- ID:
- ivo://CDS.VizieR/J/A+A/636/A65
- Title:
- DG Tau B ALMA observations
- Short Name:
- J/A+A/636/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemical composition of planets is determined by the distribution of the various molecular species in the protoplanetary disk at the time of their formation. To date, only a handful of disks have been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-outflow sources in Taurus, we report on new ALMA Band 6 (1.3mm) observations with 0.15" (20au) resolution toward the embedded young star DG Tau B. Images of the continuum emission reveals a dust disk with rings and, putatively, a leading spiral arm. The disk, as well as the prominent outflow cavities, are detected in CO, H_2_CO, CS, and CN; instead, they remain undetected in SO_2_, HDO, and CH_3_OH. From the absorption of the back-side outflow, we inferred that the disk emission is optically thick in the inner 50au. This morphology explains why no line emission is detected from this inner region and poses some limitations toward the calculation of the dust mass and the characterization of the inner gaseous disk. The H_2_CO and CS emission from the inner 200au is mostly from the disk, and their morphology is very similar. The CN emission significantly differs from the other two molecules as it is observed only beyond 150au. This ring-like morphology is consistent with previous observations and the predictions of thermochemical disk models. Finally, we constrained the disk-integrated column density of all molecules. In particular, we found that the CH_3_OH/H_2_CO ratio must be smaller than ~2, making the methanol non-detection still consistent with the only such ratio available from the literature (1.27 in TW Hya).
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4402. 3D-HST+CANDELS catalog
- ID:
- ivo://CDS.VizieR/J/ApJS/214/24
- Title:
- 3D-HST+CANDELS catalog
- Short Name:
- J/ApJS/214/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 3D-HST and CANDELS programs have provided WFC3 and ACS spectroscopy and photometry over ~900arcmin^2^ in five fields: AEGIS, COSMOS, GOODS-North, GOODS-South, and the UKIDSS UDS field. All these fields have a wealth of publicly available imaging data sets in addition to the Hubble Space Telescope (HST) data, which makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range. In this paper we describe a photometric analysis of the CANDELS and 3D-HST HST imaging and the ancillary imaging data at wavelengths 0.3-8{mu}m. Objects were selected in the WFC3 near-IR bands, and their SEDs were determined by carefully taking the effects of the point-spread function in each observation into account. A total of 147 distinct imaging data sets were used in the analysis.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/5133
- Title:
- 3DHST CANDELS redshift compilation
- Short Name:
- J/MNRAS/475/5133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We established an accurate comparison between observationally and theoretically estimated major merger rates over a large range of mass (logM_bar_/M_{sun}_=9.9-11.4) and redshift (z=0.7-1.6). For this, we combined a new estimate of the merger rate from an exhaustive count of pairs within the virial radius of massive galaxies at z~1.265 and cross-validated with their morphology, with estimates from the morpho-kinematic analysis of two other samples. Theoretical predictions were estimated using semi-empirical models with inputs matching the properties of the observed samples, while specific visibility time-scales scaled to the observed samples were used. Both theory and observations are found to agree within 30 per cent of the observed value, which provides strong support to the hierarchical assembly of galaxies over the probed ranges of mass and redshift. Here, we find that ~60 per cent of population of local massive (M_stellar_=10^10.3-11.6^M_{sun}_) galaxies would have undergone a wet major merger since z=1.5, consistently with previous studies. Such recent mergers are expected to result in the (re-)formation of a significant fraction of local disc galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/27
- Title:
- 3D-HST Survey: grism spectra master catalog
- Short Name:
- J/ApJS/225/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present reduced data and data products from the 3D-HST survey, a 248-orbit HST Treasury program. The survey obtained WFC3 G141 grism spectroscopy in four of the five CANDELS fields: AEGIS, COSMOS, GOODS-S, and UDS, along with WFC3 H_140_ imaging, parallel ACS G800L spectroscopy, and parallel I_814_ imaging. In a previous paper, we presented photometric catalogs in these four fields and in GOODS-N, the fifth CANDELS field. Here we describe and present the WFC3 G141 spectroscopic data, again augmented with data from GO-1600 in GOODS-N (PI: B. Weiner). We developed software to automatically and optimally extract interlaced two-dimensional (2D) and one-dimensional (1D) spectra for all objects in the Skelton+ (2014, J/ApJS/214/24) photometric catalogs. The 2D spectra and the multi-band photometry were fit simultaneously to determine redshifts and emission line strengths, taking the morphology of the galaxies explicitly into account. The resulting catalog has redshifts and line strengths (where available) for 22548 unique objects down to JH_IR_<=24 (79609 unique objects down to JH_IR<=26). Of these, 5459 galaxies are at z>1.5 and 9621 are at 0.7<z<1.5, where H{alpha} falls in the G141 wavelength coverage. The typical redshift error for JH_IR_<=24 galaxies is {sigma}_z_~0.003x(1+z), i.e., one native WFC3 pixel. The 3{sigma} limit for emission line fluxes of point sources is 2.1x10^-17^erg/s/cm^2^.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A56
- Title:
- Diagnostic for accretion/outflow in NGC 2264
- Short Name:
