Zobrazeno 1 - 10
of 138
pro vyhledávání: '"Butt, Yousaf"'
Autor:
Butt, Yousaf
Publikováno v:
Nature, Vol 460, p. 701 (2009)
The origin of Galactic cosmic-ray ions has remained an enigma for almost a century. Although it has generally been thought that they are accelerated in the shock waves associated with powerful supernova explosions-for which there have been recent cla
Externí odkaz:
http://arxiv.org/abs/1009.3664
Autor:
Butt, Yousaf M.
I point out a correlation between gamma-ray emissivity and the historical star formation rate in the Large Magellanic Cloud ~12.5 Myr ago. This correlation bolsters the view that CRs in the LMC are accelerated by conglomerations of supernova remnants
Externí odkaz:
http://arxiv.org/abs/1002.4840
Autor:
Butt, Yousaf M., Bykov, Andrei M.
Superbubbles (SBs) are amongst the greatest injectors of energy into the Galaxy, and have been proposed to be the acceleration site of Galactic cosmic rays. They are thought to be powered by the fast stellar winds and powerful supernova explosions of
Externí odkaz:
http://arxiv.org/abs/0802.3805
The mysterious very high energy gamma-ray source, TeV J2032+4130, is coincident with the powerful Cygnus OB2 stellar association, though a physical association between the two remains uncertain. It is possible that the detected very high energy photo
Externí odkaz:
http://arxiv.org/abs/0802.2964
For more than fifty years, it has been believed that cosmic ray (CR) nuclei are accelerated to high energies in the rapidly expanding shockwaves created by powerful supernova explosions. Yet observational proof of this conjecture is still lacking. Re
Externí odkaz:
http://arxiv.org/abs/0801.4954
Autor:
Anchordoqui, Luis A., Beacom, John F., Butt, Yousaf M., Goldberg, Haim, Palomares-Ruiz, Sergio, Weiler, Thomas J., Wesolowski, Justin
TeV gamma-rays can result from the photo-de-excitation of PeV cosmic ray nuclei after their parents have undergone photo-disintegration in an environment of ultraviolet photons. This process is proposed as a candidate explanation of the recently disc
Externí odkaz:
http://arxiv.org/abs/0706.0517
Autor:
Butt, Yousaf
Publikováno v:
Nature 446:986-987,2007
A 'News & Views' article -- no abstract.
Externí odkaz:
http://arxiv.org/abs/0705.2228
Autor:
Butt, Yousaf
I comment on the -- apparent -- diffuse X-ray emission reported by Horns et al. in their XMM observations of TeV J2032+4130
Externí odkaz:
http://arxiv.org/abs/0705.0189
Autor:
Butt, Yousaf M., Combi, Jorge A., Drake, Jeremy, Finley, John P., Konopelko, Alexander, Lister, Matthew, Rodriguez, Jerome, Shepherd, Debra
The HEGRA gamma-ray source TeV J2032+4130 is considered the prototypical 'dark accelerator', since it was the first TeV source detected with no firm counterparts at lower frequencies. The Whipple collaboration observed this source in 2003-5 and the e
Externí odkaz:
http://arxiv.org/abs/astro-ph/0611731
Autor:
Torres, Diego F., Zhang, Shu, Reimer, Olaf, Barcons, Xavier, Corral, Amalia, Bosch-Ramon, Valentí, Paredes, Josep M., Romero, Gustavo E., Qu, Jin Lu, Collmar, Werner, Schönfelder, Volker, Butt, Yousaf
Publikováno v:
Astrophys.SpaceSci.309:17-21,2007
The COMPTEL unidentified source GRO J 1411-64 was observed by INTEGRAL and XMM-Newton in 2005. The Circinus Galaxy is the only source detected within the 4$\sigma$ location error of GRO J1411-64, but in here excluded as the possible counterpart. At s
Externí odkaz:
http://arxiv.org/abs/astro-ph/0611362