- ID:
- ivo://CDS.VizieR/J/A+A/659/A145
- Title:
- A WISE view on extreme AGB stars
- Short Name:
- J/A+A/659/A145
- Date:
- 18 Mar 2022 08:25:03
- Publisher:
- CDS
- Description:
- Variability is a key property of stars on the asymptotic giant branch (AGB). Their pulsation period is related to the luminosity and mass-loss rate (MLR) of the star. Long-period variables (LPVs) and Mira variables are the most prominent of all types of variability of evolved stars. However, the reddest, most obscured AGB stars are too faint in the optical and have eluded large variability surveys. Our goal is to obtain a sample of LPVs with large MLRs by analysing WISE W1 and W2 light curves (LCs) for about 2000 sources, photometrically selected to include known C-stars with the 11.3 micron silicon carbide dust feature in absorption, and Galactic O-stars with periods longer than 1000 days. Epoch photometry was retrieved from the AllWISE and NEOWISE database and fitted with a sinus curve. Photometry from other variability surveys was also downloaded and fitted. For a subset of 316 of the reddest stars, spectral energy distributions (SEDs) were constructed, and, together with mid-infrared (MIR) spectra when available, fitted with a dust radiative transfer programme in order to derive MLRs. WISE based LCs and fits to the data are presented for all stars. Periods from the literature and periods from refitting other literature data are presented. The results of the spatial correlation with several (IR) databases is presented. About one-third of the sources are found to be not real, but it appears that these cannot be easily filtered out by using WISE flags. Some are clones of extremely bright sources, and in some cases the LCs show the known pulsation period. Inspired by a recent paper, a number of non-variable OH/IRs are identified. Based on a selection on amplitude, a sample of about 750 (candidate) LPVs is selected of which 145 have periods beyond 1000 days, many of them being new. For the subset of the stars with the colours of C-rich extremely red objects (EROs) the fitting of the SEDs (and available MIR spectra) separates them into C- and O-rich objects. Interestingly, the fitting of MIR spectra of mass-losing C-stars is shown to be a powerful tracer of interstellar reddening when AV larger than 2 mag. The number of Galactic EROs appears to be complete up to about 5 kpc and a total dust return rate in the solar neighbourhood for this class is determined. In the LMC 12 additional EROs are identified. Although this represents only about 0.15% of the total known LMC C-star population adding their MLRs increases the previously estimated dust return by 8%. Based on the EROs in the Magellanic Clouds, a bolometric period luminosity is derived. It is pointed out that due to their faintness, EROs and similar O-rich objects are ideal targets for a NIR version of Gaia to obtain distances, observing in the K-band or, even more efficiently, in the L-band.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/244/24
- Title:
- A z=0 Multiwavelength Galaxy Synthesis (z0MGS). I.
- Short Name:
- J/ApJS/244/24
- Date:
- 14 Mar 2022 07:45:54
- Publisher:
- CDS
- Description:
- We present an atlas of ultraviolet and infrared images of ~15750 local (d<~50Mpc) galaxies, as observed by NASA's Wide-field Infrared Survey Explorer (WISE) and Galaxy Evolution Explorer (GALEX) missions. These maps have matched resolution (FWHM 7.5" and 15"), matched astrometry, and a common procedure for background removal. We demonstrate that they agree well with resolved intensity measurements and integrated photometry from previous surveys. This atlas represents the first part of a program (the z=0 Multiwavelength Galaxy Synthesis) to create a large, uniform database of resolved measurements of gas and dust in nearby galaxies. This atlas allows us estimate local and integrated star formation rates (SFRs) and stellar masses (M_*_) across the local galaxy population in a uniform way. In the appendix, we use the population synthesis fits of Salim+ (2016ApJS..227....2S and 2018ApJ...859...11S) to calibrate integrated M_*_ and SFR estimators based on GALEX and WISE. Because they leverage a Sloan Digital Sky Survey (SDSS)-based training set of >100000 galaxies, these calibrations have high precision and allow us to rigorously compare local galaxies to SDSS results. We provide these SFR and M_*_ estimates for all galaxies in our sample and show that our results yield a "main sequence" of star-forming galaxies comparable to previous work. We also show the distribution of intensities from resolved galaxies in NUV-to-WISE1 versus WISE1-to-WISE3 space, which captures much of the key physics accessed by these bands.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/55
- Title:
- AzTEC/ASTE survey at 1.1mm toward the SMC
- Short Name:
- J/ApJ/835/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first 1.1mm continuum survey toward the Small Magellanic Cloud (SMC) was performed using the AzTEC instrument installed on the ASTE 10m telescope. This survey covered 4.5deg^2^ of the SMC with 1{sigma} noise levels of 5-12mJy/beam, and 44 extended objects were identified. The 1.1mm extended emission has good spatial correlation with Herschel 160{mu}m, indicating that the origin of the 1.1mm extended emission is thermal emission from a cold dust component. We estimated physical properties using the 1.1mm and filtered Herschel data (100, 160, 250, 350, and 500{mu}m). The 1.1mm objects show dust temperatures of 17-45K and gas masses of 4x10^3^-3x10^5^M_{sun}_, assuming single-temperature thermal emission from the cold dust with an emissivity index, {beta}, of 1.2 and a gas-to-dust ratio of 1000. These physical properties are very similar to those of giant molecular clouds (GMCs) in our galaxy and the Large Magellanic Cloud. The 1.1mm objects also displayed good spatial correlation with the Spitzer 24{mu}m and CO emission, suggesting that the 1.1mm objects trace the dense gas regions as sites of massive star formation. The dust temperature of the 1.1mm objects also demonstrated good correlation with the 24{mu}m flux connected to massive star formation. This supports the hypothesis that the heating source of the cold dust is mainly local star-formation activity in the 1.1mm objects. The classification of the 1.1mm objects based on the existence of star-formation activity reveals the differences in the dust temperature, gas mass, and radius, which reflects the evolution sequence of GMCs.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/33
