3 research outputs found
MAGIC discovery of Very High Energy Emission from the FSRQ PKS 1222+21
Very High Energy (VHE) gamma-ray emission from the flat spectrum radio quasar
(FSRQ) PKS 1222+21 (4C 21.35, z=0.432) was detected with the MAGIC Cherenkov
telescopes during a short observation (~0.5 hr) performed on 2010 June 17. The
MAGIC detection coincides with high energy MeV/GeV gamma-ray activity measured
by the Large Area Telescope (LAT) on board the Fermi satellite. The VHE
spectrum measured by MAGIC extends from about 70 GeV up to at least 400 GeV and
can be well described by a power law dN/dE \propto E^-Gamma with a photon index
Gamma= 3.75+/-0.27stat +/-0.2syst. The averaged integral flux above 100 GeV is
(4.56+/-0.46)x10^(-10) cm^-2 s^-1 (~1 Crab Nebula flux). The VHE flux measured
by MAGIC varies significantly within the 30 min exposure implying a flux
doubling time of about 10 min. The VHE and MeV/GeV spectra, corrected for the
absorption by the extragalactic background light (EBL), can be described by a
single power law with photon index 2.72+/-0.34 between 3 GeV and 400 GeV, and
is consistent with emission belonging to a single component in the jet. The
absence of a spectral cutoff constrains the gamma-ray emission region outside
the Broad Line Region, which would otherwise absorb the VHE gamma-rays.
Together with the detected fast variability, this challenges present emission
models from jets in FSRQ. Moreover, the combined Fermi/LAT and MAGIC spectral
data yield constraints on the density of the Extragalactic Background Light in
the UV-optical to near-infrared range that are compatible with recent models.Comment: 6 pages, 5 figur
Discovery of VHE\u3b3-rays from the blazar 1ES\ua01215+303 with the MAGIC telescopes and simultaneous multi-wavelength observations
Context. We present the discovery of very high energy (VHE, E > 100GeV)
gamma-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes
and simultaneous multi-wavelength data in a broad energy range from radio to
gamma-rays. Aims. We study the VHE gamma-ray emission from 1ES 1215+303 and its
relation to the emissions in other wavelengths. Methods. Triggered by an
optical outburst, MAGIC observed the source in January-February 2011 for 20.3
hrs. The target was monitored in the optical R-band by the KVA telescope that
also performed optical polarization measurements. We triggered target of
opportunity observations with the Swift satellite and obtained simultaneous and
quasi-simultaneous data from the Fermi Large Area Telescope and from the
Mets\"ahovi radio telescope. We also present the analysis of older MAGIC data
taken in 2010. Results. The MAGIC observations of 1ES 1215+303 carried out in
January-February 2011 resulted in the first detection of the source at VHE with
a statistical significance of 9.4 sigma. Simultaneously, the source was
observed in a high optical and X-ray state. In 2010 the source was observed in
a lower state in optical, X-ray, and VHE, while the GeV gamma-ray flux and the
radio flux were comparable in 2010 and 2011. The spectral energy distribution
obtained with the 2011 data can be modeled with a simple one zone SSC model,
but it requires extreme values for the Doppler factor or the electron energy
distribution.Comment: 10 pages, 8 figures, accepted to A&