Access to Astronomical Catalogues

← Click to display the menu
J/A+A/520/A47    Blazars in the Swift-BAT hard X-ray sky    (Maselli+, 2010)

The blazar content of the Swift-BAT hard X-ray sky. Maselli A., Cusumano G., Massaro E., La Parola V., Segreto A., Sbarufatti B. <Astron. Astrophys. 520, A47 (2010)> =2010A&A...520A..47M
ADC_Keywords: Active gal. nuclei ; BL Lac objects ; QSOs ; X-ray sources Keywords: galaxies: active - galaxies: BL Lacertae objects - radiation mechanisms: non-thermal Abstract: We present the results of a study on the blazar content in the 15-150keV map of the entire sky obtained analyzing 39 months of data collected by the BAT telescope aboard the Swift satellite. We performed a cross-correlation of the significance map, obtained with a dedicated highly efficient algorithm (Segreto et al., 2010A&A...510A..47S) for data processing and image reconstruction of the BAT survey data, with the blazar population of the Roma-BZCAT (Massaro et al., 2009, Cat. J/A+A/495/691). After corrections for source confusion and spurious detections, we found significance excesses higher than two standard deviations for 304 sources; the corresponding fraction of expected spurious associations is about 20%. We selected hard X-ray blazars according to their significance level and carried out a statistical analysis to characterise their emission properties. A sample of 121 blazars detected at a significance level sigma>3 is discussed in greater detail. The fraction of blazars with uncertain classification in this sample is considerable, more than twice with respect to the percentage obtained considering all the blazars classified in the Roma-BZCAT. We attribute the X-ray flux of the majority of selected BL Lac objects to the synchrotron emission. Description: We reported the list of hard X-ray blazars obtained adopting sigma=3 as detection threshold: with this choice a number of three spurious sources over a total of 121 blazars is expected. Each blazar is identified by a three-letter code, where the first two are BZ for blazar and the third one specifies the type, followed by the truncated equatorial coordinates (J2000). The codes are defined in the "Note (1)" below. We obtained 69 FSRQs, 24 BL Lac objects and 28 blazars of uncertain classification, representing 4.4%, 2.4% and 11.0% of the corresponding populations classified in the BZCAT, respectively. This sample has been compared with other lists and catalogues found in literature (Tueller et al., 2010, Cat. J/ApJS/186/378, Ajello et al. 2009ApJ...699..603A, Cusumano et al., 2010, Cat. J/A+A/510/A48). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 90 121 Blazars detected at sigma>3
See also: J/ApJS/186/378 : Hard X-ray survey from Swift-BAT 2004-2006 (Tueller+, 2010) J/A+A/510/A48 : Palermo Swift-BAT Hard X-ray Catalogue (Cusumano+, 2010) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 13 A13 --- Name Source name (1) 15- 35 A21 --- OName Other designation 39- 45 F7.3 deg RAdeg Right ascension (J2000) 47- 53 F7.3 deg DEdeg Declination (J2000) 55- 59 F5.3 --- z ? Redshift 60 A1 --- u_z [?] Comment (uncertainty) on redshift 62- 67 F6.2 fW/m2 FX ? X-ray flux (in 10^-12^erg/cm2/s) (2) 68 A1 --- n_FX [*] Comment on X-ray flux (2) 70- 77 E8.4 --- X/R ? Ratio between X-ray and radio emission (3) 79- 84 F6.2 --- Sigma Significance in the 39-month 15-150keV map 86 A1 --- T [y] Included in the list of Tueller et al. (2010, Cat. J/ApJS/186/378) 88 A1 --- A [y] Included in the list of Ajello et al. (2009ApJ...699..603A) 90 A1 --- C [y] Included in the list of Cusumano et al. (2010, Cat. J/A+A/510/A48)
Note (1): The classifications are: BZB = BL Lac objects, used for AGNs with a featureless optical spectrum or only with absorption lines of galaxian origin and weak and narrow emission lines BZQ = flat-spectrum radio quasars, with an optical spectrum showing broad emission lines and dominant blazar characteristics BZU = blazars of uncertain type, adopted for sources with peculiar characteristics but also showing blazar activity: for instance, occasional presence/absence of broad spectral lines or features, transition objects between a radio galaxy and a BL Lac, galaxies hosting a low luminosity blazar nucleus, etc. Note (2): X-ray flux in the 0.1-2.4keV energy band, or in the 0.5-2.0keV band in the case of a recent Swift-XRT observation (marked with * ). Note (3): The adimensional factor PHI_XR represents the ratio between the X-ray and the radio emission; the formula is given in the text. This ratio has proved to be a reliable index to determine the LBL or HBL classification of BL Lac objects (Giommi et al., 1999MNRAS.310..465G) and the value phiXR=1 can be considered a lower limit for HBL sources
Acknowledgements: Alessandro Maselli, maselli(at)
(End) Alessandro Maselli [INAF-IASF Palermo], Patricia Vannier [CDS] 25-Jun-2010
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

catalogue service