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J/AJ/135/2453    Sample of BL Lac objects from SDSS and FIRST   (Plotkin+, 2008)

A large sample of BL Lac objects from the SDSS and FIRST. Plotkin R.M., Anderson S.F., Hall P.B., Margon B., Voges W., Schneider D.P., Stinson G., York D.G. <Astron. J., 135, 2453-2469 (2008)> =2008AJ....135.2453P
ADC_Keywords: BL Lac objects ; Photometry, SDSS ; Radio sources Keywords: BL Lacertae objects: general - galaxies: active - quasars: general - surveys Abstract: We present a large sample of 501 radio-selected BL Lac candidates from a combination of Sloan Digital Sky Survey (SDSS) Data Release 5 optical spectroscopy and the Faint Images of the Radio Sky at 20cm (FIRST) radio survey; this is one of the largest BL Lac samples yet assembled, and each object emerges with homogeneous data coverage. Each candidate is detected in the radio from FIRST and confirmed in SDSS optical spectroscopy to have (1) no emission feature with measured rest-equivalent width larger than 5Å and (2) no measured CaII H/K depression larger than 40%. We subdivide our sample into 426 higher-confidence candidates and 75 lower-confidence candidates. Description: We select BL Lac candidates from the combination of the SDSS Data Release 5 (DR5) spectroscopic database (Adelman-McCarthy et al., 2007, Cat. II/276) in the optical and from the FIRST survey catalog (Becker et al., 1995, Cat. VIII/71) in the radio. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table5.dat 113 501 Observed parameters of BL Lac candidates table6.dat 79 501 Derived parameters of BL Lac candidates
See also: VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003) II/276 : The SDSS Photometric Catalog, Release 5 (Adelman-McCarthy+, 2007) Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 18 A18 --- SDSS SDSS Name ( 20- 22 A3 --- Class [BL? ] higher confidence BL Lac class (BL), or lower confidence BL Lac class (BL?) 24 A1 --- N [NSO] Source in NED as BL Lac? (3) 26- 34 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) 36- 44 F9.5 deg DEdeg Declination in decimal degrees (J2000) 46- 50 F5.2 mag umag SDSS u-band psf magnitude 52- 56 F5.2 mag gmag SDSS g-band psf magnitude 58- 62 F5.2 mag rmag SDSS r-band psf magnitude 64- 68 F5.2 mag imag SDSS i-band psf magnitude 70- 74 F5.2 mag zmag SDSS z-band psf magnitude 76- 80 F5.3 --- z ? Redshift from SDSS spectroscopy 82 A1 --- q_z [LRTU] z quality (4) 84- 89 F6.3 --- C ? Measured H/K break strength (5) 91- 97 F7.2 mJy f1.4 Integrated FIRST 1.4GHz observed flux density 99-113 A15 --- Comm Additional comments (6)
Note (3): Classification in NED as BL Lac? code as follows: N = not listed as a BL Lac S = listed as a BL Lac in NED and credited as an SDSS discovery O = listed as a BL Lac in NED and credited as a non-SDSS discovery Note (4): Flag on z as follows: R = Reliable T = Tentative L = Lower Limit from Intervening Absorption U = Uncertain Note (5): for objects showing an H/K break in their spectra. Note (6): States why each lower confidence candidate is listed as such in column "Class", and marks those objects that are identified as BL Lacs in either Collinge et al (2005, Cat. J/AJ/129/2542) or in Anderson et al (2007, Cat. J/AJ/133/313): lowSN = listed as BL? due to low signal-to-noise (100<SN≤125); contam? = listed as BL? due to possible contamination from a nearby source in the SDSS fiber spectrum ew = listed as BL? because the SDSS spectrum shows at least one line that can show a rest frame equivalent width larger or smaller than 5 Angstroms depending on the choice of continuum C05 = appears as a BL Lac candidate in Collinge et al. (2005, Cat. J/AJ/129/2542) A07 = appears as a BL Lac candidate in Anderson et al. (2007, Cat. J/AJ/133/313)
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 18 A18 --- SDSS SDSS Name ( 20- 24 F5.3 --- z ? Redshift from SDSS spectroscopy 26- 32 F7.2 mJy f1.4 Integrated FIRST 1.4GHz observed flux density 34- 38 F5.2 [10-7W/Hz] logL5 Calculated monochromatic radio luminosity at rest frame 5GHz in erg/s/Hz (log scale) 40- 44 F5.2 mag Omag Extinction corrected optical magnitude in filter closest to rest frame 500nm 46- 50 F5.2 [10-7W/Hz] logLopt Calculated monochromatic optical luminosity at rest frame 500nm (5000Å) (log scale) 52 A1 --- X [Y/N] Source is a RASS X-ray source? (8) 54- 58 F5.3 ct/s Xrate RASS measured X-ray count rate (8) 60- 64 F5.2 [10-7W/Hz] logLx Calculated monochromatic X-ray luminosity at rest frame 1keV in erg/s/Hz (log scale) (8) 66- 69 F4.2 --- SI.RO Broad-band radio/optical spectral index 71- 74 F4.2 --- SI.OX Broad-band optical/X-ray spectral index 76- 79 F4.2 --- SI.RX Broad-band radio/X-ray spectral index
Note (8): Flag "X" means: Y = SDSS object matches to a RASS source; N = SDSS object does not match to a RASS source. In this case, the columns "Xrate" and "logLx" are upper limits, and columns "SI.OX" and "SI.RX" are lower limits.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 14-Jan-2011
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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