- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3674
- Title:
- IC 348 circumstellar discs ALMA data
- Short Name:
- J/MNRAS/478/3674
- Date:
- 10 Dec 2021 00:10:52
- Publisher:
- CDS
- Description:
- We present a 1.3mm continuum survey of the young (2-3Myr) stellar cluster IC 348 that lies at a distance of 310pc and is dominated by low-mass stars (M*~0.1-0.6M_{sun}_). We observed 136 Class II sources (discs that are optically thick in the infrared) at 0.8arcsec (200au) resolution with a 3{sigma} sensitivity of ~0.45mJy (M_dust_~1.3M_{Earth}_). We detect 40 of the targets and construct a mm-continuum luminosity function. We compare the disc mass distribution in IC 348 to those of younger and older regions, taking into account the dependence on stellar mass. We find a clear evolution in disc masses from 1 to 5-10Myr. The disc masses in IC 348 are significantly lower than those in Taurus (1-3Myr) and Lupus (1-3Myr), similar to those of Chamaleon I, (2-3Myr) and {sigma} Ori (3-5Myr) and significantly higher than in Upper Scorpiusrpius (5-10Myr). About 20 discs in our sample (~5 percent of the cluster members) have estimated masses (dust+gas)>1M_Jup_ and hence might be the precursors of giant planets in the cluster. Some of the most massive discs include transition objects with inner opacity holes based on their infrared Spectral Energy Distribution (SEDs). From a stacking analysis of the 96 non-detections, we find that these discs have a typical dust mass of just <=0.4M_{Earth}_, even though the vast majority of their infrared SEDs remain optically thick and show little signs of evolution. Such low-mass discs may be the precursors of the small rocky planets found by Kepler around M-type stars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/371/1744
- Title:
- Identification of nitride dust
- Short Name:
- J/MNRAS/371/1744
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nitride dust is predicted to form in small amounts around carbon stars, but the most likely candidate species such as aluminium nitride (AlN) have not yet been detected. Recently, {alpha}-Si_3_N_4_ was inferred to be the main carrier of the 8.5-12.5um absorption band(s) of an extreme carbon star (AFGL 5625), based on comparison with laboratory KBr dispersion spectra. However, this absorption band has also been attributed to silicon carbide (SiC) and C_3_. To investigate whether or not nitride dust has truly been detected and if it is present in other extreme carbon stars, we (i) gathered new laboratory infrared (IR) absorbance spectra from a suite of nitride compounds, including Si_3_N_4_, using the thin film technique which provides correct relative intensities of weak and strong peaks, and (ii) compared these data to Infrared Space Observatory Short Wavelength Spectrometer (ISO SWS) spectra of seven different extreme carbon stars which also show broad absorption features around ~11m.
- ID:
- ivo://CDS.VizieR/J/ApJS/238/29
- Title:
- IGRINS spectral library
- Short Name:
- J/ApJS/238/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a library of high-resolution (R~45000) and high signal-to-noise ratio (S/N>=200) near-infrared spectra for stars of a wide range of spectral types and luminosity classes. The spectra were obtained with the Immersion GRating INfrared Spectrograph covering the full range of the H (1.496-1.780{mu}m) and K (2.080-2.460{mu}m) atmospheric windows. The targets were primarily selected for being MK standard stars covering a wide range of effective temperatures and surface gravities, with metallicities close to the solar value. Currently, the library includes flux-calibrated and telluric-absorption-corrected spectra of 84 stars, with prospects for expansion to provide denser coverage of the parametric space. Throughout the H and K atmospheric windows, we identified spectral lines that are sensitive to Teff or logg and defined corresponding spectral indices. We also provide their equivalent widths (EWs). For those indices, we derive empirical relations between the measured EWs and the stellar atmospheric parameters. Therefore, the derived empirical equations can be used to calculate the Teff and logg of a star without requiring stellar atmospheric models.
- ID:
- ivo://CDS.VizieR/J/ApJ/845/157
- Title:
- IMF in 3 low-redshift strong lenses from SNELLS
- Short Name:
- J/ApJ/845/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high-{sigma} ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M*/L using lensing and stellar dynamics. We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy & van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2-3{sigma} tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08M_{sun}_. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to <2{sigma}. There is moderate evidence for a reduced number of low-mass stars in the SNELLS spectra, but no such evidence in a composite spectrum of matched-{sigma} ETGs drawn from the SDSS. Such variation in the form of the IMF at low stellar masses (m<~0.3M_{sun}_), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M*/L relative to the mean matched-{sigma} ETG. We provide the spectra used in this study to facilitate future comparisons.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/131
- Title:
- Infrared absorbance of water H_2_O/H_2_O_2_ ice
- Short Name:
- J/ApJ/743/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent surface chemistry experiments have shown that the hydrogenation of molecular oxygen on interstellar dust grains is a plausible formation mechanism, via hydrogen peroxide (H_2_O_2_), for the production of water (H_2_O) ice mantles in the dense interstellar medium. Theoretical chemistry models also predict the formation of a significant abundance of H_2_O_2_ ice in grain mantles by this route. At their upper limits, the predicted and experimental abundances are sufficiently high that H_2_O_2_ should be detectable in molecular cloud ice spectra. To investigate this further, laboratory spectra have been obtained for H_2_O_2_/H_2_O ice films between 2.5 and 200um, from 10 to 180K, containing 3%, 30%, and 97% H_2_O_2_ ice. Integrated absorbances for all the absorption features in low-temperature H_2_O_2_ ice have been derived from these spectra. For identifying H_2_O_2_ ice, the key results are the presence of unique features near 3.5, 7.0, and 11.3um. Comparing the laboratory spectra with the spectra of a group of 24 protostars and field stars, all of which have strong H_2_O ice absorption bands, no absorption features are found that can definitely be identified with H_2_O_2_ ice. In the absence of definite H_2_O_2_ features, the H_2_O_2_ abundance is constrained by its possible contribution to the weak absorption feature near 3.47um found on the long-wavelength wing of the 3um H_2_O ice band. This gives an average upper limit for H_2_O_2_, as a percentage of H_2_O, of 9%+/-4%. This is a strong constraint on parameters for surface chemistry experiments and dense cloud chemistry models.
