J/A+A/401/927 The HRX-BL Lac sample (Beckmann+, 2003)
The HRX-BL Lac sample - Evolution of BL Lac objects.
Beckmann V., Engels D., Bade N., Wucknitz O.
<Astron. Astrophys. 401, 927 (2003)>
=2003A&A...401..927B 2003A&A...401..927B
ADC_Keywords: BL Lac objects ; X-ray sources
Keywords: BL Lacertae objects: general - X-rays: galaxies
Abstract:
The unification of X-ray and radio selected BL Lacs has been an
outstanding problem in the blazar research in the past years. Recent
investigations have shown that the gap between the two classes can be
filled with intermediate objects and that apparently all differences
can be explained by mutual shifts of the peak frequencies of the
synchrotron and inverse Compton component of the emission. We study
the consequences of this scheme using a new sample of X-ray selected
BL Lac objects comprising 104 objects with z<0.9 and a mean redshift
of 0.34. 77 BL Lacs, of which the redshift could be determined for 64
(83%) objects, form a complete sample.
Description:
The BL Lac subsample was selected on an area of 1687deg^2 with a
counter-rate limit of hcps≥0.075s-1 and on additional 1150deg2
with a limit of hcps≥0.15s-1. This sample was analyzed by
Bade et al. (1998A&A...334..459) and is referred here as the
HRX-BL Lac core sample. It consists of 39 BL Lacs, 34 of which are
also part of the present sample.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table8.dat 73 223 Objects from the RASS-BSC/NVSS correlation.
An X-ray count rate limit hcps≥0.09 was applied.
table9.dat 84 104 The HRX-BL Lac sample
(Hamburg-RASS Bright X-ray AGN sample)
--------------------------------------------------------------------------------
See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
Table 2: Spectroscopic follow-up observation runs.
--------------------------------------------------------------------------------
Telescope & Instrument Date #nights #objects (b)
--------------------------------------------------------------------------------
3.5 m Calar Alto (MOSCA) March 1997 4 30
WHT / La Palma (ISIS) April 1997 2 19
3.5 m Calar Alto (MOSCA) Feb. 1998 6 9
3.5 m Calar Alto (MOSCA) Feb. 1999 ∼1 (a) 9
--------------------------------------------------------------------------------
Notes: a: Morning and evening hours of three nights.
b: Number of objects observed in this observation run
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (J2000.0)
4- 5 I2 min RAm Right ascension (J2000.0)
7- 10 F4.1 s RAs Right ascension (J2000.0)
12 A1 --- DE- Declination sign (J2000.0)
13- 14 I2 deg DEd Declination (J2000.0)
16- 17 I2 arcmin DEm Declination (J2000.0)
19- 20 I2 arcsec DEs Declination (J2000.0)
22- 43 A22 --- Source Name
44- 51 F8.5 --- z ? Redshift
52 A1 --- n_z [*C] Note on Redshift (1)
55- 72 A18 --- Class Classificiation
73 A1 --- n_Class [*C] Note on Class (1)
--------------------------------------------------------------------------------
Note (1): Notes as follows:
* = new entries first presented here
C = confirmed identifications/redshifts
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 21 A21 --- Name Name (1)
22 A1 --- n_Name [*] Note on Name (1)
23- 25 A3 --- New [new ] new: new identification
28- 29 I2 h RAh Right ascension (J2000.0)
31- 32 I2 min RAm Right ascension (J2000.0)
34- 37 F4.1 s RAs Right ascension (J2000.0)
39 A1 --- DE- Declination sign (J2000.0)
40- 41 I2 deg DEd Declination (J2000.0)
43- 44 I2 arcmin DEm Declination (J2000.0)
46- 47 I2 arcsec DEs Declination (J2000.0)
49- 54 F6.4 --- z ? Redshift
55 A1 --- u_z [?] ?: uncertain redshifts
57- 62 F6.2 10-15W/m2 FX ROSAT PSPC (0.5-2.0keV) flux
in 10-12erg/cm2/s
64- 68 F5.1 mJy F1.4GHz Radio flux at 1.4GHz
70- 73 F4.1 mag Bmag B magnitude
75 A1 --- n_Bmag [1] 1: B magnitudes determined with the
Calar Alto 1.23m telescope
77- 80 F4.1 mag Kmag ? K magnitude
82- 84 I3 % CaBreak ? CA break index percentage (2)
--------------------------------------------------------------------------------
Note (1): Objects not included in the complete sample marked with an asterisk.
Note (2): The calcium break index (Ca-break) is defined as:
CABreak[%]=100*[(Fupper-Flower)/Fupper]
with Fupper and Flower being the mean fluxes measured in the
3750Å<lambda<3950Å and 4050Å<lambda<4250Å objects
rest frame band respectively.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 29-Apr-2003