J/A+AS/109/267 Radio to X-Ray distribution of BL Lac Objects (Giommi+, 1995)
Radio to X-ray energy distribution of BL Lacertae objects
Giommi P., Ansari S.G., Micol A.
<Astron. Astrophys. Suppl. Ser. 109, 267 (1995)>
=1995A&AS..109..267G 1995A&AS..109..267G (SIMBAD/NED Reference)
ADC_Keywords: BL Lac objects ; Radio sources ; X-ray sources
Keywords: BL Lacertae objects: general - radio continuum: galaxies -
X-ray: galaxies
Description (Abstract):
We present multifrequency spectra of a large number of radio and X-ray
selected BL Lacertae objects constructed using non-simultaneous
archival data. The data were obtained using the European Space
Information System (ESIS) and are from several radio and optical
catalogues, the IRAS Faint Source Catalogue, the Einstein and the
EXOSAT databases. The sample includes 121 BL Lacs that have been
extracted from the 1Jy (1991ApJ...374..431S 1991ApJ...374..431S) and the S4
(1994A&AS..103..349S 1994A&AS..103..349S) radio surveys, the Einstein IPC Slew Survey, the
Einstein Extended Medium Sensitivity Survey (EMSS), the EXOSAT High
Galactic Latitude Survey, and from the compilations of Giommi et al.
(1990ApJ...356..432G 1990ApJ...356..432G) and Veron & Veron (1993ESOSR..13....1V 1993ESOSR..13....1V). We find
that the shape of the radio to infra-red spectrum of Radio Selected
and X-ray Selected BL Lacs is very similar. The difference between
these two classes of objects is instead evident in the optical/X-ray
part of the spectrum. The classical radio discovered BL Lacs are
characterized by an energy spectrum with a sharp cutoff in the
IR/optical band while in most of the X-ray discovered objects the
turnover is located near the UV/X-ray band or at higher frequencies.
For a given X-ray flux this diversity can give rise to radio fluxes
different by a factor of 100 or more. We argue that BL Lac objects may
be a single population of sources characterized by a wide range of
energy cutoffs. In this scenario BL Lacs discovered in radio surveys
are representative of the entire population, while objects
characterized by an energy break near the X-ray band, which are
abundantly detected at X-ray frequencies, are intrinsically a small
minority.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 78 39 Radio selected BL Lacs 1Jy and S4 surveys
table2.dat 78 44 X-ray selected BL Lacs from the Einstein
IPC Slew Survey
table3.dat 78 45 Serendipitous X-ray BL Lacs Einstein EMSS
and EXOSAT HGLS
table4.dat 78 12 Miscellaneous BL Lacs
table5.dat 46 1386 Multifrequency data
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Byte-by-byte Description of file: table1.dat table2.dat table3.dat table4.dat
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Bytes Format Units Label Explanations
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2- 15 A14 --- Name Source name
17- 49 A33 --- Other Other names
51- 52 I2 h RAh Right ascension J2000.0
54- 55 I2 min RAm Right ascension J2000.0
57- 60 F4.1 s RAs Right ascension J2000.0
62 A1 --- DE- Declination sign
63- 64 I2 deg DEd Declination J2000.0
66- 67 I2 arcmin DEm Declination J2000.0
69- 70 I2 arcsec DEs Declination J2000.0
72- 78 A7 --- Ref References (1)
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Note (1): The references are
1 =1992ApJS...80..257E 1992ApJS...80..257E Elvis at al. 1992
2 =1990ApJS...72..567G 1990ApJS...72..567G Gioia et al. 1990, catalog VII/152
3 =1990ApJ...356..432G 1990ApJ...356..432G Giommi et al., 1990
4 =1991ApJ...378...77G 1991ApJ...378...77G Giommi et al. 1991
5 =1993ApJ...412..541S 1993ApJ...412..541S Schachter et al. 1993
6 =1991ApJ...374..431S 1991ApJ...374..431S Stickel et al.1991
7 =1994A&AS..103..349S 1994A&AS..103..349S Stickel & Kuehr 1994
8 =1991ApJS...76..813S 1991ApJS...76..813S Stocke et al. 1991, catalog VII/152
9 =1993ESOSR..13....1V 1993ESOSR..13....1V Veron & Veron, 1993, catalog VII/166
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name
17- 23 E7.1 Hz nu Frequency
25- 32 E8.2 mW/m2 SX Flux in the X-ray band, where the
measurements are often near the instruments
sensitivity limit
34- 41 E8.2 mW/m2 e_SX []? rms uncertainty on flux
42- 45 A4 --- Ref References where the original flux (or count
rate) can be found (1)
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Note (1): The references are
1 =1991ApJS...75....1B 1991ApJS...75....1B Becker, White & Edwards, 1991; catalog VIII/13
2 =1979AuJPS..46....1B 1979AuJPS..46....1B Bolton Savage & Wright, 1979
Austral. J. Phys. Suppl. 46, 1
3 =1992ApJS...80..257E 1992ApJS...80..257E Elvis et al. 1992
4 Dixon 1976, Proc. IAU Coll. 35, 167
5 =1990ApJ...356..432G 1990ApJ...356..432G Giommi et al., 1990
6 =1991ApJ...378...77G 1991ApJ...378...77G Giommi et al. 1991
7 Moshir 1991, British Interplanet. Soc. J. 44, 495
8 =1991ApJS...76..813S 1991ApJS...76..813S Stocke et al. 1991 (EMSS)
9 =1994A&AS..103..349S 1994A&AS..103..349S Stickel & Kuer 1994
10 =1993ESOSR..13....1V 1993ESOSR..13....1V Veron & Veron 1993, catalog VII/166
11 =1992ApJS...79..331W 1992ApJS...79..331W White & Becker 1992; catalog VIII/17
12 Einstein IPC database
13 EXOSAT database
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Historical Notes:
* Table 5 was incomplete before Feb. 24, 1995.
(End) Patricia Bauer [CDS] 24-Feb-1995