Detection of TeV photons from the active galaxy Markarian 421
نویسندگان
چکیده
منابع مشابه
Markarian 421’s Unusual Satellite Galaxy
We present Hubble Space Telescope (HST) imagery and photometry of the active galaxy Markarian 421 and its companion galaxy 14 arcsec to the ENE. The HST images indicate that the companion is a morphological spiral rather than elliptical as previous ground–based imaging has concluded. The companion has a bright, compact nucleus, appearing unresolved in the HST images. This is suggestive of Seyfe...
متن کاملTeV OBSERVATIONS OF THE VARIABILITY AND SPECTRUM OF MARKARIAN 421
Markarian 421 was the first extragalactic source to be detected with high statistical certainty at TeV energies. The Whipple Observatory gamma-ray telescope has been used to observe the Active Galactic Nucleus, Markarian 421 in 1996 and 1997. The rapid variability observed in TeV gamma rays in previous years is confirmed. Doubling times as short as 15 minutes are reported with flux levels reach...
متن کاملThe June 2008 Flare of Markarian 421 from Optical to Tev Energies
We present optical, X-ray, high energy (/ 30 GeV) and very high energy (' 100 GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high energy γ-ray signal was detected by AGILE with √ TS = 4.5 on June 9–15, with F (E > 100 MeV) = 42 −12 × 10 photons cm s. This flaring state is brighter than the average flux observed by EGRET by a factor of...
متن کاملSimultaneous X-Ray and TeV Observations of a Rapid Flare from Markarian 421.
Mrk 421 was observed for about 2 days with BeppoSAX in 1998 April as part of a worldwide multiwavelength campaign. A large, well-defined flare was observed in X-rays. The same flare was observed simultaneously at TeV energies by the Whipple Observatory gamma-ray telescope. These data provide (1) the first evidence that the X-ray and TeV intensities are well correlated on timescales of hours and...
متن کاملObservation of gamma - rays greater than 10 TeV from Markarian 421
We have observed Markarian 421 in January and March 2001 with the CANGAROO-II imaging Cherenkov telescope during an extraordinarily high state at TeV energies. From 14 hours observations at very large zenith angles, Institute for Cosmic Ray Research, University of Tokyo, Chiba 277-8582, Japan Department of Physics, Kyoto University, Kyoto 606-8502, Japan MSSSO, Australian National University, A...
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ژورنال
عنوان ژورنال: Nature
سال: 1992
ISSN: 0028-0836,1476-4687
DOI: 10.1038/358477a0