- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1701
- Title:
- High-frequency QPO in black hole binaries
- Short Name:
- J/MNRAS/426/1701
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the analysis of a large data base of X-ray observations of 22 galactic black hole transients with the Rossi X-Ray Timing Explorer throughout its operative life for a total exposure time of ~12ms. We excluded persistent systems and the peculiar source GRS 1915+105, as well as the most recently discovered sources. The semi-automatic homogeneous analysis was aimed at the detection of high-frequency (100-1000Hz) quasi-periodic oscillations (QPO), of which several cases were previously reported in the literature.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/442/1135
- Title:
- High-mass X-ray binaries in the Magellanic Clouds
- Short Name:
- J/A+A/442/1135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A81
- Title:
- High-mass X-ray binaries in the SMC
- Short Name:
- J/A+A/586/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The last comprehensive catalogue of high-mass X-ray binaries in the Small Magellanic Cloud (SMC) was published about ten years ago. Since then new such systems were discovered, mainly by X-ray observations with Chandra and XMM-Newton. For the majority of the proposed HMXBs in the SMC no X-ray pulsations were discovered as yet, and unless other properties of the X-ray source and/or the optical counterpart confirm their HMXB nature, they remain only candidate HMXBs. From a literature search we collected a catalogue of 148 confirmed and candidate HMXBs in the SMC and investigated their properties to shed light on their real nature. Based on the sample of well-established HMXBs (the pulsars), we investigated which observed properties are most appropriate for a reliable classification. We defined different levels of confidence for a genuine HMXB based on spectral and temporal characteristics of the X-ray sources and colour-magnitude diagrams from the optical to the infrared of their likely counterparts. We also took the uncertainty in the X-ray position into account. We identify 27 objects that probably are misidentified because they lack an infrared excess of the proposed counterpart. They were mainly X-ray sources with a large positional uncertainty. This is supported by additional information obtained from more recent observations. Our catalogue comprises 121 relatively high-confidence HMXBs (the vast majority with Be companion stars). About half of the objects show X-ray pulsations, while for the rest no pulsations are known as yet. A comparison of the two subsamples suggests that long pulse periods in excess of a few 100s are expected for the "non-pulsars", which are most likely undetected because of aperiodic variability on similar timescales and insufficiently long X-ray observations. The highest X-ray variability together with the lowest observed minimum fluxes for short-period pulsars indicate that in addition to the eccentricity of the orbit, its inclination against the plane of the Be star circum-stellar disc plays a major role in determining the outburst behaviour. The large population of HMXBs in the SMC, in particular Be X-ray binaries, provides the largest homogeneous sample of such systems for statistical population studies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2095
- Title:
- HMXBs in nearby galaxies
- Short Name:
- J/MNRAS/419/2095
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on a homogeneous set of X-ray, infrared and ultraviolet observations from Chandra, Spitzer, GALEX and 2MASS archives, we study populations of high-mass X-ray binaries (HMXBs) in a sample of 29 nearby star-forming galaxies and their relation with the star formation rate (SFR). In agreement with previous results, we find that HMXBs are a good tracer of the recent star formation activity in the host galaxy and their collective luminosity and number scale with the SFR, in particular, LX~~2.6x10^39^SFR. However, the scaling relations still bear a rather large dispersion of rms~0.4dex, which we believe is of a physical origin. We present the catalog of 1057 X-ray sources detected within the D25 ellipse for galaxies of our sample and construct the average X-ray luminosity function (XLF) of HMXBs with substantially improved statistical accuracy and better control of systematic effects than achieved in previous studies. The XLF follows a power law with slope of 1.6 in the log(LX)~35-40 luminosity range with a moderately significant evidence for a break or cut-off at LX~10^40^erg/s. As before, we did not find any features at the Eddington limit for a neutron star or a stellar mass black hole. We discuss implications of our results for the theory of binary evolution. In particular we estimate the fraction of compact objects that once upon their lifetime experienced an X-ray active phase powered by accretion from a high mass companion and obtain a rather large number, fX~0.2x(0.1Myr/{tau}x) ({tau}x is the life time of the X-ray active phase). This is about 4 orders of magnitude more frequent than in LMXBs. We also derive constrains on the mass distribution of the secondary star in HMXBs.
