J/MNRAS/426/833 Faint reddened AGNs in VLA-FIRST (Varga+, 2012)
Revealing a strongly reddened, faint active galactic nucleus population by
stacking deep co-added images.
Varga J., Csabai I., Dobos L.
<Mon. Not. R. Astron. Soc., 426, 833-850 (2012)>
=2012MNRAS.426..833V 2012MNRAS.426..833V
ADC_Keywords: Active gal. nuclei ; Radio sources
Keywords: methods: data analysis - techniques: image processing -
galaxies: active - quasars: general - radio continuum: galaxies
Abstract:
More than half of the sources identified by recent radio sky surveys
have not been detected by wide-field optical surveys. We present a
study, based on our co-added image stacking technique, in which our
aim is to detect the optical emission from unresolved, isolated radio
sources of the Very Large Array (VLA) Faint Images of the Radio Sky at
Twenty-cm (FIRST) survey that have no identified optical counterparts
in the Sloan Digital Sky Survey (SDSS) Stripe 82 co-added data set.
From the FIRST catalogue, 2116 such radio point sources were selected,
and cut-out images, centred on the FIRST coordinates, were generated
from the Stripe 82 images. The already co-added cut-outs were stacked
once again to obtain images of high signal-to-noise ratio, in the hope
that optical emission from the radio sources would become detectable.
Multiple stacks were generated, based on the radio luminosity of the
point sources. The resulting stacked images show central peaks similar
to point sources. The peaks have very red colours with steep optical
spectral energy distributions.
Description:
For the present analysis, we use the 1400-MHz radio data from the VLA
FIRST survey (Becker et al., 1995ApJ...450..559B 1995ApJ...450..559B) and the u-, g-, r-,
i- and z-band optical images from the SDSS Stripe 82 co-added data set
(Abazajian et al., 2009ApJS..182..543A 2009ApJS..182..543A).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 35 2116 Deep co-add stack (DCS) sample: 2116 point sources
from the VLA FIRST
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See also:
VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)
J/A+A/416/35 : Radio Emission from VLA FIRST Survey AGN (Wadadekar, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.7 deg RAdeg Right ascension in decimal degrees (J2000)
13- 22 F10.7 deg DEdeg Declination in decimal degrees (J2000)
24- 29 F6.2 mJy Fint 1400MHz integrated flux density (VLA FIRST survey)
31- 35 F5.3 mJy rms rms at source position (in mJy/beam)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Apr-2013