201 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
Fluctuating Non-linear Non-equilibrium System in Terms of Nambu Thermodynamics
It is shown that the structure of non-equilibrium thermodynamic system far
from equilibrium can be captured in terms of a generalized "Nambu dynamics", in
the presence of fluctuation effects in non-equilibrium thermodynamics. As
concrete examples, chemical reaction systems with time oscillation, such as the
Belousov-Zhabotinsky reaction (BZ reaction), are examined. The quantization of
Nambu brackets arises naturally, which is expected to have applications in
other regions such as fluid mechanics and string theory.Comment: 13 pages, 8 figure
The Mean Absorption Line Spectra of a Selection of Luminous z~6 Lyman Break Galaxies
We examine the absorption line spectra of a sample of 31 luminous (M_UV=-23)
Lyman break galaxies at redshift z~6 using data taken with the FOCAS and OSIRIS
spectrographs on the Subaru and GTC telescopes. For two of these sources we
present longer exposure data taken at higher spectral resolution from ESO's
X-shooter spectrograph. Using these data, we demonstrate the practicality of
stacking our lower resolution data to measure the depth of various interstellar
and stellar absorption lines to probe the covering fraction of low ionization
gas and the gas-phase and stellar metallicities near the end of the era of
cosmic reionization. From maximum absorption line depths of SiII1260 and
CII1334, we infer a mean covering fraction of >0.85+/-0.16 for our sample. This
is larger than that determined using similar methods for lower luminosity
galaxies at slightly lower redshifts, suggesting that the most luminous
galaxies appear to have a lower escape fraction than fainter galaxies, and
therefore may not play a prominent role in concluding reionization. Using
various interstellar absorption lines we deduce gas-phase metallicities close
to solar indicative of substantial early enrichment. Using selected stellar
absorption lines, we model our spectra with a range of metallicities using
techniques successfully employed at lower redshift and deduce a stellar
metallicity of 0.4 +0.3/-0.1 solar, consistent with the stellar mass - stellar
metallicity relation recently found at z~3-5. We discuss the implications of
these metallicity estimates for the typical ages of our luminous galaxies and
conclude our results imply initial star formation at redshifts z~10, consistent
with independent analyses of earlier objects.Comment: 13 pages, 10 figures, 3 tables, Accepted for Publication in Ap
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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