J/A+A/621/A19 ATESP 5 GHz radio survey. IV. (Ricci+, 2019)
The ATESP 5 GHz radio survey.
IV. 19, 38, and 94 GHz observations and radio spectral energy distributions.
Ricci R., Prandoni I., De Ruiter H.R., Parma P.
<Astron. Astrophys. 621, A19 (2019)>
=2019A&A...621A..19R 2019A&A...621A..19R (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Radio sources
Keywords: radio continuum: general - Galaxy: evolution - surveys - catalogs
Abstract:
It is now established that the faint radio population is a mixture of
star-forming galaxies and faint active galactic nuclei (AGNs), with
the former dominating below S1.4GHz∼100uJy and the latter at larger
flux densities. The faint radio AGN component can itself be separated
into two main classes, mainly based on the host-galaxy properties:
sources associated with red/early-type galaxies (like radio galaxies)
are the dominant class down to ∼100uJy; quasar/Seyfert-like sources
contribute an additional 10-20%. One of the major open questions
regarding faint radio AGNs is the physical process responsible for
their radio emission. This work aims at investigating this issue, with
particular respect to the AGN component associated with red/early-type
galaxies. Such AGNs show, on average, flatter radio spectra than radio
galaxies and are mostly compact (≤30kpc in size). Various scenarios
have been proposed to explain their radio emission. For instance they
could be core/core-jet dominated radio galaxies, low-power BL LACs, or
advection dominated accretion flow (ADAF) systems.
We used the Australia Telescope Compact Array (ATCA) to extend a
previous follow-up multi-frequency campaign to 38 and 94GHz. This
campaign focuses on a sample of 28 faint radio sources associated with
early-type galaxies extracted from the ATESP 5GHz survey. Such data,
together with those already at hand, are used to perform radio
spectral and variability analyses. Both analyses can help us to
disentangle between core- and jet-dominated sources, as well as to
verify the presence of ADAF/ADAF+jet systems. Additional
high-resolution observations at 38GHz were carried out to
characterise the radio morphology of these sources on kiloparsec
scales.
Most of the sources (25/28) were detected at 38GHz, while only one
(ATESP5J224547-400324) of the twelve sources observed at 94 GHz was
detected. From the analysis of the radio spectra we confirmed our
previous findings that pure ADAF models can be ruled out. Only eight
out of the 28 sources were detected in the 38-GHz high-resolution (0.6
arcsec) radio images and of those eight only one showed a tentative
core-jet structure. Putting together spectral, variability,
luminosity, and linear size information we conclude that different
kinds of sources compose our AGN sample: (a) luminous and large
(≥100kpc) classical radio galaxies (∼18% of the sample); (b) compact
(confined within their host galaxies), low-luminosity, power-law
(jet-dominated) sources (∼46% of the sample); and (c) compact, flat
(or peaked) spectrum, presumably core-dominated, radio sources (∼36%
of the sample). Variability is indeed preferentially associated with
the latter.
Description:
(ATESP) survey for a complete sub-sample of Optical/IR Multi-band
selected early-type radio galaxies are displayed in the ASCII table.
The original survey data at 1.4 and 5GHz were published in Prandoni
et al. (2000A&AS..146...41P 2000A&AS..146...41P, Cat. VIII/63) and Prandoni et al. (2006,
Cat. J/A+A/457/517). A higher frequency follow-up at 5, 8 and 19 GHz
was presented in Prandoni et al. (2010A&A...510A..42P 2010A&A...510A..42P). The flux
densities of the 28 souces making up the early-type complete
sub-sample observed in Sep 2011 and July 2012 follow-up campaigns with
the Australia Telescope Compact Array (ATCA) at the radio frequencies
of 19, 38 and 94 GHz are presented in the ASCII table. 2011 38-GHz
flux densities are showed both at high- (HR: 0.6 arcsec) and low- (LR:
10-15 arcsec) angular resolutions.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 126 28 ATESP follow-up table
--------------------------------------------------------------------------------
See also:
VIII/63 : ATESP radio survey. II. (Prandoni+, 2000)
J/A+A/457/517 : ATESP 5 GHz radio survey. I. (Prandoni+, 2006)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Seq Source designation (srcNN)
7- 20 A14 --- ATESP Source name (JHHMMSS+DDMMSS)
22 A1 --- l_S14 [=<] 1.4-GHz flux density upper limit flag (1)
23- 27 F5.2 mJy S14 ? 1.4-GHz flux density in ATESP survey
29- 32 F4.2 mJy e_S14 ? 1.4-GHz flux density error
34 A1 --- l_S5 [=<] 5-GHz flux density upper limit flag (1)
35- 39 F5.2 mJy S5 5-GHz flux density in ATESP survey
41- 44 F4.2 mJy e_S5 5-GHz flux density error
46 A1 --- l_S19-11 [=<] 19-GHz flux density upper limit flag (1)
47- 52 F6.3 mJy S19-11 ? 19-GHz flux density in 2011 ATCA follow-up
54- 58 F5.3 mJy e_S19-11 ? 19-GHz flux density error
60 A1 --- l_S38LR [=<] 38-GHz LR flux density flag (1)
61- 66 F6.3 mJy S38LR ? 38-GHz LR flux density in 2011 ATCA follow-up
68- 72 F5.3 mJy e_S38LR ? 38-GHz LR flux density flag (1)
74 A1 --- l_S38HR [=<] 38-GHz HR flux density marker
75- 79 F5.3 mJy S38HR ? 38-GHz HR flux density in 2011 ATCA follow-up
81- 86 F6.3 mJy e_S38HR ? 38-GHz HR flux density flag (1)
88 A1 --- l_S94 [=<] 94-GHz flux density marker
89- 94 F6.3 mJy S94 ? 94-GHz flux density in 2011 ATCA follow-up
96-100 F5.3 mJy e_S94 ? 94-GHz flux density flag (1)
102 A1 --- l_S19-12 [=<] 19-GHz flux density marker
103-107 F5.3 mJy S19-12 ? 19-GHz flux density in 2012 ATCA follow-up
109-113 F5.3 mJy e_S19-12 ? 19-GHz flux density flag (1)
115 A1 --- l_S38 [=<] 38-GHz flux density marker
116-120 F5.3 mJy S38 ? 38-GHz flux density in 2012 ATCA follow-up
122-126 F5.3 mJy e_S38 ? 38-GHz flux density flag (1)
--------------------------------------------------------------------------------
Note (1): "<" stands for 3-sigma upper limit; "=" stands for detection.
--------------------------------------------------------------------------------
Acknowledgements:
Roberto Ricci, ricci(at)ira.inaf.it
References:
Prandoni et al., Paper I 2006A&A...457..517P 2006A&A...457..517P, Cat. J/A+A/457/517
Mignano et al., Paper II 2008A&A...477..459M 2008A&A...477..459M
Prandoni et al., Paper III 2010A&A...510A..42P 2010A&A...510A..42P
(End) Roberto Ricci [INAF-IRA, Italy], Patricia Vannier [CDS] 18-Dec-2018