J/A+A/311/384 ROSAT observations of BL Lacertae objects (Lamer+ 1996)
ROSAT observations of BL Lacertae objects.
Lamer G., Brunner H., Staubert R.
<Astron. Astrophys. 311, 384 (1996)>
=1996A&A...311..384L 1996A&A...311..384L (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; X-ray sources
Mission_Name: ROSAT
Keywords: galaxies: active - BL Lacertae objects: general -
radio continuum: galaxies - X-rays: galaxies
Description:
We present soft X-ray spectra of 74 BL Lacertae objects observed with
the PSPC detector on board of the ROSAT satellite. The sample contains
all BL Lac objects detected during the pointed observation phase as a
target or serendipitously. We have investigated the soft X-ray and
broad band spectral properties and discuss the consequences for the
X-ray emission processes. For the first time a clear dependence of the
X-ray spectral steepness on the radio to X-ray spectral energy
distribution is found: αrx and αx are correlated in
the X-ray selected (XBL) subsample and anticorrelated in the radio
selected (RBL) subsample. The objects with intermediate αrx
values thus do have the steepest soft X-ray spectra. Simulated PSPC
spectra based on a set of simple two component multifrequency spectra
are in good agreement with the measurements and suggest a broad range
of synchrotron cutoff energies. We have calculated synchrotron
self-Compton beaming factors for a subsample of radio bright objects
and find a correlation of the beaming factors δIC with
αrx and αx. The most extreme RBL objects are very
similar to flat spectrum radio quasars in all their broad band and
X-ray properties.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 56 73 List of PSPC observations
table3 63 74 X-ray and broad band spectra
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Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Object name
13- 18 I6 --- ROR ROSAT observation request (ROR) number
19 A1 --- n_ROR [-] '-' when two ROR numbers
20- 25 I6 --- ROR2 ? Second ROR number
27- 35 A9 --- Date Completed date
39- 43 I5 s Exp Exposition time
46- 53 E8.0 --- Counts Net counts
54- 56 I3 --- e_Counts ? rms uncertainty on Counts
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Byte-by-byte Description of file: table3
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Object name
14- 18 F5.2 10+20cm-2 NH,gal Galactic hydrogen column density
19 A1 --- n_NH,gal Note on NH,gal (1)
22- 26 F5.2 10+20cm-2 NH,fit ? Fitted hydrogen column density
29- 33 F5.2 10+20cm-2 e_NH,fit ? rms uncertainty on NH,fit
35- 40 F6.2 uJy F1keV Flux at 1 keV
42- 45 F4.2 --- alpha Spectral index between .1kev and 2.4keV
49- 52 F4.2 --- e_alpha rms uncertainty on alpha
54- 57 F4.2 --- alpharx X-ray spectral index
59- 63 F5.2 --- deltaIC ? Inverse Compton beaming factor
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Note (1): a: Elvis et al. 1989, other values: Stark et al. 1992
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References:
Elvis M. et al., 1989, AJ, 97, 777 =1989AJ.....97..777E 1989AJ.....97..777E
Stark A.A. et al., 1992, ApJS, 79, 77 =1992ApJS...79...77S 1992ApJS...79...77S
(End) Patricia Bauer [CDS] 26-Mar-1996