Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A theory of photospheric emission from relativistic, collimated outflows
Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC). AlbaNova, Dept Phys, Royal Inst Technol KTH, Stockholm, Sweden.
Harvard Smithsonian Ctr Astrophys, Cambridge, MA ,USA.
Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC). AlbaNova, Dept Phys, Royal Inst Technol KTH, Stockholm, Sweden.
2013 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 428, no 3, 2430-2442 p.Article in journal (Refereed) Published
Abstract [en]

Relativistic outflows in the form of jets are common in many astrophysical objects. By their very nature, jets have angle-dependent velocity profiles, Gamma = Gamma(r,theta, phi), where Gamma is the outflow Lorentz factor. In this work we consider photospheric emission from non-dissipative jets with various Lorentz factor profiles, of the approximate form Gamma approximate to Gamma(0)/[(theta/theta(j))(p) + 1], where theta(j) is the characteristic jet opening angle. In collimated jets, the observed spectrum depends on the viewing angle, theta(v). We show that for narrow jets (theta(j)Gamma(0) less than or similar to few), the obtained low-energy photon index is alpha approximate to -1 (dN/dE alpha E-alpha), independent of viewing angle, and weakly dependent on the Lorentz factor gradient (p). A similar result is obtained for wider jets observed at theta(v) approximate to theta(j). This result is surprisingly similar to the average low-energy photon index seen in gamma-ray bursts. For wide jets (theta(j)Gamma(0) greater than or similar to few) observed at theta(v) << theta(j), a multicolour blackbody spectrum is obtained. We discuss the consequences of this theory on our understanding of the prompt emission in gamma-ray bursts.

Place, publisher, year, edition, pages
Oxford University Press, 2013. Vol. 428, no 3, 2430-2442 p.
Keyword [en]
plasmas, radiation mechanisms: thermal, radiative transfer, scattering, gamma-ray burst: general
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:su:diva-90810DOI: 10.1093/mnras/sts219ISI: 000318230700043OAI: oai:DiVA.org:su-90810DiVA: diva2:627420
Note

AuthorCount:3;

Available from: 2013-06-11 Created: 2013-06-11 Last updated: 2017-12-06Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
The Oskar Klein Centre for Cosmo Particle Physics (OKC)
In the same journal
Monthly notices of the Royal Astronomical Society
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 15 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf