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J/ApJS/179/306            Radio galaxy morphologies             (Russell+, 2008)

Optical morphologies of millijansky radio galaxies observed by the Hubble Space Telescope and in the very large array FIRST survey. Russell J., Ryan R.E.Jr, Cohen S.H., Windhorst R.A., Waddington I. <Astrophys. J. Suppl. Ser., 179, 306-318 (2008)> =2008ApJS..179..306R (SIMBAD/NED BibCode)
ADC_Keywords: Photometry, HST ; Galaxies, radio ; Morphology Keywords: galaxies: starburst - radio continuum: galaxies Abstract: We report on a statistical study of 51 radio galaxies at the millijansky flux level selected from the Faint Images of the Radio Sky at Twenty cm survey, including their optical morphologies and structure obtained with the Hubble Space Telescope (HST). Our optical imaging is significantly deeper (∼2mag) than previous studies with the superior angular resolution of space-based imaging. We that find 8/51 (16%) of the radio sources have no optically identifiable counterpart to AB∼24mag. For the remaining 43 sources, only 25 are sufficiently resolved in the HST images to reliably assign a visual classification: 15 (60%) are elliptical galaxies, two (8%) are late-type spiral galaxies, one (4%) is an S0, three (12%) are pointlike objects (quasars), and four (16%) are merger systems. We find a similar distribution of optical types with measurements of the Sersic index. Description: We begin by correlating the positions from the FIRST catalog with the HST WFPC2 Archive. We excise 300x300 pixel "postage stamp" images from the astrometrically corrected and stacked WFPC2 mosaics centered on each FIRST source position. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 73 43 Targeted sources removed from sample table3.dat 32 8 Unidentified radio sources table4.dat 79 54 Flux results table5.dat 76 51 Morphological and structural results
See also: B/hst : HST Archived Exposures Catalog (STScI, 2007) VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003) II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 16 A16 --- FIRST Radio source name (JHHMMSS.s-DDMMSS) (G1) 18- 27 F10.6 deg RAdeg Right ascension in degree (J2000) 29- 38 F10.6 deg DEdeg Declination in degree (J2000) 40- 43 F4.2 mJy S1.4GHz Integrated flux at 1.4GHz from FIRST, cat. VIII/71 45- 73 A29 --- WFPC2 WFPC2 target (targname) (1)
Note (1): This is the header keyword for the field target from the WFPC2 images.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 16 A16 --- FIRST Radio source name (JHHMMSS.s-DDMMSS) (G1) 18- 22 A5 --- Passband F814W or F606W bandpass 24- 27 F4.1 mag Limit Limiting I or V band AB magnitude (1) 29- 32 F4.2 mJy S1.4GHz Integrated flux at 1.4GHz from FIRST cat.
Note (1): The limiting AB magnitude in specified filter given as 50% completeness limit following Snigula et al. (2002MNRAS.336.1329S).
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 16 A16 --- FIRST Radio source name (JHHMMSS.s-DDMMSS) (G1) 18 A1 --- Band [VI] V or I band (1) 20- 24 F5.2 mag mag ?=- V or I band magnitude 26- 30 F5.2 mag/arcsec2 SB ?=- Surface brightness within effective radius (see Re in table 5) 32- 35 F4.2 mJy S1.4GHz Integrated flux at 1.4GHz from FIRST cat. 37- 40 F4.1 mag Depth ?=- Field depth (2) 42- 46 F5.2 --- LR ?=- Likelihood ratio (3) 48- 52 F5.2 mag i'mag ?=- SDSS-DR5 i' band magnitude (4) 54- 57 F4.2 mag e_i'mag ? Error in i'mag 59- 63 F5.2 mag (g'-r') ?=- SDSS-DR5 (g'-r') color index (4) 65- 68 F4.2 mag e_(g'-r') ? Error in (g'-r') color index 70- 74 F5.2 mag (r'-i') ?=- SDSS-DR5 (r'-i') color index (4) 76- 79 F4.2 mag e_(r'-i') ? Error in (r'-i') color index
Note (1): V and I refer to the HST WFPC2 bandpasses F606W or F814W, respectively. Note (2): The 50% completeness limit as determined by the Snigula et al. (2002MNRAS.336.1329S) method (see Section 2.4). Note (3): The likelihood ratio (LR) technique described by de Ruiter et al. (1977A&AS...28..211D). Objects with LR≥2 are a positive identification. (See section 2.4 for the complete equation) Note (4): Obtained from SDSS DR5 (Adelman-McCarthy et al., 2007, Cat. II/276, superseded by Cat. II/294, SDSS-DR7).
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 16 A16 --- FIRST Radio source name (JHHMMSS.s+DDMMSS) (G1) 18- 21 F4.2 arcsec Re ?=- Effective radius (1) 23- 26 F4.2 --- n ?=- The Sersic index (2) 28- 31 F4.2 --- e_n ? Error in n 33- 36 F4.2 --- Chi2V ?=- Reduced Chi^2^_nu_ (3) 38- 41 F4.1 --- ANNt ?=- Artificial Neural Network type classification (4) 43- 56 A14 --- VisType Morphology of optical counterpart (5) 58- 76 A19 --- WFPC2 WFPC2 target (6)
Note (1): Half-light radius as measured by LMORPHO (Odewahn et al. 1996). Note (2): Defined by eq. (6): I(r)=Ieexp{-bn[(R/Re)1/n-1]} where Ie is the intensity at the effective radius Re and bn is a constant defined in terms of n, which describes the shape of the profile (e.g., Graham & Driver, 2005PASA...22..118G). Note (3): Reduced chi2ν between the observed profile and below eq. (6). Note (4): Artificial Neural Network type classification as measured by LMORPHO (Odewahn et al., 1996ApJ...472L..13O). Note (5): Morphology of optical counterpart including flags as follows: E = Elliptical galaxy SBb-SBc = Late-type spiral galaxy S0 = S0 galaxy ps = pointlike object (quasar) Merger = merger system x = objects too small to assign a reliable morphology xC = object is compact xE = object is extended UNID = unidentified Note (6): This is the header keyword for the field target from the WFPC2 images, which helped us assess the "randomness" of each WFPC2 field.
Global Notes: Note (G1): The name of the source as per IAU recommendations, as used by FIRST: Jhhmmss.s+ddmmss in which the coordinates are equinox J2000.0 and are truncated (Becker et al., 1995ApJ...450..559B).
History: From electronic version of the journal
(End) Emmanuelle Perret [CDS] 16-Sep-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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