The blazar content in the Swift -BAT hard X-ray sky

A. Maselli, G. Cusumano, E. Massaro, V. La Parola, A. Segreto, Boris Sbarufatti

Research output: Contribution to journalArticle

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Abstract

Aims. We present the results from a study of the blazar content in the 15-150 keV map of the entire sky obtained analysing 39 months of data collected by the BAT telescope aboard the Swift satellite. Methods. We performed a cross-correlation of the significance map, obtained with a dedicated highly efficient algorithm for data processing and image reconstruction of the BAT survey data, with the blazar population of the Roma-BZCAT. After corrections for source confusion and spurious detections, we found significance excesses higher than two standard deviations for 304 sources, and the corresponding fraction of expected spurious associations is ∼20%. We selected hard X-ray blazars according to their significance level and carried out a statistical analysis to characterise their emission properties. Results. A sample of 121 blazars detected at a significance level σ > 3 is discussed in greater detail. The fraction of blazars with uncertain classification in this sample is considerable (∼23%), more than twice the percentage obtained considering all the blazars classified in the Roma-BZCAT (∼9%). We attribute the X-ray flux of the majority of selected BL Lac objects to the synchrotron emission.

Original languageEnglish (US)
Article numberA47
JournalAstronomy and Astrophysics
Volume520
Issue number6
DOIs
StatePublished - Sep 30 2010

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blazars
sky
statistical analysis
x rays
confusion
image reconstruction
cross correlation
standard deviation
synchrotrons
telescopes
detection
method

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Maselli, A., Cusumano, G., Massaro, E., La Parola, V., Segreto, A., & Sbarufatti, B. (2010). The blazar content in the Swift -BAT hard X-ray sky. Astronomy and Astrophysics, 520(6), [A47]. https://doi.org/10.1051/0004-6361/201014331
Maselli, A. ; Cusumano, G. ; Massaro, E. ; La Parola, V. ; Segreto, A. ; Sbarufatti, Boris. / The blazar content in the Swift -BAT hard X-ray sky. In: Astronomy and Astrophysics. 2010 ; Vol. 520, No. 6.
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Maselli, A, Cusumano, G, Massaro, E, La Parola, V, Segreto, A & Sbarufatti, B 2010, 'The blazar content in the Swift -BAT hard X-ray sky', Astronomy and Astrophysics, vol. 520, no. 6, A47. https://doi.org/10.1051/0004-6361/201014331

The blazar content in the Swift -BAT hard X-ray sky. / Maselli, A.; Cusumano, G.; Massaro, E.; La Parola, V.; Segreto, A.; Sbarufatti, Boris.

In: Astronomy and Astrophysics, Vol. 520, No. 6, A47, 30.09.2010.

Research output: Contribution to journalArticle

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AU - Maselli, A.

AU - Cusumano, G.

AU - Massaro, E.

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AU - Segreto, A.

AU - Sbarufatti, Boris

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N2 - Aims. We present the results from a study of the blazar content in the 15-150 keV map of the entire sky obtained analysing 39 months of data collected by the BAT telescope aboard the Swift satellite. Methods. We performed a cross-correlation of the significance map, obtained with a dedicated highly efficient algorithm for data processing and image reconstruction of the BAT survey data, with the blazar population of the Roma-BZCAT. After corrections for source confusion and spurious detections, we found significance excesses higher than two standard deviations for 304 sources, and the corresponding fraction of expected spurious associations is ∼20%. We selected hard X-ray blazars according to their significance level and carried out a statistical analysis to characterise their emission properties. Results. A sample of 121 blazars detected at a significance level σ > 3 is discussed in greater detail. The fraction of blazars with uncertain classification in this sample is considerable (∼23%), more than twice the percentage obtained considering all the blazars classified in the Roma-BZCAT (∼9%). We attribute the X-ray flux of the majority of selected BL Lac objects to the synchrotron emission.

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