منابع مشابه
The Quiescent Emission Spectrum of Cen X-4 and Other X-ray Transients Containing Neutron Stars
We use the observed optical-UV and X-ray emission spectrum of Cen X-4 during quiescence to constrain models for the accretion flow in this system. We argue that the optical-UV emission is not due to an optically-thick quiescent accretion disk, nor due to synchrotron emission from an Advection-Dominated Accretion Flow (ADAF). Emission from the bright spot could account for the observed optical-U...
متن کاملFurther Constraints on Thermal Quiescent X - Ray Emission from Sax J 1808 . 4 - 3658
We observed SAX J1808.4-3658 (1808), the first accreting millisecond pulsar, in deep quiescence with XMM-Newton and (near-simultaneously) Gemini-South. The X-ray spectrum of 1808 is similar to that observed in quiescence in 2001 and 2006, describable by an absorbed power-law with photon index 1.74 ± 0.11 and unabsorbed X-ray luminosity LX = 7.9 ± 0.7 × 10 31 ergs s, for NH = 1.3 × 10 21 cm. Fit...
متن کاملThe Variable Quiescence of Cen X - 4
Cen X-4 is one of the best studied low-mass neutron star transients in quiescence. Thanks to XMM-Newton large throughput, Cen X-4 was observed at the highest signal to noise ever. This allowed us to disclose rapid (> 100 s), large (45 ± 7 rms in the 10 −4 − 1 Hz range) intensity variability, especially at low energies. In order to highlight the cause of this variability, we divided the data int...
متن کاملA Thermal Bremsstrahlung Model for the Quiescent X-ray Emission from Sagittarius A*
I consider the thermal bremsstrahlung emission from hot accretion flows (Bondi/ADAFs), taking into account the finite size of the observing telescope’s beam (Rbeam) relative to the Bondi accretion radius (RA). For Rbeam4RA, soft X-ray emission from the hot interstellar medium surrounding the black hole dominates the observed emission, while for Rbeam5RA, hard X-ray emission from the accretion f...
متن کاملQuiescent X-ray Emission from an Evolved Brown Dwarf ?
I report on the X-ray detection of Gl 569 Bab. During a 25 ksec Chandra observation the binary brown dwarf is for the first time spatially separated in X-rays from the flare star primary Gl 569 A. Companionship to Gl 569 A constrains the age of the brown dwarf pair to 300 − 800 Myr. The observation presented here is only the second X-ray detection of an evolved brown dwarf. About half of the ob...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2010
ISSN: 0004-637X,1538-4357
DOI: 10.1088/0004-637x/720/2/1325