Abstract
Active galactic nuclei play a crucial role in the accretion and ejection of gas in galaxies. Although their outflows are well studied, finding direct evidence of accretion has proved very difficult and has so far been done for very few sources. A promising way to study the significance of cold accretion is by observing the absorption of an active galactic nucleus's extremely bright radio emission by the cold gas lying along the line of sight. As such, we present ALMA CO(1-0) and CO(2-1) observations of the Hydra-A brightest cluster galaxy (z = 0.054) which reveal the existence of cold, molecular gas clouds along the line of sight to the galaxy's extremely bright and compact mm-continuum source. They have apparent motions relative to the central supermassive black hole of between-43 and-4 km s-1 and are most likely moving along stable, low ellipticity orbits. The identified clouds form part of a ∼109 M⊙, approximately edge-on disc of cold molecular gas. With peak CO(2-1) optical depths of τ = 0.88 +0.06-0.06, they include the narrowest and by far the deepest absorption of this type which has been observed to date in a brightest cluster galaxy.
| Original language | English |
|---|---|
| Pages (from-to) | 229-238 |
| Number of pages | 10 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 485 |
| Issue number | 1 |
| DOIs | |
| State | Published - May 1 2019 |
Bibliographical note
Publisher Copyright:© 2019 Oxford University Press. All rights reserved.
Funding
The work of SB and CO was supported by NSERC (Natural Sciences and Engineering Research Council of Canada). This work used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by BIS National E-infrastructure capital grant ST/K00042X/1, STFC capital grant ST/H008519/1, and STFC DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure. MG is supported by the National Aeronautics and Space Administration (NASA) through Einstein Postdoctoral Fellowship Award Number PF5-160137 issued by the Chandra X-ray Observatory Center, which is operated by the SAO for and on behalf of NASA under contract NAS8-03060. Support for this work was also provided by Chandra grant GO7-18121X. TR is supported by the Science and Technology Facilities Council (STFC) through grant ST/R504725/1. ACE acknowledges support from STFC grant ST/P00541/1. GRT acknowledges support from the National Aeronautics and Space Administration (NASA) through Chandra Award Number GO7-8128X8, issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060.
| Funders | Funder number |
|---|---|
| European Commission | |
| Natural Sciences and Engineering Research Council of Canada | |
| Durham University | |
| UK Industrial Decarbonization Research and Innovation Centre | |
| Science and Technology Facilities Council | ST/R001049/1, ST/R00689X/1, ST/M007618/1, ST/M007073/1, ST/M007065/1, ST/R504725/1, ST/R002371/1, ST/P002293/1, ST/M007006/1, ST/R001006/1, ST/R000832/1, ST/K003267/1, ST/R001014/1, ST/M006948/1, ST/H008519/1, ST/P00541/1, ST/T001372/1, ST/I00162X/1 |
| Seventh Framework Programme | 340442 |
| National Aeronautics and Space Administration | GO7-18121X, GO7-8128X8, PF5-160137, NAS8-03060 |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | 1816537 |
| BIS National E-infrastructure capital | ST/K00042X/1 |
Keywords
- galaxies: ISM
- galaxies: clusters: individual: Hydra-A
- radio lines: galaxies
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science