2020A&A...635A.167H

Query : 2020A&A...635A.167H

2020A&A...635A.167H - Astronomy and Astrophysics, volume 635A167-167 (2020/3-1)

Detection of very-high-energy γ-ray emission from the colliding wind binary η Car with H.E.S.S.

HESS COLLABORATION, ABDALLA H., ADAM R., AHARONIAN F., AIT BENKHALI F., ANGUNER E.O., ARAKAWA M., ARCARO C., ARMAND C., ARMSTRONG T., ASHKAR H., BACKES M., BARBOSA MARTINS V., BARNARD M., BECHERINI Y., BERGE D., BERNLOHR K., BLACKWELL R., BOTTCHER M., BOISSON C., BOLMONT J., BONNEFOY S., BREGEON J., BREUHAUS M., BRUN F., BRUN P., BRYAN M., BUCHELE M., BULIK T., BYLUND T., CAROFF S., CAROSI A., CASANOVA S., CERRUTI M., CHAND T., CHANDRA S., CHEN A., COLAFRANCESCO S., COTTER G., CURYLO M., DAVIDS I.D., DAVIES J., DEIL C., DEVIN J., DEWILT P., DIRSON L., DJANNATI-ATAI A., DMYTRIIEV A., DONATH A., DOROSHENKO V., DYKS J., EGBERTS K., EICHHORN F., EMERY G., ERNENWEIN J.-P., ESCHBACH S., FEIJEN K., FEGAN S., FIASSON A., FONTAINE G., FUNK S., FUSSLING M., GABICI S., GALLANT Y.A., GATE F., GIAVITTO G., GIUNTI L., GLAWION D., GLICENSTEIN J.F., GOTTSCHALL D., GRONDIN M.-H., HAHN J., HAUPT M., HEINZELMANN G., HENRI G., HERMANN G., HINTON J.A., HOFMANN W., HOISCHEN C., HOLCH T.L., HOLLER M., HORBE M., HORNS D., HUBER D., IWASAKI H., JAMROZY M., JANKOWSKY D., JANKOWSKY F., JARDIN-BLICQ A., JOSHI V., JUNG-RICHARDT I., KASTENDIECK M.A., KATARZYNSKI K., KATSURAGAWA M., KATZ U., KHANGULYAN D., KHELIFI B., KING J., KLEPSER S., KLUZNIAK W., KOMIN N., KOSACK K., KOSTUNIN D., KRETER M., LAMANNA G., LEMIERE A., LEMOINE-GOUMARD M., LENAIN J.-P., LESER E., LEVY C., LOHSE T., LYPOVA I., MACKEY J., MAJUMDAR J., MALYSHEV D., MALYSHEV D., MARANDON V., MARCHEGIANI P., MARCOWITH A., MARES A., MARTI-DEVESA G., MARX R., MAURIN G., MEINTJES P.J., MODERSKI R., MOHAMED M., MOHRMANN L., MOORE C., MORRIS P., MOULIN E., MULLER J., MURACH T., NAKASHIMA S., NAKASHIMA K., DE NAUROIS M., NDIYAVALA H., NIEDERWANGER F., NIEMIEC J., OAKES L., O'BRIEN P., ODAKA H., OHM S., DE ONA WILHELMI E., OSTROWSKI M., PANTER M., PARSONS R.D., PERENNES C., PETRUCCI P.-O., PEYAUD B., PIEL Q., PITA S., POIREAU V., PRIYANA NOEL A., PROKHOROV D.A., PROKOPH H., PUHLHOFER G., PUNCH M., QUIRRENBACH A., RAAB S., RAUTH R., REIMER A., REIMER O., REMY Q., RENAUD M., RIEGER F., RINCHIUSO L., ROMOLI C., ROWELL G., RUDAK B., RUIZ-VELASCO E., SAHAKIAN V., SAILER S., SAITO S., SANCHEZ D.A., SANTANGELO A., SASAKI M., SCALICI M., SCHLICKEISER R., SCHUSSLER F., SCHULZ A., SCHUTTE H.M., SCHWANKE U., SCHWEMMER S., SEGLAR-ARROYO M., SENNIAPPAN M., SEYFFERT A.S., SHAFI N., SHININGAYAMWE K., SIMONI R., SINHA A., SOL H., SPECOVIUS A., SPENCER S., SPIR-JACOB M., STAWARZ L., STEENKAMP R., STEGMANN C., STEPPA C., TAKAHASHI T., TAVERNIER T., TAYLOR A.M., TERRIER R., TIZIANI D., TLUCZYKONT M., TOMANKOVA L., TRICHARD C., TSIROU M., 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., VINCENT P., VINK J., VOLK H.J., VUILLAUME T., WADIASINGH Z., WAGNER S.J., WATSON J., WERNER F., WHITE R., WIERZCHOLSKA A., YANG R., YONEDA H., ZACHARIAS M., ZANIN R., ZDZIARSKI A.A., ZECH A., ZORN J. and ZYWUCKA N.

