Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope

Sei Hayashi; F. Kajino; T. Naito; A. Asahara; G. V. Bicknell; R. W. Clay; Y. Doi; P. G. Edwards; R. Enomoto; S. Gunji; S. Hara; T. Hara; T. Hattori; C. Itoh; S. Kabuki; H. Katagiri; A. Kawachi; T. Kifune; L. T. Ksenofontov; H. Kubo; T. Kurihara; R. Kurosaka; J. Kushida; Y. Matsubara; Y. Miyashita; Y. Mizumoto; M. Mori; H. Mori; H. Muraishi; Y. Muraki; T. Nakase; D. Nishida; K. Nishijima; M. Ohishi; K. Okumura; J. R. Patterson; R. J. Protheroe; N. Sakamoto; K. Sakurazawa; D. L. Swaby; T. Tanimori; H. Tanimura; G. Thornton; F. Tokanai; K. Tsuchiya; T. Uchida; S. Watanabe; T. Yamaoka; S. Yanagita; T. Yoshida; T. Yoshikoshi

doi:10.1016/j.astropartphys.2009.06.006

Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope

Sei Hayashi^*, F. Kajino, T. Naito, A. Asahara, G. V. Bicknell, R. W. Clay, Y. Doi, P. G. Edwards, R. Enomoto, S. Gunji, S. Hara, T. Hara, T. Hattori, C. Itoh, S. Kabuki, H. Katagiri, A. Kawachi, T. Kifune, L. T. Ksenofontov, H. KuboT. Kurihara, R. Kurosaka, J. Kushida, Y. Matsubara, Y. Miyashita, Y. Mizumoto, M. Mori, H. Mori, H. Muraishi, Y. Muraki, T. Nakase, D. Nishida, K. Nishijima, M. Ohishi, K. Okumura, J. R. Patterson, R. J. Protheroe, N. Sakamoto, K. Sakurazawa, D. L. Swaby, T. Tanimori, H. Tanimura, G. Thornton, F. Tokanai, K. Tsuchiya, T. Uchida, S. Watanabe, T. Yamaoka, S. Yanagita, T. Yoshida, T. Yoshikoshi

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate VHE gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect VHE gamma rays using the 10 m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2 h for ON source, and 80.8 h for OFF source data. No significant excess of VHE gamma rays has been found at three regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and have set constraints on the strengths of the magnetic fields assuming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are 4.3 μG for the center of the brightest X-ray emission region and 6.3 μG for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.

Original language	English
Pages (from-to)	112-119
Number of pages	8
Journal	Astroparticle Physics
Volume	32
Issue number	2
DOIs	https://doi.org/10.1016/j.astropartphys.2009.06.006
Publication status	Published - Sept 2009

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10.1016/j.astropartphys.2009.06.006

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Hayashi, S., Kajino, F., Naito, T., Asahara, A., Bicknell, G. V., Clay, R. W., Doi, Y., Edwards, P. G., Enomoto, R., Gunji, S., Hara, S., Hara, T., Hattori, T., Itoh, C., Kabuki, S., Katagiri, H., Kawachi, A., Kifune, T., Ksenofontov, L. T., ... Yoshikoshi, T. (2009). Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope. Astroparticle Physics, 32(2), 112-119. https://doi.org/10.1016/j.astropartphys.2009.06.006

@article{eb5a347550464e5cb8ff7a9895b2abaf,

title = "Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope",

abstract = "SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate VHE gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect VHE gamma rays using the 10 m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2 h for ON source, and 80.8 h for OFF source data. No significant excess of VHE gamma rays has been found at three regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and have set constraints on the strengths of the magnetic fields assuming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are 4.3 μG for the center of the brightest X-ray emission region and 6.3 μG for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.",

keywords = "Gamma rays: observations, ISM: individual (W50), jets, Stars: individual (SS433)",

author = "Sei Hayashi and F. Kajino and T. Naito and A. Asahara and Bicknell, {G. V.} and Clay, {R. W.} and Y. Doi and Edwards, {P. G.} and R. Enomoto and S. Gunji and S. Hara and T. Hara and T. Hattori and C. Itoh and S. Kabuki and H. Katagiri and A. Kawachi and T. Kifune and Ksenofontov, {L. T.} and H. Kubo and T. Kurihara and R. Kurosaka and J. Kushida and Y. Matsubara and Y. Miyashita and Y. Mizumoto and M. Mori and H. Mori and H. Muraishi and Y. Muraki and T. Nakase and D. Nishida and K. Nishijima and M. Ohishi and K. Okumura and Patterson, {J. R.} and Protheroe, {R. J.} and N. Sakamoto and K. Sakurazawa and Swaby, {D. L.} and T. Tanimori and H. Tanimura and G. Thornton and F. Tokanai and K. Tsuchiya and T. Uchida and S. Watanabe and T. Yamaoka and S. Yanagita and T. Yoshida and T. Yoshikoshi",

