2018MNRAS.475.5041S

Query : 2018MNRAS.475.5041S

2018MNRAS.475.5041S - Mon. Not. R. Astron. Soc., 475, 5041-5058 (2018/April-3)

A search for faint high-redshift radio galaxy candidates at 150 MHz.

SAXENA A., JAGANNATHAN P., ROTTGERING H.J.A., BEST P.N., INTEMA H.T., ZHANG M., DUNCAN K.J., CARILLI C.L. and MILEY G.K.

Abstract (from CDS):

Ultrasteep spectrum (USS) radio sources are good tracers of powerful radio galaxies at z > 2. Identification of even a single bright radio galaxy at z > 6 can be used to detect redshifted 21 cm absorption due to neutral hydrogen in the intervening intergalactic medium. Here we describe a new sample of high-redshift radio galaxy (HzRG) candidates constructed from the TIFR GMRT Sky Survey First Alternative Data Release survey at 150 MHz. We employ USS selection (α <= -1.3) in ∼10 000 deg2, in combination with strict size selection and non-detections in all-sky optical and infrared surveys. We apply flux density cuts that probe a unique parameter space in flux density (50 mJy < S150 < 200 mJy) to build a sample of 32 HzRG candidates. Follow-up Karl G. Jansky Very Large Array (VLA) observations at 1.4 GHz with an average beam size of 1.3 arcsec revealed ∼ 48 per cent of sources to have a single radio component. P-band (370 MHz) imaging of 17 of these sources revealed a flattening radio SED for 10 sources at low frequencies, which is expected from compact HzRGs. Two of our sources lie in fields where deeper multiwavelength photometry and ancillary radio data are available and for one of these we find a best-fitting photo-z of 4.8 ± 2.0. The other source has zphot = 1.4 ± 0.1 and a small angular size (3.7 arcsec), which could be associated with an obscured star-forming galaxy or with a 'dead' elliptical. One USS radio source not part of the HzRG sample but observed with the VLA none the less is revealed to be a candidate giant radio galaxy with a host galaxy photo-z of 1.8 ± 0.5, indicating a size of 875 kpc.

Abstract Copyright: © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: high-redshift - galaxies: jets - radio continuum: galaxies

Nomenclature: Table A.1: [SJR2018] USSNNNA N=51.

