16 research outputs found
Evidence of galaxy interaction in the Narrow-line Seyfert 1 galaxy IRAS17020+4544 seen by NOEMA
The narrow-line Seyfert 1 galaxy IRAS17020+4544 is one of the few sources
where both an X-ray ultra-fast outflow and a molecular outflow were observed to
be consistent with energy conservation. However, IRAS17020+4544 is less massive
and has a much more modest active galactic nucleus (AGN) luminosity than the
other examples. Using recent CO(1-0) observations with the NOrthern Extended
Millimeter Array (NOEMA), we characterised the molecular gas content of the
host galaxy for the first time. We found that the molecular gas is distributed
into an apparent central disc of 1.1x10^9 Msun, and a northern extension
located up to 8 kpc from the centre with a molecular gas mass M_H2~10^8 Msun.
The molecular gas mass and the CO dynamics in the northern extension reveal
that IRAS 17020+4544 is not a standard spiral galaxy, instead it is interacting
with a dwarf object corresponding to the northern extension. This interaction
possibly triggers the high accretion rate onto the super massive black hole.
Within the main galaxy, which hosts the AGN, a simple analytical model predicts
that the molecular gas may lie in a ring, with less molecular gas in the
nuclear region. Such distribution may be the result of the AGN activity which
removes or photodissociates the molecular gas in the nuclear region (AGN
feedback). Finally, we have detected a molecular outflow of mass
M_H2=(0.7-1.2)x10^7 Msun in projection at the location of the northern galaxy,
with a similar velocity to that of the massive outflow reported in previous
millimeter data obtained by the Large Millimeter Telescope.Comment: Published in MNRAS, Volume 501, Issue 1, Pages 219-22
The host galaxies of active galactic nuclei with powerful relativistic jets
We present deep near-infrared (NIR) images of a sample of 19 intermediate-redshift (0.3 1027 W Hz-1), previously classified as flat-spectrum radio quasars. We also compile host galaxy and nuclear magnitudes for blazars from literature. The combined sample (this work and compilation) contains 100 radio-loud AGN with host galaxy detections and a broad range of radio luminosities L1.4 GHz ~ 1023.7-1028.3 W Hz-1, allowing us to divide our sample into high-luminosity blazars (HLBs) and low-luminosity blazars (LLBs). The host galaxies of our sample are bright and seem to follow the μe-Reff relation for ellipticals and bulges. The two populations of blazars show different behaviours in the MK,nuclear -MK,bulge plane, where a statistically significant correlation is observed for HLBs. Although it may be affected by selection effects, this correlation suggests a close coupling between the accretion mode of the central supermassive black hole and its host galaxy, which could be interpreted in terms of AGN feedback. Our findings are consistent with semi-analytical models where low-luminosity AGN emit the bulk of their energy in the form of radio jets, producing a strong feedback mechanism, and high-luminosity AGN are affected by galaxy mergers and interactions, which provide a common supply of cold gas to feed both nuclear activity and star formation episodes.Peer reviewe
The host galaxies of AGN with powerful relativistic jets
<p>We present deep Near-infrared (NIR) images of a sample of 19 intermediate-redshift (0.310^27 WHz^-1), previously classified as flat-spectrum radio quasars. We also compile host galaxy and nuclear magnitudes for blazars from literature. The combined sample (this work and compilation) contains 100 radio-loud AGN with host galaxy detections and a broad range of radio luminosities L1.4GHz = 10^23.7 - 10^28.3WHz^-1, allowing us to divide our sample into high-excitation (quasar-mode; HERGs) and low-excitation (radio-mode; LERGs) radio galaxies. The host galaxies of our sample are bright and seem to follow the Kormendy relation. Nuclear emission (dominated by non-thermal mechanisms) and host-galaxy magnitudes show a slightly negative weak trend for LERGs. On the other hand, the m_bulge -m_nuc relation is statistically significant for HERGs. Although it may be affected by selection effects, this correlation suggests a close coupling between the relativistic jets and their host galaxy. Our findings are consistent with the excitation state (LERG/HERG) scenario. In this view, LERGs emit the bulk of their energy in the form of radio jets, producing a strong feedback mechanism, and HERGs are affected by galaxy mergers and interactions, which provide a common supply of cold gas to feed both nuclear activity and star formation episodes.</p