year = "2009",

month = sep,

doi = "10.1016/j.astropartphys.2009.06.006",

language = "English",

volume = "32",

pages = "112--119",

journal = "Astroparticle Physics",

issn = "0927-6505",

publisher = "Elsevier B.V.",

number = "2",

}

Hayashi, S, Kajino, F, Naito, T, Asahara, A, Bicknell, GV, Clay, RW, Doi, Y, Edwards, PG, Enomoto, R, Gunji, S, Hara, S, Hara, T, Hattori, T, Itoh, C, Kabuki, S, Katagiri, H, Kawachi, A, Kifune, T, Ksenofontov, LT, Kubo, H, Kurihara, T, Kurosaka, R, Kushida, J, Matsubara, Y, Miyashita, Y, Mizumoto, Y, Mori, M, Mori, H, Muraishi, H, Muraki, Y, Nakase, T, Nishida, D, Nishijima, K, Ohishi, M, Okumura, K, Patterson, JR, Protheroe, RJ, Sakamoto, N, Sakurazawa, K, Swaby, DL, Tanimori, T, Tanimura, H, Thornton, G, Tokanai, F, Tsuchiya, K, Uchida, T, Watanabe, S, Yamaoka, T, Yanagita, S, Yoshida, T & Yoshikoshi, T 2009, 'Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope', Astroparticle Physics, vol. 32, no. 2, pp. 112-119. https://doi.org/10.1016/j.astropartphys.2009.06.006

TY - JOUR

T1 - Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope

AU - Hayashi, Sei

AU - Kajino, F.

AU - Naito, T.

AU - Asahara, A.

AU - Bicknell, G. V.

AU - Clay, R. W.

AU - Doi, Y.

AU - Edwards, P. G.

AU - Enomoto, R.

AU - Gunji, S.

AU - Hara, S.

AU - Hara, T.

AU - Hattori, T.

AU - Itoh, C.

AU - Kabuki, S.

AU - Katagiri, H.

AU - Kawachi, A.

AU - Kifune, T.

AU - Ksenofontov, L. T.

AU - Kubo, H.

AU - Kurihara, T.

AU - Kurosaka, R.

AU - Kushida, J.

AU - Matsubara, Y.

AU - Miyashita, Y.

AU - Mizumoto, Y.

AU - Mori, M.

AU - Mori, H.

AU - Muraishi, H.

AU - Muraki, Y.

AU - Nakase, T.

AU - Nishida, D.

AU - Nishijima, K.

AU - Ohishi, M.

AU - Okumura, K.

AU - Patterson, J. R.

AU - Protheroe, R. J.

AU - Sakamoto, N.

AU - Sakurazawa, K.

AU - Swaby, D. L.

AU - Tanimori, T.

AU - Tanimura, H.

AU - Thornton, G.

AU - Tokanai, F.

AU - Tsuchiya, K.

AU - Uchida, T.

AU - Watanabe, S.

AU - Yamaoka, T.

AU - Yanagita, S.

AU - Yoshida, T.

AU - Yoshikoshi, T.

PY - 2009/9

Y1 - 2009/9

N2 - SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate VHE gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect VHE gamma rays using the 10 m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2 h for ON source, and 80.8 h for OFF source data. No significant excess of VHE gamma rays has been found at three regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and have set constraints on the strengths of the magnetic fields assuming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are 4.3 μG for the center of the brightest X-ray emission region and 6.3 μG for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.

AB - SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate VHE gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect VHE gamma rays using the 10 m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2 h for ON source, and 80.8 h for OFF source data. No significant excess of VHE gamma rays has been found at three regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and have set constraints on the strengths of the magnetic fields assuming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are 4.3 μG for the center of the brightest X-ray emission region and 6.3 μG for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.

KW - Gamma rays: observations

KW - ISM: individual (W50), jets

KW - Stars: individual (SS433)

UR - http://www.scopus.com/inward/record.url?scp=69549089807&partnerID=8YFLogxK

U2 - 10.1016/j.astropartphys.2009.06.006

DO - 10.1016/j.astropartphys.2009.06.006

M3 - Article

SN - 0927-6505

VL - 32

SP - 112

EP - 119

JO - Astroparticle Physics

JF - Astroparticle Physics

IS - 2

ER -

Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope

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