2014A&A...564A...5A

Query : 2014A&A...564A...5A

2014A&A...564A...5A - Astronomy and Astrophysics, volume 564A, 5-5 (2014/4-1)

Contemporaneous observations of the radio galaxy NGC 1275 from radio to very high energy γ-rays.

ALEKSIC J., ANSOLDI S., ANTONELLI L.A., ANTORANZ P., BABIC A., BANGALE P., BARRES DE ALMEIDA U., BARRIO J.A., BECERRA GONZALEZ J., BEDNAREK W., BERGER K., BERNARDINI E., BILAND A., BLANCH O., BOCK R.K., BONNEFOY S., BONNOLI G., BORRACCI F., BRETZ T., CARMONA E., CAROSI A., CARRETO FIDALGO D., COLIN P., COLOMBO E., CONTRERAS J.L., CORTINA J., COVINO S., DA VELA P., DAZZI F., DE ANGELIS A., DE CANEVA G., DE LOTTO B., DELGADO MENDEZ C., DOERT M., DOMINGUEZ A., DOMINIS PRESTER D., DORNER D., DORO M., EINECKE S., EISENACHER D., ELSAESSER D., FARINA E., FERENC D., FONSECA M.V., FONT L., FRANTZEN K., FRUCK C., GARCIA LOPEZ R.J., GARCZARCZYK M., GARRIDO TERRATS D., GAUG M., GIAVITTO G., GODINOVIC N., GONZALEZ MUNOZ A., GOZZINI S.R., HADAMEK A., HADASCH D., HERRERO A., HILDEBRAND D., HOSE J., HRUPEC D., IDEC W., KADENIUS V., KELLERMANN H., KNOETIG M.L., KRAUSE J., KUSHIDA J., LA BARBERA A., LELAS D., LEWANDOWSKA N., LINDFORS E., LOMBARDI S., LOPEZ M., LOPEZ-COTO R., LOPEZ-ORAMAS A., LORENZ E., LOZANO I., MAKARIEV M., MALLOT K., MANEVA G., MANKUZHIYIL N., MANNHEIM K., MARASCHI L., MARCOTE B., MARIOTTI M., MARTINEZ M., MAZIN D., MENZEL U., MEUCCI M., MIRANDA J.M., MIRZOYAN R., MORALEJO A., MUNAR-ADROVER P., NAKAJIMA D., NIEDZWIECKI A., NILSSON K., NOWAK N., ORITO R., OVERKEMPING A., PAIANO S., PALATIELLO M., PANEQUE D., PAOLETTI R., PAREDES J.M., PAREDES-FORTUNY X., PARTINI S., PERSIC M., PRADA F., PRADA MORONI P.G., PRANDINI E., PREZIUSO S., PULJAK I., REINTHAL R., RHODE W., RIBO M., RICO J., RODRIGUEZ GARCIA J., RUEGAMER S., SAGGION A., SAITO T., SAITO K., SALVATI M., SATALECKA K., SCALZOTTO V., SCAPIN V., SCHULTZ C., SCHWEIZER T., SHORE S.N., SILLANPAEAE A., SITAREK J., SNIDARIC I., SOBCZYNSKA D., SPANIER F., STAMATESCU V., STAMERRA A., STEINBRING T., STORZ J., SUN S., SURIC T., TAKALO L., TAVECCHIO F., TERZIC T., TESCARO D., TESHIMA M., THAELE J., TIBOLLA O., TORRES D.F., TOYAMA T., TREVES A., UELLENBECK M., VOGLER P., WAGNER R.M., ZANDANEL F., ZANIN R., BALMAVERDE B., KATAOKA J., REKOLA R. and TAKAHASHI Y.

Abstract (from CDS):

The radio galaxy NGC1275, recently identified as a very high energy (VHE, >100GeV) γ-ray emitter by MAGIC, is one of the few non-blazar active galactic nuclei detected in the VHE regime. The purpose of this work is to better understand the origin of the γ-ray emission and locate it within the galaxy. We studied contemporaneous multifrequency observations of NGC1275 and modeled the overall spectral energy distribution. We analyzed unpublished MAGIC observations carried out between October 2009 and February 2010, and the previously published observations taken between August 2010 and February 2011. We studied the multiband variability and correlations by analyzing data of Fermi-LAT in the 100MeV-100GeV energy band, as well as Chandra (X-ray), KVA (optical), and MOJAVE (radio) data taken during the same period. Using customized Monte Carlo simulations corresponding to early MAGIC stereoscopic data, we detect NGC1275 also in the earlier MAGIC campaign. The flux level and energy spectra are similar to the results of the second campaign. The monthly light curve above 100GeV shows a hint of variability at the 3.6σ level. In the Fermi-LAT band, both flux and spectral shape variabilities are reported. The optical light curve is also variable and shows a clear correlation with the γ-ray flux above 100MeV. In radio, three compact components are resolved in the innermost part of the jet. One of these components shows a similar trend as the Fermi-LAT and KVA light curves. The γ-ray spectra measured simultaneously with MAGIC and Fermi-LAT from 100MeV to 650GeV can be well fitted either by a log-parabola or by a power-law with a subexponential cutoff for the two observation campaigns. A single-zone synchrotron-self-Compton model, with an electron spectrum following a power-law with an exponential cutoff, can explain the broadband spectral energy distribution and the multifrequency behavior of the source. However, this model suggests an untypical low bulk-Lorentz factor or a velocity alignment closer to the line of sight than the parsec-scale radio jet.

Abstract Copyright: ∼

Journal keyword(s): galaxies: active - gamma rays: galaxies - galaxies: jets - galaxies: individual: NGC 1275

Simbad objects: 6

Full paper

View the references in ADS

Number of rows : 6

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Mag R	Mag I	Sp type	#ref 1850 - 2024	#notes
1	IC 310	rG	03 16 42.9787569912	+41 19 29.615579544		14.3				~	281	2
2	ACO 426	ClG	03 19 47.2	+41 30 47						~	2257	1
3	3C 84	Sy2	03 19 48.1599902040	+41 30 42.108850836		13.10	12.48	11.09		~	4008	3
4	M 1	SNR	05 34 30.9	+22 00 53						~	6191	1
5	M 87	AGN	12 30 49.42338414	+12 23 28.0436859	10.16	9.59	8.63		7.49	~	7192	3
6	NAME Centaurus A	Sy2	13 25 27.61521044	-43 01 08.8050291		8.18	6.84	6.66		~	4484	3

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