- 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.
Number of results to display per page
Search Results
- 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/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/ApJ/615/887
- Title:
- Localization of SGR 1627-41 and AXP 1E1841-045
- Short Name:
- J/ApJ/615/887
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precise localizations of AXP 1E1841-045 and SGR 1627-41 with Chandra. We obtained new infrared observations of SGR 1627-41 and reanalyzed archival observations of AXP 1E1841-045 in order to refine their positions and search for infrared counterparts.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A4
- Title:
- LOFAR imaging of Arp299 at 150MHz
- Short Name:
- J/A+A/658/A4
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the spatially resolved emission of Arp 299 revealed by 150 MHz international baseline Low-Frequency Array (LOFAR) and 1.4, 5.0, and 8.4GHz Very Large Array (VLA) observations. Nowadays, LOFAR allows to compare its resolution with the VLA ones. These will allow us to obtain pixel-by-pixel spectral imdex maps and local radio SEDs. With this information we recover the nature of the ISM around the main structures (either clumpy or continuous), as well as magnetic fields. The 150MHz image also shows structures never seen before, pointing out that these radio-frequencies observations are a perfect tool to detect them.
- ID:
- ivo://CDS.VizieR/J/ApJ/823/157
- Title:
- LOS velocities & [Fe/H] of Pal 5 tidal stream
- Short Name:
- J/ApJ/823/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Subaru/Faint Object Camera and Spectrograph and Keck/Deep Imaging Multi-Object Spectrometer medium-resolution spectroscopy of a tidally disrupting Milky Way (MW) globular cluster Palomar 5 (Pal 5) and its tidal stream. The observed fields are located to cover an angular extent of ~17{deg} along the stream, providing an opportunity to investigate a trend in line-of-sight velocities (V_los_) along the stream, which is essential to constrain its orbit and underlying gravitational potential of the MW's dark matter halo. A spectral fitting technique is applied to the observed spectra to obtain stellar parameters and metallicities ([Fe/H]) of the target stars. The 19 stars most likely belonging to the central Pal 5 cluster have a mean V_los_ of -58.1+/-0.7km/s and metallicity [Fe/H]=-1.35+/-0.06dex, both of which are in good agreement with those derived in previous high-resolution spectroscopic studies. Assuming that the stream stars have the same [Fe/H] as the progenitor cluster, the derived [Fe/H] and V_los_ values are used to estimate the possible V_los_ range of the member stars at each location along the stream. Because of the heavy contamination of the field MW stars, the estimated V_los_ range depends on prior assumptions about the stream's V_los_, which highlights the importance of more definitely identifying the member stars using proper motion and chemical abundances to obtain unbiased information of V_los_ in the outer part of the Pal 5 stream. The models for the gravitational potential of the MW's dark matter halo that are compatible with the estimated V_los_ range are discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/249
- Title:
- Low-luminosity embedded protostar population
- Short Name:
- J/ApJS/179/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for all embedded protostars with internal luminosities <=1.0L_{sun}_ in the full sample of nearby, low-mass star-forming regions surveyed by the Spitzer Space Telescope Legacy Project "From Molecular Cores to Planet Forming Disks" (c2d). We present a set of selection criteria used to identify candidates from the Spitzer data and examine complementary data to decide whether each candidate is truly an embedded protostar. Between 75% and 85% of cores classified as starless prior to being observed by Spitzer remain starless to our luminosity sensitivity; the remaining 15%-25% harbor low-luminosity, embedded protostars. We compile complete spectral energy distributions for all 50 objects and calculate standard evolutionary signatures (L_bol_, T_bol_, and L_bol_/L_smm_) and argue that these objects are inconsistent with the simplest picture of star formation, wherein mass accretes from the core onto the protostar at a constant rate.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A138
- Title:
- Low-luminosity type-1 QSO sample. V.
- Short Name:
- J/A+A/587/A138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared (NIR) H+K-band long-slit spectra of eleven galaxies that were obtained with SOFI at the NTT (ESO). The galaxies are chosen from the low-luminosity type-1 quasi-stellar object (LLQSO) sample, which comprises the 99 closest (z<=0.06) QSOs from the Hamburg/ESO survey for bright UV-excess QSOs. These objects are ideal targets to study the gap between local Seyfert galaxies and high-redshift quasars because they show much stronger AGN activity than local objects, but are still close enough for a detailed structural analysis. We fit hydrogen recombination, molecular hydrogen, and [FeII] lines after carefully subtracting the continuum emission. From the broad Pa{alpha} components, we estimated black hole masses and enlarged the sample of LLQSOs that deviate from the MBH-Lbulge relations of inactive galaxies from 12 to 16 objects. All objects show emission from hot dust (T~1200K) as well as stellar contribution. However, the respective fractions vary strongly among the objects. More than half of the objects show H_2_ emission lines, which indicate a large reservoir of molecular gas that is needed to feed the AGN and star formation. In the NIR diagnostic diagram all objects lie in the location of AGN-dominated objects. However, most of the objects show indications of star formation activity, suggesting that their offset location with respect to MBH-Lbulge relations of inactive galaxies may be a consequence of overluminous bulges.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A111
- Title:
- Low-mass stars in Coma Ber
- Short Name:
- J/A+A/544/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Little is known about the population of the Coma Berenices open cluster (age~500Myr) below 0.2M_{sun}_, and statistics show that there is a prominent deficit of very low-mass objects in this mass range compared to younger open clusters with ages of <250Myr. We search for very low-mass stars and substellar objects (brown dwarfs) in the Coma open cluster to derive the present-day cluster mass function below 0.2M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/153/84
- Title:
- Low-resolution near-infrared stellar spectra from CIBER
- Short Name:
- J/AJ/153/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared (0.8-1.8{mu}m) spectra of 105 bright (m_J_<10) stars observed with the low-resolution spectrometer on the rocket-borne Cosmic Infrared Background Experiment. As our observations are performed above the Earth's atmosphere, our spectra are free from telluric contamination, which makes them a unique resource for near-infrared spectral calibration. Two-Micron All-Sky Survey photometry information is used to identify cross-matched stars after reduction and extraction of the spectra. We identify the spectral types of the observed stars by comparing them with spectral templates from the Infrared Telescope Facility library. All the observed spectra are consistent with late F to M stellar spectral types, and we identify various infrared absorption lines.