- J/A+A/642/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 2264 is a young cluster whose accretion properties can be investigated in detail by taking advantage of the FLAMES data in the context of the Gaia-ESO Survey. In fact, the analysis of the H{alpha} emission line profile can provide us with information about the accretion and ejection activity of young stars. However, a strong nebular emission that contributes to the H{alpha} emission can alter the profiles, with consequences for their physical interpretation. Our study is aimed at investigating the accretion and ejection properties of NGC 2264 by applying a proper treatment of the sky contribution to the H{alpha} and forbidden emission lines (FELs; [SII] and [NII] doublets). We developed a tool, the OH{alpha}NA-method, to handle the strong nebular contribution and spectra with spurious profiles of the H{alpha} and FELs, namely altered H{alpha} profiles or absorption features artificially created where emission lines (FELs) are expected. We derived the quantitative measurements of relevant parameters to describe the accretion and ejection processes in young members of NGC 2264, focusing on reliable quantities derived from the width of the lines, which is relatively unaffected by the nebular emission, unlike the intensity peak, which can be altered significantly. We derive the quantitative measurements related to the H{alpha} emission line and discuss the comparison between the original and sky-subtracted spectra. We thus reveal possible profile alterations with consequences for their physical interpretation. Furthermore, we show the analysis of the variability for multi-epoch observations, also deriving the velocity of the infalling and outflowing plasma from the wings of the broad H{alpha} emission line (in accreting stars). We also explore the mass accretion rate versus full width at zero intensity of the H{alpha} line, namely dM/dt versus FWZI(H{alpha}), a correlation based on the width of the emission line, which is expected to be more robust with respect to any measurement derived from the peak (e.g., H{alpha}_10%_) and possibly altered by the nebular contribution. We are able to ascertain that more than 20% of the confirmed accretors, which have already been identified in NGC 2264, are affected by the alteration of their line profiles due to the contribution of the nebular emission. Therefore, this is an important issue to consider when investigating accretion and ejection processes in young stellar clusters. While a small fraction of spectra can be unequivocally classified as either unaffected by nebular emission or dominated by nebular emission, the majority (>90%) represent intermediate cases whose spectral features have to be investigated in detail to derive reliable measurements of the relevant parameters and their physical implications.
- ID:
- ivo://CDS.VizieR/J/AN/316/39
- Title:
- Diameter-limited Northern sky galaxies catalog
- Short Name:
- J/AN/316/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to understand if the differences between the SSRS of Da Costa et al. (1988ApJ...327..544D) (which is diameter limited) and the CfA survey (Huchra et al., 1995, Cat. <VII/193>) (which is magnitude limited) are real or induced by the different selection criteria, the CfA survey has been directly compared with a diameter-limited sample covering the same region of the sky (UDLS, Bardelli et al., 1991A&A...248..354B, Zucca et al., 1991MNRAS.253..401Z). In this paper we present the data for the galaxies in the UDLS sample, in an updated version which collects velocity information from the literature until June 1993, leaving us with a velocity completeness better than ~95%.
- ID:
- ivo://CDS.VizieR/J/ApJ/746/101
- Title:
- Diameters and temperatures of AFG stars
- Short Name:
- J/ApJ/746/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have executed a survey of nearby, main-sequence A-, F-, and G-type stars with the CHARA Array, successfully measuring the angular diameters of forty-four stars with an average precision of ~1.5%. We present new measures of the bolometric flux, which in turn leads to an empirical determination of the effective temperature for the stars observed. In addition, these CHARA-determined temperatures, radii, and luminosities are fit to Yonsei-Yale model isochrones to constrain the masses and ages of the stars. These results are compared to indirect estimates of these quantities obtained by collecting photometry of the stars and applying them to model atmospheres and evolutionary isochrones. We find that for most cases, the models overestimate the effective temperature by ~1.5%-4% when compared to our directly measured values. The overestimated temperatures and underestimated radii in these works appear to cause an additional offset in the star's surface gravity measurements, which consequently yield higher masses and younger ages, in particular for stars with masses greater than ~1.3 M_{sun}_. Additionally, we compare our measurements to a large sample of eclipsing binary stars, and excellent agreement is seen within both data sets. Finally, we present temperature relations with respect to (B-V) and (V-K) colors as well as spectral type, showing that calibration of effective temperatures with errors ~1% is now possible from interferometric angular diameters of stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/680/728
- Title:
- Diameters of exoplanet host stars
- Short Name:
- J/ApJ/680/728
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the angular diameters for a sample of 24 exoplanet host stars using Georgia State University's CHARA Array interferometer. We use these improved angular diameters together with Hipparcos parallax measurements to derive linear radii and to estimate the stars' evolutionary states.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1559
- Title:
- Diameters of Galactic open star clusters
- Short Name:
- J/AJ/131/1559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present paper presents a tabulation of data on all 600 Galactic open clusters for which it is currently possible to calculate linear diameters. As expected, the youngest "clusters", with ages <15Myr, contain a significant (>=20%) admixture of associations. Among intermediate-age clusters, with ages in the range 15Myr to 1.5Gyr, the median cluster diameter is found to increase with age. Small, compact clusters are rare among objects with ages >1.5Gyr. Open clusters with ages >1Gyr appear to form what might be termed a "cluster thick disk", part of which consists of objects that were probably captured gravitationally by the main body of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/620/961
- Title:
- Diameters of Mira stars in JHK' bands
- Short Name:
- J/ApJ/620/961
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first spatially resolved observations of a sample of 23 Mira stars simultaneously measured in the near-infrared J, H, and K' bands. The technique used was optical long-baseline interferometry, and we present for each star visibility amplitude measurements as a function of wavelength. We also present characteristic sizes at each spectral band, obtained by fitting the measured visibilities to a simple uniform disk model. This approach reveals the general relation J diameter < H diameter < K' diameter.