Abstract (from CDS):


Aims. Colliding wind binary systems have long been suspected to be high-energy (HE; 100MeV<E<100GeV) γ-ray emitters. η Car is the most prominent member of this object class and is confirmed to emit phase-locked HE γ rays from hundreds of MeV to ∼100GeV energies. This work aims to search for and characterise the very-high-energy (VHE; E >100 GeV) γ-ray emission from η Car around the last periastron passage in 2014 with the ground-based High Energy Stereoscopic System (H.E.S.S.).
Methods. The region around η Car was observed with H.E.S.S. between orbital phase p=0.78-1.10, with a closer sampling at p~=0.95 and p~=1.10 (assuming a period of 2023 days). Optimised hardware settings as well as adjustments to the data reduction, reconstruction, and signal selection were needed to suppress and take into account the strong, extended, and inhomogeneous night sky background (NSB) in the η Car field of view. Tailored run-wise Monte-Carlo simulations (RWS) were required to accurately treat the additional noise from NSB photons in the instrument response functions.
Results. H.E.S.S. detected VHE γ-ray emission from the direction of η Car shortly before and after the minimum in the X-ray light-curve close to periastron. Using the point spread function provided by RWS, the reconstructed signal is point-like and the spectrum is best described by a power law. The overall flux and spectral index in VHE γ rays agree within statistical and systematic errors before and after periastron. The γ-ray spectrum extends up to at least ∼400 GeV. This implies a maximum magnetic field in a leptonic scenario in the emission region of 0.5Gauss. No indication for phase-locked flux variations is detected in the H.E.S.S. data.

Abstract Copyright: © ESO 2020

Journal keyword(s): astroparticle physics - radiation mechanisms: non-thermal - binaries: general - stars: individual: eta Car - stars: Wolf-Rayet - cosmic rays

Simbad objects: 10

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Number of rows : 10
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 M 1 SNR 05 34 31.8 +22 01 03           ~ 6516 1
2 EQ J104422.8-595751.8 ? 10 44 22.80 -59 57 51.8           ~ 1 0
3 NGC 3372 HII 10 45 02.23 -59 41 59.8           ~ 1071 2
4 * eta Car s*b 10 45 03.545808 -59 41 03.95124 6.37 7.03 6.48 6.123 4.41 LBV 2543 0
5 2FGL J1046.8-6005c gam 10 46 42.3 -60 10 24           ~ 18 0
6 4FGL J1048.5-5923 gam 10 48 32.8 -59 23 32           ~ 7 0
7 PG 1553+113 BLL 15 55 43.0440048528 +11 11 24.365649948 14.91 14.72 14.57 13.99   ~ 672 1
8 HD 193793 WR* 20 20 27.9757908696 +43 51 16.286840244 6.90 7.25 6.85 4.58   WC7pd+O5.5fc 754 0
9 MR 112 WR* 20 35 47.0859278605 +41 22 44.703520146     12.64 12.16   WC6+O8I-IIf 162 1
10 EM* AS 431 WR* 20 36 43.6322747712 +40 21 07.442607924     13.73 12.51   WN8(h)+B0.5V 228 0

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