105 research outputs found
Far-infrared and accretion luminosities of the present-day active galactic nuclei
We investigate the relation between star formation (SF) and black hole
accretion luminosities, using a sample of 492 type-2 active galactic nuclei
(AGNs) at z < 0.22, which are detected in the far-infrared (FIR) surveys with
AKARI and Herschel. We adopt FIR luminosities at 90 and 100 um as SF
luminosities, assuming the proposed linear proportionality of star formation
rate with FIR luminosities. By estimating AGN luminosities from [OIII]5007 and
[OI]6300 emission lines, we find a positive linear trend between FIR and AGN
luminosities over a wide dynamical range. This result appears to be
inconsistent with the recent reports that low-luminosity AGNs show essentially
no correlation between FIR and X-ray luminosities, while the discrepancy is
likely due to the Malmquist and sample selection biases. By analyzing the
spectral energy distribution, we find that pure-AGN candidates, of which FIR
radiation is thought to be AGN-dominated, show significantly low-SF activities.
These AGNs hosted by low-SF galaxies are rare in our sample (~ 1%). However,
the low fraction of low-SF AGN is possibly due to observational limitations
since the recent FIR surveys are insufficient to examine the population of
high-luminosity AGNs hosted by low-SF galaxies.Comment: Accepted for publication in ApJ, 13 pages, 9 figure
A delay analogue of the box and ball system arising from the ultra-discretization of the delay discrete Lotka-Volterra equation
A delay analogue of the box and ball system (BBS) is presented. This new
soliton cellular automaton is constructed by the ultra-discretization of the
delay discrete Lotka-Volterra equation, which is an integrable delay analogue
of the discrete Lotka-Volterra equation. This delay BBS requires multiple time
initial states for time evolution, thus it has various types of soliton
patterns. Soliton patterns generated by the delay BBS are classified into
normal solitons and abnormal solitons. Normal solitons can be discussed
analytically, while abnormal solitons show various phenomena which are not
explained easily. Finally, we show that the delay BBS is equivalent to the BBS
with K kinds of balls if we consider only normal solitons
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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