Change search
ReferencesLink to record
Permanent link

Direct link
Variable jet properties in GRB 110721A: time resolved observations of the jet photosphere
KTH, School of Engineering Sciences (SCI), Physics.
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.ORCID iD: 0000-0002-9769-8016
KTH, School of Engineering Sciences (SCI), Physics.ORCID iD: 0000-0003-4378-8785
Show others and affiliations
2013 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 433, no 4, 2739-2748 p.Article in journal (Refereed) Published
Abstract [en]

Fermi Gamma-ray Space Telescope observations of GRB 110721A have revealed two emission components from the relativistic jet: emission from the photosphere, peaking at similar to 100 keV, and a non-thermal component, which peaks at similar to 1000 keV. We use the photospheric component to calculate the properties of the relativistic outflow. We find a strong evolution in the flow properties: the Lorentz factor decreases with time during the bursts from G similar to 1000 to similar to 150 (assuming a redshift z = 2; the values are only weakly dependent on unknown efficiency parameters). Such a decrease is contrary to the expectations from the internal shocks and the isolated magnetar birth models. Moreover, the position of the flow nozzle measured from the central engine, r(0), increases by more than two orders of magnitude. Assuming a moderately magnetized outflow we estimate that r(0) varies from 10(6) to similar to 10(9) cm during the burst. We suggest that the maximal value reflects the size of the progenitor core. Finally, we show that these jet properties naturally explain the observed broken power-law decay of the temperature which has been reported as a characteristic for gamma-ray burst pulses.

Place, publisher, year, edition, pages
2013. Vol. 433, no 4, 2739-2748 p.
Keyword [en]
gamma-ray burst: individual: GRB 110721A
National Category
Physical Sciences
URN: urn:nbn:se:kth:diva-127493DOI: 10.1093/mnras/stt863ISI: 000322405900004ScopusID: 2-s2.0-84881118688OAI: diva2:644841

QC 20130902

Available from: 2013-09-02 Created: 2013-08-30 Last updated: 2013-09-02Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Ryde, FelixAxelsson, MagnusLarsson, JosefinLundman, ChristofferMoretti, ElenaNymark, Tanja
By organisation
PhysicsParticle and Astroparticle Physics
In the same journal
Monthly notices of the Royal Astronomical Society
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 29 hits
ReferencesLink to record
Permanent link

Direct link