J/MNRAS/500/22 New constraints on the 1.4GHz source counts (Bonato+, 2021)
New constraints on the 1.4 GHz source number counts and luminosity functions in
the Lockman Hole field.
Bonato M., Prandoni I., De Zotti G., Brienza M., Morganti R., Vaccari M.
<Mon. Not. R. Astron. Soc., 500, 22-33 (2021)>
=2021MNRAS.500...22B 2021MNRAS.500...22B (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Galaxies ; Millimetric/submm sources ;
Radio sources ; Redshifts
Keywords: galaxies: abundances - galaxies: active - galaxies: photometry -
submillimetre: galaxies
Abstract:
We present a study of the 1173 sources brighter than
S1.4GHz=120µJy detected over an area of ∼1.4deg2 in the Lockman
Hole field. Exploiting the multiband information available in this
field for ∼79 per cent of the sample, sources have been classified
into radio loud (RL) active galactic nuclei (AGNs), star-forming
galaxies (SFGs), and radio quiet (RQ) AGNs, using a variety of
diagnostics available in the literature. Exploiting the observed tight
anticorrelations between IRAC band 1 or band 2 and the source redshift
we could assign a redshift to 177 sources missing a spectroscopic
measurement or a reliable photometric estimate. A Monte Carlo approach
was used to take into account the spread around the mean relation. The
derived differential number counts and luminosity functions at several
redshifts of each population show a good consistency with models and
with earlier estimates made using data from different surveys and
applying different approaches. Our results confirm that below
∼300µJy SFGs+RQ AGNs overtake RL AGNs that dominate at brighter
flux densities. We also confirm earlier indications of a similar
evolution of RQ AGNs and SFGs. Finally, we discuss the angular
correlation function of our sources and highlight its sensitivity to
the criteria used for the classification.
Description:
The sample we use is extracted from the full catalogue of radio
sources published in Prandoni et al. (2018MNRAS.481.4548P 2018MNRAS.481.4548P, Cat.
J/MNRAS/481/4548). The sub-region of interest covers ∼1.4deg2 at the
centre of the 1.4GHz WSRT mosaic. This region is characterized by
lowest, roughly uniform rms noise (∼11µJy/b) and is completely
covered by the mentioned SERVS Data Fusion and by the UKIDSS-DXS deep
K-band mosaic (Lawrence et al. 2007MNRAS.379.1599L 2007MNRAS.379.1599L, Cat. II/314),
which were extensively used for the source identification and
classification processes. As described in Prandoni et al.
(2018MNRAS.481.4548P 2018MNRAS.481.4548P, Cat. J/MNRAS/481/4548), only sources brighter
than S≥120µJy (i.e. with S/N≥10σ) were considered.
By taking advantage of the available optical/IR images, we further
refined this number by inspecting radio/optical/IR overlays. After
discarding obvious random pairs the number of confirmed multiple
sources decreased to 76 (in comparison with 183 sources in Prandoni
et al.), 15 of which are located in the region of interest.
Correspondingly, the number of single-component sources with
S>120µJy in this region increased to 1158 so, in total, we have
1173 sources, 921 (908 single and 13 multiple) of which have an IRAC
counterpart within 1.75arcsec.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 63 1173 Source catalogue
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See also:
J/MNRAS/481/4548 : New constraints on the 1.4GHz source counts
(Prandoni+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Source name (LHWJHHMMSS+DDMMSS)
19- 26 F8.4 deg RAdeg Right ascension (J2000)
28- 34 F7.4 deg DEdeg Declination (J2000)
36- 41 A6 --- Class Source classification (1)
43- 45 I3 % Classrel Classification reliability (2)
47- 50 F4.2 --- z ? Redshift
52- 57 F6.2 mJy S1.4 1.4GHz flux density (3)
59- 63 F5.3 mJy sigma Local rms noise value
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Note (1): Classification as follows:
RL AGN = radio-loud active galactic nucleus (473/1173)
RQ AGN = radio-quiet active galactic nucleus (127/1173)
SFG = star-forming galaxy (307/1173)
x = unclassified source (266/1173)
Note (2): For IRAC identified sources lacking a reliable redshift determination
we give the reliability of the classification defined as the
percentage of simulations described in Section 2.1 yielding such
classification
Note (3): In the case of extended sources, S1.4GHz is the flux density
measured by summing all the pixels above a 3σ threshold (see
Prandoni et al. 2018MNRAS.481.4548P 2018MNRAS.481.4548P, Cat. J/MNRAS/481/4548 for
details)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 14-Sep-2023