J/AJ/115/1253 Deep X-Ray Radio Blazar Survey (DXRBS). I. (Perlman+ 1998)
The Deep X-ray Radio Blazar Survey. I. Methods and first results.
Perlman E.S., Padovani P., Giommi P., Sambruna R., Jones L.R.,
Tzioumis A., Reynolds J.
<Astron. J. 115, 1253 (1998)>
=1998AJ....115.1253P 1998AJ....115.1253P
ADC_Keywords: QSOs ; BL Lac objects ; Surveys ; X-ray sources ; Radio sources
Keywords: BL Lacertae objects: general - quasars: general - radio continuum -
surveys
Abstract:
We have undertaken a survey, the Deep X-Ray Radio Blazar Survey
(DXRBS), of archived, pointed ROSAT Position Sensitive Proportional
Counter data for blazars by correlating the ROSAT WGACAT database with
several publicly available radio catalogs, restricting our candidate
list to serendipitous flat radio spectrum sources (αr≤0.70,
where Sν∝ν-αr_^). We discuss our survey methods,
identification procedure, and first results. Our survey is found to be
95% efficient at finding flat-spectrum radio-loud quasars (FSRQs; 59
of our first 85 identifications) and BL Lacertae objects (22 of our
first 85 identifications), a figure that is comparable to or greater
than that achieved by other radio and X-ray survey techniques. The
identifications presented here show that all previous samples of
blazars (even when taken together) did not representatively survey the
blazar population, missing critical regions of (LX, LR) parameter
space within which large fractions of the blazar population lie.
Particularly important is the identification of a large population of
FSRQs (≥25% of DXRBS FSRQs) with ratios of X-ray to radio luminosity
≥10-6(αrx≤0.78). In addition, as a result of our greater
sensitivity, the DXRBS has already more than doubled the number of
FSRQs in complete samples with 5GHz (radio) luminosities between
1031.5 and 1033.5ergs/s/Hz, and fills in the region of parameter space
between X-ray-selected and radio-selected samples of BL Lac objects.
The DXRBS is the very first sample to contain statistically
significant numbers of blazars at low luminosities, approaching what
should be the lower end of the FSRQ luminosity function.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 116 102 Positional information
table4.dat 90 102 Newly identified objects
table6.dat 76 97 Previously identified blazars
notes.dat 80 182 Individual notes
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See also:
IX/12 : The WGACAT version of ROSAT sources (White+ 1995)
VIII/38 : The Parkes-MIT-NRAO 4.85GHz (PMN) Surveys (Griffith+ 1993-1996)
VIII/40 : GB6 catalog of radio sources at 4.85GHz (Gregory+ 1996)
VIII/15 : Parkes Radio Sources Catalogue (PKSCAT90) (Wright+ 1990)
J/MNRAS/323/757 : Deep X-Ray Radio Blazar Survey (DXRBS). II. (Landt+, 2001)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [WGA]
5- 16 A12 --- 1WGA WGACAT name
18- 19 I2 h RAh WGACAT right ascension (J2000)
21- 22 I2 min RAm WGACAT right ascension (J2000)
24- 27 F4.1 s RAs WGACAT right ascension (J2000)
29 A1 --- DE- WGACAT declination sign
30- 31 I2 deg DEd WGACAT declination (J2000)
33- 34 I2 arcmin DEm WGACAT declination (J2000)
36- 37 I2 arcsec DEs WGACAT declination (J2000)
39- 42 F4.1 arcsec oWGA Offset from field center in X-ray
44- 45 I2 arcsec eWGA WGACAT error (1)
47- 48 I2 h RA1h PMN or GB6 right ascension (J2000)
50- 51 I2 min RA1m PMN or GB6 right ascension (J2000)
53- 56 F4.1 s RA1s PMN or GB6 right ascension (J2000)
58 A1 --- DE1- PMN or GB6 declination sign
59- 60 I2 deg DE1d PMN or GB6 declination (J2000)
62- 63 I2 arcmin DE1m PMN or GB6 declination (J2000)
65- 66 I2 arcsec DE1s PMN or GB6 declination (J2000)
68- 69 I2 h RA2h Optical Counterpart right ascension (J2000)
71- 72 I2 min RA2m Optical Counterpart right ascension (J2000)
74- 77 F4.1 s RA2s Optical Counterpart right ascension (J2000)
79 A1 --- DE2- Optical Counterpart declination sign
80- 81 I2 deg DE2d Optical Counterpart declination (J2000)
83- 84 I2 arcmin DE2m Optical Counterpart declination (J2000)
86- 87 I2 arcsec DE2s Optical Counterpart declination (J2000)
89- 96 A8 --- Source Source (2)
98-102 F5.2 arcsec Offset Absolute offset (X-O) value
104-105 I2 arcsec eCount Counterpart error
107-111 F5.2 arcsec Error Cumulative error
113-116 F4.2 --- o/e Ratio of Offset to Error
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Note (1): WGACAT positional error circles. This was done as follows:
WGACAT was cross-correlated with the Hipparcos Input Catalogue (Cat.
