排序方式: 共有19条查询结果,搜索用时 15 毫秒
11.
Anomalous X‐ray Pulsars and Soft Gamma‐ray Repeaters are believed to be magnetars: isolated neutron stars powered by the decay of extremely high magnetic fields. We review some of the main results obtained with XMM‐Newton and discuss the prospects for future observations of this small but extremely interesting class of objects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
L. Ducci L. Sidoli S. Mereghetti A. Paizis P. Romano 《Monthly notices of the Royal Astronomical Society》2009,398(4):2152-2165
We have developed a stellar wind model for OB supergiants to investigate the effects of accretion from a clumpy wind on the luminosity and variability properties of high-mass X-ray binaries. Assuming that the clumps are confined by ram pressure of the ambient gas and exploring different distributions for their mass and radii, we computed the expected X-ray light curves in the framework of the Bondi–Hoyle accretion theory, modified to take into account the presence of clumps. The resulting variability properties are found to depend not only on the assumed orbital parameters but also on the wind characteristics. We have then applied this model to reproduce the X-ray light curves of three representative high-mass X-ray binaries: two persistent supergiant systems (Vela X−1 and 4U 1700−377) and the supergiant fast X-ray transient IGR J11215−5952. The model can reproduce the observed light curves well, but requiring in all cases an overall mass loss from the supergiant about a factor of 3–10 smaller than the values inferred from ultraviolet lines studies that assume a homogeneous wind. 相似文献
13.
Tanvir N. R. Le Floc’h E. Christensen L. Caruana J. Salvaterra R. Ghirlanda G. Ciardi B. Maio U. D’Odorico V. Piedipalumbo E. Campana S. Noterdaeme P. Graziani L. Amati L. Bagoly Z. Balázs L. G. Basa S. Behar E. De Cia A. Valle M. Della De Pasquale M. Frontera F. Gomboc A. Götz D. Horvath I. Hudec R. Mereghetti S. O’Brien P. T. Osborne J. P. Paltani S. Rosati P. Sergijenko O. Stanway E. R. Szécsi D. Tot́h L. V. Urata Y. Vergani S. Zane S. 《Experimental Astronomy》2021,52(3):219-244
Experimental Astronomy - At peak, long-duration gamma-ray bursts are the most luminous sources of electromagnetic radiation known. Since their progenitors are massive stars, they provide a tracer... 相似文献
14.
Amati L. O’Brien P.T. Götz D. Bozzo E. Santangelo A. Tanvir N. Frontera F. Mereghetti S. Osborne J. P. Blain A. Basa S. Branchesi M. Burderi L. Caballero-García M. Castro-Tirado A. J. Christensen L. Ciolfi R. De Rosa A. Doroshenko V. Ferrara A. Ghirlanda G. Hanlon L. Heddermann P. Hutchinson I. Labanti C. Le Floch E. Lerman H. Paltani S. Reglero V. Rezzolla L. Rosati P. Salvaterra R. Stratta G. Tenzer C. 《Experimental Astronomy》2021,52(3):183-218
Experimental Astronomy - THESEUS, one of the two space mission concepts being studied by ESA as candidates for next M5 mission within its Comsic Vision programme, aims at fully exploiting Gamma-Ray... 相似文献
15.
Observations obtained in the last years challenged the widespread notion that rotation-powered neutron stars are steady X-ray emitters. Besides a few allegedly rotation-powered neutron stars that showed ‘magnetar-like’ variability, a particularly interesting case is that of PSR B0943+10. Recent observations have shown that this pulsar, well studied in the radio band where it alternates between a bright and a quiescent mode, displays significant X-ray variations, anticorrelated in flux with the radio emission. The study of such synchronous radio/X-ray mode switching opens a new window to investigate the processes responsible for the pulsar radio and high-energy emission. Here we review the main X-ray properties of PSR B0943+10 derived from recent coordinated X-ray and radio observations. 相似文献
16.
A. De Luca P. A. Caraveo S. Mereghetti A. Tiengo G. F. Bignami 《Astrophysics and Space Science》2007,308(1-4):231-238
1E 161348-5055 (1E) is a compact object lying at the center of the 2000 year old Supernova Remnant (SNR) RCW103. Its original
identification as an isolated, radio-quiet neutron star has been questioned in recent years by the observation of a significant
long-term variability, as well as by reports of a possible periodicity at ∼6 hours. Here we report conclusive evidence for
a strong (nearly 50%) periodic modulation of 1E at 6.67±0.03 hours, discovered during a long (90 ks) XMM-Newton observation
performed in August 2005, when the source was in a “low state”. The source spectrum varies along the 6.67 hr cycle. No fast
pulsations are seen. 1E could be a very young binary system, possibly composed of a compact object and a low-mass star in
an eccentric orbit. This would be the first example of a low-mass X-ray binary (LMXB) associated with a SNR, and thus the
first LMXB for which we know the precise birth date, just 2000 years ago. Alternatively, if it is an isolated neutron star,
the unprecedented combination of age, period and variability may only fit in a very unusual scenario, featuring a peculiar
magnetar, dramatically slowed-down over 2000 years, possibly by a supernova debris disc.
相似文献
17.
Sandro Mereghetti 《Astronomy and Astrophysics Review》2008,15(4):225-287
Two classes of X-ray pulsars, the anomalous X-ray pulsars and the soft gamma-ray repeaters, have been recognized in the last
decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the
observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar
model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible
relations between these sources and other classes of neutron stars and astrophysical objects are also discussed. 相似文献
18.
Andrea Tiengo Paolo Esposito Sandro Mereghetti Lara Sidoli Diego Götz Marco Feroci Roberto Turolla Silvia Zane Gian Luca Israel Luigi Stella Peter Woods 《Astrophysics and Space Science》2007,308(1-4):33-37
We present a systematic analysis of all the BeppoSAX data of SGR1900+14. The observations spanning five years show that the source was brighter than usual on two occasions: ~20 days after the August 1998 giant flare and during the 105?s long X-ray afterglow following the April 2001 intermediate flare. In the latter case, we explore the possibility of describing the observed short term spectral evolution only with a change of the temperature of the blackbody component. In the only BeppoSAX observation performed before the giant flare, the spectrum of the SGR1900+14 persistent emission was significantly harder and detected also above 10 keV with the PDS instrument. In the last BeppoSAX observation (April 2002) the flux was at least a factor 1.2 below the historical level, suggesting that the source was entering a quiescent period. 相似文献
19.
Rosati P. Basa S. Blain A. W. Bozzo E. Branchesi M. Christensen L. Ferrara A. Gomboc A. O’Brien P. T. Osborne J. P. Rossi A. Schüssler F. Spurio M. Stergioulas N. Stratta G. Amati L. Casewell S. Ciolfi R. Ghirlanda G. Grimm S. Guetta D. Harms J. Le Floc’h E. Longo F. Maggiore M. Mereghetti S. Oganesyan G. Salvaterra R. Tanvir N. R. Turriziani S. Vergani S. D. Balman S. Caruana J. Erkut M. H. Guidorzi G. Frontera F. Martin-Carrillo A. Paltani S. Porquet D. Sergijenko O. 《Experimental Astronomy》2021,52(3):407-437
Experimental Astronomy - The proposed THESEUS mission will vastly expand the capabilities to monitor the high-energy sky. It will specifically exploit large samples of gamma-ray bursts to probe the... 相似文献