- Title:
- BANYAN. VII. Candidate YMG members from BASS
- Short Name:
- J/ApJS/219/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a near-infrared (NIR) spectroscopic follow-up survey of 182 M4-L7 low-mass stars and brown dwarfs (BDs) from the BANYAN All-Sky Survey (BASS) for candidate members of nearby, young moving groups (YMGs). We confirm signs of low gravity for 42 new BD discoveries with estimated masses between 8 and 75M_Jup_ and identify previously unrecognized signs of low gravity for 24 known BDs. We refine the fraction of low-gravity dwarfs in the high-probability BASS sample to ~82%. We use this unique sample of 66 young BDs, supplemented with 22 young BDs from the literature, to construct new empirical NIR absolute magnitude and color sequences for low-gravity BDs. We show that low-resolution NIR spectroscopy alone cannot differentiate between the ages of YMGs younger than ~120Myr, and that the BT-Settl atmosphere models do not reproduce well the dust clouds in field or low-gravity L-type dwarfs. We obtain a spectroscopic confirmation of low gravity for 2MASS J14252798-3650229, which is a new ~27M_Jup_, L4 {gamma} bona fide member of AB Doradus. We identify a total of 19 new low-gravity candidate members of YMGs with estimated masses below 13M_Jup_, 7 of which have kinematically estimated distances within 40pc. These objects will be valuable benchmarks for a detailed atmospheric characterization of planetary-mass objects with the next generation of instruments. We find 16 strong candidate members of the Tucana-Horologium association with estimated masses between 12.5 and 14M_Jup_, a regime where our study was particularly sensitive. This would indicate that for this association there is at least one isolated object in this mass range for every 17.5_-5.0_^+6.6^ main-sequence stellar member, a number significantly higher than expected based on standard log-normal initial mass function, however, in the absence of radial velocity and parallax measurements for all of them, it is likely that this over-density is caused by a number of young interlopers from other associations.
- ID:
- ivo://CDS.VizieR/J/ApJ/856/23
- Title:
- BANYAN. XI. The BANYAN {Sigma} algorithm
- Short Name:
- J/ApJ/856/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BANYAN {Sigma} is a new Bayesian algorithm to identify members of young stellar associations within 150pc of the Sun. It includes 27 young associations with ages in the range ~1-800Myr, modeled with multivariate Gaussians in six-dimensional (6D) XYZUVW space. It is the first such multi-association classification tool to include the nearest sub-groups of the Sco-Cen OB star-forming region, the IC2602, IC2391, Pleiades and Platais 8 clusters, and the {rho} Ophiuchi, Corona Australis, and Taurus star formation regions. A model of field stars is built from a mixture of multivariate Gaussians based on the Besancon Galactic model. The algorithm can derive membership probabilities for objects with only sky coordinates and proper motion, but can also include parallax and radial velocity measurements, as well as spectrophotometric distance constraints from sequences in color-magnitude or spectral type-magnitude diagrams. BANYAN {Sigma} benefits from an analytical solution to the Bayesian marginalization integrals over unknown radial velocities and distances that makes it more accurate and significantly faster than its predecessor BANYAN II. A contamination versus hit rate analysis is presented and demonstrates that BANYAN {Sigma} achieves a better classification performance than other moving group tools available in the literature, especially in terms of cross-contamination between young associations. An updated list of bona fide members in the 27 young associations, augmented by the Gaia-DR1 release, as well as all parameters for the 6D multivariate Gaussian models for each association and the Galactic field neighborhood within 300 pc are presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/745/147
- Title:
- Binaries among debris disk stars
- Short Name:
- J/ApJ/745/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of 628 AU. We found that 25%+/-4% of our debris disk systems are binary or triple star systems, substantially less than the expected ~50%. The period distribution for these suggests a relative lack of systems with 1-100 AU separations. Only a few systems have blackbody disk radii comparable to the binary/triple separation. Together, these two characteristics suggest that binaries with intermediate separations of 1-100 AU readily clear out their disks. We find that the fractional disk luminosity, as a proxy for disk mass, is generally lower for multiple systems than for single stars at any given age. Hence, for a binary to possess a disk (or form planets) it must either be a very widely separated binary with disk particles orbiting a single star or it must be a small separation binary with a circumbinary disk.
