2017A&A...598A..78I


Query : 2017A&A...598A..78I

2017A&A...598A..78I - Astronomy and Astrophysics, volume 598A, 78-78 (2017/2-1)

The GMRT 150 MHz all-sky radio survey First alternative data release TGSS ADR1.

INTEMA H.T., JAGANNATHAN P., MOOLEY K.P. and FRAIL D.A.

Abstract (from CDS):

We present the first full release of a survey of the 150 MHz radio sky, observed with the Giant Metrewave Radio Telescope (GMRT) between April 2010 and March 2012 as part of the TIFR GMRT Sky Survey (TGSS) project. Aimed at producing a reliable compact source survey, our automated data reduction pipeline efficiently processed more than 2000 h of observations with minimal human interaction. Through application of innovative techniques such as image-based flagging, direction-dependent calibration of ionospheric phase errors, correcting for systematic offsets in antenna pointing, and improving the primary beam model, we created good quality images for over 95 percent of the 5336 pointings. Our data release covers 36 900deg2 (or 3.6πsteradians) of the sky between -53° and +90° declination (Dec), which is 90 percent of the total sky. The majority of pointing images have a noise level below 5mJy/beam with an approximate resolution of 25''x25'' (or 25''x25''/cos(Dec-19°) for pointings south of 19° declination). We have produced a catalog of 0.62 Million radio sources derived from an initial, high reliability source extraction at the seven sigma level. For the bulk of the survey, the measured overall astrometric accuracy is better than two arcseconds in right ascension and declination, while the flux density accuracy is estimated at approximately ten percent. Within the scope of the TGSS alternative data release (TGSS ADR) project, the source catalog, as well as 5336 mosaic images (5°x5°) and an image cutout service, are made publicly available at the CDS as a service to the astronomical community. Next to enabling a wide range of different scientific investigations, we anticipate that these survey products will provide a solid reference for various new low-frequency radio aperture array telescopes (LOFAR, LWA, MWA, SKA-low), and can play an important role in characterizing the epoch-of-reionisation (EoR) foreground. The TGSS ADR project aims at continuously improving the quality of the survey data products. Near-future improvements include replacement of bright source snapshot images with archival targeted observations, using new observations to fill the holes in sky coverage and replace very poor quality observational data, and an improved flux calibration strategy for less severely affected observational data.

Abstract Copyright: © ESO, 2017

Journal keyword(s): surveys - catalogs - radio continuum: general - techniques: image processing

VizieR on-line data: <Available at CDS (J/A+A/598/A78): table3.dat>

Nomenclature: Table 3: TGSSADR JHHMMSS.s+DDMMSS N=623604.

Simbad objects: 17

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Number of rows : 17
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 3C 48 QSO 01 37 41.2995845985 +33 09 35.079126038   16.62 16.20     ~ 2618 2
2 NAME Per B AGN 04 37 04.37510272 +29 40 13.8184969   21.7       ~ 485 2
3 NAME Pic A Sy1 05 19 49.7230919028 -45 46 43.855209977   15.73 15.77 14.85   ~ 585 1
4 M 1 SNR 05 34 31.94 +22 00 52.2           ~ 5800 4
5 ICRF J054236.1+495107 Sy1 05 42 36.13789843 +49 51 07.2337251   18.45 17.80 17.210   ~ 1340 1
6 3C 196 Sy1 08 13 36.056090 +48 13 02.63597   18.36 17.79     ~ 496 2
7 NAME Hya A LIN 09 18 05.651 -12 05 43.99   14.38 14.8     ~ 943 1
8 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6497 3
9 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 4134 3
10 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825107   17.51 17.25     ~ 3931 2
11 3C 295 Sy2 14 11 20.467 +52 12 09.52   22.34 20.80 18.54   ~ 923 5
12 NAME Hercules A rG 16 51 08.024 +04 59 34.91     18.25     ~ 443 1
13 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3734 3
14 ICRF J182931.7+484446 Sy1 18 29 31.7812801678 +48 44 46.158815781   17.05 16.81 16.860   ~ 652 1
15 NAME Cyg A Sy2 19 59 28.35645829 +40 44 02.0966496   16.22 15.10     ~ 2192 2
16 NAME Cas A SNR 23 23 24.000 +58 48 54.00     14.30     ~ 2534 1
17 3C 468.1 G 23 50 54.80 +64 40 19.0           ~ 67 1

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2021.10.22-10:07:11

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