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

Abdalla H, Adam R, Aharonian F, Benkhali FA, Anguner EO, Arakawa M, Arcaro C, Armand C, Armstrong T, Ashkar H, Backes M, Martins VB, Barnard M, Becherini Y, Berge D, Bernloehr 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 ID, 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 JP, Eschbach S, Feijen K, Fegan S, Fiasson A, Fontaine G, Funk S, Fussling M, Gabici S, Gallant YA, Gate F, Giavitto G, Giunti L, Glawion D, Glicenstein JF, Gottschall D, Grondin MH, Hahn J, Haupt M, Heinzelmann G, Henri G, Hermann G, Hinton JA, Hofmann W, Hoischen C, Holch TL, Holler M, Hörbe M, Horns D, Huber D, Iwasaki H, Jamrozy M, Jankowsky D, Jankowsky F, Jardin-Blicq A, Joshi V, Jung-Richardt I, Kastendieck MA, Nski KKP, 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 JP, Leser E, Levy C, Lohse T, Lypova I, Mackey J, Majumdar J, Malyshev D, Malyshev D, Marandon V, Marchegiani P, Marcowith A, Mares A, Martí-Devesa G, Marx R, Maurin G, Meintjes PJ, 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, Wilhelmi EDO, Ostrowski M, Panter M, Parsons RD, Perennes C, Petrucci PO, Peyaud B, Piel Q, Pita S, Poireau V, Noel AP, Prokhorov DA, 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 DA, Santangelo A, Sasaki M, Scalici M, Schlickeiser R, Schussler F, Schulz A, Schutte HM, Schwanke U, Schwemmer S, Seglar-Arroyo M, Senniappan M, Seyffert AS, Shafi N, Shiningayamwe K, Simoni R, Sinha A, Sol H, Specovius A, Spencer ST, Spir-Jacob M, Stawarz L, Steenkamp R, Stegmann C, Steppa C, Takahashi T, Tavernier T, Taylor AM, Terrier R, Tiziani D, Tluczykont M, Tomankova L, Trichard C, Tsirou M, Tsuji N, Tuffs R, Uchiyama Y, Van Der Walt DJ, van Eldik C, Van Rensburg C, Van Soelen B, Vasileiadis G, Veh J, Venter C, Vincent P, Vink J, Volk HJ, Vuillaume T, Wadiasingh Z, Wagner SJ, Watson J, Werner F, White R, Wierzcholska A, Yang R, Yoneda H, Zacharias M, Zanin R, Zdziarski AA, Zech A, Zorn J, Żywucka N (2020)


Publication Type: Journal article

Publication year: 2020

Journal

Book Volume: 635

Article Number: ARTN A167

DOI: 10.1051/0004-6361/201936761

Abstract

Aims. Colliding wind binary systems have long been suspected to be high-energy (HE; 100 MeV < E < 100 GeV) 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 ~100 GeV 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 0.5 Gauss. No indication for phase-locked flux variations is detected in the H.E.S.S. data.

Authors with CRIS profile

How to cite

APA:

Abdalla, H., Adam, R., Aharonian, F., Benkhali, F.A., Anguner, E.O., Arakawa, M.,... Żywucka, N. (2020). Detection of very-high-energy γ -ray emission from the colliding wind binary η Car with H.E.S.S. Astronomy & Astrophysics, 635. https://doi.org/10.1051/0004-6361/201936761

MLA:

Abdalla, H., et al. "Detection of very-high-energy γ -ray emission from the colliding wind binary η Car with H.E.S.S." Astronomy & Astrophysics 635 (2020).

BibTeX: Download