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Start Over Subject magellanic clouds Subject x-ray sources
1. A ROSAT PSPC X-Ray Survey of the SMC
ID:
ivo://CDS.VizieR/J/A+AS/136/81
Title:
A ROSAT PSPC X-Ray Survey of the SMC
Short Name:
J/A+AS/136/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a systematic search for point-like and moderately extended soft (0.1-2.4keV) X-ray sources in a raster of nine pointings covering a field of 8.95deg^2^ and performed with the ROSAT PSPC between October 1991 and October 1993 in the direction of the Small Magellanic Cloud (SMC). We detect 248 objects which we include in the first version of our SMC catalogue of soft X-ray sources. We set up seven source classes defined by selections in the count rate, hardness ratio and source extent. We find five high luminosity super-soft sources (1E 0035.4-7230, 1E 0056.8-7146, RX J0048.4-7332, RX J0058.6-7146 and RX J0103-7254), one low-luminosity super-soft source RX J0059.6-7138 correlating with the planetary nebula L357, 51 candidate hard X-ray binaries including eight bright hard X-ray binary candidates, 19 supernova remnants (SNRs), 19 candidate foreground stars and 53 candidate background active galactic nuclei (and quasars). We give a likely classification for ~60% of the catalogued sources. The total count rate of the detected point-like and moderately extended sources in our catalogue is 6.9+/-0.3s^-1, comparable to the background subtracted total rate from the integrated field of ~6.1+/-0.1s^-1.
2. ASCA sources in the SMC
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.
3. A search for SNR 0519-69.0 progenitors
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.
4. Binary central stars of SMC PNe
ID:
ivo://CDS.VizieR/J/A+A/561/A8
Title:
Binary central stars of SMC PNe
Short Name:
J/A+A/561/A8
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Optical Gravitational Lensing Experiment (OGLE), originally designed to search for microlensing events, provides a rich and uniform data set suitable for studying the variability of certain types of objects. We used the OGLE data to study the photometry of central stars of planetary nebulae (PNe) in the Small Magellanic Cloud (SMC). In particular, we searched for close binary central stars with the aim to constrain the binary fraction and period distribution in the SMC. We also searched for PNe mimics and removed them from the PNe sample. We identified 52 counterparts of PNe in the SMC in the I-band images from the OGLE-II and OGLE-III surveys. We analysed the time-series photometry of the PNe. Spectra of the photometric variables were obtained to constrain the nature of the objects or search for additional evidence for binarity. Eight variables were found. Of these, seven objects are PNe mimics, including one symbiotic star candidate. One close binary central star of PN with a period of 1.15 or 2.31 day was discovered. The obtained binary fraction for the SMC PNe and the observational biases are discussed in terms of the OGLE observations.
5. Chandra Small Magellanic Cloud Wing Survey
ID:
ivo://CDS.VizieR/J/MNRAS/383/330
Title:
Chandra Small Magellanic Cloud Wing Survey
Short Name:
J/MNRAS/383/330
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have detected 523 sources in a survey of the Small Magellanic Cloud (SMC) Wing with Chandra. By cross-correlating the X-ray data with optical and near-infrared catalogues, we have found 300 matches. Using a technique that combines X-ray colours and X-ray to optical flux ratios, we have been able to assign preliminary classifications to 265 of the objects. Our identifications include four pulsars, one high-mass X-ray binary (HMXB) candidate, 34 stars and 185 active galactic nuclei (AGN). In addition, we have classified 32 sources as hard AGN which are likely absorbed by local gas and dust, and nine soft AGN whose nature is still unclear. Considering the abundance of HMXBs discovered so far in the Bar of the SMC the number that we have detected in the Wing is low.
6. Chandra SMC deep field sources
ID:
ivo://CDS.VizieR/J/ApJ/716/1217
Title:
Chandra SMC deep field sources
Short Name:
J/ApJ/716/1217
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a pair of 100ks Chandra observations in the Small Magellanic Cloud (SMC) to survey high-mass X-ray binaries (HMXBs), stars, and low-mass X-ray binaries (LMXBs)/cataclysmic variables down to L_x_=4.3x10^32^erg/s. The two SMC Deep Fields (DFs) are located in the most active star-forming region of the bar, with Deep Field-1 positioned at the most pulsar-rich location identified from previous surveys. Two new pulsars were discovered in the outburst: CXOU J004929.7-731058 (P=892s), CXOU J005252.2-721715 (P=326s), and three new HMXB candidates were identified. Of the 15 Be-pulsars now known in the field, 13 were detected, with pulsations seen in 9 of them. Bright optical counterparts exist for 40 of the X-ray sources, of which 33 are consistent with early-type stars (M_V_<-2, B-V<0.2), and are the subject of a companion paper. The results point to an underlying HMXB population density up to double that of active systems. The full catalog of 394 point sources is presented along with detailed analyses of timing and spectral properties.
