultraviolet observations of the Spiderweb galaxy. Our results support the notion that giant galaxies in clusters formed from extended regions of recycled gas at high redshift.
Collapse
Affiliation(s)
- B H C Emonts
- Centro de Astrobiología (Consejo Superior de Investigaciones Científicas-Instituto Nacional de Técnica Aerospacial), Carretera de Torrejón a Ajalvir, km 4, 28850 Torrejón de Ardoz, Madrid, Spain.
| | - M D Lehnert
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 6 et Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7095, Institut d'Astrophysique de Paris, 75014 Paris, France
| | - M Villar-Martín
- Centro de Astrobiología (Consejo Superior de Investigaciones Científicas-Instituto Nacional de Técnica Aerospacial), Carretera de Torrejón a Ajalvir, km 4, 28850 Torrejón de Ardoz, Madrid, Spain.,Facultad de Ciencias, Unidad Asociada Consejo Superior de Investigaciones Científicas, Astro-Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
| | - R P Norris
- Commonwealth Scientific and Industrial Research Organisation, Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710, Australia.,Western Sydney University, Penrith South, NSW 1797, Australia
| | - R D Ekers
- Commonwealth Scientific and Industrial Research Organisation, Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710, Australia
| | - G A van Moorsel
- National Radio Astronomy Observatory, Socorro, NM 87801, USA
| | - H Dannerbauer
- Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain.,Departamento Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain.,Institut für Astrophysik, Universität Wien, 1180 Wien, Austria
| | - L Pentericci
- Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Roma, 00040 Monteporzio (RM), Italy
| | - G K Miley
- Leiden Observatory, University of Leiden, 2300 RA Leiden, Netherlands
| | - J R Allison
- Commonwealth Scientific and Industrial Research Organisation, Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710, Australia
| | - E M Sadler
- Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006, Australia
| | - P Guillard
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 6 et Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7095, Institut d'Astrophysique de Paris, 75014 Paris, France
| | - C L Carilli
- National Radio Astronomy Observatory, Socorro, NM 87801, USA.,Cavendish Laboratory, Cambridge CB3 0HE, UK
| | - M Y Mao
- Joint Institute for Very Long Baseline Interferometry, European Research Infrastructure Consortium, 7990 AA Dwingeloo, Netherlands.,Jodrell Bank Observatory, University of Manchester, Macclesfield, Cheshire SK11 9DL, UK
| | - H J A Röttgering
- Leiden Observatory, University of Leiden, 2300 RA Leiden, Netherlands
| | - C De Breuck
- European Southern Observatory, 85748 Garching, Germany
| | - N Seymour
- International Centre for Radio Astronomy Research, Curtin University, Perth, Australia
| | - B Gullberg
- Centre for Extragalactic Astronomy, Department of Physics, Durham University, Durham DH1 3LE, UK
| | - D Ceverino
- Centro de Astrobiología (Consejo Superior de Investigaciones Científicas-Instituto Nacional de Técnica Aerospacial), Carretera de Torrejón a Ajalvir, km 4, 28850 Torrejón de Ardoz, Madrid, Spain.,Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, 69120 Heidelberg, Germany
| | - P Jagannathan
- National Radio Astronomy Observatory, Socorro, NM 87801, USA
| | - J Vernet
- European Southern Observatory, 85748 Garching, Germany
| | - B T Indermuehle
- Commonwealth Scientific and Industrial Research Organisation, Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710, Australia
| |
Collapse
|
8
|
Tremblay GR, Oonk JBR, Combes F, Salomé P, O'Dea CP, Baum SA, Voit GM, Donahue M, McNamara BR, Davis TA, McDonald MA, Edge AC, Clarke TE, Galván-Madrid R, Bremer MN, Edwards LOV, Fabian AC, Hamer S, Li Y, Maury A, Russell HR, Quillen AC, Urry CM, Sanders JS, Wise MW. Cold, clumpy accretion onto an active supermassive black hole. Nature 2016; 534:218-21. [PMID: 27279215 DOI: 10.1038/nature17969] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/22/2016] [Indexed: 11/09/2022]
Abstract
Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds--a departure from the 'hot mode' accretion model--although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z = 0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities produce a rain of cold clouds that fall towards the galaxy's centre, sustaining star formation amid a kiloparsec-scale molecular nebula that is found at its core. The observations show that these cold clouds also fuel black hole accretion, revealing 'shadows' cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole, which serves as a bright backlight. Corroborating evidence from prior observations of warmer atomic gas at extremely high spatial resolution, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it.
Collapse
Affiliation(s)
- Grant R Tremblay
- Yale Center for Astronomy and Astrophysics, Yale University, 52 Hillhouse Avenue, New Haven, Connecticut 06511, USA.,European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
| | - J B Raymond Oonk
- ASTRON, Netherlands Institute for Radio Astronomy, PO Box 2, 7990 AA Dwingeloo, The Netherlands.,Leiden Observatory, Leiden University, Niels Borhweg 2, NL-2333 CA Leiden, The Netherlands
| | - Françoise Combes
- Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Observatoire de Paris, PSL Research University, College de France, CNRS, Sorbonne University, Paris, France
| | - Philippe Salomé
- Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Observatoire de Paris, PSL Research University, College de France, CNRS, Sorbonne University, Paris, France
| | - Christopher P O'Dea
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.,School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, New York 14623, USA
| | - Stefi A Baum
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.,Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, New York 14623, USA
| | - G Mark Voit
- Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824-2320, USA
| | - Megan Donahue
- Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824-2320, USA
| | - Brian R McNamara
- Physics and Astronomy Department, Waterloo University, 200 University Avenue West, Waterloo, Ontario N2L 2GL, Canada
| | - Timothy A Davis
- European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany.,School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK
| | - Michael A McDonald
- Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Alastair C Edge
- Department of Physics, Durham University, Durham DHL 3LE, UK
| | - Tracy E Clarke
- Naval Research Laboratory Remote Sensing Division, Code 7213, 4555 Overlook Avenue Southwest, Washington DC 20375, USA
| | - Roberto Galván-Madrid
- European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany.,Instituto de Radioastronomía y Astrofísica, UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán, Mexico
| | - Malcolm N Bremer
- H. W. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - Louise O V Edwards
- Yale Center for Astronomy and Astrophysics, Yale University, 52 Hillhouse Avenue, New Haven, Connecticut 06511, USA
| | - Andrew C Fabian
- Institute of Astronomy, Cambridge University, Madingly Road, Cambridge CB3 0HA, UK
| | - Stephen Hamer
- Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Observatoire de Paris, PSL Research University, College de France, CNRS, Sorbonne University, Paris, France
| | - Yuan Li
- Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, Michigan 48109, USA
| | - Anaëlle Maury
- Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu CNRS-Université Paris Diderot, CE-Saclay, F-91191 Gif-sur-Yvette, France
| | - Helen R Russell
- Institute of Astronomy, Cambridge University, Madingly Road, Cambridge CB3 0HA, UK
| | - Alice C Quillen
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - C Megan Urry
- Yale Center for Astronomy and Astrophysics, Yale University, 52 Hillhouse Avenue, New Haven, Connecticut 06511, USA
| | - Jeremy S Sanders
- Max-Planck-Institut für Extraterrestrische Physik, 85748 Garching bei München, Germany
| | - Michael W Wise
- ASTRON, Netherlands Institute for Radio Astronomy, PO Box 2, 7990 AA Dwingeloo, The Netherlands
| |
Collapse
|