- ID:
- ivo://CDS.VizieR/J/MNRAS/438/2642
- Title:
- LMC PNe multiwavelength photometry
- Short Name:
- J/MNRAS/438/2642
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper examines, compares and plots optical, near- and mid-infrared (MIR) photometric data for 605 planetary nebulae (PNe) in the Large Magellanic Cloud (LMC). With the aid of multiwavelength surveys such as the Spitzer legacy programme Surveying the Agents of a Galaxy's Evolution, the Two Micron All Sky Survey and the Magellanic Cloud Photometric Survey, plots have been constructed to expose the relative contributions from molecular hydrogen, polycyclic aromatic hydrocarbons, forbidden emission lines, warm dust continuum and stellar emission at various bands. Besides identifying trends, these plots have helped to reveal PN mimics including six previously known PNe in the outer LMC which are re-classified as other object types. Together with continuing follow-up optical observations, the data have enabled a substantial reduction in the number of PNe previously tagged as 'likely' and 'possible'. The total number of LMC PNe is adjusted to 715 but with a greater degree of confidence in regard to classification. In each colour-colour plot, the more highly evolved LMC PNe are highlighted for comparison with younger, brighter PNe. The faintest and most evolved PNe typically cluster in areas of colour-colour space occupied by ordinary stars. Possible reasons for the wide disparity in infrared colour-colour ratios, such as evolution and dust composition, are presented for evaluation. A correlation is found between the optical luminosity of PNe, emission-line ratios and the MIR dust luminosity at various bands. Luminosity functions using the four Infrared Array Camera and Multiband Imaging Photometer of Spitzer (MIPS) [24] bands are directly compared, revealing an increasing accumulation of PNe within the brightest two magnitudes at longer wavelengths. A correlation is also found between the MIPS [24] band and the [OIII] 5007 and H{beta} fluxes.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/1468
- Title:
- LMC post-AGB, post-RGB star and YSOs
- Short Name:
- J/MNRAS/454/1468
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a search for optically visible post-Asymptotic Giant Branch (post- AGB) stars in the Large Magellanic Cloud (LMC). First, we selected candidates with a mid-IR excess and then obtained their optical spectra. We disentangled contaminants with unique spectra such as M-stars, C-stars, planetary nebulae, quasi-stellar objects and background galaxies. Subsequently, we performed a detailed spectroscopic analysis of the remaining candidates to estimate their stellar parameters such as effective temperature, surface gravity (logg), metallicity ([Fe/H]), reddening and their luminosities. This resulted in a sample of 35 likely post-AGB candidates with late-G to late-A spectral types, low logg, and [Fe/H]<-0.5. Furthermore, our study con- firmed the existence of the dusty post-Red Giant Branch (post-RGB) stars, discovered previously in our SMC survey, by revealing 119 such objects in the LMC. These objects have mid-IR excesses and stellar parameters (Teff, logg, [Fe/H]) similar to those of post-AGB stars except that their luminosities (<2500L_{sun}_), and hence masses and radii, are lower. These post-RGB stars are likely to be products of binary interaction on the RGB. The post-AGB and post-RGB objects show SED properties similar to the Galactic post-AGB stars, where some have a surrounding circumstellar shell, while some others have a surrounding stable disc similar to the Galactic post-AGB binaries. This study also resulted in a new sample of 162 young stellar objects, identified based on a robust logg criterion. Other interesting outcomes include objects with an UV continuum and an emission line spectrum; luminous supergiants; hot main-sequence stars; and 15 B[e] star candidates, 12 of which are newly discovered in this study.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/78
- Title:
- LMC pre-main sequences stars mass accretion rates
- Short Name:
- J/MNRAS/421/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of three star-forming regions, spanning the age range 1-14Myr, located between the 30 Doradus complex and supernova SN 1987A in the Large Magellanic Cloud (LMC). We reliably identify about 1000 pre-main-sequence (PMS) star candidates actively undergoing mass accretion and estimate their stellar properties and mass accretion rate (dM/dt). Our measurements represent the largest dM/dt data set of low-metallicity stars presented so far. As such, they offer a unique opportunity to study on a statistical basis the mass accretion process in the LMC and, more in general, the evolution of the mass accretion process around low-metallicity stars.
- ID:
- ivo://CDS.VizieR/J/A+A/423/97
- Title:
- LMC RR Lyrae radial velocities
- Short Name:
- J/A+A/423/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the radial velocities, metallicities and the K-band magnitudes of 74 RR Lyrae stars in the inner regions of the LMC. The intermediate resolution spectra and infrared images were obtained with FORS1 at the ESO VLT and with the SOFI infrared imager at the ESO NTT.
- ID:
- ivo://CDS.VizieR/J/AJ/137/4810
- Title:
- LMC-SAGE AGB star candidates
- Short Name:
- J/AJ/137/4810
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present empirical relations describing excess emission from evolved stars in the Large Magellanic Cloud (LMC) using data from the Spitzer Space Telescope Surveying the Agents of a Galaxy's Evolution (SAGE) survey which includes the Infrared Array Camera (IRAC) 3.6, 4.5, 5.8, and 8.0um and Multiband Imaging Photometer (MIPS) 24, 70, and 160um bands. We combine the SAGE data with the Two Micron All Sky Survey (2MASS; J, H, and Ks) and the optical Magellanic Cloud Photometric Survey (MCPS; U, B, V, and I) point source catalogs in order to create complete spectral energy distributions (SEDs) of the asymptotic giant branch (AGB) star candidates in the LMC. AGB star outflows are among the main producers of dust in a galaxy, and this mass loss results in an excess in the fluxes observed in the 8 and 24um bands. The aim of this work is to investigate the mass loss return by AGB stars to the interstellar medium of the LMC by studying the dependence of the infrared excess flux on the total luminosity.
