- ID:
- ivo://CDS.VizieR/J/ApJ/859/5
- Title:
- Surface brightness profiles of NGC2784 group vs Virgo
- Short Name:
- J/ApJ/859/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate surface brightness profiles (SBPs) of dwarf galaxies in field, group, and cluster environments. With deep BVI images from the Korea Microlensing Telescope Network Supernova Program, SBPs of 38 dwarfs in the NGC 2784 group are fitted by a single-exponential or double-exponential model. We find that 53% of the dwarfs are fitted with single-exponential profiles ("Type I"), while 47% of the dwarfs show double-exponential profiles; 37% of all dwarfs have smaller sizes for the outer part than the inner part ("Type II"), while 10% have a larger outer than inner part ("Type III"). We compare these results with those in the field and in the Virgo cluster, where the SBP types of 102 field dwarfs are compiled from a previous study and the SBP types of 375 cluster dwarfs are measured using SDSS r-band images. As a result, the distributions of SBP types are different in the three environments. Common SBP types for the field, the NGC 2784 group, and the Virgo cluster are Type II, Type I and II, and Type I and III profiles, respectively. After comparing the sizes of dwarfs in different environments, we suggest that since the sizes of some dwarfs are changed due to environmental effects, SBP types are capable of being transformed and the distributions of SBP types in the three environments are different. We discuss possible environmental mechanisms for the transformation of SBP types.
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- ID:
- ivo://CDS.VizieR/J/ApJ/892/31
- Title:
- Teff and metallicities of M dwarfs in APOGEE DR14
- Short Name:
- J/ApJ/892/31
- Date:
- 07 Mar 2022 13:23:27
- Publisher:
- CDS
- Description:
- M dwarfs have enormous potential for our understanding of structure and formation on both Galactic and exoplanetary scales through their properties and compositions. However, current atmosphere models have limited ability to reproduce spectral features in stars at the coolest temperatures (Teff<4200K) and to fully exploit the information content of current and upcoming large-scale spectroscopic surveys. Here we present a catalog of spectroscopic temperatures, metallicities, and spectral types for 5875 M dwarfs in the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and Gaia-DR2 surveys using The Cannon (Ness+ 2015, J/ApJ/808/16 ; Casey+ 2016, arXiv:1603.03040; Ho+ 2017, J/ApJ/836/5; Behmard+ 2019ApJ...876...68B): a flexible, data-driven spectral-modeling and parameter-inference framework demonstrated to estimate stellar-parameter labels (Teff, logg, [Fe/H], and detailed abundances) to high precision. Using a training sample of 87 M dwarfs with optically derived labels spanning 2860K<Teff<4130K calibrated with bolometric temperatures, and -0.5<[Fe/H]<0.5dex calibrated with FGK binary metallicities, we train a two-parameter model with predictive accuracy (in cross-validation) to 77K and 0.09dex respectively. We also train a one-dimensional spectral classification model using 51 M dwarfs with Sloan Digital Sky Survey optical spectral types ranging from M0 to M6, to predictive accuracy of 0.7 types. We find Cannon temperatures to be in agreement to within 60 K compared to a subsample of 1702 sources with color-derived temperatures, and Cannon metallicities to be in agreement to within 0.08 dex metallicity compared to a subsample of 15 FGK+M or M+M binaries. Finally, our comparison between Cannon and APOGEE pipeline (ASPCAP DR14) labels finds that ASPCAP is systematically biased toward reporting higher temperatures and lower metallicities for M dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/458/293
- Title:
- Temperature calibration for A & mid F-type stars
- Short Name:
- J/A+A/458/293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the {Delta}a photometric system, it is possible to study very distant galactic and even extragalactic clusters with a high level of accuracy. The new calibration presented is a powerful extension. Because no a-priori reddening-free photometric parameters are available for the investigated spectral range, we have applied the dereddening calibrations of the Stromgren uvby{beta} system and compared them with extinction models for the Milky Way. We derived an empirical temperature calibration for the {Delta}a photometric system for A-type to mid F-type with a mean of the error for the whole sample of {Delta}T(eff) is 134K which is lower than the value in Paper I (Paunzen et al., 2005, Cat. <J/A+A/444/941>) for hotter stars. No statistically significant effect of the rotational velocity on the precision of the calibration was found.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A120
- Title:
- TESS OBA-type eclipsing binaries
- Short Name:
- J/A+A/652/A120
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Intermediate- to high-mass stars are the least numerous types of stars and they are less well understood than their more numerous low-mass counterparts in terms of their internal physical processes. Modelling the photometric variability of a large sample of main-sequence intermediate- to high-mass stars in eclipsing binary systems will help to improve the models for such stars. Our goal is to compose a homogeneously compiled sample of main-sequence intermediate- to high-mass OBA-type dwarfs in eclipsing binary systems from TESS photometry. We search for binaries with and without pulsations and determine their approximate ephemerides. Our selection starts from a catalogue of dwarfs with colours corresponding to those of OBA-type dwarfs in the TESS Input Catalog. We develop a new automated method aimed at detecting eclipsing binaries in the presence of strong pulsational and/or rotational signal relative to the eclipse depths and apply it to publicly available 30-min cadence TESS light curves. Using targets with TESS magnitudes below 15 and cuts in the 2MASS magnitude bands of J-H<0.045 and J-K<0.06 as most stringent criteria, we arrive at a total of 189 981 intermediate- to high-mass candidates, 91193 of which have light curves from at least one of two data reduction pipelines. The eclipsing binary detection and subsequent manual check for false positives resulted in 3155 unique OBA-type eclipsing binary candidates. Our sample of eclipsing binary stars in the intermediate- to high-mass regime allows for future binary (and asteroseismic) modelling with the aim to better understand the internal physical processes in this hot part of the main sequence.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/L9
- Title:
- TESS obs. of massive O and B stars
- Short Name:
- J/ApJ/872/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Uncertainties in stellar structure and evolution theory are largest for stars undergoing core convection on the main sequence. A powerful way to calibrate the free parameters used in the theory of stellar interiors is asteroseismology, which provides direct measurements of angular momentum and element transport. We report the detection and classification of new variable O and B stars using high-precision short-cadence (2 minutes) photometric observations assembled by the Transiting Exoplanet Survey Satellite (TESS). In our sample of 154 O and B stars, we detect a high percentage (90%) of variability. Among these we find 23 multiperiodic pulsators, 6 eclipsing binaries, 21 rotational variables, and 25 stars with stochastic low-frequency variability. Several additional variables overlap between these categories. Our study of O and B stars not only demonstrates the high data quality achieved by TESS for optimal studies of the variability of the most massive stars in the universe, but also represents the first step toward the selection and composition of a large sample of O and B pulsators with high potential for joint asteroseismic and spectroscopic modeling of their interior structure with unprecedented precision.
