2010A&A...516L..11G

Query : 2010A&A...516L..11G

2010A&A...516L..11G - Astronomy and Astrophysics, volume 516, L11-11 (2010/6-2)

AGILE detection of GeV γ-ray emission from the SNR W28.

GIULIANI A., TAVANI M., BULGARELLI A., STRIANI E., SABATINI S., CARDILLO M., FUKUI Y., KAWAMURA A., OHAMA A., FURUKAWA N., TORII K., SANO H., AHARONIAN F.A., VERRECCHIA F., ARGAN A., BARBIELLINI G., CARAVEO P.A., CATTANEO P.W., CHEN A.W., COCCO V., COSTA E., D'AMMANDO F., DEL MONTE E., DE PARIS G., DI COCCO G., DONNARUMMA I., EVANGELISTA Y., FEROCI M., FIORINI M., FROYSLAND T., FUSCHINO F., GALLI M., GIANOTTI F., LABANTI C., LAPSHOV Y., LAZZAROTTO F., LIPARI P., LONGO F., MARISALDI M., MEREGHETTI S., MORSELLI A., MORETTI E., PACCIANI L., PELLIZZONI A., PEROTTI F., PICOZZA P., PILIA M., PREST M., PUCELLA G., RAPISARDA M., RAPPOLDI A., SOFFITTA P., TRIFOGLIO M., TROIS A., VALLAZZA E., VERCELLONE S., VITTORINI V., ZAMBRA A., ZANELLO D., PITTORI C., SANTOLAMAZZA P., GIOMMI P., COLAFRANCESCO S. and SALOTTI L.

Abstract (from CDS):

Supernova remnants (SNRs) are believed to be the main sources of Galactic cosmic rays. Molecular clouds associated with SNRs can produce gamma-ray emission by means of the interaction of accelerated particles with the concentrated gas. The middle-aged SNR W28, because of its associated system of dense molecular clouds, provides an excellent opportunity to test this hypothesis. We present the AGILE/GRID observations of SNR W28, and compare them with observations at other wavelengths (TeV and ¹²CO (J=1->0) molecular line emission). The gamma-ray flux detected by AGILE from the dominant source associated with W28 is (14±5)x10^–8ph/cm2/s for E>400MeV. This source is positionally well correlated with the TeV emission observed by the HESS telescope. The local variations in the GeV to TeV flux ratio imply that there is a difference between the CR spectra of the north-west and south molecular cloud complexes. A model based on a hadronic-induced interaction and diffusion with two molecular clouds at different distances from the W28 shell can explain both the morphological and spectral features observed by both AGILE in the MeV-GeV energy range and the HESS telescope in the TeV energy range. The combined set of AGILE and H.E.S.S. data strongly support a hadronic model for the gamma-ray production in W28.

Abstract Copyright: ∼

Journal keyword(s): acceleration of particles - diffusion - ISM: supernova remnants - gamma rays: ISM

CDS comments: In ref list Abdo et al. 2009 is Abdo 2009ApJS..183...46A

Simbad objects: 5

Full paper

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Number of rows : 5

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Sp type	#ref 1850 - 2023	#notes
1	[AAB2008b] southern cloud	MoC	18 00 30.0	-24 05 00	~	3	1
2	HESS J1800-240	gam	18 00 37	-23 59.8	~	25	0
3	SNR G006.4-00.1	SNR	18 01 22.7	-23 17 20	~	719	1
4	[AAB2008b] northeastern cloud	MoC	18 02 00.0	-23 20 00	~	4	1
5	1AGL J1803-2258	gam	18 03 00.0	-22 58 00	~	2	1

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