2018A&A...612A...9H

Query : 2018A&A...612A...9H

2018A&A...612A...9H - Astronomy and Astrophysics, volume 612A9-9 (2018/4-1)

Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with H.E.S.S.

HESS COLLABORATION, ABDALLA H., ABRAMOWSKI A., AHARONIAN F., AIT BENKHALI F., AKHPERJANIAN A.G., ANDERSSON T., ANGUNER E.O., ARAKAWA M., ARRIETA M., AUBERT P., BACKES M., BALZER A., BARNARD M., BECHERINI Y., BECKER TJUS J., BERGE D., BERNHARD S., BERNLOHR K., BLACKWELL R., BOTTCHER M., BOISSON C., BOLMONT J., BONNEFOY S., BORDAS P., BREGEON J., BRUN F., BRUN P., BRYAN M., BUCHELE M., BULIK T., CAPASSO M., CARR J., CASANOVA S., CERRUTI M., CHAKRABORTY N., CHAVES R.C.G., CHEN A., CHEVALIER J., COFFARO M., COLAFRANCESCO S., COLOGNA G., CONDON B., CONRAD J., CUI Y., DAVIDS I.D., DECOCK J., DEGRANGE B., DEIL C., DEVIN J., DEWILT P., DIRSON L., DJANNATI-ATAI A., DOMAINKO W., DONATH A., DRURY L.O., DUTSON K., DYKS J., EDWARDS T., EGBERTS K., EGER P., ERNENWEIN J.-P., ESCHBACH S., FARNIER C., FEGAN S., FERNANDES M.V., FIASSON A., FONTAINE G., FORSTER A., FUNK S., FUSSLING M., GABICI S., GALLANT Y.A., GARRIGOUX T., GIAVITTO G., GIEBELS B., GLICENSTEIN J.F., GOTTSCHALL D., GOYAL A., GRONDIN M.-H., HAHN J., HAUPT M., HAWKES J., HEINZELMANN G., HENRI G., HERMANN G., HINTON J.A., HOFMANN W., HOISCHEN C., HOLCH T.L., HOLLER M., HORNS D., IVASCENKO A., IWASAKI H., JACHOLKOWSKA A., JAMROZY M., JANIAK M., JANKOWSKY D., JANKOWSKY F., JINGO M., JOGLER T., JOUVIN L., JUNG-RICHARDT I., KASTENDIECK M.A., KATARZYNSKI K., KATSURAGAWA M., KATZ U., KERSZBERG D., KHANGULYAN D., KHELIFI B., KING J., KLEPSER S., KLOCHKOV D., KLUZNIAK W., KOLITZUS D., KOMIN N., KOSACK K., KRAKAU S., KRAUS M., KRUGER P.P., LAFFON H., LAMANNA G., LAU J., LEES J.-P., LEFAUCHEUR J., LEFRANC V., LEMIERE A., LEMOINE-GOUMARD M., LENAIN J.-P., LESER E., LOHSE T., LORENTZ M., LIU R., LOPEZ-COTO R., LYPOVA I., MARANDON V., MARCOWITH A., MARIAUD C., MARX R., MAURIN G., MAXTED N., MAYER M., MEINTJES P.J., MEYER M., MITCHELL A.M.W., MODERSKI R., MOHAMED M., MOHRMANN L., MORA K., MOULIN E., MURACH T., NAKASHIMA S., DE NAUROIS M., NIEDERWANGER F., NIEMIEC J., OAKES L., O'BRIEN P., ODAKA H., OHM S., OSTROWSKI M., OYA I., PADOVANI M., PANTER M., PARSONS R.D., PEKEUR N.W., PELLETIER G., PERENNES C., PETRUCCI P.-O., PEYAUD B., PIEL Q., PITA S., POON H., PROKHOROV D., PROKOPH H., PUHLHOFER G., PUNCH M., QUIRRENBACH A., RAAB S., RAUTH R., REIMER A., REIMER O., RENAUD M., DE LOS REYES R., RICHTER S., RIEGER F., ROMOLI C., ROWELL G., RUDAK B., RULTEN C.B., SAHAKIAN V., SAITO S., SALEK D., SANCHEZ D.A., SANTANGELO A., SASAKI M., SCHLICKEISER R., SCHUSSLER F., SCHULZ A., SCHWANKE U., SCHWEMMER S., SEGLAR-ARROYO M., SETTIMO M., SEYFFERT A.S., SHAFI N., SHILON I., SIMONI R., SOL H., SPANIER F., SPENGLER G., SPIES F., STAWARZ L., STEENKAMP R., STEGMANN C., STYCZ K., SUSHCH I., TAKAHASHI T., TAVERNET J.-P., TAVERNIER T., TAYLOR A.M., TERRIER R., TIBALDO L., TIZIANI D., TLUCZYKONT M., TRICHARD C., TSUJI N., TUFFS R., UCHIYAMA Y., VAN DER WALT D.J., VAN ELDIK C., VAN RENSBURG C., VAN SOELEN B., VASILEIADIS G., VEH J., VENTER C., VIANA A., VINCENT P., VINK J., VOISIN F., VOLK H.J., VUILLAUME T., WADIASINGH Z., WAGNER S.J., WAGNER P., WAGNER R.M., WHITE R., WIERZCHOLSKA A., WILLMANN P., WORNLEIN A., WOUTERS D., YANG R., ZABOROV D., ZACHARIAS M., ZANIN R., ZDZIARSKI A.A., ZECH A., ZEFI F., ZIEGLER A. and ZYWUCKA N.

