J/MNRAS/440/696 HI absorption in nearby radio galaxies (Allison+, 2014)
A search for HI absorption in nearby radio galaxies using HIPASS.
Allison J.R., Sadler E.M., Meekin A.M.
<Mon. Not. R. Astron. Soc., 440, 696-718 (2014)>
=2014MNRAS.440..696A 2014MNRAS.440..696A
ADC_Keywords: Galaxies, nearby ; H I data ; Galaxies, radio
Keywords: methods: data analysis - galaxies: active - galaxies: ISM -
galaxies: nuclei - radio lines: galaxies
Abstract:
Using archival data from the Hi Parkes All-Sky Survey (HIPASS), we
have searched for 21cm line absorption in 204 nearby radio and
star-forming galaxies with continuum flux densities greater than
S1.4∼250mJy within the redshift range 0<cz<12000km/s. By applying a
detection method based on Bayesian model comparison, we successfully
detect and model absorption against the radio-loud nuclei of four
galaxies, of which the Seyfert 2 galaxy 2MASX J130804201-2422581 was
previously unknown. All four detections were achieved against compact
radio sources, which include three active galactic nuclei (AGNs) and a
nuclear starburst, exhibiting high dust and molecular gas content. Our
results are consistent with the detection rate achieved by the recent
ALFALFA (Arecibo Legacy Fast Arecibo L-band Feed Array) Hi absorption
pilot survey by Darling et al. and we predict that the full ALFALFA
survey should yield more than three to four times as many detections
as we have achieved here. Furthermore, we predict that future all-sky
surveys on the Square Kilometre Array precursor telescopes will be
able to detect such strong absorption systems associated with type 2
AGNs at much higher redshifts, providing potential targets for
detection of H2O megamaser emission at cosmological redshifts.
Description:
Our sample selection was driven by the brightest radio sources in the
National Radio Astronomy Observatory Very Large Array Sky Survey
(NVSS, ν=1.4GHz; Condon et al., 1998, Cat. VIII/65), the Sydney
University Molonglo Sky Survey (SUMSS, ν=843MHz; Mauch et al.,
2003, Cat. VIII/81) and the second epoch Molonglo Galactic Plane
Survey (MGPS-2, ν=843MHz; Murphy et al., 2007, Cat. VIII/82).
Together, the footprints of these three surveys fully overlap the sky
coverage of HIPASS down to continuum flux densities of a few mJy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 137 204 Properties of 204 galaxies searched for
HI absorption in HIPASS
refs.dat 65 48 References
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/81 : Sydney University Molonglo Sky Survey (SUMSS V2.1) (Mauch+ 2008)
VIII/82 : 2nd Epoch Molonglo Galactic Plane Survey (MGPS-2) (Murphy+, 2007)
VIII/73 : HI Parkes All Sky Survey Catalogue (HIPASS) (Meyer+, 2004)
VIII/89 : Northern HI Parkes All Sky Survey Catalogue (HIPASS) (Wong+, 2006)
J/A+A/544/A18 : Radio galaxies of the local universe (van Velzen+, 2012)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 25 A25 --- Name Galaxy name
27- 28 I2 h RAh Right ascension (J2000) (1)
30- 31 I2 min RAm Right ascension (J2000)
33- 37 F5.2 s RAs Right ascension (J2000)
39 A1 --- DE- Declination sign (J2000) (1)
40- 41 I2 deg DEd Declination (J2000)
43- 44 I2 arcmin DEm Declination (J2000)
46- 49 F4.1 arcsec DEs Declination (J2000)
51- 55 I5 km/s cz [129/11980] Systemic redshift
57- 59 I3 km/s e_cz ? rms uncertainty on cz
61- 62 I2 --- Ref [1/48] Reference code, in refs.dat file
64- 70 I7 mJy S.84 ?=- SUMSS/MGPS-2 mean flux density at 843MHz (2)
72- 76 I5 mJy e_S.84 ?=- rms uncertainty on S843 (2)
77- 81 I5 --- n.84 ?=- Number of radio components in the
SUMSS/MGPS-2 image (4)
83- 88 I6 mJy S1.4 ?=- NVSS total flux at 1.4GHz (3)
90- 93 I4 mJy e_S1.4 ?=- rms uncertainty on S1.4 (3)
95- 98 I4 --- n1.4 ?=- Number of radio components in the
NVSS image (4)
100-105 I6 mJy SCHI ?=- Beam-weighted flux density from the 1.4GHz
CHIPASS compact source map (5)
107-113 I7 mJy S100 ?=- IRAS flux density at 100um (6)
115-120 I6 mJy S60 ?=- IRAS flux density at 60um (6)
122-126 F5.2 mag Ksmag ?=- 2MASS Ks magnitude (7)
128-131 I4 Jy.km/s SHI ?=- Integrated HI emission from HIPASS (8)
133 A1 --- Mc [jpgu] Morphological code (9)
135-137 A3 --- Samp Sample: 1=radio-optical, 2=van Velzen (10)
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Note (1): Right ascension and declination are given for the centre position
used to extract the HIPASS spectrum.
Note (2): flux density at 843 MHz from the SUMSS/MGPS-2
(Mauch et al., 2003, Cat. VIII/81; Murphy et al., 2007, Cat. VIII/82).
Note (3): total flux density at 1.4GHz from NVSS total flux density at 1.4GHz
(Condon et al., 1998, Cat. VIII/65).
Note (4): from van Velzen et al. 2012. Note that where available
we have used the SUMSS/MGPS-2 and NVSS total flux densities compiled by
van Velzen et al. (2012, Cat. J/A+A/544/A18).
Note (5): beam-weighted flux density extracted within a single HIPASS beamwidth
from the 1.4GHz CHIPASS (Continuum HIPASS) compact source map (Calabretta
et al., 2014PASA...31....7C 2014PASA...31....7C).
Note (6): from the IRAS Faint Source, Point Source and Galaxy Catalogues
(Beichman et al., 1988, Cat. II/274; Rice et al., 1988, Cat. VII/109;
Knapp et al., 1989, Cat. J/ApJS/70/329; Moshir et al., 1992, Cat. II/156;
Sanders et al., 2003, Cat. J/AJ/126/1607).
Note (7): Ks is the apparent Ks-band magnitude, within the 20mag/arcsec2
isophote, from the 2MASS (Skrutskie et al., 2006, Cat. VII/233).
Note (8): from HIPASS (Koribalski et al. 2004, Cat. J/AJ/128/16,
Meyer et al., 2004, Cat. VIII/73; Wong et al. 2006, Cat. VIII/89).
Note (9): The radio morphology classifications are as those given by
van Velzen et al. 2012 (J/A+A/544/A18):
p = point sources
g = star-forming galaxies
j = jets and lobes
u = unknown
Note (10): samples are:
1 = radio-optical matches with 6dF, CfA redshift survey, and NED
2 = galaxies in van Velzen et al. 2012 (J/A+A/544/A18)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref [1/48] Refence code
4- 22 A19 --- BibCode Bibcode
24- 44 A21 --- Aut Author's name
46- 65 A20 --- Com Comments
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 19-Jan-2015