- ID:
- ivo://CDS.VizieR/J/AJ/136/18
- Title:
- LMC SAGE. New candidate YSOs
- Short Name:
- J/AJ/136/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ~1000 new candidate Young Stellar Objects (YSOs) in the Large Magellanic Cloud selected from Spitzer Space Telescope data, as part of the Surveying the Agents of a Galaxy's Evolution (SAGE) Legacy program. The YSOs, detected by their excess infrared (IR) emission, represent early stages of evolution, still surrounded by disks and/or infalling envelopes. Previously, fewer than 20 such YSOs were known. The candidate YSOs were selected from the SAGE Point Source Catalog from regions of color-magnitude space least confused with other IR-bright populations.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3139
- Title:
- LMC SAGE. New variable evolved stars and YSOs
- Short Name:
- J/AJ/137/3139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results and source lists of variable sources in the Large Magellanic Cloud (LMC) for which we detect thermal infrared variability from the Surveying the Agents of a Galaxy's Evolution (SAGE) survey, which had two epochs of photometry separated by 3 months. The SAGE survey mapped a 7{deg}x7{deg} region of the LMC using the Infrared Array Camera (IRAC) and the MIPS instruments on board Spitzer. Variable sources are identified using a combination of the IRAC 3.6, 4.5, 5.8, 8.0um bands and the MIPS 24um bands. An error-weighted flux difference between the two epochs is used to assess the variability. Of the ~3 million sources detected at both epochs, we find ~2000 variable sources for which we provide electronic catalogs. Most of the variable sources can be classified as asymptotic giant branch (AGB) stars. A large fraction (>66%) of the extreme AGB stars are variable and only smaller fractions of carbon-rich (6.1%) and oxygen-rich (2.0%) stars are detected as variable sources. We also detect a population of variable young stellar object candidates.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A133
- Title:
- LMC S154 (LHA 120-S 154) light curves
- Short Name:
- J/A+A/624/A133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical nova outburst has been suggested for a number of extragalactic symbiotic stars, but in none of the systems has it been proven. In this work we study the nature of one of these systems, LMC S154. We gathered archival photometric observations in order to determine the timescales and nature of variability in this system. Additionally we carried out photometric and spectroscopic monitoring of the system and fitted synthetic spectra to the observations. Carbon abundance in the photosphere of the red giant is significantly higher than that derived for the nebula, which confirms pollution of the circumbinary material by the ejecta from nova outburst. The photometric and spectroscopic data show that the system reached quiescence in 2009, which means that for the first time all of the phases of a nova outburst were observed in an extragalactic symbiotic star. The data indicate that most probably there were three outbursts observed in LMC S154, which would make this system a member of a rare class of symbiotic recurrent novae. The recurrent nature of the system is supported by the discovery of coronal lines in the spectra, which are observed only in symbiotic stars with massive white dwarfs and with short-recurrence-time outbursts. Gathered evidence is sufficient to classify LMC S154 as the first bona fide extragalactic symbiotic nova, which is likely a recurrent nova. It is also the first nova with a carbon-rich donor.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/145
- Title:
- LMC & SMC evolved stars detected with Herschel
- Short Name:
- J/ApJ/811/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using observations from the Herschel Inventory of The Agents of Galaxy Evolution (HERITAGE) survey of the Magellanic Clouds (MC), we have found 35 evolved stars and stellar end products that are bright in the far-infrared. These 28 (LMC) and 7 (SMC) sources were selected from the 529 evolved star candidates in the HERITAGE far-infrared point source catalogs. Our source identification method is based on spectral confirmation, spectral energy distribution characteristics, careful examination of the multiwavelength images and includes constraints on the luminosity, resulting in a thoroughly vetted list of evolved stars. These sources span a wide range in luminosity and hence initial mass. We found 13 low- to intermediate-mass evolved stars, including asymptotic giant branch (AGB) stars, post-AGB stars, planetary nebulae, and a symbiotic star. We also identify 10 high mass stars, including 4 of the 15 known B[e] stars in the MC, 3 extreme red supergiants that are highly enshrouded by dust, a Luminous Blue Variable, a Wolf-Rayet star, and two supernova remnants. Further, we report the detection of 9 probable evolved objects which were previously undescribed in the literature. These sources are likely to be among the dustiest evolved objects in the MC. The Herschel emission may either be due to dust produced by the evolved star or it may arise from swept-up interstellar medium material.
- ID:
- ivo://CDS.VizieR/J/AJ/116/723
- Title:
- LMC star clusters ages and metallicity
- Short Name:
- J/AJ/116/723
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Washington system CT_1_ color-magnitude diagrams of 13 star clusters and their surrounding fields that lie in the outer parts of the LMC disk (r>4{deg}), as well as a comparison inner cluster. The total area covered is large (2/3deg^2^), allowing us to study the clusters and their fields individually and in the context of the entire Galaxy. Ages are determined by means of the magnitude difference {delta}T_1_ between the giant branch clump and the turnoff, while metallicities are derived from the location of the giant and subgiant branches as compared with fiducial star clusters. This yields a unique data set in which ages and metallicities for both a significant sample of clusters and their fields are determined homogeneously. We find that in most cases the stellar population of each star cluster is quite similar to that of the field where it is embedded, sharing its mean age and metallicity. The old population (t>=10Gyr) is detected in most fields as a small concentration of stars on the horizontal branch blueward and faintward of the prominent clump.
