2001A&A...369..787P

Query : 2001A&A...369..787P

2001A&A...369..787P - Astronomy and Astrophysics, volume 369787-796 (2001/4-3)

The ATESP radio survey. IV. Optical identifications and spectroscopy in the EIS-A region.

PRANDONI I., GREGORINI L., PARMA P., DE RUITER H.R., VETTOLANI G., ZANICHELLI A., WIERINGA M.H. and EKERS R.D.

Abstract (from CDS):

This paper is the fourth in a series reporting the results of the ATESP radio survey, which was made at 1.4GHz with the Australia Telescope Compact Array. The survey consists of 16 radio mosaics with ∼8"x14" resolution and uniform sensitivity (1 σ noise level ∼79µJy) over the region covered by the ESO Slice Project redshift survey (∼26deg2 at δ~-40°). The ATESP survey has produced a catalogue of 2967 radio sources down to a flux limit of ∼0.5mJy (6 σ). In this paper we present the optical identifications over a 3 sq deg region coinciding with the Patch A of the public ESO Imaging Survey (EIS). In this region deep photometry and 95% complete object catalogues in the I band are available down to I∼22.5. These data allowed us to identify 219 of the 386 ATESP sources present in the region. This corresponds to an identification rate of ∼57%. For a magnitude-limited sample of 70 optically identified sources with I<19.0 we have obtained complete and good quality spectroscopic data at the ESO 3.6m telescope at La Silla. This data allowed us to determine redshift measurements and reliable spectroscopic classification for all sources (except one). From the analysis of the spectroscopic sample we find that the composition of the faint radio source population abruptly changes going from mJy to sub-mJy fluxes: the early-type galaxies largely dominate the mJy population (60%), while star forming processes become important in the sub-mJy regime. Starburst and post-starburst galaxies go from 13% at S≥1mJy to 39% at S<1mJy. Nevertheless, at sub-mJy fluxes, early-ype galaxies still constitute a significant fraction (25%) of the whole population. Furthermore we show that, due to the distribution of radio-to-optical ratios, sub-mJy samples with fainter spectroscopic follow-ups should be increasingly sensitive to the population of early-type galaxies, while a larger fraction of star-forming galaxies would be expected in µJy samples. We compare our results with others obtained from studies of sub-mJy samples and we show how the existing discrepancies can be explained in terms of selection effects.

