An Enigmatic PeVatron in an Area around H ii Region G35.6−0.5

dc.contributor.authorCao Z.
dc.contributor.authorAharonian F.
dc.contributor.authorAxikegu
dc.contributor.authorBai Y.X.
dc.contributor.authorBao Y.W.
dc.contributor.authorBastieri D.
dc.contributor.authorBi X.J.
dc.contributor.authorBi Y.J.
dc.contributor.authorBian W.
dc.contributor.authorBukevich A.V.
dc.contributor.authorCao Q.
dc.contributor.authorCao W.Y.
dc.contributor.authorCao Z.
dc.contributor.authorChang J.
dc.contributor.authorChang J.F.
dc.contributor.authorChen A.M.
dc.contributor.authorChen B.Q.
dc.contributor.authorChen E.S.
dc.contributor.authorChen H.X.
dc.contributor.authorChen L.
dc.contributor.authorChen L.
dc.contributor.authorChen L.
dc.contributor.authorChen M.J.
dc.contributor.authorChen M.L.
dc.contributor.authorChen Q.H.
dc.contributor.authorChen S.
dc.contributor.authorChen S.H.
dc.contributor.authorChen S.Z.
dc.contributor.authorChen T.L.
dc.contributor.authorChen Y.
dc.contributor.authorCheng N.
dc.contributor.authorCheng Y.D.
dc.contributor.authorChu M.C.
dc.contributor.authorCui M.Y.
dc.contributor.authorCui S.W.
dc.contributor.authorCui X.H.
dc.contributor.authorCui Y.D.
dc.contributor.authorDai B.Z.
dc.contributor.authorDai H.L.
dc.contributor.authorDai Z.G.
dc.contributor.authorDanzengluobu
dc.contributor.authorDong X.Q.
dc.contributor.authorDuan K.K.
dc.contributor.authorFan J.H.
dc.contributor.authorFan Y.Z.
dc.contributor.authorFang J.
dc.contributor.authorFang J.H.
dc.contributor.authorFang K.
dc.contributor.authorFeng C.F.
dc.contributor.authorFeng H.
dc.contributor.authorFeng L.
dc.contributor.authorFeng S.H.
dc.contributor.authorFeng X.T.
dc.contributor.authorFeng Y.
dc.contributor.authorFeng Y.L.
dc.contributor.authorGabici S.
dc.contributor.authorGao B.
dc.contributor.authorGao C.D.
dc.contributor.authorGao Q.
dc.contributor.authorGao W.
dc.contributor.authorGao W.K.
dc.contributor.authorGe M.M.
dc.contributor.authorGe T.T.
dc.contributor.authorGeng L.S.
dc.contributor.authorGiacinti G.
dc.contributor.authorGong G.H.
dc.contributor.authorGou Q.B.
dc.contributor.authorGu M.H.
dc.contributor.authorGuo F.L.
dc.contributor.authorGuo J.
dc.contributor.authorGuo X.L.
dc.contributor.authorGuo Y.Q.
dc.contributor.authorGuo Y.Y.
dc.contributor.authorHan Y.A.
dc.contributor.authorHannuksela O.A.
dc.contributor.authorHasan M.
dc.contributor.authorHe H.H.
dc.contributor.authorHe H.N.
dc.contributor.authorHe J.Y.
dc.contributor.authorHe Y.
dc.contributor.authorHor Y.K.
dc.contributor.authorHou B.W.
dc.contributor.authorHou C.
dc.contributor.authorHou X.
dc.contributor.authorHu H.B.
dc.contributor.authorHu Q.
dc.contributor.authorHu S.C.
dc.contributor.authorHuang C.
dc.contributor.authorHuang D.H.
dc.contributor.authorHuang T.Q.
dc.contributor.authorHuang W.J.
dc.contributor.authorHuang X.T.
dc.contributor.authorHuang X.Y.
dc.contributor.authorHuang Y.
dc.contributor.authorHuang Y.Y.
dc.contributor.authorJi X.L.
dc.contributor.authorJia H.Y.
dc.contributor.authorJia K.
dc.contributor.authorJiang H.B.
dc.contributor.authorJiang K.
dc.contributor.correspondenceCao Z.