Abstract (from CDS):

The diffuse very high-energy (VHE; >100GeV) γ-ray emission observed in the central 200pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal distance of about 130pc to the Galactic centre (GC), where the flux rapidly decreases. This was initially interpreted as the result of a burst-like injection of energetic particles 104yr ago, but a recent more sensitive H.E.S.S. analysis revealed that the cosmic-ray (CR) density profile drops with the distance to the centre, making data compatible with a steady cosmic PeVatron at the GC. In this paper, we extend this analysis to obtain, for the first time, a detailed characterisation of the correlation with matter and to search for additional features and individual γ-ray sources in the inner 200pc. Taking advantage of 250h of H.E.S.S. data and improved analysis techniques, we perform a detailed morphology study of the diffuse VHE emission observed from the GC ridge and reconstruct its total spectrum. To test the various contributions to the total γ-ray emission, we used an iterative 2D maximum-likelihood approach that allows us to build a phenomenological model of the emission by summing a number of different spatial components. We show that the emission correlated with dense matter covers the full CMZ and that its flux is about half the total diffuse emission flux. We also detect some emission at higher latitude that is likely produced by hadronic collisions of CRs in less dense regions of the GC interstellar medium. We detect an additional emission component centred on the GC and extending over about 15 pc that is consistent with the existence of a strong CR density gradient and confirms the presence of a CR accelerator at the very centre of our Galaxy. We show that the spectrum of full ridge diffuse emission is compatible with that previously derived from the central regions, suggesting that a single population of particles fills the entire CMZ. Finally, we report the discovery of a VHE γ-ray source near the GC radio arc and argue that it is produced by the pulsar wind nebula candidate G0.13-0.11.

Abstract Copyright: © ESO 2018

Journal keyword(s): gamma rays: general - gamma rays: ISM - Galaxy: center - cosmic rays

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 3FHL J1746.2-2852 LXB 17 44 33.09 -28 44 27.0           ~ 559 0
2 NAME Sgr C MoC 17 44 36.3 -29 28 13           ~ 400 0
3 2CG 359+00 gam 17 45 11 -30 11.9           ~ 104 0
4 NAME Fermi Bubbles bub 17 45 -29.0           ~ 525 0
5 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
6 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4970 3
7 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 561 0
8 NAME Sickle HII 17 46 15.2 -28 49 49           ~ 128 0
9 NAME X-Ray Thread G0.13-0.11 X 17 46.4 -28 53           ~ 7 1
10 NAME Sgr B MoC 17 47 02 -28 25.4           ~ 241 0
11 SNR G000.9+00.1 SNR 17 47.3 -28 09           ~ 222 1
12 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2443 1
13 NAME Sgr D MoC 17 48 41.75 -28 01 45.0           ~ 137 1

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