1999/06/11 by M. Catanese, Catanese, M., I. H. Bond +82
Physics and Astronomy · #Astrophysics (astro-ph) #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Gamma-ray bursts and supernovae #Historical Astronomy and Related Studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9906209
4 pages, 1 figure, to be published in the proceedings of the 26th ICRC (Salt Lake City, 1999)
arxiv created 1999/06/11 · openalex publication_date 1999/06/11 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Markarian 421 was observed for about four days with BeppoSAX and the Whipple Observatory gamma-ray telescope in April 1998. A pronounced, well-defined, flare with hour-scale variability was observed simultaneously in X-rays and very high energy gamma-rays. These data provide the first evidence that the X-ray and TeV intensities are well correlated on time-scales of hours. While the rise of the flare occurred on a similar time-scale in the two wavebands, the decay of the flare was much more rapid in gamma rays, providing the first clear indication that the X-ray and gamma-ray emission may not be completely correlated in Markarian 421.