BATSE observations of the Piccinotti sample of active galactic nuclei

被引:28
作者
Malizia, A [1 ]
Bassani, L
Zhang, SN
Dean, AJ
Paciesas, WS
Palumbo, GGC
机构
[1] Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England
[2] CNR, Ist Technol & Radiaz Extraterr, I-40129 Bologna, Italy
[3] Univ Space Res Assoc, Huntsville, AL 35806 USA
[4] Univ Alabama, Dept Phys, Huntsville, AL 35899 USA
[5] Univ Bologna, Dept Astron, Bologna, Italy
关键词
galaxies : active; gamma rays : observations; X-rays : galaxies;
D O I
10.1086/307409
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
BATSE Earth-occultation data have been used to search for emission in the 20-100 keV band from all sources in the Piccinotti sample, which represents the only complete 2-10 keV survey to date of the extragalactic sky down to a limiting flux of 3.1 x 10(-11) ergs cm(-2) s(-1). Nearly 4 yr of observations have been analyzed to reach a 5 sigma sensitivity level of about 7.8 x 10(-11) ergs cm(-2) s(-1) in the band considered. Of the 36 sources in the sample:, 14 have been detected above the 5 sigma confidence level, while marginal detection (3 less than or equal to sigma less than or equal to 5) can be claimed for 13 sources; for nine objects 2 sigma upper limits are reported. A comparison of BATSE results with data at higher energies is used to estimate the robustness of our data analysis: while the detection level of each source is reliable, the flux measurement maybe overestimated in some sources by as much as 35%, probably because of incomplete data cleaning. Comparison of BATSE fluxes with X-ray fluxes obtained in the 2-10 keV range and averaged over years indicates that a canonical power law of photon index 1.7 gives a good description of the broadband spectra of bright active galactic nuclei (AGNs) and that spectral breaks preferentially occur above 100 keV.
引用
收藏
页码:637 / 641
页数:5
相关论文
共 41 条
[1]  
ANTONELLI LA, 1998, IN PRESS P 3 INTEGRA
[2]  
BASSANI L, 1993, ASTRON ASTROPHYS SUP, V97, P89
[3]  
BASSANI L, 1998, IN PRESS P 3 INTEGRA
[4]  
BASSANI L, 1998, IN PRESS MEM SOC AST
[5]  
BASSANI L, 1985, P MANCH C ACT GAL NU, P252
[6]  
CAPPI M, 1998, IN PRESS MEM SOC AST
[7]   Multiwavelength observations of a flare from Markarian 501 [J].
Catanese, M ;
Bradbury, SM ;
Breslin, AC ;
Buckley, JH ;
CarterLewis, DA ;
Cawley, MF ;
Dermer, CD ;
Fegan, DJ ;
Finley, JP ;
Gaidos, JA ;
Hillas, AM ;
Johnson, WN ;
Krennrich, F ;
Lamb, RC ;
Lessard, RW ;
Macomb, DJ ;
McEnery, JE ;
Moriarty, P ;
Quinn, J ;
Rodgers, AJ ;
Rose, HJ ;
Samuelson, FW ;
Sembroski, GH ;
Srinivasan, R ;
Weekes, TC ;
Zweerink, J .
ASTROPHYSICAL JOURNAL, 1997, 487 (02) :L143-L146
[8]   ON THE X-RAY-SPECTRA OF BL LACERTAE OBJECTS [J].
CILIEGI, P ;
BASSANI, L ;
CAROLI, E .
ASTROPHYSICAL JOURNAL, 1995, 439 (01) :80-89
[9]  
CILIEGI P, 1993, APJS, V83, P111
[10]  
CONNAUGHTON V, 1998, IN PRESS BL LAC PHEN