J/A+A/604/A43 HI in nearby radio sources (Maccagni+, 2017)
Kinematics and physical conditions of H I in nearby radio sources.
The last survey of the old Westerbork Synthesis Radio Telescope.
Maccagni F.M., Morganti R., Oosterloo T.A., Gereb K., Maddox N.
<Astron. Astrophys., 604, A43 (2017)>
=2017A&A...604A..43M 2017A&A...604A..43M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Galaxies, nearby ; H I data
Keywords: radio lines: ISM - radio lines: galaxies - galaxies: nuclei -
galaxies: ISM - infrared: ISM
Abstract:
We present an analysis of the properties of neutral hydrogen (HI) in
248 nearby (0.02<z<0.25) radio galaxies with S1.4GHz>30mJy and for
which optical spectroscopy is available. The observations were carried
out with the Westerbork Synthesis Radio Telescope as the last large
project before the upgrade of the telescope with phased array feed
receivers (Apertif). The sample covers almost four orders of magnitude
in radio power from logP1.4GHz=22.5W/Hz and 26.2W/Hz. We detect HI
in absorption in 27%±5.5% of the objects. The detections are found
over the full range of radio power. However, the distribution and
kinematics of the absorbing HI gas appear to depend on radio power,
the properties of the radio continuum emission, and the dust content
of the sources. Among the sources where HI is detected, gas with
kinematics deviating from regular rotation is more likely found as the
radio power increases.In the great majority of these cases, the HI
profile is asymmetric with a significant blue-shifted component. This
is particularly common for sources with logP1.4GHz>24W/Hz, where the
radio emission is small, possibly because these radio sources are
young. The same is found for sources that are bright in the
mid-infrared, i.e. sources rich in heated dust.In these sources, the
HI is outflowing likely under the effect of the interaction with the
radio emission. Conversely, in dust-poor galaxies, and in sources with
extended radio emission, at all radio powers we only detect HI
distributed in a rotating disk. Stacking experiments show that in
sources for which we do not detect HI in absorption directly, the HI
has a column density that is lower than
3.5x1017(Tspin/cf)cm-2. We use our results to predict the
number and type of HI absorption lines that will be detected by the
upcoming surveys of the Square Kilometre Array precursors and
pathfinders (Apertif, MeerKAT, and ASKAP).
Description:
We expand the sample of radio sources presented in Gereb et al.
(2014A&A...569A..35G 2014A&A...569A..35G, hereafter G14) and Gereb et al. (2015, Cat.
J/A+A/575/A44, hereafter G15) to lower radio fluxes and radio powers.
As in those studies, we selected the sources by cross-correlating the
seventh data release of the Sloan Digital Sky Survey catalogue (SDSS
DR7; York et al. 2000AJ....120.1579Y 2000AJ....120.1579Y) with the Faint Images of the
Radio Sky at Twenty-cm catalogue (FIRST; Becker et al.
1995ApJ...450..559B 1995ApJ...450..559B, See Cat. VIII/92). The sources lie above
declination DE>10° and between 07h51m00s and 17h22m25s in right
ascension. The sources are restricted to the redshift range
0.02<z<0.25, which is the redshift interval covered by the WSRT
observing band, 1150-1400MHz. The sample of G14 and G15 was limited
to sources brighter than 50mJy and consists of 101 sources. In the
present study, we selected all sources that have radio core flux
density 30mJy<S1.4GHz<50mJy. This includes 219 sources, of which
183 were successfully observed before the telescope was switched off
for the upgrade of the receivers.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 114 242 *Table of sources
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Note on tablea1.dat: Erroneous Rtype corrected in agreement with the
author Filippo Maccagni
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See also:
J/A+A/575/A44 : HI absorption in flux-selected radio AGNs (Gereb+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Source Source name (JHHMMSS.ss+DDMMSS.s)
20 A1 --- n_Source [*] Note on Source (1)
22- 27 F6.4 --- zopt Optical redshift measured from the
SDSS spectrum
30- 36 F7.2 mJy S1.4GHz Flux density at 1.4GHz
38- 42 F5.2 W/Hz P1.4GHz Radio power at 1.4GHz
44 A1 --- RType [CEI] Radio type (2)
46- 50 A5 --- WType WISE type (3)
52 A1 --- l_Noise Limit flag on Noise
53- 57 F5.2 mJy Noise 3σ detection limit of the HI spectrum
61- 66 F6.4 --- tauPeak ?=- Peak optical depth of the HI detection
68- 72 F5.2 km/s Inttaudv ?=- Integrated optical depth of the HI line
74- 79 F6.2 km/s FWHM ?=- Full width at half maximum
81- 85 F5.2 km/s e_FWHM ?=- rms uncertainty on FWHM
88- 93 F6.2 km/s FW20 ?=- Full width at 20% of the peak flux
95- 99 F5.2 km/s e_FW20 ?=- rms uncertainty on FW20
101-107 F7.2 km/s Cent ?=- Position of the centroid of the line
109-114 F6.2 km/s e_Cent ?=- rms uncertainty on Cent
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Note (1): Galaxies denoted by (*) have been presented in Gereb et al.
(2014A&A...569A..35G 2014A&A...569A..35G), and Gereb et al. (2015, Cat. J/A+A/575/A44.
Note (2): Radio classification as follows:
C = compact source
E = extended source
I = interacting source
Note (3): WISE colour-colour classification (see Sect. 2.2) as follows:
dp = dust poor galaxy
12um = 12um bright galaxy
4.6um = 4.6um bright galaxy
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History:
* From electronic version of the journal. Erroneous Rtype corrected
in agreement with the author Filippo Maccagni.
(End) Patricia Vannier [CDS] 23-Oct-2017