164 research outputs found
Detection of extended millimeter emission in the host galaxy of 3C273 and its implications for QSO feedback via high dynamic range ALMA imaging
We estimate the amount of negative feedback energy injected into the ISM of
the host galaxy of 3C273, a prototypical radio loud quasar. We obtained 93, 233
and 343 GHz continuum images with the Atacama Large Millimeter/Sub-millimeter
Array (ALMA). After self calibration and point source subtraction, we reach an
image dynamic range of at 93\ GHz, at 233\ GHz and
at 343\ GHz. These are currently the highest image dynamic range
obtained using ALMA. We detect spatially extended millimeter emission
associated with the host galaxy, cospatial with the Extended Emission Line
Region (EELR) observed in the optical. The millimeter spectral energy
distribution and comparison with centimeter data show that the extended
emission cannot be explained by dust thermal emission, synchrotron or thermal
bremsstrahlung arising from massive star formation. We interpret the extended
millimeter emission as thermal bremsstrahlung from gas directly ionized by the
central source. The extended flux indicates that at least of the
bolometric flux of the nuclear source was used to ionize atomic hydrogen in the
host galaxy. The ionized gas is estimated to be as massive as to
, but the molecular gas fraction with respect to the
stellar mass is consistent with other ellipticals, suggesting that direct
ionization ISM by the QSO may not be sufficient to suppress star formation, or
we are witnessing a short timescale before negative feedback becomes
observable. The discovery of a radio counterpart to EELRs provides a new
pathway to studying the QSO-host ISM interaction
The Complete Infrared View of Active Galactic Nuclei from the 70-month Swift/BAT Catalog
We systematically investigate the near- (NIR) to far-infrared (FIR)
photometric properties of a nearly complete sample of local active galactic
nuclei (AGN) detected in the Swift/Burst Alert Telescope (BAT) all-sky ultra
hard X-ray (14-195 keV) survey. Out of 606 non-blazar AGN in the Swift/BAT
70-month catalog at high galactic latitude of , we obtain IR
photometric data of 604 objects by cross-matching the AGN positions with
catalogs from the WISE, AKARI, IRAS, and Herschel infrared observatories. We
find a good correlation between the ultra-hard X-ray and mid-IR (MIR)
luminosities over five orders of magnitude (). Informed by previous measures of the intrinsic
spectral energy distribution of AGN, we find FIR pure-AGN candidates whose FIR
emission is thought to be AGN-dominated with low starformation activity. We
demonstrate that the dust covering factor decreases with the bolometric AGN
luminosity, confirming the luminosity-dependent unified scheme. We also show
that the completeness of the WISE color-color cut in selecting Swift/BAT AGN
increases strongly with 14-195 keV luminosity.Comment: 24 pages, 11 figures, accepted for publication in ApJ. The full list
of Table 1 is available at
http://www.kusastro.kyoto-u.ac.jp/~ichikawa/table1_MRT.tx
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