- ID:
- ivo://CDS.VizieR/J/MNRAS/402/691
- Title:
- SMC RR Lyrae stars light curve analysis
- Short Name:
- J/MNRAS/402/691
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a careful and detailed light curve analysis of RR Lyrae stars in the Small Magellanic Cloud (SMC) discovered by the Optical Gravitational Lensing Experiment (OGLE) project. Out of 536 single-mode RR Lyrae stars selected from the data base, we have investigated the physical properties of 335 'normal-looking' RRab stars and 17 RRc stars that have good quality photometric light curves. We have also been able to estimate the distance modulus of the cloud which is in good agreement with those determined from other independent methods.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/545/A128
- Title:
- SMC XMM-Newton images
- Short Name:
- J/A+A/545/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although numerous archival XMM-Newton observations existed towards the Small Magellanic Cloud (SMC) before 2009, only a fraction of the whole galaxy had been covered. Between May 2009 and March 2010, we carried out an XMM-Newton survey of the SMC, to ensure a complete coverage of both its bar and wing. Thirty-three observations of 30 different fields with a total exposure of about one Ms filled the previously missing parts. We systematically processed all available SMC data from the European Photon Imaging Camera. After rejecting observations with very high background, we included 53 archival and the 33 survey observations. We produced images in five different energy bands. We applied astrometric boresight corrections using secure identifications of X-ray sources and combined all the images to produce a mosaic covering the main body of the SMC. We present an overview of the XMM-Newton observations, describe their analysis, and summarise our first results, which will be presented in detail in follow-up papers. Here, we mainly focus on extended X-ray sources, such as supernova remnants (SNRs) and clusters of galaxies, that are seen in our X-ray images. Our XMM-Newton survey represents the deepest complete survey of the SMC in the 0.15-12.0keV X-ray band. We propose three new SNRs that have low surface brightnesses of a few 10^-14^erg/s/cm^2^/arcmin^2^ and large extents. In addition, several known remnants appear larger than previously measured at either X-rays or other wavelengths extending the size distribution of SMC SNRs to larger values.
- ID:
- ivo://CDS.VizieR/J/A+AS/142/41
- Title:
- SMC X-ray sources ROSAT PSPC catalogue
- Short Name:
- J/A+AS/142/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of 517 discrete X-ray sources in a 6{deg}x6{deg} field covering the Small Magellanic Cloud (SMC). The catalogue was derived from the pointed ROSAT PSPC observations performed between October 1991 and May 1994 and is complementary to the Large Magellanic Cloud (LMC) catalogue published by Haberl & Pietsch (1999, Cat. <J/A+AS/139/277>). We followed the same identification scheme and used, among other information, X-ray hardness ratios and spatial extent to classify unknown sources as candidates for active galactic nuclei (AGN), foreground stars, supernova remnants (SNRs), supersoft sources (SSSs) and X-ray binaries. For 158 sources a likely source type is given, from which 46 sources are suggested as background AGN (including candidates resulting from a comparison of X-ray and radio images). Nearly all of the X-ray binaries known in the SMC were detected in ROSAT PSPC observations; most of them with luminosities below 10^36^erg/s suggesting that the fraction of high luminosity X-ray binary systems in the Magellanic Clouds (MCs) is not significantly larger than in our galaxy. Seventeen X-ray sources are associated with SNRs found in earlier work and we suggest here two additional extended sources as SNR candidates. Three very soft sources are newly classified as SSSs from which one is identified with the symbiotic star LIN 358 in the SMC.
- ID:
- ivo://CDS.VizieR/J/ApJ/669/327
- Title:
- S3MC: YSOs in N66, in SMC
- Short Name:
- J/ApJ/669/327
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Spitzer Space Telescope observations from the Spitzer Survey of the Small Magellanic Cloud (S^3^MC) to study the young stellar content of N66, the largest and brightest HII region in the SMC. In addition to large numbers of normal stars, we detect a significant population of bright, red infrared sources that we identify as likely to be young stellar objects (YSOs). We use spectral energy distribution (SED) fits to classify objects as ordinary (main-sequence or red giant) stars, asymptotic giant branch stars, background galaxies, and YSOs.
505. SN 1987A 3mm image
- ID:
- ivo://CDS.VizieR/J/A+A/541/L2
- Title:
- SN 1987A 3mm image
- Short Name:
- J/A+A/541/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The proximity of core-collapse supernova 1987A (SN 1987A) in the Large Magellanic Cloud (LMC) and its rapid evolution make it a unique case study of the development of a young supernova remnant. We aim at resolving the remnant of SN 1987A for the first time in the 3-mm band (at 94GHz).