- ID:
- ivo://CDS.VizieR/J/ApJS/248/31
- Title:
- HST & Chandra obs. of elliptical galaxies
- Short Name:
- J/ApJS/248/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate X-ray binary (XRB) luminosity function (XLF) scaling relations for Chandra-detected populations of low-mass XRBs (LMXBs) within the footprints of 24 early-type galaxies. Our sample includes Chandra and Hubble Space Telescope observed galaxies at D<~25Mpc that have estimates of the globular cluster (GC) specific frequency (S_N_) reported in the literature. As such, we are able to directly classify X-ray-detected sources as being coincident with unrelated background/foreground objects, GCs, or sources that are within the fields of the galaxy targets. We model the GC and field LMXB population XLFs for all galaxies separately and then construct global models characterizing how the LMXB XLFs vary with galaxy stellar mass and S_N_. We find that our field LMXB XLF models require a component that scales with S_N_ and has a shape consistent with that found for the GC LMXB XLF. We take this to indicate that GCs are "seeding" the galactic field LMXB population, through the ejection of GC LMXBs and/or the diffusion of the GCs in the galactic fields themselves. However, we also find that an important LMXB XLF component is required for all galaxies that scales with stellar mass, implying that a substantial population of LMXBs are formed "in situ," which dominates the LMXB population emission for galaxies with S_N_<~2. For the first time, we provide a framework quantifying how directly associated GC LMXBs, GC-seeded LMXBs, and in situ LMXBs contribute to LMXB XLFs in the broader early-type galaxy population.
- ID:
- ivo://CDS.VizieR/J/ApJ/448/683
- Title:
- Hyades RASS observations
- Short Name:
- J/ApJ/448/683
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a complete X-ray survey of the Hyades cluster region using the ROSAT All-Sky Survey (RASS). Our survey covers over 900deg^2^ of the sky. Over 185 optically identified Hyades were detected down to a limiting X-ray luminosity of ~1-2x10^28^ergs/s (0.1-1.8keV); among solar-like stars, i.e., main-sequence stars of spectral type G, the RASS detection rate is ~90%. The presence of many binary systems in the cluster is a key factor influencing the X-ray luminosity function. Short-period (~ a few days or less) binaries are anomalously X-ray bright, as might be expected; however, the X-ray luminosity functions of K and possibly M binaries of all types are significantly different from their single counterparts, confirming the results of Pye et al. (1994MNRAS.266..798P) for a smaller K star sample drawn from deep ROSAT pointings. Comparison with Einstein Observatory studies of a subset of Hyades stars demonstrates a general lack of significant (> a factor of 2) long-term X-ray variability. This may be the result of the dominance of a small-scale, turbulent dynamo in the younger Hyades stars compared to the large-scale, cyclic dynamo observed in the Sun.
