J/MNRAS/392/1403 GMRT radios sources around J0916+6348 field (Sirothia+, 2009)
Deep low-frequency observations with the Giant Metrewave Radio Telescope:
a search for relic radio emission.
Sirothia S.K., Saikia D.J., Ishwara-Chandra C.H., Kantharia N.G.
<Mon. Not. R. Astron. Soc., 392, 1403-1412 (2009)>
=2009MNRAS.392.1403S 2009MNRAS.392.1403S
ADC_Keywords: Radio sources ; Galaxies, radio
Keywords: galaxies: active - galaxies: clusters: general -
radio continuum: galaxies
Abstract:
We present deep multifrequency observations using the Giant Metrewave
Radio Telescope (GMRT) at 153, 244, 610 and 1260MHz of a field
centred on J0916+6348, to search for evidence of fossil radio lobes
which could be due to an earlier cycle of episodic activity of the
parent galaxy, as well as haloes and relics in clusters of galaxies.
We do not find any unambiguous evidence of episodic activity in a list
of 374 sources, suggesting that such activity is rare even in
relatively deep low-frequency observations. We examine the spectra of
all the sources by combining our observations with those from the
Westerbork Northern Sky Survey (WENSS), NRAO (National Radio Astronomy
Observatories) VLA (Very Large Array) Sky Survey (NVSS) and the Faint
Images of the Radio Sky at Twenty-Centimeters Survey (FIRST).
Description:
Observations were made on 2005 December 12 at 153MHz, 2005 November 26
at 244MHz and 610MHz, and on 2008 April 22 at 1260MHz, on the Giant
Metrewave Radio Telescope (Pune, India).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 96 317 The steep-spectrum sources with a spectral index
steeper than 1.3
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [GMRT]
5- 17 A13 --- GMRT Source name (HHMMSS+DDMMSS) (1)
19- 20 I2 h RAh Right ascension (J2000)
22- 23 I2 min RAm Right ascension (J2000)
25- 28 F4.1 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 40 F4.1 arcsec DEs [0/60] Declination (J2000)
42- 45 F4.2 deg Dist Distance of the centroid of the source in the
150MHz image from the pointing centre
47- 52 F6.1 mJy S153 Total flux density at 153MHz
54- 59 F6.1 mJy S244 Total flux density at 224MHz
61- 66 F6.1 mJy S330 ?=- Total flux density at 330MHz
68- 73 F6.1 mJy S610 ?=- Total flux density at 610MHz
75- 78 F4.1 mJy S1260 ?=- Total flux density at 1260MHz
80- 85 F6.1 mJy S1400 ?=- Total flux density at 1400MHz
87- 91 F5.2 --- SI ?=- Spectral index from a linear least-squares
fit for which the spectrum could be
satisfactorily fitted with a straight spectrum
93- 96 A4 --- Cl Structural classification (2)
--------------------------------------------------------------------------------
Note (1): Sources identified as [SSI2009] JHHMMSS+DDMMSS in Simbad.
Note (2): Class as follows:
D = double-lobe source
E = diffuse extended emission without a clear double-lobed structure
S = single source
T = triple source with a possible core component
Cplx = complex source
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 18-Aug-2009