I/196), and the offsets between the two databases were obtained for
six bins of the distance from the WGACAT field center (0'-10',
10'-20', etc.). These values range from 13" (for the inner 10' of the
PSPC field) to 53" (for the 50'-60' ring).
Note (2): Source codes are:
APM: APM survey
GB6: Green Bank 6cm catalog, Cat. VIII/40
PMN: Parkes-MIT-NRAO catalog, Cat. VIII/27
ATCA: Austalian Telescope Compact Array, this paper
NVSS: NRAO VLA Sky Survey, Condon et al., 1998AJ....115.1693C 1998AJ....115.1693C
FIRST: FIRST project, Gregg et al., 1996AJ....112..407G 1996AJ....112..407G;
Laurent-Muehleisen et al., 1998, in prep. (see VIII/51)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [WGA]
5- 16 A12 --- 1WGA WGACAT name
18- 22 F5.3 ct/s Crate ROSAT count rate
24- 31 E8.2 mW/m2 F(0.1-2.0) 0.1-2.0keV flux
33- 37 F5.3 uJy F1keV Flux density at 1keV
39- 44 F6.2 --- log(FX/FR) ? X-flux to radio-flux ratio
46- 49 I4 mJy F6cm ? Flux density at 6cm
51- 55 F5.2 --- SI ? Radio spectral index
57 A1 --- l_Bmag Limit flag on Bmag
58- 61 F4.1 mag Bmag ? B magnitude
63 A1 --- l_Rmag Limit flag on Rmag
64- 67 F4.1 mag Rmag ? R magnitude
69- 75 A7 --- Class Classification (1)
77- 81 F5.3 --- z ? Redsifht
82 A1 --- u_z [?] Uncertainty flag on z
84- 86 A3 --- Cat Other catalogs (2)
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Note (1): Classification is coded as follws:
RG: radio galaxy
FSRQ: flat-spectrum radio-loud quasar
SSRQ: steep-spectrum radio-loud quasar
BL Lac: BL Lac object
Note (2): Other catalogs are numbered as follows:
1: RASS Bright Source Catalog, Cat. IX/10
2: HBQS, Homogeneous Bright QSO Survey, Cat. J/A+AS/112/347
3: V Zwicky Catalog of Galaxies, Cat. VII/190
4: 4C, Fourth Cambridge Survey, Cat. VIII/4
5: Einstein Slew Survey, Elvis et al., 1992ApJS...80..257E 1992ApJS...80..257E
6: FIRST Bright Quasar Survey, See Cat. VIII/51
7: B3, Third Bologna Survey, Cat. VIII/37
8: Las Campanas Redshift Survey, Cat. VII/203
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Source name
17- 21 F5.3 ct/s Crate ROSAT count rate
23- 30 E8.2 mW/m2 F(0.1-2.0) 0.1-2.0keV flux
32- 37 F6.3 uJy F1keV Flux density at 1keV
39- 44 F6.2 --- log(FX/FR) X-flux to radio-flux ratio
46- 50 I5 mJy F6cm Flux density at 6cm
52- 56 F5.2 --- SI Radio spectral index
58- 61 F4.1 mag Vmag ? V magnitude
63- 68 A6 --- Class Classification (1)
70 A1 --- l_z Limit flag on z
71- 75 F5.3 --- z ? Redsifht
76 A1 --- u_z [?] Uncertainty flag on z
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Note (1): Classification is:
RG: radio galaxy
FSRQ: flat-spectrum radio-loud quasar
BL Lac: BL Lac object
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [WGA]
5- 16 A12 --- 1WGA WGACAT name (repeated of more than 1 line)
18- 80 A63 --- Note Text of the note
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History:
* 11-Aug-1998: From AJ electronic version
* 18-Apr-2005: in the notes, corrected the name
WGA J1057.7-7724 into J1057.6-7724
and in the tables 3 and 4, corrected the name
J2317.4-4213 into J2317.9-4213
(End) Patricia Bauer [CDS] 11-Aug-1998