- ID:
- ivo://CDS.VizieR/J/A+A/359/227
- Title:
- Lindroos binary systems X-ray emission
- Short Name:
- J/A+A/359/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the X-ray emission from binary systems extracted from the Lindroos catalogue (Lindroos, 1986A&A...156..223L) based on the ROSAT All-Sky survey as well as ROSAT PSPC and HRI pointings. The studied sample consists of visual binary systems comprised of early-type primaries and late-type secondaries. The ages of the systems were determined by Lindroos (1985, Cat. II/127) from uvby{beta} photometry of the primaries. These ages range between 33 and 135Myr, so if the late-type secondaries are physically bound to the early-type primaries, they could be Post-T Tauri stars (PTTS). We have found strong X-ray emission from several secondaries. This fact together with their optical and IR data, make them bona fide PTTS candidates. We have also detected X-ray emission from several early-type primaries and, in particular, from most of the late-B type stars. Because their HRI hardness ratios are similar to those from resolved late-type stars, the presence of an unresolved late-type companion seems to be the cause of this emission.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A130
- Title:
- List of 1254 X-ray bursts
- Short Name:
- J/A+A/606/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- When the upper layer of an accreting neutron star experiences a thermonuclear runaway of helium and hydrogen, it exhibits an X-ray burst of a few keV with a cool-down phase of typically 1 minute. When there is a surplus of hydrogen, hydrogen fusion is expected to simmer during that same minute due to the rp process, which consists of rapid proton captures and slow {beta}-decays of proton-rich isotopes. We have analyzed the high-quality light curves of 1254 X-ray bursts, obtained with the Proportional Counter Array on the Rossi X-ray Timing Explorer between 1996 and 2012, to systematically study the cooling and rp process. This is a follow-up of a study on a selection of 37 bursts from systems that lack hydrogen and show only cooling during the bursts.We find that the bolometric light curves are well described by the combination of a power law and a one-sided Gaussian. The power-law decay index is between 1.3 and 2.1 and similar to that for the 37-bursts sample. There are individual bursters with a narrower range. The Gaussian is detected in half of all bursts, with a typical standard deviation of 50s and a fluence ranging up to 60% of the total fluence. The Gaussian appears consistent with being due to the rp process. The Gaussian fluence fraction suggests that the layer where the rp process is active is underabundant in H by a factor of at least five with respect to cosmic abundances. Ninety-four percent of all bursts from ultracompact X-ray binaries lack the Gaussian component, and the remaining 6% are marginal detections. This is consistent with a hydrogen deficiency in these binaries. We find no clear correlation between the power law and Gaussian light-curve components.
- ID:
- ivo://CDS.VizieR/J/A+A/533/A33
- Title:
- LMXBs detected in nearby galaxies
- Short Name:
- J/A+A/533/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the archival data from the Chandra observations of nearby galaxies, we study different sub populations of low-mass X-ray binaries (LMXBs) - dynamically formed systems in globular clusters (GCs) and in the nucleus of M 31 and (presumably primordial) X-ray binaries in the fields of galaxies. Our aim is to produce accurate luminosity distributions of X-ray binaries in different environments, suitable for quantitative comparison with each other and with the output of population synthesis calculations. Our sample includes seven nearby galaxies (M 31, Maffei 1, Centaurus A, M 81, NGC 3379, NGC 4697, and NGC 4278) and the Milky Way, which together provide relatively uniform coverage down to the luminosity limit of 10^35^erg/s. In total we have detected 185 LMXBs associated with GCs, 35 X-ray sources in the nucleus of M 31, and 998 field sources of which ~365 are expected to be background AGN. We combine these data, taking special care to accurately account for X-ray and optical incompleteness corrections and the removal of the contamination from the cosmic X-ray background sources, to produce luminosity distributions of X-ray binaries in different environments to far greater accuracy than has been obtained previously.
- ID:
- ivo://CDS.VizieR/J/ApJ/689/983
- Title:
- LMXBs in early-type galaxies. I. Chandra
- Short Name:
- J/ApJ/689/983
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a Chandra survey of LMXBs in 24 early-type galaxies. Correcting for detection incompleteness, the X-ray luminosity function (XLF) of each galaxy is consistent with a power law with negative logarithmic differential slope, {beta}~2.0. However, {beta} strongly correlates with incompleteness, indicating the XLF flattens at low-L_X_. Although the XLFs are similar, we find evidence of some variation between galaxies. The high-L_X_ XLF slope does not correlate with age, but may correlate with [{alpha}/Fe]. Considering only LMXBs with L_X_>10^37^ergs/s, matching the LMXBs with globular clusters (GCs) identified in HST observations of 19 of the galaxies, we find the probability a GC hosts an LMXB is proportional to L^{alpha}^_GC_Z^{gamma}^_Fe_ where {alpha}=1.01+/-0.19 and {gamma}=0.33+/-0.11. The spatial distribution of LMXBs resembles that of GCs, and the specific frequency of LMXBs is proportional to the GC specific luminosity, consistent with the hypothesis that all LMXBs form in GCs.
