J/ApJS/143/1 FIRST-APM Source Catalog (McMahon+, 2002)
Optical counterparts for 70,000 radio sources:
APM identifications for the FIRST radio survey.
McMahon R.G., White R.L., Helfand D.J., Becker R.H.
<Astrophys. J. Suppl. Ser. 143, 1 (2002)>
=2002ApJS..143....1M 2002ApJS..143....1M
ADC_Keywords: Radio sources ; QSOs ; Surveys ; Cross identifications
Keywords: catalogs - galaxies: general - quasars: general -
radio continuum: general - surveys
Abstract:
We describe a program to identify optical counterparts to radio
sources from the VLA FIRST survey using the Cambridge APM scans of the
POSS-I plates. We use radio observations covering 4150deg2 of the
north Galactic cap to a 20cm flux density threshold of 1.0mJy; the
382,892 sources detected all have positional uncertainties of <1"
(radius of 90% confidence). Our description of the APM catalog,
derived from the 148 POSS-I O and E plates covering this region,
includes an assessment of its astrometric and photometric accuracy, a
photometric recalibration using the Minnesota APS catalog, a
discussion of the classification algorithm, and quantitative tests of
the catalog's reliability and completeness. We go on to show how the
use of FIRST sources as astrometric standards allows us to improve the
absolute astrometry of the POSS plates by nearly an order of magnitude
to ∼0.15" rms. Matching the radio and optical catalogs yields
counterparts for over 70,000 radio sources; we include detailed
discussions of the reliability and completeness of these
identifications as a function of optical and radio morphology, optical
magnitude and color, and radio flux density. An analysis of the
problem of radio sources with complex morphologies (e.g., double-lobed
radio galaxies) is included. We conclude with a brief discussion of
the source classes represented among the radio sources with identified
counterparts.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 129 496791 FIRST-APM Source Catalog
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See also:
VIII/71 : The FIRST Survey, Version 2003Apr (Becker+ 2003)
VIII/59 : the FIRST Survey, version 1999Jul (White+ 1999)
I/267 : The APM-North Catalogue (McMahon+, 2000)
http://sundog.stsci.edu/ : The VLA FIRST Survey Home Page
http://www.ast.cam.ac.uk/~apmcat/ : APM Catalog Home Page
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Radio hour of Right Ascension (J2000) (1)
4- 5 I2 min RAm Radio minute of Right Ascension (J2000) (1)
7- 12 F6.3 s RAs Radio second of Right Ascension (J2000) (1)
14 A1 --- DE- Radio sign of the Declination (J2000) (1)
15- 16 I2 deg DEd Radio degree of Declination (J2000) (1)
18- 19 I2 arcmin DEm Radio arcminute of Declination (J2000) (1)
21- 25 F5.2 arcsec DEs Radio arcsecond of Declination (J2000) (1)
27- 32 F6.2 arcsec oRA Right Ascension offset to the optical object
34- 39 F6.2 arcsec oDE Declination offset to the optical object
41- 45 F5.2 arcsec Sep Radius to the optical object
47- 48 I2 --- Eclass APM classification on E (red) plate (2)
50- 55 F6.2 --- Epsf APM psf parameter on E (red) plate (3)
57- 62 F6.2 mag Emag E (red) plate magnitude (1)(4)
64- 65 I2 --- Oclass APM classification on O (blue) plate (2)
67- 72 F6.2 --- Opsf APM psf parameter on O (blue) plate (3)
74- 79 F6.2 mag Omag O (blue) plate magnitude (1)(4)
81- 86 F6.2 mag O-E The (O-E) plate color (5)
88- 92 I5 --- Plate ?=-99.99 Number of POSS-I plate
94-101 F8.2 mJy Fpeak FIRST peak radio flux density at 1.4GHz (6)
103-111 F9.2 mJy Fint FIRST integrated radio flux density (6)
113-117 F5.1 arcsec Fmaj FIRST source deconvolved major axis (6)(7)
119-123 F5.1 arcsec Fmin FIRST source deconvolved minor axis (6)(7)
125-129 F5.1 deg FPA FIRST position angle (6)
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Note (1): APM positions and magnitudes have been calibrated
as described in the paper.
Note (2): APM classification:
-1 = stellar
1 = non-stellar
2 = blended
0 = noise
Note (3): Measures by how many σ the object deviates from being a
point-source.
Note (4): Negative magnitudes indicate that source is undetected on the plate.
In that case, the absolute value of the magnitude is an upper limit.
Note (5): -9.99 = object is detected on only one plate.
Note (6): The radio parameters are described in more detail in
White, Becker, Helfand, & Gregg (1997ApJ...475..479W 1997ApJ...475..479W, Cat. VIII/59)
and on the FIRST web pages (http://sundog.stsci.edu).
Note (7): Negative values indicate that the source size before deconvolution
was smaller than the beam, so the source is unresolved along that axis.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 12-Nov-2002