- ID:
- ivo://CDS.VizieR/J/A+A/584/A41
- Title:
- SNR IKT 16 X-ray image
- Short Name:
- J/A+A/584/A41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IKT 16 is an X-ray and radio-faint supernova remnant (SNR) in the Small Magellanic Cloud (SMC). A detailed X-ray study of this SNR with XMM-Newton confirmed the presence of a hard X-ray source near its centre, indicating the detection of the first composite SNR in the SMC. With a dedicated Chandra observation we aim to resolve the point source and confirm its nature. We also acquire new ATCA observations of the source at 2.1GHz with improved flux density estimates and resolution. We perform detailed spatial and spectral analysis of the source. With the highest resolution X-ray and radio image of the centre of the SNR available today, we resolve the source and confirm its pulsar wind nebula (PWN) nature. Further, we constrain the geometrical parameters of the PWN and perform spectral analysis for the point source and the PWN separately. We also test for the radial variations of the PWN spectrum and its possible east west asymmetry. The X-ray source at the centre of IKT 16 can be resolved into a symmetrical elongated feature centring a point source, the putative pulsar. Spatial modelling indicates an extent of 5.2" of the feature with its axis inclined at 82{deg} east from north, aligned with a larger radio feature consisting of two lobes almost symmetrical about the X-ray source. The picture is consistent with a PWN which has not yet collided with the reverse shock. The point source is about three times brighter than the PWN and has a hard spectrum of spectral index 1.1 compared to a value 2.2 for the PWN. This points to the presence of a pulsar dominated by non-thermal emission. The expected dE/dt is ~10^37^erg/s and spin period <100ms. However, the presence of a compact nebula unresolved by Chandra at the distance of the SMC cannot completely be ruled out.
- ID:
- ivo://CDS.VizieR/J/AJ/138/510
- Title:
- Spectral classification of N159/N160 stars
- Short Name:
- J/AJ/138/510
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic study of the N159/N160 massive star-forming region south of 30 Doradus in the Large Magellanic Cloud, classifying a total of 189 stars in the field of the complex. Most of them belong to O and early B spectral classes; we have also found some uncommon and very interesting spectra, including members of the Onfp class, a Be P Cygni star, and some possible multiple systems. Using spectral types as broad indicators of evolutionary stages, we considered the evolutionary status of the region as a whole. We infer that massive stars at different evolutionary stages are present throughout the region, favoring the idea of a common time for the origin of recent star formation in the N159/N160 complex as a whole, while sequential star formation at different rates is probably present in several subregions.
- ID:
- ivo://CDS.VizieR/J/ApJ/699/150
- Title:
- Spectral classifications of Massive YSOs in LMC
- Short Name:
- J/ApJ/699/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and categorize Spitzer infrared spectrometer spectra of 294 objects in the Large Magellanic Cloud (LMC) to create the largest and most complete catalog of massive young stellar object (YSO) spectra in the LMC. Target sources were identified from infrared photometry and multiwavelength images indicative of young, massive stars highly enshrouded in their natal gas and dust clouds. Several objects have been spectroscopically identified as non-YSOs and have features similar to more-evolved stars such as red supergiants, asymptotic giant branch (AGB), and post-AGB stars. Our sample primarily consists of 277 objects we identify as having spectral features indicative of embedded YSOs. The remaining sources are comprised of seven C-rich evolved sources, eight sources dominated by broad silicate emission, and one source with multiple broad emission features.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/54
- Title:
- Spectra of a rare low-mass Wolf-Rayet star in LMC
- Short Name:
- J/ApJ/888/54
- Date:
- 25 Oct 2021 10:12:43
- Publisher:
- CDS
- Description:
- We report the serendipitous discovery of an object, UVQSJ060819.93-715737.4, with a spectrum dominated by extremely intense, narrow CII emission lines. The spectrum is similar to those of the very rare, late-type [WC11] low-mass Wolf-Rayet stars. Despite the recognition of these stars as a distinct class decades ago, there remains barely a handful of Galactic members, all of which are also planetary-nebula central stars. Although no obvious surrounding nebulosity is present in J0608, [OII], [NII], and [SII] emission suggest the presence of an inconspicuous, low-excitation nebula. There is low-amplitude incoherent photometric variability on timescales of days to years, as well as numerous prominent P Cygni profiles, implying mass loss. There are indications of a binary companion. The star is located on the outskirts of the LMC, and the observed radial velocity (~+250km/s) and proper motion strongly suggest membership. If indeed an LMC member, this is the first extragalactic late [WC] star, and the first with an accurately determined luminosity, as the Galactic examples are too distant for precise parallax determinations. A high-quality, broad-coverage spectrum of the prototype of the late [WC] class, CPD -56 8032, is also presented. We discuss different excitation mechanisms capable of producing the great strength of the CII emission. Numerous autoionizing levels of C II are definitely populated by processes other than dielectronic recombination. Despite the spectacular emission spectra, observational selection makes objects such as these difficult to discover. Members of the [WC11] class may in fact be considerably more common than the handful of previously known late [WC] stars.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A71
- Title:
- Spectra of 14 Magellanic Cloud planetary nebulae
- Short Name:
- J/A+A/642/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained new spectra of fourteen Magellanic Cloud planetary nebulae with the South African Large Telescope to determine heating rates of their central stars and to verify evolutionary models of post asymptotic giant branch stars. We compared new spectra with observations made in previous years. Five planetary nebulae showed an increase of the excitation with time. Four of their central stars exhibit [WC] features in their spectra, including three new detections. This raises the total number of [WC] central stars of PNe in the Magellanic Clouds to ten. We compared determined heating rates of the four [WC] central stars with the He burning post asymptotic giant branch evolutionary tracks and the remaining star with the H-burning tracks. Determined heating rates are consistent with the evolutionary models for both H and He-burning post asymptotic giant branch stars. The central stars of the PNe which show the fastest increase of excitation are also the most luminous in the sample. This indicates that [WC] central stars in the Magellanic Clouds evolve faster than H-burning central stars and originate from more massive progenitors.
