Abstract
To advance our understanding of the fuelling and feedback processes
which power the Universe's most massive black holes, we require a
significant increase in our knowledge of the molecular gas which exists
in their immediate surroundings. However, the behaviour of this gas is
poorly understood due to the difficulties associated with observing it
directly. We report on a survey of 18 brightest cluster galaxies lying
in cool cores, from which we detect molecular gas in the core regions of
eight via carbon monoxide (CO), cyanide (CN) and silicon monoxide (SiO)
absorption lines. These absorption lines are produced by cold molecular
gas clouds which lie along the line of sight to the bright continuum
sources at the galaxy centres. As such, they can be used to determine
many properties of the molecular gas which may go on to fuel
supermassive black hole accretion and AGN feedback mechanisms. The
absorption regions detected have velocities ranging from -45 to 283 km
s-1 relative to the systemic velocity of the galaxy, and have
a bias for motion towards the host supermassive black hole. We find that
the CN N = 0 - 1 absorption lines are typically 10 times stronger than
those of CO J = 0 - 1. This is due to the higher electric dipole moment
of the CN molecule, which enhances its absorption strength. In terms of
molecular number density CO remains the more prevalent molecule with a
ratio of CO/CN ˜10, similar to that of nearby galaxies. Comparison
of CO, CN and H I observations for these systems shows many different
combinations of these absorption lines being detected.
Original language | English |
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Article number | stz2138 |
Pages (from-to) | 349-365 |
Number of pages | 17 |
Journal | Monthly Notices of the Royal Astronomical Society, Advance Access |
Volume | 489 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2 Aug 2019 |
Keywords
- galaxies: active
- galaxies: ISM
- galaxies: clusters: general
- radio continuum: galaxies
- radio lines: ISM