J/ApJ/744/177 VLBA 5GHz observations of Fermi/LAT AGNs (Linford+, 2012)
Contemporaneous VLBA 5 GHz observations of Large Area Telescope detected
blazars.
Linford J.D., Taylor G.B., Romani R.W., Helmboldt J.F., Readhead A.C.S.,
Reeves R., Richards J.L.
<Astrophys. J., 744, 177 (2012)>
=2012ApJ...744..177L 2012ApJ...744..177L
ADC_Keywords: Active gal. nuclei ; BL Lac objects ; QSOs ; Radio continuum ;
Gamma rays ; Redshifts
Keywords: galaxies: active - galaxies: jets - galaxies: nuclei -
gamma rays: galaxies - radio continuum: galaxies
Abstract:
The radio properties of blazars detected by the Large Area Telescope
(LAT) on board the Fermi Gamma-ray Space Telescope have been observed
contemporaneously by the Very Long Baseline Array (VLBA). In total,
232 sources were observed with the VLBA. Ninety sources that were
previously observed as part of the VLBA Imaging and Polarimetry Survey
(VIPS) have been included in the sample, as well as 142 sources not
found in VIPS. This very large, 5GHz flux-limited sample of active
galactic nuclei (AGNs) provides insights into the mechanism that
produces strong γ-ray emission. In particular, we see that
γ-ray emission is related to strong, uniform magnetic fields in
the cores of the host AGN. Included in this sample are non-blazar AGNs
such as 3C84, M82, and NGC 6251. For the blazars, the total VLBA radio
flux density at 5GHz correlates strongly with γ-ray flux. The
LAT BL Lac objects tend to be similar to the non-LAT BL Lac objects,
but the LAT flat-spectrum radio quasars (FSRQs) are significantly
different from the non-LAT FSRQs. Strong core polarization is
significantly more common among the LAT sources, and core fractional
polarization appears to increase during LAT detection.
Description:
We obtained time on the VLBA to observe Fermi/LAT-detected sources
from 2009 November to 2010 July. We had a total of seven observing
runs and collected 5GHz data on 232 sources. The first three observing
runs were follow-up observations on 90 sources in the VLBA Imaging and
Polarimetry Survey (VIPS; Helmboldt et al. 2007, Cat. J/ApJ/658/203)
and new 5GHz observations of 7 sources in the MOJAVE sample (Lister et
al. 2009, Cat. J/AJ/137/3718). The remaining 135 sources were selected
from the Fermi 1FGL as sources which were associated with a source in
the Combined Radio All-Sky Targeted Eight GHz Survey (CRATES; Healey
et al. 2007, Cat. J/ApJS/171/61) with high (≥80%) probability, had a
flux density of at least 30mJy in CRATES, and were not in VIPS or
MOJAVE. Of the 232 sources, 95 are BL Lac objects, 107 are FSRQs, and
30 are other types of active galactic nuclei (AGNs; radio galaxies,
AGN of unknown type, and 1 starburst galaxy).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 135 232 Source data
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See also:
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/A+A/535/A69 : AGN Fermi/LAT γ-ray and 37GHz fluxes (Nieppola+, 2011)
J/ApJ/741/30 : Radio/γ-ray correlation in AGN (Ackermann+, 2011)
J/ApJ/742/27 : 15GHz and jet properties of MOJAVE blazars (Lister+, 2011)
J/ApJ/722/L7 : Fermi/LAT detected MOJAVE AGNs (Pushkarev+, 2010)
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/718/587 : The Fermi-AT20G catalog (Mahony+, 2010)
J/AJ/137/3718 : 15GHz monitoring of AGN jets with VLBA (Lister+, 2009)
J/ApJ/658/203 : VLBA imaging and polarimetry survey at 5GHz (Helmboldt+, 2007)
J/ApJS/171/61 : All-Sky Survey of Flat-Spectrum Radio Sources (Healey+, 2007)
http://www.physics.purdue.edu/astro/MOJAVE/ : the MOJAVE home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Radio source name ([J/F]HHMMm+DDMM) (1)
12 A1 --- f_Name [c] c: MOJAVE source (2)
14- 17 A4 --- --- [1FGL]
19- 30 A12 --- 1FGL 1FGL name (JHHMM.m+DDMM)
31 A1 --- f_1FGL [a] multiple associated radio sources (3)
33- 49 A17 --- OName Alternative name
51- 52 I2 h RAh Hour of right ascension (J2000)
54- 55 I2 min RAm Minute of right ascension (J2000)
57- 63 F7.4 s RAs Second of right ascension (J2000)
65 A1 --- DE- Sign of declination (J2000)
66- 67 I2 deg DEd Degree of declination (J2000)
69- 70 I2 arcmin DEm Arcminute of declination (J2000)
72- 77 F6.3 arcsec DEs Arcsecond of declination (J2000)
79- 81 A3 --- Otype Optical object type (4)
83- 86 A4 --- Class Automated source classification (5)
88- 95 F8.6 --- z [0.0006/3.04]? Redshift from 1LAC
(Cat. J/ApJ/715/429), unless flagged
96 A1 --- f_z [b] b: redshift obtained from NED
98-104 F7.1 mJy S5 [14/16200] Total VLBA flux density at 5GHz
106-112 F7.2 10-5ph/m2/s Flux [9/1356] Fermi/LAT γ-ray flux
for 100MeV to 100GeV
114-118 F5.2 10-5ph/m2/s e_Flux [3/35]?=0 Flux uncertainty
120-127 E8.3 K TB [4.7e+08/2.4e+12] Core brightness
temperature (6)
129-130 I2 deg Ang [1/81]? Opening angle
132-135 I4 deg dPA ? Change in jet position angle (ΔPA)
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Note (1): If name starts with "J" it is a VIPS (Helmboldt et al. 2007,
Cat. J/ApJ/658/203) or MOJAVE source;
if name starts with "F" it is a new source.
Note (2): For more data, visit the MOJAVE Web site:
http://www.physics.purdue.edu/astro/MOJAVE/MOJAVEIItable.html or see
Lister et al. (2009, Cat. J/AJ/137/3718).
Note (3):
a = A LAT source which is associated with multiple radio sources with high
(≥80%) probability in 1LAC, Cat. J/ApJ/715/429.
Note (4): Optical type, from 1LAC; Abdo et al. 2010, Cat. J/ApJ/715/429,
as follows:
bzb = BL Lac object;
bzq = FSRQ (flat-spectrum radio quasar);
agn = non-blazar AGN;
agu = AGN of uncertain type;
sbg = starburst galaxy
Note (5): Automated source classification as follows:
LJET = long jet;
SJET = short jet;
PS = point source;
CPLX = complex.
Note (6): Core brightness temperature as measured by automated program
(Helmboldt et al. 2007, Cat. J/ApJ/658/203).
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 21-Jun-2013