Abstract Copyright: ∼

Journal keyword(s): surveys - radio continuum: galaxies - galaxies: evolution

Simbad objects: 73

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Number of rows : 73
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME Phoenix Deep Field reg 01 14 -45.7           ~ 27 0
2 NGC 3310 AGN 10 38 45.85707 +53 30 11.8940   12.45 12.15     ~ 809 1
3 NAME Hubble Deep Field reg 12 36 49.5 +62 12 58           ~ 1967 1
4 ATESP J223503-394900 Rad 22 35 03.43 -39 49 00.2           ~ 2 0
5 ATESP J223542-402627 Rad 22 35 42.18 -40 26 27.8           ~ 2 0
6 LEDA 596390 rG 22 35 59.6075177448 -39 35 33.285176268   17.55   15.99 15.29 ~ 8 0
7 ATESP J223601-393705 rG 22 36 01.5031868808 -39 37 05.648008344         17.87 ~ 4 0
8 ATESP J223602-401923 Rad 22 36 02.37 -40 19 23.1           ~ 2 0
9 ATESP J223603-400420 Rad 22 36 03.65 -40 04 20.5           ~ 2 0
10 ATESP J223606-402609 Rad 22 36 06.94 -40 26 09.5           ~ 2 0
11 NVSS J223620-401713 Rad 22 36 20.8 -40 17 15           ~ 3 1
12 ATESP J223634-402740 Rad 22 36 34.58 -40 27 40.4           ~ 2 0
13 ATESP J223636-400444 Rad 22 36 36.47 -40 04 44.3           ~ 2 0
14 ATESP J223656-402554 rG 22 36 56.682 -40 25 54.94         17.58 ~ 3 0
15 NVSS J223704-393145 Rad 22 37 03.79 -39 31 43.3           ~ 3 1
16 LEDA 2793880 Sy2 22 37 33.0306778917 -40 21 43.191458718           ~ 6 0
17 ATESP J223747-393612 Rad 22 37 47.44 -39 36 12.4           ~ 2 0
18 2MASX J22381274-3940195 BLL 22 38 12.7517517456 -39 40 19.100695224     18.70     ~ 21 1
19 NVSS J223845-395340 Rad 22 38 45.8 -39 53 43           ~ 3 1
20 ATESP J223848-393345 Rad 22 38 48.74 -39 33 45.6           ~ 2 0
21 ATESP J223916-394125 Rad 22 39 16.86 -39 41 25.9           ~ 2 0
22 ATESP J224011-393753 Rad 22 40 11.76 -39 37 53.0           ~ 2 0
23 ATESP J224019-394558 Rad 22 40 19.40 -39 45 58.6           ~ 2 0
24 ATESP J224106-400400 Rad 22 41 06.14 -40 04 00.3           ~ 2 0
25 ATESP J224115-394817 Rad 22 41 15.39 -39 48 17.9           ~ 2 0
26 ATESP J224120-394844 Rad 22 41 20.24 -39 48 44.0           ~ 2 0
27 ATESP J224139-394150 Rad 22 41 39.16 -39 41 50.2           ~ 2 0
28 ATESP J224139-394857 Sy2 22 41 39.50 -39 48 57.3           ~ 4 0
29 ATESP J224147-394855 Rad 22 41 47.04 -39 48 55.9           ~ 2 0
30 ATESP J224151-400634 rG 22 41 51.416 -40 06 35.22     21.27   18.69 ~ 3 0
31 ATESP J224157-402505 Rad 22 41 57.59 -40 25 05.0           ~ 2 0
32 NVSS J224227-395624 Rad 22 42 27.2 -39 56 24           ~ 3 1
33 ATESP J224240-400625 Rad 22 42 40.15 -40 06 25.9           ~ 2 0
34 ATESP J224247-395539 Rad 22 42 47.07 -39 55 39.0           ~ 2 0
35 ATESP J224311-393751 Rad 22 43 11.73 -39 37 51.9           ~ 2 0
36 NVSS J224314-400255 Rad 22 43 14.3 -40 02 55           ~ 3 1
37 ATESP J224322-400839 rG 22 43 22.375 -40 08 40.92     18.63   17.61 ~ 3 0
38 ATESP J224325-395519 rG 22 43 25.078 -39 55 20.59         18.23 ~ 3 0
39 ATESP J224327-395904 Rad 22 43 27.84 -39 59 04.1           ~ 2 0
40 ATESP J224342-400759 Rad 22 43 42.64 -40 07 59.2           ~ 2 0
41 ATESP J224417-394307 Rad 22 44 17.66 -39 43 07.3           ~ 2 0
42 ATESP J224422-393846 Rad 22 44 22.65 -39 38 46.3           ~ 2 0
43 ATESP J224426-401916 rG 22 44 26.733 -40 19 16.86     18.84   17.40 ~ 3 0
44 ATESP J224448-394635 Rad 22 44 48.05 -39 46 35.8           ~ 2 0
45 ATESP J224507-394702 Rad 22 45 07.98 -39 47 02.3           ~ 2 0
46 ATESP J224512-395254 Rad 22 45 12.70 -39 52 54.2           ~ 2 0
47 2MASX J22451346-4000517 Rad 22 45 13.4693574720 -40 00 51.911146224           ~ 2 0
48 ATESP J224523-393440 Rad 22 45 23.86 -39 34 40.1           ~ 2 0
49 NVSS J224548-400323 Rad 22 45 47.8650550584 -40 03 24.277852908           ~ 4 1
50 ATESP J224557-393557 Rad 22 45 57.11 -39 35 57.1           ~ 2 0
51 ATESP J224612-395312 Rad 22 46 12.68 -39 53 12.8           ~ 2 0
52 ATESP J224628-401207 Rad 22 46 28.51 -40 12 07.1           ~ 2 0
53 ATESP J224639-393324 Rad 22 46 39.69 -39 33 24.4           ~ 2 0
54 ATESP J224640-401710 Rad 22 46 40.96 -40 17 10.8           ~ 2 0
55 ATESP J224654-400108 Rad 22 46 54.03 -40 01 08.7           ~ 3 0
56 NVSS J224720-394113 Rad 22 47 20.9 -39 41 15           ~ 3 1
57 ATESP J224729-402001 Rad 22 47 29.47 -40 20 01.6           ~ 2 0
58 NVSS J224750-400142 Rad 22 47 50.7 -40 01 44           ~ 4 1
59 ATESP J224758-394046 Rad 22 47 58.31 -39 40 46.4           ~ 2 0
60 [VV2006] J224803.0-400513 QSO 22 48 03.0598036296 -40 05 12.900795288     18.04     ~ 5 0
61 ATESP J224811-395642 Rad 22 48 11.86 -39 56 42.2           ~ 2 0
62 IRAS F22453-4013 G 22 48 21.39407 -39 57 04.4780           ~ 6 0
63 ATESP J224829-394805 Rad 22 48 29.52 -39 48 05.4           ~ 2 0
64 ATESP J224906-394246 Rad 22 49 06.23 -39 42 46.6           ~ 2 0
65 ATESP J224911-400859 Rad 22 49 11.52 -40 08 59.2           ~ 3 0
66 ATESP J224913-394651 Rad 22 49 13.79 -39 46 51.0           ~ 2 0
67 ATESP J224941-395146 Rad 22 49 41.57 -39 51 46.4           ~ 2 0
68 ATESP J224958-395855 Rad 22 49 58.32 -39 58 55.9           ~ 4 0
69 ATESP J225008-400425 Rad 22 50 08.87 -40 04 25.1           ~ 3 0
70 ATESP J225010-395033 Rad 22 50 10.48 -39 50 33.1           ~ 2 0
71 ATESP J225027-394448 Rad 22 50 27.01 -39 44 48.1           ~ 2 0
72 ATESP J225029-400332 Rad 22 50 29.09 -40 03 32.9           ~ 2 0
73 ATESP J225033-394646 Rad 22 50 33.48 -39 46 46.5           ~ 2 0

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