We present a new edition of the catalogue of the low-mass X-ray binaries in the Galaxy and the Magellanic Clouds. The catalogue contains source name(s), coordinates, finding chart, X-ray luminosity, ...system parameters, and stellar parameters of the components and other characteristic properties of 187 low-mass X-ray binaries, together with a comprehensive selection of the relevant literature. The aim of this catalogue is to provide the reader with some basic information on the X-ray sources and their counterparts in other wavelength ranges (γ-rays, UV, optical, IR, and radio). Some sources, however, are only tentatively identified as low-mass X-ray binaries on the basis of their X-ray properties similar to the known low-mass X-ray binaries. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the low-mass nature of the X-ray binary this is mentioned. Literature published before 1 October 2006 has, as far as possible, been taken into account.
We present a new edition of the catalogue of high-mass X-ray binaries in the Galaxy. The catalogue contains source name(s), coordinates, finding chart, X-ray luminosity, system parameters, and ...stellar parameters of the components and other characteristic properties of 114 high-mass X-ray binaries, together with a comprehensive selection of the relevant literature. The aim of this catalogue is to provide the reader with some basic information on the X-ray sources and their counterparts in other wavelength ranges (γ-rays, UV, optical, IR, radio). About 60% of the high-mass X-ray binary candidates are known or suspected Be/X-ray binaries, while 32% are supergiant/X-ray binaries. Some sources, however, are only tentatively identified as high-mass X-ray binaries on the basis of their X-ray properties similar to the known high-mass X-ray binaries. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the high-mass nature of the X-ray binary this is mentioned. Literature published before 1 October 2005 has, as far as possible, been taken into account.
Soft γ-ray repeaters (SGRs) emit multiple, brief (∼0.1-s), intense outbursts of low-energy γ-rays. They are extremely rare-three are known in our Galaxy and one in the Large Magellanic Cloud. Two ...SGRs are associated with young supernova remnants (SNRs), and therefore most probably with neutron stars, but it remains a puzzle why SGRs are so different from 'normal' radio pulsars. Here we report the discovery of pulsations in the persistent X-ray flux of SGR1806 − 20, with a period of 7.47 s and a spindown rate of 2.6 × 10−3 s yr−1. We argue that the spindown is due to magnetic dipole emission and find that the pulsar age and (dipolar) magnetic field strength are ∼1,500 years and 8× 1014 gauss, respectively. Our observations demonstrate the existence of 'magnetars', neutron stars with magnetic fields about 100 times stronger than those of radio pulsars, and support earlier suggestions, that SGR bursts are caused by neutron-star 'crustquakes' produced by magnetic stresses. The 'magnetar' birth rate is about one per millennium-a substantial fraction of that of radio pulsars. Thus our results may explain why some SNRs have no radio pulsars.
A catalogue of low-mass X-ray binaries Liu, Q. Z.; van Paradijs, J.; van den Heuvel, E. P. J.
Astronomy & astrophysics,
03/2001, Letnik:
368, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We present a catalogue of low-mass X-ray binaries. The catalogue is an updated version of the catalogue of van Paradijs (CITE). This new catalogue contains 150 sources, 31 new low-mass X-ray binaries ...in addition to the 119 sources listed in van Paradijs' catalogue. The aim of this catalogue is to help the reader gain easy access to the recent literature (up to about August 2000) on individual sources, and to provide of some basic information on the X-ray sources and their counterparts in other wavelength ranges (UV, optical, IR, and radio). In cases where there is some doubt about the low-mass nature of the X-ray binary, this is mentioned. In an appendix we list the Anomalous X-ray Pulsars (AXPs), which nowadays are no longer thought to be low-mass X-ray binaries.
We present a catalogue of high-mass X-ray binaries in the Magellanic Clouds. The catalogue lists source name(s), coordinates, apparent magnitudes, orbital parameters, and X-ray luminosity of 128 ...high-mass X-ray binaries, together with stellar parameters of the components, other characteristic properties and a comprehensive selection of the relevant literature. The aim of this catalogue is to provide easy access to the basic information on the X-ray sources and their counterparts in other wavelength ranges (UV, optical, IR, radio). Most of the sources are identified to be Be/X-ray binaries. Some sources, however, are only tentatively identified as high-mass X-ray binaries on the basis of a transient character and/or a hard X-ray spectrum. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the high-mass nature of the X-ray binary this is mentioned. Literature published before 1 May 2005 has, as far as possible, been taken into account.
