File Download
  Links for fulltext
     (May Require Subscription)
Supplementary

Article: K-shell emission of neutral iron line from sagittarius B2 excited by subrelativistic protons

TitleK-shell emission of neutral iron line from sagittarius B2 excited by subrelativistic protons
Authors
KeywordsCosmic rays
Galaxy: center
ISM: clouds
X-rays: ISM
Issue Date2011
PublisherNihon Tenmon Gakkai. The Journal's web site is located at http://www.asj.or.jp/pasj/
Citation
Publications Of The Astronomical Society Of Japan, 2011, v. 63 n. 3, p. 535-541 How to Cite?
AbstractWe investigated the emission of the Kα iron line from massive molecular clouds in the galactic center (GC). We assumed that at present the total flux of this emission consists of a time-variable component generated by primary, X-ray photons ejected by Sagittarius A* (Sgr A*) in the past, and a relatively weak quasi-stationary component excited by the impact of protons that were generated by star accretion onto the central black hole. The level of background emission was estimated from a rise of the 6.4 keV line intensity in the direction of several molecular clouds, which we interpreted as being a stage when the X-ray front ejected by Sgr A* entered into these clouds. Regarding the 6.4 keV emission before this intensity jump, we interpreted it as emission generated by subrelativistic cosmic rays there. The cross-section of Kα vacancies produced by protons differs from that of electrons or X-rays. Therefore, we expect that this processes can be distinguished from an analysis of the equivalentwidth of the iron line; also, the time variations of the width can be predicted. The line intensity from the clouds depends on their distance from Sgr A* and the coefficient of spatial diffusion near the galactic center. We expect that in a few years the line intensity for the cloud G0.11-0.11, which is relatively close to Sgr A*, will decrease to a level of ≲10% from its present value. For the cloud Sagittarius B2 (Sgr B2) the situation is more intricate. If the diffusion coefficient is D ≳ 10 27cm 2 s -1, the expected stationary flux should be about 10% of its level in 2000. In the opposite case the line intensity from Sgr B2 should drop down to zero because the protons do not reach the cloud. © 2011. Astronomical Society of Japan.
Persistent Identifierhttp://hdl.handle.net/10722/139655
ISSN
2015 Impact Factor: 1.961
2015 SCImago Journal Rankings: 0.804
References

 

DC FieldValueLanguage
dc.contributor.authorDogiel, Ven_HK
dc.contributor.authorChernyshov, Den_HK
dc.contributor.authorKoyama, Ken_HK
dc.contributor.authorNobukawa, Men_HK
dc.contributor.authorCheng, KSen_HK
dc.date.accessioned2011-09-23T05:52:57Z-
dc.date.available2011-09-23T05:52:57Z-
dc.date.issued2011en_HK
dc.identifier.citationPublications Of The Astronomical Society Of Japan, 2011, v. 63 n. 3, p. 535-541en_HK
dc.identifier.issn0004-6264en_HK
dc.identifier.urihttp://hdl.handle.net/10722/139655-
dc.description.abstractWe investigated the emission of the Kα iron line from massive molecular clouds in the galactic center (GC). We assumed that at present the total flux of this emission consists of a time-variable component generated by primary, X-ray photons ejected by Sagittarius A* (Sgr A*) in the past, and a relatively weak quasi-stationary component excited by the impact of protons that were generated by star accretion onto the central black hole. The level of background emission was estimated from a rise of the 6.4 keV line intensity in the direction of several molecular clouds, which we interpreted as being a stage when the X-ray front ejected by Sgr A* entered into these clouds. Regarding the 6.4 keV emission before this intensity jump, we interpreted it as emission generated by subrelativistic cosmic rays there. The cross-section of Kα vacancies produced by protons differs from that of electrons or X-rays. Therefore, we expect that this processes can be distinguished from an analysis of the equivalentwidth of the iron line; also, the time variations of the width can be predicted. The line intensity from the clouds depends on their distance from Sgr A* and the coefficient of spatial diffusion near the galactic center. We expect that in a few years the line intensity for the cloud G0.11-0.11, which is relatively close to Sgr A*, will decrease to a level of ≲10% from its present value. For the cloud Sagittarius B2 (Sgr B2) the situation is more intricate. If the diffusion coefficient is D ≳ 10 27cm 2 s -1, the expected stationary flux should be about 10% of its level in 2000. In the opposite case the line intensity from Sgr B2 should drop down to zero because the protons do not reach the cloud. © 2011. Astronomical Society of Japan.en_HK
dc.languageengen_US
dc.publisherNihon Tenmon Gakkai. The Journal's web site is located at http://www.asj.or.jp/pasj/en_HK
dc.relation.ispartofPublications of the Astronomical Society of Japanen_HK
dc.subjectCosmic raysen_HK
dc.subjectGalaxy: centeren_HK
dc.subjectISM: cloudsen_HK
dc.subjectX-rays: ISMen_HK
dc.titleK-shell emission of neutral iron line from sagittarius B2 excited by subrelativistic protonsen_HK
dc.typeArticleen_HK
dc.identifier.emailCheng, KS: hrspksc@hkucc.hku.hken_HK
dc.identifier.authorityCheng, KS=rp00675en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.scopuseid_2-s2.0-79959672812en_HK
dc.identifier.hkuros195655en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-79959672812&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume63en_HK
dc.identifier.issue3en_HK
dc.identifier.spage535en_HK
dc.identifier.epage541en_HK
dc.publisher.placeJapanen_HK
dc.identifier.scopusauthoridDogiel, V=6603566238en_HK
dc.identifier.scopusauthoridChernyshov, D=14059433800en_HK
dc.identifier.scopusauthoridKoyama, K=7403116560en_HK
dc.identifier.scopusauthoridNobukawa, M=24073693500en_HK
dc.identifier.scopusauthoridCheng, KS=9745798500en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats