Related papers: X-ray Flares from Markarian 501
During remarkable flaring activity in 1997 Markarian 501 was the brightest source in the sky at TeV energies, outshining the Crab Nebula by a factor of up to 10. Periods of flaring activity each lasting a few days were observed…
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…
We present results from multi-wavelength study of intense flaring activity from a high frequency peaked BL Lac object Mrk 421. The source was observed in its flaring state on February 16, 2010 with the $TACTIC$ at energies above 1.5 TeV.…
The blazar Markarian 421 (Mrk 421) is one of the brightest sources in the extragalactic X-ray/TeV sky. It is also one of the fastest varying TeV $\gamma$-ray sources, showing flaring activity on time scales as short as tens of minutes. To…
Mrk~421 is one of the most fascinating blazars, widely studied across the electromagnetic spectrum using observations at various wavebands, from radio to the TeV gamma ray bands. We present the first detailed spectral and timing analysis of…
We present the results of a multiwavelength campaign for Mrk 501 performed in March 1996 with ASCA, EGRET, Whipple, and optical telescopes. In the X-ray band, a spectral break was observed around 2 keV. We report here for the first time the…
The gamma-ray emission above 250 GeV from the BL Lac object Markarian 421 was observed by the CAT Cherenkov imaging telescope between December, 1996, and June, 2000. In 1998, the source produced a series of small flares, making it the…
One of remarkable features of the gamma ray blazar Markarian 501 is the reported shape of the TeV spectrum, which during strong flares of the source remains essentially stable despite dramatic variations of the absolute gamma-ray flux. I…
We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with special focus on the multi-band flux correlations. The dataset has been collected through an…
The energy spectrum of Markarian~421 in flaring states has been measured from 0.3 to 10 TeV using both small zenith angle and large zenith angle observations with the Whipple Observatory 10 m imaging telescope. The large zenith angle…
We report on the findings of a 364 ksec observation of the BL LAC object Mrk 421 with the X-ray observatory Suzaku. The analysis in this paper uses fluxes and hardness ratios in the broad energy range from 0.5 keV to 30 keV. During the…
The origin of the gamma-ray emission of the blazar Mrk 421 is still a matter of debate. We used 5.5 years of unbiased observing campaign data, obtained using the FACT telescope and the Fermi LAT detector at TeV and GeV energies, the longest…
The energy dissipation mechanism in blazar jet is unknown. Blazar's flares could provide insights on this problem. Here we report statistical results of XMM-Newton X-ray flares of Mrk 421. We analyze all public XMM-Newton X-ray observations…
A flare from the TeV blazar Mrk 421, occurring in March 2010, was observed for 13 consecutive days from radio to very high energy (VHE, E > 100 GeV) gamma-rays with MAGIC, VERITAS, Whipple, FermiLAT, MAXI, RXTE, Swift, GASP-WEBT, and…
We report on the VLBI follow-up observations using the Japanese VLBI Network (JVN) array at 22 GHz for the largest X-ray flare of TeV blazar Mrk 421 that occurred in mid-February, 2010. The total of five epochs of observations were…
Using the cross-spectral method, we confirm the existence of the X-ray hard lags discovered with cross-correlation function technique during a large flare of Mrk 421 observed with BeppoSAX . For the 0.1--2 versus 2--10keV light curves, both…
The blazar Mrk 501 (z=0.034) was observed at very-high-energy (VHE, $E\gtrsim 100$~GeV) gamma-ray wavelengths during a bright flare on the night of 2014 June 23-24 (MJD 56832) with the H.E.S.S. phase-II array of Cherenkov telescopes. Data…
The TeV blazar Ton 599 has exhibited a peculiar flare in 2017 November. The temporal variation of the source is studied using simultaneous $\gamma$-ray data from $\textit{Fermi}$ Large Area Telescope and radio data from Owens Valley Radio…
We observed the BL Lac object Markarian 421 with the X-ray satellite RXTE and the Whipple Air Cerenkov Telescope during a two week correlated X-ray/gamma-ray campaign in May 1996. Two dramatic outbursts with extremely rapid and strong flux…
In April 2013, the TeV blazar Markarian~421 underwent one of its most powerful emission outbursts to date. An extensive multi-instrument campaign featuring MAGIC, VERITAS, and \textit{NuSTAR} provided comprehensive very-high-energy (VHE; $E…