2020A&A...642A.190M

Query : 2020A&A...642A.190M

2020A&A...642A.190M - Astronomy and Astrophysics, volume 642A190-190 (2020/10-1)

MAGIC observations of the diffuse γ-ray emission in the vicinity of the Galactic center.

MAGIC COLLABORATION, ACCIARI V.A., ANSOLDI S., ANTONELLI L.A., ARBET ENGELS A., BAACK D., BABIC A., BANERJEE B., BARRES DE ALMEIDA U., BARRIO J.A., BECERRA GONZALEZ J., BEDNAREK W., BELLIZZI L., BERNARDINI E., BERTI A., BESENRIEDER J., BHATTACHARYYA W., BIGONGIARI C., BILAND A., BLANCH O., BONNOLI G., BOSNJAK Z., BUSETTO G., CAROSI R., CERIBELLA G., CHAI Y., CHILINGARYAN A., CIKOTA S., COLAK S.M., COLIN U., COLOMBO E., CONTRERAS J.L., CORTINA J., COVINO S., D'ELIA V., DA VELA P., DAZZI F., DE ANGELIS A., DE LOTTO B., DELFINO M., DELGADO J., DEPAOLI D., DI PIERRO F., DI VENERE L., DO SOUTO ESPINEIRA E., DOMINIS PRESTER D., DONINI A., DORNER D., DORO M., ELSAESSER D., FALLAH RAMAZANI V., FATTORINI A., FERNANDEZ-BARRAL A., FERRARA G., FIDALGO D., FOFFANO L., FONSECA M.V., FONT L., FRUCK C., FUKAMI S., GARCIA LOPEZ R.J., GARCZARCZYK M., GASPARYAN S., GAUG M., GIGLIETTO N., GIORDANO F., GODINOVIC N., GREEN D., GUBERMAN D., HADASCH D., HAHN A., HERRERA J., HOANG J., HRUPEC D., HUTTEN M., INADA T., INOUE S., ISHIO K., IWAMURA Y., JOUVIN L., KERSZBERG D., KUBO H., KUSHIDA J., LAMASTRA A., LELAS D., LEONE F., LINDFORS E., LOMBARDI S., LONGO F., LOPEZ M., LOPEZ-COTO R., LOPEZ-ORAMAS A., LOPORCHIO S., MACHADO DE OLIVEIRA FRAGA B., MAGGIO C., MAJUMDAR P., MAKARIEV M., MALLAMACI M., MANEVA G., MANGANARO M., MANNHEIM K., MARASCHI L., MARIOTTI M., MARTINEZ M., MASUDA S., MAZIN D., MICANOVIC S., MICELI D., MINEV M., MIRANDA J.M., MIRZOYAN R., MOLINA E., MORALEJO A., MORCUENDE D., MORENO V., MORETTI E., MUNAR-ADROVER P., NEUSTROEV V., NIGRO C., NILSSON K., NINCI D., NISHIJIMA K., NODA K., NOGUES L., NOTHE M., NOZAKI S., PAIANO S., PALACIO J., PALATIELLO M., PANEQUE D., PAOLETTI R., PAREDES J.M., PENIL P., PERESANO M., PERSIC M., PRADA MORONI P.G., PRANDINI E., PULJAK I., RHODE W., RIBO M., RICO J., RIGHI C., RUGLIANCICH A., SAHA L., SAHAKYAN N., SAITO T., SAKURAI S., SATALECKA K., SCHMIDT K., SCHWEIZER T., SITAREK J., SNIDARIC I., SOBCZYNSKA D., SOMERO A., STAMERRA A., STROM D., STRZYS M., SUDA Y., SURIC T., TAKAHASHI M., TAVECCHIO F., TEMNIKOV P., TERZIC T., TESHIMA M., TORRES-ALBA N., TOSTI L., TSUJIMOTO S., VAGELLI V., VAN SCHERPENBERG J., VANZO G., VAZQUEZ ACOSTA M., VIGORITO C.F., VITALE V., VOVK I., WILL M. and ZARIC D.

Abstract (from CDS):

Aims. In the presence of a sufficient amount of target material, γ-rays can be used as a tracer in the search for sources of Galactic cosmic rays (CRs). Here we present deep observations of the Galactic center (GC) region with the MAGIC telescopes and use them to infer the underlying CR distribution and to study the alleged PeV proton accelerator at the center of our Galaxy.
Methods. We used data from ≃100h observations of the GC region conducted with the MAGIC telescopes over five years (from 2012 to 2017). Those were collected at high zenith angles (58-70 deg), leading to a larger energy threshold, but also an increased effective collection area compared to low zenith observations. Using recently developed software tools, we derived the instrument response and background models required for extracting the diffuse emission in the region. We used existing measurements of the gas distribution in the GC region to derive the underlying distribution of CRs. We present a discussion of the associated biases and limitations of such an approach.
Results. We obtain a significant detection for all four model components used to fit our data (Sgr A*, "Arc", G0.9+0.1, and an extended component for the Galactic Ridge). We observe no significant difference between the γ-ray spectra of the immediate GC surroundings, which we model as a point source (Sgr A*) and the Galactic Ridge. The latter can be described as a power-law with index 2 and an exponential cut-off at around 20 TeV with the significance of the cut-off being only 2σ. The derived cosmic-ray profile hints to a peak at the GC position and with a measured profile index of 1.2±0.3 is consistent with the 1/r radial distance scaling law, which supports the hypothesis of a CR accelerator at the GC. We argue that the measurements of this profile are presently limited by our knowledge of the gas distribution in the GC vicinity.

Abstract Copyright: © MAGIC Collaboration 2020

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

VizieR on-line data: <Available at CDS (J/A+A/642/A190): profile.dat seds.dat table1.dat list.dat fits/*>

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 - 2026	#notes
1	M 1	SNR	05 34 31.8	+22 01 03	~	6516	1
2	NAME Galactic Center	reg	17 45 39.60213	-29 00 22.0000	~	16269	0
3	NAME Sgr A*	X	17 45 40.03599	-29 00 28.1699	~	4970	3
4	SNR G000.9+00.1	SNR	17 47.3	-28 09	~	222	1
5	NAME Galactic Ridge	?	~	~	~	543	1

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