TY - JOUR
T1 - A molecular absorption line survey toward the AGN of Hydra-A
AU - Rose, Tom
AU - Edge, A. C.
AU - Combes, F.
AU - Hamer, S.
AU - McNamara, B. R.
AU - Russell, H.
AU - Gaspari, M.
AU - Salomé, P.
AU - Sarazin, C.
AU - Tremblay, G. R.
AU - Baum, S. A.
AU - Bremer, M. N.
AU - Donahue, M.
AU - Fabian, A. C.
AU - Ferland, G.
AU - Nesvadba, N.
AU - O'Dea, C.
AU - Oonk, J. B. R.
AU - Peck, A. B.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - We present Atacama Large Millimeter/submillimeter Array observations of
the brightest cluster galaxy Hydra-A, a nearby (z = 0.054) giant
elliptical galaxy with powerful and extended radio jets. The
observations reveal CO(1-0), CO(2-1), 13CO(2-1), CN(2-1),
SiO(5-4), HCO+(1-0), HCO+(2-1), HCN(1-0),
HCN(2-1), HNC(1-0) and H2CO(3-2) absorption lines against the
galaxy's bright and compact active galactic nucleus. These absorption
features are due to at least 12 individual molecular clouds which lie
close to the centre of the galaxy and have velocities of approximately
-50 to +10 km s-1 relative to its recession velocity, where
positive values correspond to inward motion. The absorption profiles are
evidence of a clumpy interstellar medium within brightest cluster
galaxies composed of clouds with similar column densities, velocity
dispersions and excitation temperatures to those found at radii of
several kpc in the Milky Way. We also show potential variation in a
∼10 km s-1 wide section of the absorption profile over a
two year timescale, most likely caused by relativistic motions in the
hot spots of the continuum source which change the background
illumination of the absorbing clouds.
AB - We present Atacama Large Millimeter/submillimeter Array observations of
the brightest cluster galaxy Hydra-A, a nearby (z = 0.054) giant
elliptical galaxy with powerful and extended radio jets. The
observations reveal CO(1-0), CO(2-1), 13CO(2-1), CN(2-1),
SiO(5-4), HCO+(1-0), HCO+(2-1), HCN(1-0),
HCN(2-1), HNC(1-0) and H2CO(3-2) absorption lines against the
galaxy's bright and compact active galactic nucleus. These absorption
features are due to at least 12 individual molecular clouds which lie
close to the centre of the galaxy and have velocities of approximately
-50 to +10 km s-1 relative to its recession velocity, where
positive values correspond to inward motion. The absorption profiles are
evidence of a clumpy interstellar medium within brightest cluster
galaxies composed of clouds with similar column densities, velocity
dispersions and excitation temperatures to those found at radii of
several kpc in the Milky Way. We also show potential variation in a
∼10 km s-1 wide section of the absorption profile over a
two year timescale, most likely caused by relativistic motions in the
hot spots of the continuum source which change the background
illumination of the absorbing clouds.
KW - galaxies: clusters: individual: Hydra-A
KW - galaxies: clusters: general
KW - radio continuum: galaxies
KW - radio lines: interstellar medium
U2 - 10.1093/mnras/staa1474
DO - 10.1093/mnras/staa1474
M3 - Article (Academic Journal)
VL - 496
SP - 364
EP - 380
JO - Monthly Notices of the Royal Astronomical Society, Advance Access
JF - Monthly Notices of the Royal Astronomical Society, Advance Access
IS - 1
ER -