Spectral properties of gamma-ray detected blazars from 5 to 37 GHz

Tera¨sranta, Harri
April 2000
AIP Conference Proceedings;2000, Vol. 510 Issue 1, p352
Academic Journal
Radio monitoring data from the Metsa¨hovi Radio Observatory and the University of Michigan Radio Astronomical Observatory are used to study if the spectral indexes of the mean flux between used frequencies are different between γ-ray detected and not detected AGN. The γ-ray detected AGN seem to have a flatter spectral index towards the higher frequencies. © 2000 American Institute of Physics.


Related Articles

  • Simulations of time-dependent high energy emission from blazars. Kusunose, Masaaki; Takahara, Fumio; Li, Hui // AIP Conference Proceedings;2001, Vol. 556 Issue 1, p119 

    Blazars are a group of active galactic nuclei which emit a broad band continuum from radio to very high energy gamma-rays. Recent X-ray and gamma-ray observations show that the emission from blazars are variable on very short timescales. Based on the synchrotron-self-Compton model for emission...

  • γ-ray spectral changes during blazar outbursts. Sreekumar, P.; Hartman, R. C.; Mukherjee, R.; Pohl, M. // AIP Conference Proceedings;2001, Vol. 587 Issue 1, p314 

    We examined the archival EGRET data on time-variable γ-ray blazars for systematic variations in the spectra during different intensity states (flare/quiet). Although the changes in the individual source spectra can be well measured in only a few cases, the collective results from the blazar...

  • Microvariability in the southern gamma-ray blazar PKS 0537-441. Romero, Gustavo E.; Combi, J. A.; Cellone, S. A. // AIP Conference Proceedings;2000, Vol. 510 Issue 1, p333 

    The southern blazar PKS 0537-441 is one of the most variable active galactic nuclei. It has displayed extreme forms of variability in its emission from radio to gamma-ray wavelengths. Here we present results of new optical microvariability observations of this blazar in the V and R bands,...

  • Upper limits on low redshift AGN. Bojahr, H. // AIP Conference Proceedings;2000, Vol. 515 Issue 1, p81 

    The HEGRA IACT stereoscopic system, with an energy threshold of about 0.5 TeV, was used to search for γ-ray emission of several low redshift AGN (z<0.2), mostly BL Lacs. Here we present the results of observations that were made since June 1997 at zenith angles up to 40°. No evidence for...

  • X-ray observations of Mkn 421 with USA. Giebels, B.; Wood, K. S.; Bandyopadhyay, R. M.; Bloom, E.; Focke, W.; Fritz, G.; Godfrey, G.; Hertz, P.; Kowalski, M. P.; Lovellette, M. N.; Ray, P. S.; Reilly, K.; Saz Parkinson, P.; Scargle, J.; Shabad, G.; Wolff, M. T.; Yentis, D. // AIP Conference Proceedings;2001, Vol. 558 Issue 1, p668 

    This paper presents the first AGN detections with the USA X-ray detector on board of ARGOS. We started observing the BL Lac object Mkn421 at the end of January 2000, when it was also observed by the CAT Cerenkov telescope (see Pierre Espigat, these proceedings), and optical telescopes (but the...

  • Possible new identifications for Southern EGRET sources. Tornikoski, M.; La¨hteenma¨ki, A.; Lainela, M.; Valtaoja, E. // AIP Conference Proceedings;2001, Vol. 587 Issue 1, p673 

    We have made total flux density observations at high radio frequencies (90 and 230 GHz) of 12 Southern sources that were classified as possible ERGET identifications in the Third EGRET Catalog. Our observations confirm the blazar-nature of 9 of them. We have also studied sources that we...

  • Recent observations of 1ES2344+514 using the Whipple gamma-ray telescope. Badran for the VERITAS Collaboration, H. M. // AIP Conference Proceedings;2001, Vol. 587 Issue 1, p281 

    BL Lacertae objects are a class of AGN which are believed to be highly beamed. Very high energy gamma-rays emitted from such objects provide important information that improves our understanding of this class of objects. Only two AGNs, Mrk 421 and Mrk 501, are well established TeV emitters in...

  • Unusual properties of the radio structure of the BL Lac object 1749+701 on parsec scales. Gabuzda, D.; Lisakov, M. // Astronomy Reports;Jan2009, Vol. 53 Issue 1, p51 

    The results of simultaneous high-resolution radio observations of the BL Lac object 1749+701 at 5, 8.4, 15, and 22 GHz are presented. The source has a rich, extended structure displaying a number of interesting features: a strongly bent jet, the presence of transverse and longitudinal magnetic...

  • Search for Rapid Optical Variability in Three Gamma-Ray Loud Blazars. Poggiani, R. // Astrophysics & Space Science;Nov2006, Vol. 306 Issue 1/2, p17 

    I present the search for V, R, I rapid optical variability of three gamma-ray loud blazars, 3C 454.3, 1ES 1959+650, 1ES 2344+514, performed at the Loiano telescope. The source 3C 454.3 was observed during the decline of the May 2005 outburst. 3C 454.3 and 1ES 2344$+$514 showed rapid variability...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics