Broadband γ-Ray Spectrum of Supernova Remnant Cassiopeia A

Issued Date

2025-03-20

Resource Type

Article

ISSN

20418205

eISSN

20418213

DOI

10.3847/2041-8213/adb97c

Scopus ID

2-s2.0-105000826702

Journal Title

Astrophysical Journal Letters

Volume

982

Issue

1

Rights Holder(s)

SCOPUS

Bibliographic Citation

Astrophysical Journal Letters Vol.982 No.1 (2025)

Suggested Citation

Cao Z., Aharonian F., Bai Y.X., Bao Y.W., Bastieri D., Bi X.J., Bi Y.J., Bian W., Bukevich A.V., Cai C.M., Cao W.Y., Cao Z., Chang J., Chang J.F., Chen A.M., Chen E.S., Chen H.X., Chen L., Chen L., Chen M.J., Chen M.L., Chen Q.H., Chen S., Chen S.H., Chen S.Z., Chen T.L., Chen X.B., Chen X.J., Chen Y., Cheng N., Cheng Y.D., Chu M.C., Cui M.Y., Cui S.W., Cui X.H., Cui Y.D., Dai B.Z., Dai H.L., Dai Z.G., Danzengluobu, Diao Y.X., Dong X.Q., Duan K.K., Fan J.H., Fan Y.Z., Fang J., Fang J.H., Fang K., Feng C.F., Feng H., Feng L., Feng S.H., Feng X.T., Feng Y., Feng Y.L., Gabici S., Gao B., Gao C.D., Gao Q., Gao W., Gao W.K., Ge M.M., Ge T.T., Geng L.S., Giacinti G., Gong G.H., Gou Q.B., Gu M.H., Guo F.L., Guo J., Guo X.L., Guo Y.Q., Guo Y.Y., Han Y.A., Hannuksela O.A., Hasan M., He H.H., He H.N., He J.Y., He X.Y., He Y., ndez-Cadena S.H., Hor Y.K., Hou B.W., Hou C., Hou X., Hu H.B., Hu S.C., Huang C., Huang D.H., Huang J.J., Huang T.Q., Huang W.J., Huang X.T., Huang X.Y., Huang Y., Huang Y.Y., Ji X.L., Jia H.Y., Jia K. Broadband γ-Ray Spectrum of Supernova Remnant Cassiopeia A. Astrophysical Journal Letters Vol.982 No.1 (2025). doi:10.3847/2041-8213/adb97c Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/108596

Title

Broadband γ-Ray Spectrum of Supernova Remnant Cassiopeia A

Author(s)

Cao Z.
 Aharonian F.
 Bai Y.X.
 Bao Y.W.
 Bastieri D.
 Bi X.J.
 Bi Y.J.
 Bian W.
 Bukevich A.V.
 Cai C.M.
 Cao W.Y.
 Cao Z.
 Chang J.
 Chang J.F.
 Chen A.M.
 Chen E.S.
 Chen H.X.
 Chen L.
 Chen L.
 Chen M.J.
 Chen M.L.
 Chen Q.H.
 Chen S.
 Chen S.H.
 Chen S.Z.
 Chen T.L.
 Chen X.B.
 Chen X.J.
 Chen Y.
 Cheng N.
 Cheng Y.D.
 Chu M.C.
 Cui M.Y.
 Cui S.W.
 Cui X.H.
 Cui Y.D.
 Dai B.Z.
 Dai H.L.
 Dai Z.G.
 Danzengluobu
 Diao Y.X.
 Dong X.Q.
 Duan K.K.
 Fan J.H.
 Fan Y.Z.
 Fang J.
 Fang J.H.
 Fang K.
 Feng C.F.
 Feng H.
 Feng L.
 Feng S.H.
 Feng X.T.
 Feng Y.
 Feng Y.L.
 Gabici S.
 Gao B.
 Gao C.D.
 Gao Q.
 Gao W.
 Gao W.K.
 Ge M.M.
 Ge T.T.
 Geng L.S.
 Giacinti G.
 Gong G.H.
 Gou Q.B.
 Gu M.H.
 Guo F.L.
 Guo J.
 Guo X.L.
 Guo Y.Q.
 Guo Y.Y.
 Han Y.A.
 Hannuksela O.A.
 Hasan M.
 He H.H.
 He H.N.
 He J.Y.
 He X.Y.
 He Y.
 ndez-Cadena S.H.
 Hor Y.K.
 Hou B.W.
 Hou C.
 Hou X.
 Hu H.B.
 Hu S.C.
 Huang C.
 Huang D.H.
 Huang J.J.
 Huang T.Q.
 Huang W.J.
 Huang X.T.
 Huang X.Y.
 Huang Y.
 Huang Y.Y.
 Ji X.L.
 Jia H.Y.
 Jia K.

Author's Affiliation

Zhejiang Lab
 State Key Laboratory of Particle Detection & Electronics
 Université Paris Cité
 Yunnan Observatories
 Yerevan State University
 Nanjing University
 Shanghai Astronomical Observatory Chinese Academy of Sciences
 Institute for Nuclear Research of the Russian Academy of Sciences
 Shandong University
 Yunnan University
 Institute of High Energy Physics, Chinese Academy of Sciences
 University of Chinese Academy of Sciences
 Guangzhou University
 Tsinghua University
 Shanghai Jiao Tong University
 Sun Yat-Sen University
 University of Science and Technology of China
 Zhengzhou University
 National Astronomical Observatories Chinese Academy of Sciences
 Max-Planck-Institut für Kernphysik
 Southwest Jiaotong University
 China Center of Advanced Science and Technology World Laboratory
 Purple Mountain Observatory Chinese Academy of Sciences
 Chinese University of Hong Kong
 Hebei Normal University
 Tibet University
 TIANFU Cosmic Ray Research Center

Corresponding Author(s)

Cao Z.

Other Contributor(s)

Mahidol University

Abstract

The core-collapse supernova remnant (SNR) Cassiopeia A (Cas A) is one of the brightest galactic radio sources with an angular radius of ~2.5 ¢ . Although no extension of this source has been detected in the γ-ray band, using more than 1000 days of LHAASO data above ∼0.8 TeV, we find that its spectrum is significantly softer than those obtained with Imaging Air Cherenkov Telescopes (IACTs), and its flux near ∼1 TeV is about 2 times higher. In combination with analyses of more than 16 yr of Fermi-LAT data covering 0.1 GeV–1 TeV, we find that the spectrum above 30 GeV deviates significantly from a single power law and is best described by a smoothly broken power law with a spectral index of 1.90 ± 0.15stat (3.41 ± 0.19stat) below (above) a break energy of 0.63 ± 0.21stat TeV. Given differences in the angular resolution of LHAASO-WCDA and IACTs, TeV γ-ray emission detected with LHAASO may have a significant contribution from regions surrounding the SNR illuminated by particles accelerated earlier, which, however, are treated as background by IACTs. Detailed modeling can be used to constrain the acceleration processes of TeV particles in the early stage of SNR evolution.

Keyword(s)

Earth and Planetary Sciences
 Physics and Astronomy

Availability

URI

https://repository.li.mahidol.ac.th/handle/20.500.14594/108596

Collections

Scopus 2025