- ID:
- ivo://CDS.VizieR/J/MNRAS/397/933
- Title:
- LMC type II Cepheids JHKs magnitudes
- Short Name:
- J/MNRAS/397/933
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHKs magnitudes corrected to mean intensity are estimated for Large Magellanic Cloud (LMC) type II Cepheids in the OGLE-III survey the third phase of the Optical Gravitational Lensing Experiment (OGLE). Period-luminosity (PL) relations are derived in JHKs as well as in a reddening-free VI parameter. Within the uncertainties, the BL Her stars (P<4d) and the W Vir stars (P=4 to 20d) are colinear in these PL relations. The slopes of the infrared relations agree with those found previously for type II Cepheids in globular clusters within the uncertainties.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/105
- Title:
- LMC Washington CMT1 photometry of star clusters
- Short Name:
- J/MNRAS/473/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analysed Washington CMT1 photometry of star clusters located along the minor axis of the Large Magellanic Cloud (LMC), from the LMC optical centre up to ~39{deg} outwards to the North-West. The data base was exploited in order to search for new star cluster candidates, to produce cluster CMDs cleaned from field star contamination and to derive age estimates for a statistically complete cluster sample. We confirmed that 146 star cluster candidates are genuine physical systems, and concluded that an overall ~30 per cent of catalogued clusters in the surveyed regions are unlikely to be true physical systems. We did not find any new cluster candidates in the outskirts of the LMC (deprojected distance >~8{deg}). The derived ages of the studied clusters are in the range 7.2<log(t[yr^-1^])<=9.4, with the sole exception of the globular cluster NGC 1786 (log(t[yr^-1^])=10.10). We also calculated the cluster frequency for each region, from which we confirmed previously proposed outside-in formation scenarios. In addition, we found that the outer LMC fields show a sudden episode of cluster formation (log(t[yr^-1^])~7.8-7.9) which continued until log(t[yr^-1^])~7.3 only in the outermost LMC region. We link these features to the first pericentre passage of the LMC to the Milky Way (MW), which could have triggered cluster formation due to ram pressure interaction between the LMC and MW halo.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A12
- Title:
- LMC X-3 formation history
- Short Name:
- J/A+A/597/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have endeavoured to understand the formation and evolution of the black hole (BH) X-ray binary LMC X-3. We estimated the properties of the system at four evolutionary stages: 1) at the zero-age main-sequence (ZAMS), 2) immediately before the supernova (SN) explosion of the primary, 3) immediately after the SN, and 4) at the moment when Roche-lobe overflow began. We used a hybrid approach that combined detailed calculations of the stellar structure and binary evolution with approximate population synthesis models. This allowed us to estimate potential natal and the evolution of the BH spin. We incorporated as model constraints the most up-to-date observational information throughout, which include the binary orbital properties, the companion star mass, effective temperature, surface gravity and radius, and the BH mass and spin. We find at 5% and 95% confidence, respectively, that LMC X-3 began as a ZAMS system with the mass of the primary star in the range M_1,ZAMS_=22-31M_{sun}_ and a secondary star of M_2,ZAMS_=5.0-8.3M_{sun}_, in a wide (P_ZAMS_>~2.000days) and eccentric (e_ZAMS_>~0.18) orbit. Immediately before the SN, the primary had a mass of M_1,preSN_=11.1-18.0M_{sun}_, but the secondary star was largely unaffected. The orbital period decreased to $0.6-1.7days and is still eccentric 0>=e_preSN_>=0.44. We find that a symmetric SN explosion with no or small natal kicks (a few tens of km/s) imparted on the BH cannot be formally excluded, but large natal kicks in excess of >~120km/s increase the estimated formation rate by an order of magnitude. Following the SN, the system has a BH M_BH,postSN_=6.4-8.2M_{sun} and is set on an eccentric orbit. At the onset of the Roche-lobe overflow, the orbit is circular and has a period of P_RLO_=0.8-1.4days.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A114
- Title:
- Local Group AGB stars and red supergiants
- Short Name:
