Abstract
We report on observations of the CO (2->1) transition of a complete
subset of 11/39 of the Piccinotti (1982ApJ...253..485P) hard X-ray
selected AGN sample. All of the 11 galaxies were clearly detected. All
the galaxies in our sample are strong hard-X ray sources and thus the
sample is unbiased with respect to obscuring material. Six of the
galaxies are Seyfert 1 type objects with the rest five being reddened
Seyfert 1s, or the so called ``Narrow Line Galaxies''. Based on our high
S/N detections we investigate the relation between CO and far-infrared
luminosities. A strong correlation is found to exist for both Seyfert 1s
and Narrow Line Galaxies similar to the one seen in normal and bright
infrared galaxies. Our data also suggest that the FIR emission in
Seyferts galaxies is of thermal origin, an argument which is supported
by three different lines of evidence, the CO-FIR correlation, the
FIR/M(H_2_) dependence on dust temperature and the similarities in the
shapes of the CO and HI profiles. The relation between CO emission and
non-thermal radio power was examined next. Seyferts were found to show
an excess radio non-thermal power for a given CO luminosity (when
compared to starburst galaxies) while no differences were found between
Seyfert 1s and 2s in their CO and radio properties (Seyfert 2s were
selected from the literature). We conclude that Seyfert 1s and Narrow
Line Galaxies have very similar properties with respect to their
molecular gas reservoir. By comparing our CO observations with published
optical data we explore the distribution of the molecular clouds in the
sample galaxies. We find that in most cases the spatial distribution of
CO clouds is confined within 1-1.4kpc around the nucleus.
| Original language | English |
|---|---|
| Pages (from-to) | 493-502 |
| Journal | Astronomy & Astrophysics |
| Volume | 327 |
| Publication status | Published - 1 Nov 1997 |
Keywords / Materials (for Non-textual outputs)
- GALAXIES: ACTIVE
- ISM: MOLECULES
- GALAXIES: SEYFERTS