J/A+A/562/A64 Fermi detection of BL Lac objects (Wu+, 2014)
Why are some BL Lacertaes detected by Fermi, but others not?
Wu Z., Jiang D., Gu M., Chen L.
<Astron. Astrophys., 562, A64-64 (2014)>
=2014A&A...562A..64W 2014A&A...562A..64W
ADC_Keywords: BL Lac objects ; Radio sources ; Redshifts ; Gamma rays
Keywords: galaxies: active - BL Lacertae objects: general - galaxies: jets -
galaxies: nuclei
Abstract:
By cross-correlating an archival sample of 170 BL Lacs with a 2 year
Fermi/LAT AGN sample, we have compiled a sample of 100 BL Lacs with
Fermi detection (FBLs) and a sample of 70 non-Fermi BL Lacs (NFBLs).
We compared various parameters of FBLs with those of NFBLs, including
the redshift, the low-frequency radio luminosity at 408MHz
(L408MHz), the absolute magnitude of host galaxies (Mhost), the
polarization fraction from the NVSS survey (PNVSS), the observed
arcsecond scale radio core flux at 5GHz (Fcore), and the jet Doppler
factor. All these parameters are directly measured or derived from
available data in the literature. We found that the Doppler factor is
on average greater in FBLs than in NFBLs, and the Fermi γ-ray
detection rate is higher in sources with higher Doppler factor. In
contrast, there are no significant differences in terms of the
intrinsic parameters of redshift, L408MHz, Mhost, and PNVSS.
FBLs seem to have a higher probability of exhibiting measurable proper
motion.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 91 170 Sample of 170 BL Lac objects in Wu et al.
(2007, Cat. J/A+A/466/63)
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See also:
J/A+A/466/63 : VLBI observations of BL Lac objects (Wu+, 2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- IAU IAU source name (HHMM+DDd, J2000)
10- 25 A16 --- Source Source name
27- 31 F5.3 --- z [0.01/2.1] Redshift
32 A1 --- n_z [*] * for unknown redshift and taken as the
average redshift of LBL/IBL/HBL subclass
34- 38 F5.2 [Hz] log(nu) [11/21] Synchrotron peak frequency (1)
40- 44 F5.2 [W/Hz] logP [22/29] Total radio power at 408MHz (1)
46- 50 F5.3 Jy Fc Arcsecond scale radio flux at 5GHz Fcore (1)
52- 56 F5.2 --- delta [0.5/37.1] Doppler factor δ (1)
58- 62 F5.2 % Pol [0/12]?=- Polarization fraction from NVSS
64- 69 F6.2 mag Mhost ?=- Absolute magnitude of host galaxy (2)
71- 74 A4 --- Class Class: FBL (BL Lac with Fermi detection) or
NFBL (no Fermi detection)
76- 83 E8.2 mW/m2 Fgam ?=- Observed γ-ray flux from 2nd year
Fermi/LAT catalog [100MeV to 100GeV]
85- 89 F5.2 --- beta [0.5/26]?=- Proper motion from the literature
(Apparent parsec-scale speed of the fastest
jet feature (βapp)
91 I1 --- r_beta ? Reference for proper motion (3)
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Note (1): data first reported in Wu et al. (2007, Cat. J/A+A/466/63).
Note (2): first reported in Wu et al. (2009RAA.....9..168W 2009RAA.....9..168W) and these values
have been revised using redshift from Col. 3.
Note (3): References of proper motion as follows:
1 = Kharb et al. (2010, Cat. J/ApJ/710/764)
2 = Piner et al. (2012ApJ...758...84P 2012ApJ...758...84P)
3 = Gabuzda et al. (2000MNRAS.319.1109G 2000MNRAS.319.1109G)
4 = Jorstad et al. (2001ApJS..134..181J 2001ApJS..134..181J)
5 = Piner et al. (2006ApJ...640..196P 2006ApJ...640..196P)
6 = Kharb et al. (2008MNRAS.384..230K 2008MNRAS.384..230K)
7 = Wu et al. (2012MNRAS.424.2733W 2012MNRAS.424.2733W)
8 = Kellermann et al. (2004, Cat. J/ApJ/609/539)
9 = Lister et al. (2009ApJ...696L..22L 2009ApJ...696L..22L)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 04-Apr-2014