RT Journal Article
T1 Detection of very-high energy gamma-ray emission from NGC 1275 by the MAGIC telescopes
A1 Antoranz Canales, Pedro
A1 Barrio Uña, Juan Abel
A1 Contreras González, José Luis
A1 Fonseca González, María Victoria
A1 Miranda Pantoja, José Miguel
A1 Scapin, Valeria
AB We report on the detection of very-high energy (VHE, E > 100 GeV) gamma-ray emission from NGC 1275, the central radio galaxy of the Perseus cluster of galaxies. The source has been detected by the MAGIC telescopes with a statistical significance of 6.6s above 100 GeV in 46 h of stereo observations carried out between August 2010 and February 2011. The measured differential energy spectrum between 70 GeV and 500 GeV can be described by a power law with a steep spectral index of Gamma = -4.1 +/- 0.7(stat) +/- 0.3(syst), and the average flux above 100 GeV is F-gamma = (1.3 +/- 0.2(stat) +/- 0.3(syst)) x 10(-11) cm(-2) s(-1). These results, combined with the power-law spectrum measured in the first two years of observations by the Fermi-LAT above 100 MeV, with a spectral index of Gamma similar or equal to -2.1, strongly suggest the presence of a break or cut-off around tens of GeV in the NGC 1275 spectrum. The light curve of the source above 100 GeV does not show hints of variability on a month time scale. Finally, we report on the nondetection in the present data of the radio galaxy IC 310, previously discovered by the Fermi-LAT and MAGIC. The derived flux upper limit F-gamma(U.L.) (> 300 GeV) = 1.2 x 10(-12) cm(-2) s(-1) is a factor similar to 3 lower than the mean flux measured by MAGIC between October 2009 and February 2010, thus confirming the year time-scale variability of the source at VHE.
PB EDP Sciences
SN 0004-6361
YR 2012
FD 2012-03
LK https://hdl.handle.net/20.500.14352/43811
UL https://hdl.handle.net/20.500.14352/43811
LA eng
NO © ESO. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the Marie Curie program, by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 program, by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the Academy of Finland, by the YIP of the Helmholtz Gemeinschaft, by the DFG Cluster of Excellence “Origin and Structure of the Universe”, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0. C.P. gratefully acknowledges financial support of the Klaus Tschira Foundation
NO German MPG
NO German BMBF
NO Italian INFN
NO Swiss National Fund SNF
NO Spanish MICINN
NO Marie Curie program
NO Spanish Consolider-Ingenio program
NO Bulgarian NSF
NO Academy of Finland
NO YIP of the Helmholtz Gemeinschaft
NO DFG Cluster of Excellence "Origin and Structure of the Universe"
NO DFG Collaborative Research Centers
NO Polish MNiSzW
NO Klaus Tschira Foundation
DS Docta Complutense
RD 19 abr 2025