Zobrazeno 1 - 10
of 78
pro vyhledávání: '"Cooper, Randall"'
We analysed thermonuclear (type-I) X-ray bursts observed from the low-mass X-ray binary 4U1728-34 by RXTE, Chandra and INTEGRAL. We compared the variation in burst energy and recurrence times as a function of accretion rate with the predictions of a
Externí odkaz:
http://arxiv.org/abs/1005.4729
Autor:
Cooper, Randall L., Kaplan, David L.
We propose a new heating mechanism in magnetar crusts. Magnetars' crustal magnetic fields are much stronger than their surface fields; therefore, magnetic pressure partially supports the crust against gravity. The crust loses magnetic pressure suppor
Externí odkaz:
http://arxiv.org/abs/0910.2466
Publikováno v:
Astrophys.J.702:660-671,2009
Observationally inferred superburst ignition depths are shallower than models predict. We address this discrepancy by reexamining the superburst trigger mechanism. We first explore the hypothesis of Kuulkers et al. that exothermic electron captures t
Externí odkaz:
http://arxiv.org/abs/0903.3994
Autor:
Cooper, Randall L., Bildsten, Lars
Publikováno v:
Phys.Rev.E77:056405,2008
We investigate the crystallization rate of a one-component plasma (OCP) in the context of classical nucleation theory. From our derivation of the free energy of an arbitrary distribution of solid clusters embedded in a liquid phase, we derive the ste
Externí odkaz:
http://arxiv.org/abs/0804.3404
Autor:
Cooper, Randall L.
I construct a simple model of the convective burning layer during a type I X-ray burst to investigate the effects convection has on the stability of the layer to nonradial oscillations. A linear perturbation analysis demonstrates that the region is s
Externí odkaz:
http://arxiv.org/abs/0803.3814
Autor:
Narayan, Ramesh, Cooper, Randall L.
Publikováno v:
Astrophys.J.665:628-636,2007
The Rossi X-ray Timing Explorer has detected nearly coherent oscillations in the tails of type I X-ray bursts from 17 low-mass X-ray binaries. The oscillations are thought to be generated by brightness fluctuations associated with a surface mode on t
Externí odkaz:
http://arxiv.org/abs/astro-ph/0702690
Neutron stars in close binary star systems often accrete matter from their companion stars. Thermonuclear ignition of the accreted material in the atmosphere of the neutron star leads to a thermonuclear explosion which is observed as an X-ray burst o
Externí odkaz:
http://arxiv.org/abs/astro-ph/0702412
Autor:
Cooper, Randall L., Narayan, Ramesh
Publikováno v:
Astrophys.J.661:468-476,2007
We use the two-zone model of Cooper & Narayan to study the onset and time evolution of hydrogen-triggered type I X-ray bursts on accreting neutron stars. At the lowest accretion rates, thermally unstable hydrogen burning ignites helium as well and pr
Externí odkaz:
http://arxiv.org/abs/astro-ph/0702042
Autor:
Cooper, Randall L., Narayan, Ramesh
Publikováno v:
Astrophys.J.657:L29-L32,2007
We investigate the latitude at which type I X-ray bursts are ignited on rapidly rotating accreting neutron stars. We find that, for a wide range of accretion rates, ignition occurs preferentially at the equator, in accord with the work of Spitkovsky
Externí odkaz:
http://arxiv.org/abs/astro-ph/0701708
Autor:
Cooper, Randall L., Narayan, Ramesh
Publikováno v:
Astrophys.J.648:L123-L126,2006
We investigate the effect of the hot CNO cycle breakout reaction 15O(alpha,gamma)19Ne on the occurrence of type I X-ray bursts on accreting neutron stars. For f_rp <~ 0.1, where f_rp is a dimensionless factor by which we multiply the 15O(alpha,gamma)
Externí odkaz:
http://arxiv.org/abs/astro-ph/0608068