J/A+A/482/247 Radio detections of 3G sources (Paredes+, 2008)
Radio detections towards unidentified variable EGRET sources.
Paredes J.M., Marti J., Ishwara-Chandra C.H., Torres D.F., Romero G.E.,
Combi J.A., Bosch-Ramon V., Munoz-Arjonilla A.J., Sanchez-Sutil J.R.
<Astron. Astrophys. 482, 247 (2008)>
=2008A&A...482..247P 2008A&A...482..247P
ADC_Keywords: Gamma rays ; Radio sources ; Morphology
Keywords: radio continuum: stars - gamma rays: observations - X-rays: binaries
Abstract:
A considerable fraction of the gamma-ray sources discovered with
the Energetic Gamma-Ray Experiment Telescope (EGRET) remain
unidentified. The EGRET sources that have been properly identified are
either pulsars or variable sources at both radio and gamma-ray
wavelengths. Most of the variable sources are strong radio blazars.
However, some low galactic-latitude EGRET sources, with highly
variable gamma-ray emission, lack any evident counterpart according
to the radio data available until now.
The primary goal of this paper is to identify and characterise the
potential radio counterparts of four highly variable gamma-ray
sources in the galactic plane through mapping the radio surroundings
of the EGRET confidence contours and determining the variable radio
sources in the field whenever possible.
We have carried out a radio exploration of the fields of the selected
EGRET sources using the Giant Metrewave Radio Telescope (GMRT)
interferometer at 21 cm wavelength, with pointings being separated by
months.
Description:
This table contains information about all radio sources detected with
the Giant Metrewave Radio Telescope (GMRT) of the National Centre for
Radio Astrophysics (NCRA) in Khodad (India) towards unidentified
variable EGRET sources. The observations were carried out at 1.4 GHz
(21 cm wavelength) during February 23 and April 19, 2005. The observed
fields, each about one square deg, were those corresponding to the
EGRET sources 3EG J1735-1500, 3EG J1746-1001, 3EG J1810-1032 and
3EG J1904-1124.
Values given were determined by fitting sources with elliptical
Gaussians. Uncertainties first quoted for the peak and integrated flux
density are based on the formal errors of the fit and allow the
reliability of the detection to be judged. However, they do not
contain the error contribution due to primary beam correction as a
function of angular distance to the phase centre. An estimate of the
combined error, including primary beam correction, is separately
given. A variability index has been also computed but no value is
shown when an unrealiable result is suspected (see paper for details).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 115 151 List of GMRT sources detected
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See also:
J/ApJS/123/79 : Third EGRET catalog (3EG) (Hartman+, 1999)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name GMRT source name
18- 19 A2 --- Flag Flag (1)
21- 22 I2 h RAh Right ascension (J2000)
24- 25 I2 min RAm Right ascension (J2000)
27- 32 F6.3 s RAs Right ascension (J2000)
34- 38 F5.3 s e_RAs Error in right ascension
40 A1 --- DE- Declination sign (J2000)
41- 42 I2 deg DEd Declination (J2000)
44- 45 I2 arcmin DEm Declination (J2000)
47- 51 F5.2 arcsec DEs Declination (J2000)
53- 56 F4.2 arcsec e_DEs Error in declination
58- 62 F5.1 mJy Speak Peak flux density at 21cm (in mJy/beam)
64- 66 F3.1 mJy e_Speak Error in peak flux density (in mJy/beam)
69- 73 F5.1 mJy Sint Integrated flux density at 21cm
75- 77 F3.1 mJy e_Sint Error in integrated flux density
79- 83 F5.2 arcsec a Apparent angular size (major axis)
85- 88 F4.2 arcsec b Apparent angular size (minor axis)
90- 94 F5.1 deg PA Position angle of major axis
96- 99 F4.1 arcmin Theta Angular distance to phase centre
101-105 F5.1 mJy ceSpeak Combined error in peak flux density
(in mJy/beam)
107-111 F5.1 mJy ceSint Combined error in integrated flux density
113-115 F3.1 --- Var ? Variability index (2)
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Note (1): Flag as follows:
D = Component of an apparent double source (separation less than 45")
MD = Marginally resolved double source
T = Component of an apparent triple source
V = Candidate variable radio source
* = Extended component of a radio galaxy western lobe
Note (2): No value given when an unreliable result is suspected.
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Acknowledgements:
Josep Marti Ribas, jmarti(at)ujaen.es
(End) Patricia Vannier [CDS] 05-Mar-2008