The discovery of afterglows associated with γ-ray bursts at X-ray, optical and radio wavelengths and
the measurement of the redshifts of some of these events, has established that γ-ray bursts lie at ...extreme distances,
making them the most powerful photon-emitters known in the Universe. Here
we report the discovery of transient optical emission in the error box of
the γ-ray burst GRB980425, the light curve of which was very different
from that of previous optical afterglows associated with γ-ray bursts.
The optical transient is located in a spiral arm of the galaxy ESO184-G82,
which has a redshift velocity of only 2,550 km s−1
(ref. 6). Its optical spectrum and location
indicate that it is a very luminous supernova, which has been
identified as SN1998bw. If this supernova and GRB980425 are indeed associated,
the energy radiated in γ-rays is at least four orders of magnitude less
than in other γ-ray bursts, although its appearance was otherwise unremarkable:
this indicates that very different mechanisms can give rise to γ-ray
bursts. But independent of this association, the supernova is itself unusual,
exhibiting an unusual light curve at radio wavelengths that requires that
the gas emitting the radio photons be expanding relativistically,.
We have obtained high- and intermediate-resolution optical spectra of the black hole candidate Nova Scorpii 1994 in 1998 May/June, when the source was in complete (X-ray) quiescence. We measure the ...radial velocity curve of the secondary star and obtain a semi-amplitude of K2=215.5 ± 2.4 km s-1, which is 6 per cent lower than the only previously determined value. This new value for K2 thus reduces the binary mass function to f(M) = 2.73 ± 0.09 M⊙. Using only the high-resolution spectra, we constrain the rotational broadening of the secondary star, v sin i, to lie in the range 82.9–94.9 km s-1 (95 per cent confidence) and thus constrain the binary mass ratio to lie in the range 0.337–0.436 (95 per cent confidence). We can also combine our results with published limits for the binary inclination to constrain the mass of the compact object and secondary star to the ranges 5.5–7.9 and 1.7–3.3 M⊙ respectively (95 per cent confidence). Finally, we report on the detection of the lithium resonance line at 6707.8 Å, with an equivalent width of 55 ± 8 m Å.
The mass of the neutron star in Vela X-1 Barziv, O.; Kaper, L.; Van Kerkwijk, M. H. ...
Astronomy & astrophysics,
10/2001, Letnik:
377, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We measured the radial-velocity curve of HD 77581, the B-supergiant companion of the X-ray pulsar Vela X-1, using 183 high-resolution optical spectra obtained in a nine-month campaign. We derive ...radial-velocity amplitudes for different lines and wavelength regions, and find all are consistent with each other, as well as with values found in previous analyses. We show that one apparent exception, an anomalously low value derived from ultra-violet spectra obtained with the International Ultraviolet Explorer, was due to an error in the analysis procedures. We re-analyse all IUE spectra, and combine the resulting velocities with the ones derived from the new optical spectra presented here, as well as those derived from optical spectra published earlier. As in previous analyses, the radial velocities show strong deviations from those expected for a pure Keplerian orbit, with root-mean-square amplitudes of ~7 kms-1 for strong lines of Si4 and N3 near 4100 Å, and up to ~20 kms-1 for weaker lines of N2 and Al3 near 5700 Å. The deviations likely are related to the pronounced line-profile variations seen in our spectra. Our hope was that the deviations would average out when a sufficient number of spectra were added together. It turns out, however, that systematic deviations as a function of orbital phase are present as well, at the 3 kms-1 level, with the largest deviations occurring near inferior conjunction of the neutron star and near the phase of maximum approaching velocity. While the former might be due to a photo-ionisation wake, for which we observe direct evidence in the profiles of Hδ and Hα, the latter has no straightforward explanation. As a result, our best estimate of the radial-velocity amplitude, $K_{\rm opt}=21.7\pm1.6$ kms-1, has an uncertainty not much reduced to that found in previous analyses, in which the influence of the systematic, phase-locked deviations had not been taken into account. Combining our velocity amplitude with the accurate orbital elements of the X-ray pulsar, we infer $M_{\rm ns}\sin^3{i}=1.78\pm0.15$ $M_\odot$.
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