Related papers: Variable VHE gamma-ray emission from Markarian 501
The blazar Markarian 501 (Mrk 501) was observed above 100 GeV with the MAGIC Telescope during May, June and July 2005. The high sensitivity of the instrument made possible the detection of the source with high significance in each of the…
The Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope participated in three multiwavelength (MWL) campaigns, observing the blazar Markarian (Mkn) 421 during the nights of 2006 April 28, 29, and 2006 June 14. We analyzed the…
Markarian 501, a BL Lac object well-known as a high energy gamma-ray source, has exhibited several epochs of very high energy (VHE) gamma-ray flaring events when its synchrotron peak frequency shifted above $10^{17}$ Hz, a signature of…
In 2006 the MAGIC telescope observed the well known very high energy (VHE, > 80 GeV) blazars Mrk 421 and Mrk 501 in the course of multi-wavelength campaigns, comprising measurements in the optical, X-ray and VHE regime. MAGIC performed…
We present multiwavelength observations of the BL Lacertae object Markarian 501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated variability is seen in very high energy (VHE, E > 350 GeV) gamma-ray observations taken…
The HBL-type blazar Markarian 421 is one of the brightest TeV gamma-ray sources of the Northern sky. From December 2007 until June 2008 it was intensively observed in the VHE (E>100 GeV) band by the MAGIC gamma-ray telescope. The source…
The BL Lacertae object Markarian 501 was identified as a source of gamma-ray emission at the Whipple Observatory in March 1995. Here we present a flux variability analysis on several times-scales of the 233 hour data set accumulated over…
The very high energy (VHE; E $>$ 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54938--54956), 2009, as part of an extensive multi-wavelength campaign from radio to VHE. Strong VHE $\gamma$-ray activity was…
We present observations of the gamma-ray blazar Markarian 501 between April 17 and May 5, 2009, with the Whipple 10-m telescope, VERITAS, the Fermi Large Area Telescope (LAT), Swift and RXTE as part of a 4.5-month multi-wavelength campaign.…
The MAGIC telescope took data of very high energy gamma-ray emission from the blazar Markarian 421 (Mkn 421) between November 2004 and April 2005. We present a combined analysis of data samples recorded under different observational…
Very high energy gamma-ray emission from the BL Lac object Markarian 421 has been detected over three observing seasons on 59 nights between April 1992 and June 1994 with the Whipple 10-meter imaging Cherenkov telescope. During its initial…
We present X-ray observations of the BL Lacertae (BL Lac) object Markarian 501 (Mrk 501), taken with the Rossi X-ray Timing Explorer in 1998 May as part of a multi-wavelength campaign. The X-ray light curve shows a very rapid flare in which…
We present optical, X-ray, high energy ($\lessapprox 30$ GeV) and very high energy ($\gtrapprox 100$ GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high energy $\gamma$-ray signal…
The detection of spectral variability of the gamma-ray blazar Mrk 421 at TeV energies is reported. Observations with the Whipple Observatory 10m gamma-ray telescope taken in 2000/2001 revealed exceptionally strong and long-lasting flaring…
In this paper we report on the Markarian 501 results obtained during our TeV $\gamma$-ray observations from March 11 to May 12, 2005 and February 28 to May 7, 2006 for 112.5 hours with the TACTIC $\gamma$-ray telescope. During 2005…
Markarian 501, a nearby (z=0.033) X-ray selected BL Lacertae object, is a well established source of Very High Energy (VHE, E>=300 GeV) gamma rays. Dramatic variability in its gamma-ray emission on time-scales from years to as short as two…
A multiwavelength campaign was organized to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on…
A major flaring state of the BL Lac object Mrk 501 was observed by the High Energy Stereoscopic System (H.E.S.S.) in June, 2014. Flux levels higher than one Crab unit were recorded and rapid variability at very high energies ($\sim$2-20…
In 2008 the blazar Markarian 421 entered a very active phase and was one of the brightest sources in the sky at TeV energies, showing frequent flaring episodes. Using the data of ARGO-YBJ, a full coverage air shower detector located at…
We present optical to very-high energy (VHE) gamma-ray observations of Mrk 421 between 2008 May 24 and June 23. A high-energy (HE) gamma-ray signal was detected by AGILE-GRID during June 9-15, brighter than the average flux observed by…