7. Deep Chandra obs. of the giant HII region N11 in LMC
ID:
ivo://CDS.VizieR/J/ApJS/213/23
Title:
Deep Chandra obs. of the giant HII region N11 in LMC
Short Name:
J/ApJS/213/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
A very sensitive X-ray investigation of the giant H II region N11 in the Large Megallanic Cloud was performed using the Chandra X-ray Observatory. The 300ks observation reveals X-ray sources with luminosities down to 10^32^erg/s, increasing the number of known point sources in the field by more than a factor of five. Among these detections are 13 massive stars (3 compact groups of massive stars, 9 O stars, and one early B star) with log (L_X_/L_BOL_)~-6.5 to -7, which may suggest that they are highly magnetic or colliding-wind systems. On the other hand, the stacked signal for regions corresponding to undetected O stars yields log (L_X_/L_BOL_)~-7.3, i.e., an emission level comparable to similar Galactic stars despite the lower metallicity. Other point sources coincide with 11 foreground stars, 6 late-B/A stars in N11, and many background objects. This observation also uncovers the extent and detailed spatial properties of the soft, diffuse emission regions, but the presence of some hotter plasma in their spectra suggests contamination by the unresolved stellar population.
8. LMC variable X-ray sources
ID:
ivo://CDS.VizieR/J/A+A/344/521
Title:
LMC variable X-ray sources
Short Name:
J/A+A/344/521
Date:
21 Oct 2021
Publisher:
CDS
Description:
The ROSAT PSPC (Cat. <IX/11>) performed more than 200 pointed observations of the Large Magellanic Cloud (LMC) between 1990 and 1994. Most of the LMC was covered more than once and a large fraction at least ten times, making the PSPC observations an in valuable archive to study long-term time variability in the LMC. We performed a systematic search for variable X-ray sources in the LMC and found 27 sources which showed flux variations by factors between 3 and more than 1000. A comparison of the temporal and spectral characteristics of 15 X-ray sources which are not yet identified optically with those of the previously known sources in our sample allows to draw first conclusions about their nature. Up to six of the unidentified sources are promising candidates for high mass X-ray binaries in the LMC. Six sources are probably foreground stars, two soft objects might be supersoft sources and one source could be a black hole candidate. Most of the X-ray binary candidates are found in the area of the LMC 4 supergiant shell leading to a significant concentration of such systems in that region, consistent with the idea of being born in the stellar formation event which created the shell.
9. LMC X-ray sources ROSAT PSPC catalogue
ID:
ivo://CDS.VizieR/J/A+AS/139/277
Title:
LMC X-ray sources ROSAT PSPC catalogue
Short Name:
J/A+AS/139/277
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyzed more than 200 ROSAT PSPC observations in a 10 by 10 degree field centered on the Large Magellanic Cloud (LMC) and performed between 1990 and 1994 to derive a catalogue of X-ray sources. The list contains 758 sources with their X-ray properties. From cross-correlations of the PSPC catalogue with the SIMBAD data base and literature searches we give likely identifications for 144 X-ray sources based on positional coincidence, but taking into account X-ray properties like hardness ratios and source extent. 46 known sources are associated with supernova remnants (SNRs) and candidates in the LMC, most of them already detected by previous X-ray missions.
10. QSO Candidates in the MACHO LMC database
ID:
ivo://CDS.VizieR/J/ApJ/747/107
Title:
QSO Candidates in the MACHO LMC database
Short Name:
J/ApJ/747/107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog the 2566 QSO candidates in the MACHO LMC database. In these catalogs, we complied number of properties of the objects including RA, Dec, crossmatched IDs with several catalogs, magnitudes, photometric redshifts, etc. See Kim et al. (2011ApJ...735...68K) for the SVM (a.k.a. Support Vector Machine, a supervised machine learning algorithm) QSO classification model based on the time variability of lightcurves. We used the model to select the 2566 QSO candidates. In this work, we employed multiple diagnostics such as X-ray flux, mid-IR color and AGN SED fitting in order to select 663 promising QSO candidates among the 2,566 candidates. These candidates are flagged in the catalog. We calibrated the MACHO RA and Dec of the candidates using the UCAC3 catalog and improved the average astrometric accuracy from ~3" to ~0.5".

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