2009ApJ...699..817A

Query : 2009ApJ...699..817A

2009ApJ...699..817A - Astrophys. J., 699, 817-823 (2009/July-1)

Early Fermi gamma-ray space telescope observations of the quasar 3C 454.3.

ABDO A.A., ACKERMANN M., AJELLO M., ATWOOD W.B., AXELSSON M., BALDINI L., BALLET J., BARBIELLINI G., BASTIERI D., BATTELINO M., BAUGHMAN B.M., BECHTOL K., BELLAZZINI R., BERENJI B., BLANDFORD R.D., BLOOM E.D., BONAMENTE E., BORGLAND A.W., BOUVIER A., BREGEON J., BREZ A., BRIGIDA M., BRUEL P., BURNETT T.H., CALIANDRO G.A., CAMERON R.A., CARAVEO P.A., CASANDJIAN J.M., CAVAZZUTI E., CECCHI C., CHARLES E., CHATY S., CHEKHTMAN A., CHEUNG C.C., CHIANG J., CIPRINI S., CLAUS R., COHEN-TANUGI J., COMINSKY L.R., CONRAD J., COSTAMANTE L., CUTINI S., DERMER C.D., DE ANGELIS A., DE PALMA F., DIGEL S.W., DO COUTO E SILVA E., DONATO D., DRELL P.S., DUBOIS R., DUMORA D., FARNIER C., FAVUZZI C., FOCKE W.B., FOSCHINI L., FRAILIS M., FUHRMANN L., FUKAZAWA Y., FUNK S., FUSCO P., GARGANO F., GASPARRINI D., GEHRELS N., GERMANI S., GIEBELS B., GIGLIETTO N., GIOMMI P., GIORDANO F., GLANZMAN T., GODFREY G., GRENIER I.A., GRONDIN M.-H., GROVE J.E., GUILLEMOT L., GUIRIEC S., HANABATA Y., HARDING A.K., HARTMAN R.C., HAYASHIDA M., HAYS E., HUGHES R.E., JOHANNESSON G., JOHNSON A.S., JOHNSON R.P., JOHNSON W.N., KAMAE T., KATAGIRI H., KATAOKA J., KAWAI N., KERR M., KNODLSEDER J., KOCIAN M.L., KUEHN F., KUSS M., LATRONICO L., LEE S.-H., LEMOINE-GOUMARD M., LONGO F., LOPARCO F., LOTT B., LOVELLETTE M.N., LUBRANO P., MADEJSKI G.M., MAKEEV A., MASSARO E., MAZZIOTTA M.N., McENERY J.E., McGLYNN S., MEURER C., MICHELSON P.F., MITTHUMSIRI W., MIZUNO T., MOISEEV A.A., MONTE C., MONZANI M.E., MORSELLI A., MOSKALENKO I.V., MURGIA S., NOLAN P.L., NORRIS J.P., NUSS E., OHSUGI T., OMODEI N., ORLANDO E., ORMES J.F., PANEQUE D., PANETTA J.H., PARENT D., PELASSA V., PEPE M., PESCE-ROLLINS M., PIRON F., PORTER T.A., RAINO S., RANDO R., RAZZANO M., REIMER A., REIMER O., REPOSEUR T., REYES L.C., RITZ S., ROCHESTER L.S., RODRIGUEZ A.Y., RAHOUI F., RYDE F., SADROZINSKI H.F.-W., SAMBRUNA R., SANCHEZ D., SANDER A., SAZ PARKINSON P.M., SGRO C., SHAW M.S., SMITH D.A., SMITH P.D., SPANDRE G., SPINELLI P., STARCK J.-L., STRICKMAN M.S., SUSON D.J., TAJIMA H., TAKAHASHI H., TAKAHASHI T., TANAKA T., THAYER J.B., THAYER J.G., THOMPSON D.J., TIBALDO L., TORRES D.F., TOSTI G., TRAMACERE A., UCHIYAMA Y., USHER T.L., VILCHEZ N., VILLATA M., VITALE V., WAITE A.P., WINER B.L., WOOD K.S., YLINEN T., ZENSUS J.A. and ZIEGLER M.

Abstract (from CDS):

This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable γ-ray emission with an average flux of ∼3x10^–6 photons/cm2/s, for energies >100 MeV. The γ-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor δ>8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (δ ∼ 25). The observed γ-ray spectrum is not consistent with a simple power law, but instead steepens strongly above ∼2 GeV, and is well described by a broken power law with photon indices of ∼2.3 and ∼3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2 GeV could be due to γ-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (≲100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

Abstract Copyright: ∼

Journal keyword(s): galaxies: active - gamma rays: observations - quasars: individual: 3C 454.3

Simbad objects: 5

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Number of rows : 5

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag B	Mag V	Mag R	Sp type	#ref 1850 - 2026	#notes
1	NAME Vela	SNR	08 34.0	-45 50				~	1331	2
2	3C 279	Bla	12 56 11.16657958	-05 47 21.5251510	18.01	17.75	15.87	~	3205	2
3	QSO J1626-2951	Bla	16 26 06.02084013	-29 51 26.9712990	18.41	20.5	17.6	~	452	1
4	PSR J1836+5925	Psr	18 36 13.661	+59 25 29.77				~	153	0
5	3C 454.3	Bla	22 53 57.7480438728	+16 08 53.561508864	16.57	16.10	15.22	~	3004	2

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