Simbad objects: 65

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Number of rows : 65
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 FIRST J004828.4+115144 Rad 00 48 28.60 +11 51 43.9           ~ 1 0
2 FIRST J070318.6+515202 Rad 07 03 18.608 +51 52 02.12           ~ 1 0
3 FIRST J070319.0+515155 rG 07 03 19.086 +51 51 55.39           ~ 2 0
4 [SJR2018] USS182B Rad 07 16 22.30 +37 03 39.6           ~ 1 0
5 NVSS J071622+370338 rG 07 16 22.588 +37 03 37.72           ~ 2 0
6 [SJR2018] USS182A Rad 07 16 22.60 +37 03 36.0           ~ 1 0
7 NVSS J071737+592248 Rad 07 17 37.584 +59 22 52.12           ~ 3 1
8 FIRST J071738.2+592245 Rad 07 17 37.90 +59 22 44.4           ~ 1 0
9 [SJR2018] USS188B Rad 07 30 36.50 +48 11 02.4           ~ 1 0
10 NVSS J073036+481106 rG 07 30 36.625 +48 11 04.71           ~ 4 1
11 [SJR2018] USS188A Rad 07 30 36.70 +48 11 06.0           ~ 1 0
12 [SJR2018] USS309A Rad 07 57 51.60 +61 16 19.2           ~ 1 0
13 [SJR2018] USS309B Rad 07 57 51.60 +61 16 26.4           ~ 1 0
14 FIRST J075751.7+611624 Rad 07 57 51.713 +61 16 24.54           ~ 1 0
15 NVSS J080850+382604 Rad 08 08 49.90 +38 26 02.4           ~ 1 0
16 NVSS J081103+511444 Rad 08 11 03.226 +51 14 42.64           ~ 2 1
17 [CCH85] 0854+1809 Rad 08 57 46.861 +17 57 57.45           ~ 3 1
18 NVSS J095635+270821 Rad 09 56 35.30 +27 08 24.0           ~ 1 0
19 [SJR2018] USS483B Rad 09 59 45.80 +52 09 03.6           ~ 1 0
20 [SJR2018] USS483A Rad 09 59 46.10 +52 09 07.2           ~ 1 0
21 NVSS J095945+520905 rG 09 59 46.184 +52 09 07.71           ~ 3 1
22 FIRST J101813.4+111745 rG 10 18 13.40 +11 17 45.6           ~ 2 0
23 NAME Lockman Hole reg 10 45 00.0 +58 00 00           ~ 910 0
24 NVSS J105428+583223 Rad 10 54 29.533 +58 32 26.83           ~ 3 1
25 NVSS J110638+545022 rG 11 06 38.827 +54 50 20.16           ~ 4 1
26 [SJR2018] USS172B Rad 11 10 54.20 +61 01 58.8           ~ 1 0
27 FIRST J111055.4+610202 rG 11 10 54.238 +61 02 00.10           ~ 3 1
28 [SJR2018] USS172A Rad 11 10 55.40 +61 02 02.4           ~ 1 0
29 NVSS J113517+465904 Rad 11 35 17.618 +46 59 05.55           ~ 3 1
30 [SJR2018] USS253A Rad 11 40 06.20 +46 44 49.2           ~ 1 0
31 NVSS J114006+464452 Rad 11 40 06.224 +46 44 49.57           ~ 2 1
32 [SJR2018] USS253B Rad 11 40 06.70 +46 44 52.8           ~ 1 0
33 [SJR2018] USS253C Rad 11 40 06.70 +46 44 56.4           ~ 1 0
34 FIRST J122043.9+611907 Rad 12 20 43.90 +61 19 04.8           ~ 1 0
35 [SJR2018] USS439C Rad 12 41 58.60 +20 40 12.0           ~ 1 0
36 [SJR2018] USS439B Rad 12 41 58.80 +20 40 08.4           ~ 1 0
37 FIRST J124158.9+204009 Rad 12 41 58.998 +20 40 09.15           ~ 1 0
38 [SJR2018] USS439A Rad 12 41 59.00 +20 40 08.4           ~ 1 0
39 FIRST J131206.0+452257 rG 13 12 06.00 +45 22 55.2           ~ 2 0
40 [SJR2018] USS67A Rad 13 28 01.20 +20 28 51.6           ~ 1 0
41 FIRST J132801.6+202901 Rad 13 28 01.687 +20 29 01.14           ~ 1 0
42 [SJR2018] USS67B Rad 13 28 01.70 +20 28 58.8           ~ 1 0
43 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4558 2
44 NVSS J133911+203351 Rad 13 39 11.80 +20 33 50.4           ~ 1 0
45 [SJR2018] USS415A Rad 13 50 45.40 +22 17 16.8           ~ 1 0
46 [SJR2018] USS415B Rad 13 50 45.80 +22 17 13.2           ~ 1 0
47 FIRST J135045.8+221713 Rad 13 50 45.880 +22 17 13.67           ~ 1 0
48 [SJR2018] USS320B Rad 14 51 54.20 +40 06 54.0           ~ 1 0
49 [SJR2018] USS320A Rad 14 51 54.50 +40 06 57.6           ~ 1 0
50 NVSS J145154+400657 rG 14 51 54.573 +40 06 56.36           ~ 2 0
51 FIRST J153049.8+104931 QSO 15 30 49.885 +10 49 31.14           ~ 12 1
52 NVSS J153813+134153 rG 15 38 13.406 +13 41 53.09           ~ 3 1
53 FIRST J160819.1+123950 Rad 16 08 19.149 +12 39 50.42           ~ 1 0
54 [SJR2018] USS51A Rad 16 08 19.20 +12 39 50.4           ~ 1 0
55 [SJR2018] USS51B Rad 16 08 19.20 +12 39 54.0           ~ 1 0
56 ELAIS N1 reg 16 10 01 +54 30.6           ~ 489 0
57 FIRST J161026.1+103937 rG 16 10 26.1401572464 +10 39 37.206420552           ~ 6 0
58 [SJR2018] USS450A Rad 16 10 26.60 +10 39 21.6           ~ 1 0
59 [SJR2018] USS7A Rad 16 15 38.90 +53 27 25.2           ~ 1 0
60 [SJR2018] USS7B Rad 16 15 39.10 +53 27 28.8           ~ 1 0
61 NVSS J161539+532726 rG 16 15 39.110 +53 27 27.66           ~ 2 0
62 NVSS J161908+631247 Rad 16 19 08.310 +63 12 48.46           ~ 3 1
63 FIRST J162521.8+254648 Rad 16 25 21.80 +25 46 48.0           ~ 1 0
64 FIRST J163542.9+195826 Rad 16 35 42.940 +19 58 26.32           ~ 1 0
65 FIRST J163543.2+195833 rG 16 35 43.247 +19 58 33.84           ~ 2 0

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