- ID:
- ivo://CDS.VizieR/J/MNRAS/508/2226
- Title:
- Binary central star of V510 Pup
- Short Name:
- J/MNRAS/508/2226
- Date:
- 19 Jan 2022 13:43:04
- Publisher:
- CDS
- Description:
- Current models predict that binary interactions are a major ingredient in the formation of bipolar planetary nebulae (PNe) and pre-planetary nebulae (PPNe). Despite years of radial velocity (RV) monitoring, the paucity of known binaries amongst the latter systems means data are insufficient to examine this relationship in detail. In this work, we report on the discovery of a long-period (P=2654+/-124d) binary at the centre of the Galactic bipolar PPN IRAS 08005-2356 (V510 Pup), determined from long-term spectroscopic and near-infrared time-series data. The spectroscopic orbit is fitted with an eccentricity of 0.36+/-0.05, which is similar to that of other long-period post-AGB binaries. Time-resolved H{alpha} profiles reveal high-velocity outflows (jets) with deprojected velocities up to 231^+31^_-27_km/s seen at phases when the luminous primary is behind the jet. The outflow traced by H{alpha} is likely produced via accretion on to a main-sequence companion, for which we calculate a mass of 0.63+/-0.13M_{sun}_. This discovery is one of the first cases of a confirmed binary PPN and demonstrates the importance of high-resolution spectroscopic monitoring surveys using large telescopes in revealing binarity among these systems.
- ID:
- ivo://CDS.VizieR/J/A+A/458/461
- Title:
- Binary stars in the Orion Nebula Cluster
- Short Name:
- J/A+A/458/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a high-spatial-resolution survey for binary stars in the periphery of the Orion Nebula Cluster, at 5-15arcmin (0.65-2pc) from the cluster center. We observed 228 stars with adaptive optics systems, in order to find companions at separations of 0.13"-1.12" (60-500AU), and detected 13 new binaries. Combined with the results of Petr (1998, Ph.D. Thesis, University of Heidelberg), we have a sample of 275 objects, about half of which have masses from the literature and high probabilities to be cluster members.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/143
- Title:
- Black hole masses of z~1.4 AGNs from SXDS
- Short Name:
- J/ApJ/761/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z~1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad MgII line and 3000{AA} monochromatic luminosity. We supplement the MgII FWHM values with the H{alpha} FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V_max_ method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z=1.4 has a higher number density above 10^8^M_{sun}_ but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z=1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/4068
- Title:
- BLAGNs and NLS1s characteristics.
- Short Name:
- J/MNRAS/478/4068
- Date:
- 10 Dec 2021 00:54:07
- Publisher:
- CDS
- Description:
- investigated narrow-line Seyfert 1 galaxies (NLS1s) at optical, mid-infrared (MIR), and X-ray wavelengths, comparing them to the broad-line active galactic nuclei (BLAGNs). We found that black hole mass, coronal line luminosities, X-ray hardness ratio and X-ray, and optical and MIR luminosities are higher for the BLAGNs than for NLS1s, while policyclic aromatic hydrocarbon (PAH) contribution and the accretion rates are higher for NLS1s. Furthermore, we found some trends among spectral parameters that NLS1s have and BLAGNs do not have. The evolution of FWHM(H{beta}) with the luminosities of MIR and coronal lines, continuum luminosities, PAH contribution, H{beta} broad line luminosity, FWHM[OIII], and EW(H{beta}NLR) are important trends found for NLS1s. That may contribute to the insight that NLS1s are developing AGNs, growing their black holes, while their luminosities and FWHM(H{beta}) consequently grow, and that BLAGNs are mature, larger objects of slower and/or different evolution. Black hole mass is related to PAH contribution only for NLS1s, which may suggest that PAHs are more efficiently destroyed in NLS1s.