- ID:
- ivo://CDS.VizieR/J/A+A/638/A44
- Title:
- Infrared dark cloud G28.3 HI and CI maps
- Short Name:
- J/A+A/638/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Atomic and molecular cloud formation is a dynamical process. However, kinematic signatures of these processes are still observationally poorly constrained. Identify and characterize the cloud formation signatures in atomic and molecular gas. Targeting the cloud-scale environment of the prototypical infrared dark cloud G28.3, we employ spectral line imaging observations of the two atomic lines HI and [CI] as well as molecular lines observations in ^13^CO in the 1-0 and 3-2 transitions. The analysis comprises investigations of the kinematic properties of the different tracers, estimates of the mass flow rates, velocity structure functions, a Histogram of Oriented Gradients (HOG) study as well as comparisons to simulations. The central IRDC is embedded in a more diffuse envelope of cold neutral medium (CNM) traced by HI self-absorption (HISA) and molecular gas. The spectral line data as well as the HOG and structure function analysis indicate a possible kinematic decoupling of the HI from the other gas compounds. Spectral analysis and position-velocity diagrams reveal two velocity components that converge at the position of the IRDC. Estimated mass flow rates appear rather constant from the cloud edge toward the center. The velocity structure function analysis is consistent with gas flows being dominated by the formation of hierarchical structures. The observations and analysis are consistent with a picture where the IRDC G28 is formed at the center of two converging gas flows. While the approximately constant mass flow rates are consistent with a self-similar, gravitationally driven collapse of the cloud, external compression by, e.g., spiral arm shocks or supernovae explosions cannot be excluded yet. Future investigations should aim at differentiating the origin of such converging gas flows.
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/343
- Title:
- Infrared excesses of Hipparcos stars
- Short Name:
- J/MNRAS/427/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the fundamental parameters (temperature and luminosity) of 107619 Hipparcos stars and place these stars on a true Hertzsprung-Russell diagram. This is achieved by comparing BT-SETTL model atmospheres to spectral energy distributions (SEDs) created from Hipparcos, Tycho, Sloan Digital Sky Survey, DENIS, Two Micron All Sky Survey, MSX, AKARI, IRAS and Wide-field Infrared Survey Explorer data. We also identify and quantify from these SEDs any infrared excesses attributable to circumstellar matter. We compare our results to known types of objects, focusing on the giant branch stars. Giant star dust production (as traced by infrared excess) is found to start in earnest around 680L_{sun}_.
- ID:
- ivo://CDS.VizieR/J/other/JAD/18.3
- Title:
- Infrared extinction spectra of aerosols
- Short Name:
- J/other/JAD/18.3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared extinction spectra (500-6000cm^-1^) of a series of single-component aerosol particle ensembles representative of those found in a range of planetary and lunar atmospheres are presented. The aerosols were generated in the laboratory via condensation from the gas phase in a bath gas cooling cell, and the spectra recorded using a Fourier transform infrared spectrometer. This paper is the first in a series aimed towards building a spectral database for use in remote sensing of aerosols. The aerosol substances included here are methane, ethane, propane, butane, pentane, ethylene, acetylene, carbon dioxide, ammonia and sulfur dioxide.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/545
- Title:
- Infrared-faint radio sources catalog
- Short Name:
- J/MNRAS/439/545
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 1317 Infrared-faint radio sources (IFRSs) that, for the first time, are reliably detected in the infrared, generated by cross-correlating the Wide-field Infrared Survey Explorer (WISE) all-sky survey with major radio surveys. Our IFRSs are brighter in both radio and infrared than the first-generation IFRSs that were undetected in the infrared by the Spitzer Space Telescope. We present the first spectroscopic redshifts of IFRSs, and find that all but one of the IFRSs with spectroscopy have z>2. We also report the first X-ray counterparts of IFRSs, and present an analysis of radio spectra and polarization, and show that they include gigahertz peaked-spectrum, compact steep-spectrum and ultra-steep-spectrum sources. These results, together with their WISE infrared colours and radio morphologies, imply that our sample of IFRSs represents a population of radio-loud active galactic nuclei at z>2. We conclude that our sample consists of lower redshift counterparts of the extreme first-generation IFRSs, suggesting that the fainter IFRSs are at even higher redshift.
- ID:
- ivo://CDS.VizieR/J/A+A/419/999
- Title:
- Infrared knots along protostellar jets
- Short Name:
- J/A+A/419/999
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the near infrared spectra (0.9-2.5 micron) of protostellar jets (HH 24-26, HH72, BHR71). The observations were carried out with Sofi at R~600 with the 1x290arcsec slit. The spectra are dominated by H2 rovibrational lines (v up 5). Faint emission from ionized material in form of [FeII] and [SII] lines is also recognizable. The tables contain the observed lines together with the measured flux. The reported error derives from the rms of the baseline, multiplied by the width of the instrumental profile (30 Angstrom).