- J/A+A/609/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking. To investigate mass loss and luminosity in a large sample of evolved stars in several Local Group galaxies with a variety of metallicities and star-formation histories: the Small and Large Magellanic Cloud, and the Fornax, Carina, and Sculptor dwarf spheroidal galaxies (dSphs). Dust radiative transfer models are presented for 225 carbon stars and 171 oxygen-rich evolved stars in several Local Group galaxies for which spectra from the Infrared Spectrograph on Spitzer are available. The spectra are complemented with available optical and infrared photometry to construct spectral energy distributions. A minimisation procedure is used to determine luminosity and mass-loss rate (MLR). Pulsation periods are derived for a large fraction of the sample based on a re-analysis of existing data. New deep K-band photometry from the VMC survey and multi-epoch data from IRAC (at 4.5 micron) and AllWISE and NEOWISE have allowed us to derive pulsation periods longer than 1000 days for some of the most heavily obscured and reddened objects. We derive (dust) MLRs and luminosities for the entire sample. The estimated MLRs can differ significantly from estimates for the same objects in the literature due to differences in adopted optical constants (up to factors of several) and details in the radiative transfer modelling. Updated parameters for the super-AGB candidate MSX SMC 055 (IRAS 00483-7347) are presented. Its current mass is estimated to be 8.5 +- 1.6 solar mass, suggesting an initial mass well above 8 solar mass in agreement with estimates based on its large Rubidium abundance. Using synthetic photometry, we present and discuss color-color and color-magnitude diagrams which can be expected from the James Webb Space Telescope.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3138
- Title:
- Luminous cool supergiants in Magellanic Clouds
- Short Name:
- J/MNRAS/478/3138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The empirical upper luminosity boundary L_max_ of cool supergiants, often referred to as the Humphreys-Davidson limit, is thought to encode information on the general mass-loss behaviour of massive stars. Further, it delineates the boundary at which single stars will end their lives stripped of their hydrogen-rich envelope, which in turn is a key factor in the relative rates of Type-II to Type-Ibc supernovae from single star channels. In this paper we have revisited the issue of L_max_ by studying the luminosity distributions of cool supergiants (SGs) in the Large and Small Magellanic Clouds (LMC/SMC). We assemble highly-complete samples of cool SGs in each galaxy, and determine their spectral energy distributions from the optical to the mid-infrared using modern multi-wavelength survey data. We show that in both cases L_max_ appears to be lower than previously quoted, and is in the region of logL/L_{sun}_=5.5. There is no evidence for L_max_ being higher in the SMC than in the LMC, as would be expected if metallicity-dependent winds were the dominant factor in the stripping of stellar envelopes. We also show that L_max_ aligns with the lowest luminosity of single nitrogen-rich Wolf-Rayet stars, indicating of a change in evolutionary sequence for stars above a critical mass. From population synthesis analysis we show that the Geneva evolutionary models greatly over-predict the numbers of cool SGs in the SMC. We also argue that the trend of earlier average spectral types of cool SGs in lower metallicity environments represents a genuine shift to hotter temperatures. Finally, we use our new bolometric luminosity measurements to provide updated bolometric corrections for cool supergiants.
- ID:
- ivo://CDS.VizieR/J/ApJ/542/257
- Title:
- MACHO LMC first-overtone RR Lyrae
- Short Name:
- J/ApJ/542/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- More than 1300 variables classified provisionally as first-overtone RR Lyrae pulsators in the MACHO variable-star database of the Large Magellanic Cloud (LMC) have been subjected to standard frequency analysis. Based on the remnant power in the prewhitened spectra, we found 70% of the total population to be monoperiodic. The remaining 30% (411 stars) are classified as one of nine types according to their frequency spectra. Several types of RR Lyrae pulsational behavior are clearly identified here for the first time. Together with the earlier discovered double-mode (fundamental and first-overtone) variables, this study increased the number of known double-mode stars in the LMC to 181. During the total 6.5yr time span of the data, 10% of the stars showed strong period changes.
- ID:
- ivo://CDS.VizieR/J/AJ/135/83
- Title:
- MACHO LMC first overtone RR Lyrae
- Short Name:
- J/AJ/135/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies have indicated that many of the RR Lyrae variables in the LMC have properties similar to those in the Galactic globular cluster M3. Assuming that the M3 RR Lyrae variables follow the same relationships among period, temperature, amplitude, and Fourier phase parameter phi31 as their LMC counterparts, we have used the M3 phi31-logP relation to identify the M3-like unevolved first overtone RR Lyrae variables in 16 MACHO fields near the LMC bar.
- ID:
- ivo://CDS.VizieR/J/AJ/127/334
- Title:
- MACHO LMC first-overtone RR Lyrae variables
- Short Name:
- J/AJ/127/334
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Shapes of RR Lyrae light curves can be described in terms of Fourier coefficients that past research has linked with physical characteristics such as luminosity, mass, and temperature. Fourier coefficients have been derived for the V and R light curves of 785 overtone RR Lyrae variables in 16 MACHO fields near the bar of the LMC.
