J/MNRAS/414/1397 Radio study of double-double radio galaxy 3C293 (Joshi+, 2011)
A radio study of the double-double radio galaxy 3C293.
Joshi S.A., Nandi S., Saikia D.J., Ishwara-Chandra C.H., Konar C.
<Mon. Not. R. Astron. Soc., 414, 1397-1404 (2011)>
=2011MNRAS.414.1397J 2011MNRAS.414.1397J
ADC_Keywords: Galaxies, radio ; Radio continuum
Keywords: galaxies: active - galaxies: individual: 3C 293 - galaxies: nuclei -
radio continuum: galaxies
Abstract:
We present radio continuum observations at frequencies ranging from
∼150 to 5000MHz of the misaligned double-double radio galaxy
(DDRG) 3C 293 (J1352+3126) using the Giant Metrewave Radio Telescope
(GMRT) and the Very Large Array (VLA). The spectra of the outer lobes
and the central source are consistent with being straight, indicating
spectral ages of ≲17-23Myr for the outer lobes and ≲0.1Myr for
the central source. The north-western lobe has a prominent hotspot
suggesting that the interruption of jet activity is ≲0.1Myr,
consistent with the age of the inner double. The time-scale of
interruption of jet activity appears significantly smaller than
observed in most other DDRGs which are often associated with giant
radio sources. These observations suggest that there is a wide range
of time-scales of interruption of jet activity in active galaxies.
Description:
The analysis presented in this paper is based on radio observations
made with the GMRT and on the VLA archival data.
All sources with a peak flux density ≥7σ, where σ is the
primary beam corrected local rms noise in units of mJy/beam are
listed in tablea1.dat. The values of σ range from 8.6mJy/beam
near 3C293 to typical values of 3-4mJy/beam in regions without strong
sources. There are a total of 320 sources. All but three of the weaker
sources (J1352+3059, J1352+3039 and J1357+3111) are seen in the NVSS
images at 1400MHz. Using 5 times the rms noise in the NVSS images
yields spectral indices steeper than ∼1.2 for these three sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 46 320 Sources within 2.2° of the phase centre of
the GMRT observations at 154MHz (HPBW∼3.1°)
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See also:
J/MNRAS/395/269 : ELAIS-N1 field 325MHz observations (Sirothia+, 2009)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 23 F4.1 arcsec DEs Declination (J2000)
25- 31 F7.1 mJy Speak Peak flux density at 154MHz (in mJy/beam) (1)
33- 39 F7.1 mJy Sint Integrated flux density at 154MHz (1)
41- 45 F5.1 arcsec Size ? Angular size of the source (1)
46 A1 --- u_Size [U] U for unresolved source
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Note (1): The flux densities and source sizes have been estimated as
described in Sirothia et al. (2009, Cat. J/MNRAS/395/269).
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Nomenclature note:
Sources identified as [JNS2011] JHHMMSS.ss+DDMMSS.s in Simbad
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Feb-2012