- ID:
- ivo://CDS.VizieR/J/PASJ/55/161
- Title:
- ASCA sources in the SMC
- Short Name:
- J/PASJ/55/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made 22 observations on the Small Magellanic Cloud (SMC) and covered full regions of the main body and the eastern wing by the end of the ASCA mission. We detected 106 discrete sources with a criterion of S/N>5 and performed systematic analyses on all of the sources. We determined the source positions with an ~40" error radius (90% confidence) for sources detected in the central 20' radius of the GIS. We detected coherent pulsations from 17 sources. Among them, eight were newly discovered during this study. We classified most of these pulsars as X-ray binary pulsars (XBPs) based on their properties, such as the flux variability and the existence of an optical counterpart. We detected X-ray emission from eight supernova remnants (SNRs). Based on these ASCA results and further information from ROSAT, SAX, RXTE, CGRO, Chandra, and XMM-Newton, we compiled comprehensive catalogues of discrete X-ray sources in the Small Magellanic Cloud.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/747/L19
- Title:
- A search for SNR 0519-69.0 progenitors
- Short Name:
- J/ApJ/747/L19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for an ex-companion star in SNR 0519-69.0, located in the Large Magellanic Cloud, based on images taken with the Hubble Space Telescope with a limiting magnitude of V=26.05. SNR 0519-69.0 is confidently known to be from a Type Ia supernova based on its light echoes and X-ray spectra. The geometric center of the remnant (based on the H{alpha} and X-ray shell) is at 05:19:34.83, -69:02:06.92 (J2000). Accounting for the measurement uncertainties, the orbital velocity, and the kick velocity, any ex-companion star must be within 4.7" of this position at the 99.73% confidence level. This circle contains 27 main-sequence stars brighter than V=22.7, any one of which could be the ex-companion star left over from a supersoft source progenitor system. The circle contains no post-main-sequence stars, and this rules out the possibility of all other published single-degenerate progenitor classes (including symbiotic stars, recurrent novae, helium donors, and the spin-up/spin-down models) for this particular supernova. The only remaining possibility is that SNR 0519-69.0 was formed from either a supersoft source or a double-degenerate progenitor system.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/83
- Title:
- Associations to 1FGL sources
- Short Name:
- J/ApJ/753/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fermi Large Area Telescope (LAT) First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of {gamma}-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of source types known to emit {gamma} rays, 630 of these sources are "unassociated" (i.e., have no obvious counterparts at other wavelengths). Here, we employ two statistical analyses of the primary {gamma}-ray characteristics for these unassociated sources in an effort to correlate their {gamma}-ray properties with the active galactic nucleus (AGN) and pulsar populations in 1FGL. Based on the correlation results, we classify 221 AGN-like and 134 pulsar-like sources in the 1FGL unassociated sources. The results of these source "classifications" appear to match the expected source distributions, especially at high Galactic latitudes. While useful for planning future multiwavelength follow-up observations, these analyses use limited inputs, and their predictions should not be considered equivalent to "probable source classes" for these sources. We discuss multiwavelength results and catalog cross-correlations to date, and provide new source associations for 229 Fermi-LAT sources that had no association listed in the 1FGL catalog. By validating the source classifications against these new associations, we find that the new association matches the predicted source class in ~80% of the sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/660/1428
- Title:
- Astrometry around RX J0720.4-3125
- Short Name:
- J/ApJ/660/1428
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used a set of dedicated astrometric data from the Hubble Space Telescope to measure the parallax and proper motion of the nearby neutron star RX J0720.4-3125. At each of eight epochs over 2 years, we used the High Resolution Camera of the Advanced Camera for Surveys to measure the position of the B=26.6 target to a precision of ~2mas (~0.07pix) relative to 22 other stars. From these data we measure a parallax of plx=2.8+/-0.9mas (for a distance of 360^+170^_-90_pc) and a proper motion of mu=107.8+/-1.2mas/yr. Exhaustive testing of every stage of our analysis suggests that it is robust, with a maximum systematic uncertainty on the parallax of 0.4mas. The distance is compatible with earlier estimates made from scaling the optical emission of RX J0720.4-3125 relative to the even closer neutron star RX J1856.5-3754. The distance and proper motion imply a transverse velocity of 180^+90^_-40_km/s, comparable to velocities observed for radio pulsars. The speed and direction suggest an origin for RX J0720.4-3125 in the Trumpler 10 OB association ~0.7Myr ago, with a possible range of 0.5-1.0Myr given by the uncertainty in the distance.
- ID:
- ivo://CDS.VizieR/J/AZh/87/760
- Title:
- Astrophysical catalog of clusters of galaxies
- Short Name:
- J/AZh/87/760
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog of rich clusters of galaxies contains information about the astrometric and physical characteristics of the 213 clusters of galaxies and data about evidences of the presence of cooling flows and filaments in selected clusters. The catalog lists also the references to the sources of the data.
- ID:
- ivo://CDS.VizieR/J/ApJS/250/23
- Title:
- AstroSat/UVIT and Chandra X-ray sources in M31
- Short Name:
- J/ApJS/250/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An ultraviolet (UV) survey of M31 has been carried out during 2017-19 with the Ultra-Violet Imaging Telescope (UVIT) instrument on board the AstroSat Observatory. Here we match the M31 UVIT source catalog with the Chandra source catalog. We find 67 UVIT/Chandra sources detected in a varying number of UV and X-ray bands. The UV and X-ray photometry is analyzed using power-law and blackbody models. The X-ray types include 15 low-mass X-ray binaries (LMXBs) and five active galactic nuclei. Crossmatches with catalogs of stars, clusters, and other source types yield the following: 20 of the UVIT/Chandra sources match with M31 globular clusters, and nine with foreground stars. Three more globular clusters and two more foreground stars are consistent with the UVIT source positions although outside the Chandra match radius of 1". The UV emission of the UVIT/Chandra sources associated with globular clusters is consistent with emission from blue horizontal branch stars rather than from the X-ray source. The LMXBs in globular clusters are among the most luminous globular clusters in M31. Comparison with stellar evolutionary tracks shows that the UVIT/Chandra sources with high UV blackbody temperatures are consistent with massive (10-30M_{sun}_) stars in M31.