dc.contributor.otherMahidol University
dc.date.accessioned2025-02-01T18:29:45Z
dc.date.available2025-02-01T18:29:45Z
dc.date.issued2025-01-20
dc.description.abstractIdentifying Galactic PeVatrons (PeV particle accelerators) from ultrahigh-energy (UHE, >100 TeV) γ-ray sources plays a crucial role in revealing the origin of Galactic cosmic rays. The UHE source 1LHAASO J1857+0203u is suggested to be associated with HESS J1858+020, which may be attributed to the possible PeVatron candidate supernova remnant (SNR) G35.6−0.4 or H ii region G35.6−0.5. We perform detailed analysis on the very-high-energy and UHE γ-ray emissions toward this region with data from the Large High Altitude Air Shower Observatory (LHAASO). 1LHAASO J1857+0203u is detected with a significance of 11.6σ above 100 TeV, indicating the presence of a PeVatron. It has an extent of ∼0 . ° 18 with a power-law (PL) spectral index of ∼2.5 at 1-25 TeV and pointlike emission with a PL spectral index of ∼3.2 above 25 TeV. Using archival CO and H i data, we identify some molecular and atomic clouds that may be associated with the TeV γ-ray emissions. Our modeling indicates that the TeV γ-ray emissions are unlikely to arise from clouds illuminated by the protons that escaped from SNR G35.6−0.4. In the scenario in which H ii region G35.6−0.5 could accelerate particles to the UHE band, the observed GeV-TeV γ-ray emission could be well explained by a hadronic model with a PL spectral index of ∼2.0 and cutoff energy of ∼450 TeV. However, an origin in an evolved pulsar wind nebula cannot be ruled out.
dc.identifier.citationAstrophysical Journal Vol.979 No.1 (2025)
dc.identifier.doi10.3847/1538-4357/ad991d
dc.identifier.eissn15384357
dc.identifier.issn0004637X
dc.identifier.scopus2-s2.0-85216125175
dc.identifier.urihttps://repository.li.mahidol.ac.th/handle/20.500.14594/103149
dc.rights.holderSCOPUS
dc.subjectEarth and Planetary Sciences
dc.subjectPhysics and Astronomy
dc.titleAn Enigmatic PeVatron in an Area around H ii Region G35.6−0.5
dc.typeArticle
mu.datasource.scopushttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216125175&origin=inward
oaire.citation.issue1
oaire.citation.titleAstrophysical Journal
oaire.citation.volume979
oairecerif.author.affiliationZhejiang Lab
oairecerif.author.affiliationState Key Laboratory of Particle Detection & Electronics
oairecerif.author.affiliationUniversité Paris Cité
oairecerif.author.affiliationYunnan Observatories
oairecerif.author.affiliationNanjing University
oairecerif.author.affiliationShanghai Astronomical Observatory Chinese Academy of Sciences
oairecerif.author.affiliationInstitute for Nuclear Research of the Russian Academy of Sciences
oairecerif.author.affiliationShandong University
oairecerif.author.affiliationYunnan University
oairecerif.author.affiliationInstitute of High Energy Physics, Chinese Academy of Sciences
oairecerif.author.affiliationUniversity of Chinese Academy of Sciences
oairecerif.author.affiliationGuangzhou University
oairecerif.author.affiliationTsinghua University
oairecerif.author.affiliationShanghai Jiao Tong University
oairecerif.author.affiliationSun Yat-Sen University
oairecerif.author.affiliationUniversity of Science and Technology of China
oairecerif.author.affiliationZhengzhou University
oairecerif.author.affiliationInstitiúid Ard-Lénn Bhaile Átha Cliath
oairecerif.author.affiliationNational Astronomical Observatories Chinese Academy of Sciences
oairecerif.author.affiliationMax-Planck-Institut für Kernphysik
oairecerif.author.affiliationSouthwest Jiaotong University
oairecerif.author.affiliationChina Center of Advanced Science and Technology World Laboratory
oairecerif.author.affiliationPurple Mountain Observatory Chinese Academy of Sciences
oairecerif.author.affiliationChinese University of Hong Kong
oairecerif.author.affiliationHebei Normal University
oairecerif.author.affiliationTibet University
oairecerif.author.affiliationTIANFU Cosmic Ray Research Center

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