2021A&A...648A...2S


Query : 2021A&A...648A...2S

2021A&A...648A...2S - Astronomy and Astrophysics, volume 648A, 2-2 (2021/4-1)

The LOFAR Two-meter Sky Survey: Deep Fields Data Release 1. II. The ELAIS-N1 LOFAR deep field.

SABATER J., BEST P.N., TASSE C., HARDCASTLE M.J., SHIMWELL T.W., NISBET D., JELIC V., CALLINGHAM J.R., ROTTGERING H.J.A., BONATO M., BONDI M., CIARDI B., COCHRANE R.K., JARVIS M.J., KONDAPALLY R., KOOPMANS L.V.E., O'SULLIVAN S.P., PRANDONI I., SCHWARZ D.J., SMITH D.J.B., WANG L., WILLIAMS W.L. and ZAROUBI S.

Abstract (from CDS):

The LOFAR Two-metre Sky Survey (LoTSS) will cover the full northern sky and, additionally, aims to observe the LoTSS deep fields to a noise level of ≤10µJy/beam over several tens of square degrees in areas that have the most extensive ancillary data. This paper presents the ELAIS-N1 deep field, the deepest of the LoTSS deep fields to date. With an effective observing time of 163.7h, it reaches a root mean square noise level of ≤20µJy/beam in the central region (and below 30µJy/beam over 10 square degrees). The resolution is ∼6 arcsecs and 84862 radio sources were detected in the full area (68 square degrees) with 74127 sources in the highest quality area at less than 3 degrees from the pointing centre. The observation reaches a sky density of more than 5000 sources per square degree in the central region (∼5 square degrees). We present the calibration procedure, which addresses the special configuration of some observations and the extended bandwidth covered (115-177MHz; central frequency 146.2MHz) compared to standard LoTSS. We also describe the methods used to calibrate the flux density scale using cross-matching with sources detected by other radio surveys in the literature. We find the flux density uncertainty related to the flux density scale to be ∼6.5 per cent. By studying the variations of the flux density measurements between different epochs, we show that relative flux density calibration is reliable out to about a 3 degree radius, but that additional flux density uncertainty is present for all sources at about the 3 per cent level; this is likely to be associated with residual calibration errors, and is shown to be more significant in datasets with poorer ionosphere conditions. We also provide intra-band spectral indices, which can be useful to detect sources with unusual spectral properties. The final uncertainty in the flux densities is estimated to be ∼10 per cent for ELAIS-N1.

Abstract Copyright: © ESO 2021

Journal keyword(s): surveys - catalogs - radio continuum: general - radio continuum: galaxies

VizieR on-line data: <Available at CDS (J/A+A/648/A2): catalog.dat>

Status at CDS : Tables of objects will be appraised for possible ingestion in SIMBAD.

Simbad objects: 14

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Number of rows : 14
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 M 1 SNR 05 34 32 +22 00.8           ~ 5920 1
2 NAME Hya A LIN 09 18 05.6783347248 -12 05 43.634531472   14.38 14.8     ~ 959 1
3 NAME Lockman Hole reg 10 45 00.0 +58 00 00           ~ 791 0
4 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6671 3
5 3C 295 Sy2 14 11 20.467 +52 12 09.52   22.34 20.80 18.54   ~ 947 5
6 NAME NOAO Deep Wide Field reg 14 32 05.75 +34 16 47.5           ~ 361 0
7 PSR J1552+5437 Psr 15 52 53.33117 +54 37 05.7866           ~ 14 0
8 NVSS J160434+572801 Rad 16 04 34.3 +57 28 01           ~ 5 1
9 ELAIS N1 reg 16 10 01 +54 30.6           ~ 363 0
10 BD+55 1823 SB* 16 17 05.3518858129 +55 16 08.771396846 12.00 10.92 9.46 9.552 8.55 M1.5Ve 191 0
11 NAME Hercules A rG 16 51 07.9886687784 +04 59 35.547131472     18.25     ~ 447 1
12 ICRF J182931.7+484446 Sy1 18 29 31.7809732968 +48 44 46.160168892   17.05 16.81 16.860   ~ 658 1
13 NAME Cyg A Sy2 19 59 28.35645829 +40 44 02.0966496   16.22 15.10     ~ 2241 2
14 NAME Cas A SNR 23 23 24.000 +58 48 54.00     14.30     ~ 2601 1

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2022.06.30-22:18:57

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