- ID:
- ivo://CDS.VizieR/V/134
- Title:
- Atlas of Radio/X-ray associations (ARXA)
- Short Name:
- V/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An all-sky comprehensive catalogue of calculated radio and X-ray associations to optical objects is presented. Included are X-ray sources from XMM-Newton, Chandra and ROSAT catalogues, radio sources from NVSS, FIRST and SUMSS catalogues, and optical data, identifications and redshifts from the APM, USNO-A, SDSS-DR7 and the extant literature. This "Atlas of Radio/X-ray Associations" inherits many techniques from the predecessor Quasars.org catalog (Flesch 2004, Cat. J/A+A/427/387), but object selection is changed and processing tweaked. Optical objects presented are those which are calculated with 40% confidence to be associated with radio/X-ray detections, totalling 602570 objects in all, including 23681 double radio lobe detections. For each of these optical objects I display the calculated percentage probabilities of its being a QSO, galaxy, star, or erroneous radio / X-ray association, plus any identification from the literature. The catalogue includes 105568 uninvestigated objects listed as 40% to >99% likely to be a QSO. The catalogue is available at http://quasars.org/arxa.htm .
- ID:
- ivo://CDS.VizieR/J/ApJ/813/28
- Title:
- Autoclassification of the variable 3XMM sources
- Short Name:
- J/ApJ/813/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the current era of large surveys and massive data sets, autoclassification of astrophysical sources using intelligent algorithms is becoming increasingly important. In this paper we present the catalog of variable sources in the Third XMM-Newton Serendipitous Source catalog (3XMM) autoclassified using the Random Forest machine learning algorithm (RF). We used a sample of manually classified variable sources from the second data release of the XMM-Newton catalogs (2XMMi-DR2) to train the classifier, obtaining an accuracy of ~92%. We also evaluated the effectiveness of identifying spurious detections using a sample of spurious sources, achieving an accuracy of ~95%. Manual investigation of a random sample of classified sources confirmed these accuracy levels and showed that the Random Forest machine learning algorithm is highly effective at automatically classifying 3XMM sources. Here we present the catalog of classified 3XMM variable sources. We also present three previously unidentified unusual sources that were flagged as outlier sources by the algorithm: a new candidate supergiant fast X-ray transient, a 400s X-ray pulsar, and an eclipsing 5hr binary system coincident with a known Cepheid.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A68
- Title:
- A2163 VLA 20cm images
- Short Name:
- J/A+A/619/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study, we investigate the X-ray properties of the intracluster gas and the radio morphology of the extraordinary cluster A2163. We analyze two Suzaku observations of A2163, one in the north-east (NE) and one in the south-west (SW) direction, and use archival XMM-Newton data to remove point sources in the field of view. To compare our findings in the X-ray regime with the radio emission, we obtain radio images of the cluster from an archival VLA observation at 20cm. We identify three shock fronts in A2163 in our spectral X-ray study. A clear shock front lies in the NE direction at a distance of 1.4Mpc from the center, with a Mach number of M=1.7^+0.3^_-0.2_, estimated from the temperature discontinuity. This shock coincides with the position of a known radio relic. We identify two additional shocks in the SW direction, one with M=1.5^+0.5^_-0.3_ at a distance of 0.7Mpc, which is likely related to a cool core remnant, and a strong shock with M=3.2^+0.6^_-0.7_ at a distance of 1.3Mpc, which also closely matches the radio contours. The complex structure of A2163 as well as the different Mach numbers and shock velocities suggest a merging scenario with two unequal merging constituents, where two shock fronts emerged in an early stage of the merger and traveled outwards while an additional shock front developed in front of the merging cluster cores.
- ID:
- ivo://CDS.VizieR/J/ApJS/187/388
- Title:
- A XMM-Newton survey of the SXRB
- Short Name:
- J/ApJS/187/388
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of the soft X-ray background (SXRB) OVII and OVIII intensity between l=120{deg} and l=240{deg}, the first results of a survey of the SXRB using archival XMM-Newton observations. We do not restrict ourselves to blank-sky observations, but instead use as many observations as possible, removing bright or extended sources by hand if necessary. In an attempt to minimize contamination from near-Earth solar wind charge exchange (SWCX) emission, we remove times of high solar wind proton flux from the data. Without this filtering we are able to extract measurements from 586 XMM-Newton observations. With this filtering, ~1/2 of the observations are rendered unusable, and we are able to extract measurements from 303 observations. The oxygen intensities are typically ~0.5-10 photons/cm^2^/s/sr (line units, L.U.) for OVII and ~0-5L.U. for OVIII. The proton flux filtering does not systematically reduce the oxygen intensities measured from a given observation. However, the filtering does preferentially remove the observations with higher oxygen intensities. Our data set includes 69 directions with multiple observations, whose oxygen intensity variations can be used to constrain SWCX models. After removing observations likely to be contaminated by heliospheric SWCX emission, we use our results to examine the Galactic halo.
