J/ApJ/742/66 New Fermi/LAT extragalactic sources (Teng+, 2011)
Fermi/LAT observations of Swift/BAT Seyfert galaxies: on the contribution of
radio-quiet active galactic nuclei to the extragalactic γ-ray background.
Teng S.H., Mushotzky R.F., Sambruna R.M., Davis D.S., Reynolds C.S.
<Astrophys. J., 742, 66 (2011)>
=2011ApJ...742...66T 2011ApJ...742...66T
ADC_Keywords: Active gal. nuclei ; Gamma rays ; Galaxies, Seyfert ; QSOs ;
Cross identifications ; Surveys
Keywords: galaxies: active - galaxies: Seyfert - X-rays: galaxies -
gamma rays: diffuse background - X-rays: diffuse background
Abstract:
We present the analysis of 2.1 years of Fermi Large Area Telescope
(LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert
Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and
NGC 4945, which were identified in the Fermi first year catalog (Abdo
et al. 2010, Cat. J/ApJ/715/429), are detected. Using Swift/BAT and
radio 20cm fluxes, we define a new radio-loudness parameter RX,BAT
where radio-loud objects have logRX,BAT> -4.7. Based on this
parameter, only radio-loud sources are detected by Fermi/LAT. An upper
limit to the flux of the undetected sources is derived to be
∼2x10-11photons/cm2/s, approximately seven times lower than the
observed flux of NGC 1068. Assuming a median redshift of 0.031, this
implies an upper limit to the γ-ray (1-100GeV) luminosity of
≲3x1041erg/s. In addition, we identified 120 new Fermi/LAT sources
near the Swift/BAT Seyfert galaxies with significant Fermi/LAT
detections. A majority of these objects do not have Swift/BAT
counterparts, but their possible optical counterparts include blazars,
flat-spectrum radio quasars, and quasars.
Description:
From the individual fits, we have identified 120 new extragalactic
Fermi/LAT sources with significant detections (σ>4) in the
fields of the Swift/BAT sample (Table 2). These sources were not
included in the PSC (11 month Fermi/LAT Point Source Catalog,
Cat. J/ApJ/715/429). The optical counterparts of these objects were
identified as objects within 10' of the nominal Fermi/LAT positions.
When objects have multiple counterparts within the error circle, the
one with a radio counterpart and the brightest is selected. Only 17
of these have Swift/BAT counterparts; all but one have Swift/BAT
detection thresholds below σ<4 (a selection criterion for the
58 month Swift/BAT catalog, Baumgartner et al. 2010HEAD...11.1305B 2010HEAD...11.1305B).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 105 104 Fermi/LAT sources without Swift/BAT counterpart
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See also:
J/ApJ/726/16 : γ-ray loud blazars (Linford+, 2011)
J/ApJ/715/429 : First Fermi-LAT AGN catalog (1LAC) (Abdo+, 2010)
J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010)
J/ApJ/699/603 : Evolution of Swift/BAT blazars (Ajello+, 2009)
J/A+A/495/691 : Multifrequency cat. of blazars, Roma-BZCAT (Massaro+, 2009)
J/ApJS/175/97 : CGRaBS: γ-ray blazar candidates (Healey+, 2008)
http://fermi.gsfc.nasa.gov/ : Fermi Gamma-ray telescope home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 F8.4 deg RAdeg Right ascension in decimal degrees (J2000)
10- 17 F8.4 deg DEdeg Declination in decimal degrees (J2000)
19- 22 F4.1 --- Sign [4/19.4] Fermi/LAT detection significance
24- 48 A25 --- OID Most likely optical counterpart within 10' of
the nominal position (1)
50- 53 F4.1 arcmin Sep [0.6/10] Separation between Fermi/LAT position
and optical counterpart
55- 57 F3.1 --- BAT? [0.2/6.3]? Approximate detection significance
of the Fermi/LAT source by Swift/BAT (2)
59-105 A47 --- Comm Comments about the nature of the optical
counterpart to the Fermi/LAT source (3)
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Note (1): CGRaBS J1121+3620 is very likely a misprint for CGRaBS J1127+3620;
corrected at CDS.
Note (2): Approximate detection significance of the Fermi/LAT source by
Swift/BAT within the Swift/BAT position error of 4'.
Note (3): Abbreviations used:
FSRQ = Flat-Spectrum Radio Quasar
BAL = Broad Absoprtion Lines
GRB = Gamma-Ray Burst
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 22-Apr-2013