- ID:
- ivo://CDS.VizieR/J/AJ/135/928
- Title:
- The black hole-bulge relationship
- Short Name:
- J/AJ/135/928
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the stellar velocity dispersions ({sigma}_*_) and estimated the central black hole (BH) masses for over 900 broad-line active galactic nuclei (AGNs) observed with the Sloan Digital Sky Survey. The sample includes objects which have redshifts up to z=0.452, high-quality spectra, and host galaxy spectra dominated by an early-type (bulge) component. The AGN and host galaxy spectral components were decomposed using an eigenspectrum technique. The BH masses (M_BH_) were estimated from the AGN broad-line widths, and the velocity dispersions were measured from the stellar absorption spectra of the host galaxies. The range of black hole masses covered by the sample is approximately 10^6^<M_BH_<10^9^M_{sun}_. We find no significant evolution in the M_BH_-{sigma}_*_ relation with redshift, up to z~0.4, after controlling for possible dependences on other variables. Interested readers can contact the authors to obtain the eigenspectrum decomposition coefficients of our objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/824/86
- Title:
- The BOSS emission-line lens survey. III.
- Short Name:
- J/ApJ/824/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey GALaxy-Ly{alpha} EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Ly{alpha} emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy-LAE candidates selected from ~1.4x10^6^ galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2-3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.
- ID:
- ivo://CDS.VizieR/J/ApJS/195/10
- Title:
- The CDF-S survey: 4Ms source catalogs
- Short Name:
- J/ApJS/195/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present source catalogs for the 4Ms Chandra Deep Field-South (CDF-S), which is the deepest Chandra survey to date and covers an area of 464.5arcmin^2^. We provide a main Chandra source catalog, which contains 740 X-ray sources that are detected with wavdetect at a false-positive probability threshold of 10^-5^ in at least one of three X-ray bands (0.5-8keV, full band; 0.5-2keV, soft band; and 2-8keV, hard band) and also satisfy a binomial-probability source-selection criterion of P<0.004 (i.e., the probability of sources not being real is less than 0.004); this approach is designed to maximize the number of reliable sources detected. A total of 300 main-catalog sources are new compared to the previous 2Ms CDF-S main-catalog sources. We determine X-ray source positions using centroid and matched-filter techniques and obtain a median positional uncertainty of ~0.42". We also provide a supplementary catalog, which consists of 36 sources that are detected with wavdetect at a false-positive probability threshold of 10^-5^, satisfy the condition of 0.004<P<0.1, and have an optical counterpart with R<24. Multiwavelength identifications, basic optical/infrared/radio photometry, and spectroscopic/photometric redshifts are provided for the X-ray sources in the main and supplementary catalogs. Seven hundred sixteen (~97%) of the 740 main-catalog sources have multiwavelength counterparts, with 673 (~94% of 716) having either spectroscopic or photometric redshifts. Basic analyses of the X-ray and multiwavelength properties of the sources indicate that >75% of the main-catalog sources are active galactic nuclei (AGNs); of the 300 new main-catalog sources, about 35% are likely normal and starburst galaxies, reflecting the rise of normal and starburst galaxies at the very faint flux levels uniquely accessible to the 4Ms CDF-S.
- ID:
- ivo://CDS.VizieR/J/MNRAS/326/1455
- Title:
- The CLASS blazar survey. I.
- Short Name:
- J/MNRAS/326/1455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a new complete and well-defined sample of flat-spectrum radio sources (FSRS) selected from the Cosmic Lens All-Sky Survey (CLASS), with the further constraint of a bright (mag<=17.5) optical counterpart. The sample has been designed to produce a large number of low-luminosity blazars in order to test the current unifying models in the low-luminosity regime. In this first paper the new sample is presented and the radio properties of the 325 sources contained therein are discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/329/877
- Title:
- The CLASS blazar survey. II.
- Short Name:
- J/MNRAS/329/877
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the optical properties of the objects selected in the CLASS blazar survey. Because an optical spectrum is now available for 70 per cent of the 325 sources present in the sample, a spectral classification, based on the appearance of the emission/absorption lines, is possible. A wide variety of optical spectral types is found. Besides `classical' BL Lacs (42), BL Lac candidates (5) and high-power (P_5GHz_>10^26^W/Hz) flat spectrum radio quasars (67), a significant number of `passive' elliptical galaxies (41) is also found. Moreover, 33 broad emission line objects with a low radio power (P(5GHz)>10^26^W/Hz) are discovered, suggesting that at least a fraction (~24-30 per cent) of low-power blazars have a broad line region. Finally, 34 objects showing only narrow emission lines, either as a result of some starburst activity in the host galaxy or as a result of the presence of an active galactic nucleus, appear in the sample.
