- ID:
- ivo://CDS.VizieR/J/MNRAS/316/514
- Title:
- 28 And & 99 Her elemental abundances
- Short Name:
- J/MNRAS/316/514
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Elemental abundances of 28 And (A7III) and 99 Her (F7V), which have modest rotational velocities, are derived in a manner consistent with previous studies in this series of papers. The values for 28 And, a δ Scuti variable, show that it is slightly metal-poor, but not a classical Am star. 99 Her, which is somewhat more metal-poor, has a rather small microturbulence for its spectral type.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/727/83
- Title:
- A panchromatic study of BLAST counterparts
- Short Name:
- J/ApJ/727/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carry out a multi-wavelength study of individual galaxies detected by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and identified at other wavelengths, using data spanning the radio to the ultraviolet (UV). We develop a Monte Carlo method to account for flux boosting, source blending, and correlations among bands, which we use to derive deboosted far-infrared (FIR) luminosities for our sample. We estimate total star-formation rates (SFRs) for BLAST counterparts with z<=0.9 by combining their FIR and UV luminosities. We assess that about 20% of the galaxies in our sample show indication of a type 1 active galactic nucleus, but their submillimeter emission is mainly due to star formation in the host galaxy. We compute stellar masses for a subset of 92 BLAST counterparts; these are relatively massive objects, with a median mass of ~10^11^M_{sun}_, which seem to link the 24um and Submillimetre Common-User Bolometer Array (SCUBA) populations, in terms of both stellar mass and star formation activity.
- ID:
- ivo://CDS.VizieR/J/ApJ/894/5
- Title:
- APOGEE2-N NIR spectra of B-type stars
- Short Name:
- J/ApJ/894/5
- Date:
- 19 Jan 2022 00:59:33
- Publisher:
- CDS
- Description:
- We present a semi-empirical spectral classification scheme for normal B-type stars using near-infrared (NIR) spectra (1.5-1.7{mu}m) from the Sloan Digital Sky Survey Apache Point Observatory Galaxy Evolution Experiment (APOGEE2)-N data release 14 (DR14) database. The main motivation for working with B-type stars is their importance in the evolution of young stellar clusters; however, we also take advantage of having a numerous sample (316 stars) of B-type star candidates in APOGEE2-N, for which we also have optical (3600-9100{AA}) counterparts from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. By first obtaining an accurate spectral classification of the sources using the LAMOST DR3 spectra and the canonical spectral classification scheme, we found a linear relation between optical spectral types and the equivalent widths of the hydrogen lines of the Brackett series in the APOGEE2-N NIR spectra. This relation extends smoothly from a similar relation for O and early B stars found by Roman-Lopes+ (2018, J/ApJ/855/68). This way, we obtain a catalog of B-type sources with features in both the optical and NIR and a classification scheme refined down to one spectral subclass.
- ID:
- ivo://CDS.VizieR/J/AJ/136/614
- Title:
- Arp 2 and Ter 8 red giants equivalent widths
- Short Name:
- J/AJ/136/614
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To compare the globular clusters (GCs) associated with the Sagittarius Galaxy (Sgr) we report the results obtained from new high-resolution spectra of red giant stars in Terzan 8 and Arp 2, collected with the Magellan Inamori Kyocera Echelle (MIKE) spectrograph at Las Campanas Observatory.
- ID:
- ivo://CDS.VizieR/J/AcA/62/67
- Title:
- ASAS photometry of ROSAT sources
- Short Name:
- J/AcA/62/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric data from the ASAS - South (declination less than 29{deg}) survey have been used for identification of bright stars located near the sources from the ROSAT All Sky Survey Bright Source Catalog (RBSC). In total 6028 stars brighter than 12.5mag in I- or V-bands have been selected and analyzed for periodicity. Altogether 2302 variable stars have been found with periods ranging from 0.137d to 193d. Most of these stars have X-ray emission of coronal origin with a few cataclysmic binaries and early type stars with colliding winds. Whenever it was possible we collected data available in the literature to verify periods and to classify variable objects.
- ID:
- ivo://CDS.VizieR/J/ApJS/148/275
- Title:
- ASCA AGN optical identifications
- Short Name:
- J/ApJS/148/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of optical spectroscopic identifications of a bright subsample of 2-10keV hard X-ray-selected sources from the ASCA Medium Sensitivity Survey in the northern sky (AMSSn). The flux limit of the subsample is 3x10^-13^erg/s/cm^2^ in the 2-10keV band. All but one of the 87 hard X-ray-selected sources are optically identified, with AGNs (including broad-line AGNs, narrow-line AGNs, and three BL Lac objects), seven clusters of galaxies, and one galactic star. It is the largest complete sample of hard X-ray-selected AGNs at the bright flux limit. Amounts of absorption to their nuclei are estimated to be hydrogen column densities (NH) of up to 3x10^23^cm^-2^ from their X-ray spectra. Optical properties of X-ray absorbed AGNs with N_H_>1x10^22^cm^-2^ indicate the effects of dust absorption: at redshifts z<0.6, AGNs without broad H{beta} emission lines have significantly larger NH-values than AGNs with broad H{beta} emission lines. At z>0.6, the X-ray absorbed AGNs have a large hard X-ray to optical flux ratio (logf_2-10keV_/f_R_>+1). However, three X-ray absorbed z>0.6 AGNs show strong broad lines. In combination with hard X-ray-selected AGN samples from the ASCA Large Sky Survey, the ASCA Deep Survey in the Lockman Hole, and Chandra Deep Field North, the luminosity distributions of absorbed (N_H_>1x10^22^cm^-2^) and less-absorbed (N_H_<1x10^22^cm^-2^) AGNs are compared.
- ID:
- ivo://CDS.VizieR/J/A+AS/147/5
- Title:
- AS 78 & MWC 657 spectroscopy
- Short Name:
- J/A+AS/147/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of low- and high-resolution spectroscopic and multicolour photometric observations of two early-type emission-line stars, AS 78 and MWC 657. They were identified by Dong & Hu (1991ChA&A..15..275D) with the IRAS sources 03549+5602 and 22407+6008, respectively, among many other sources displaying a very strong infrared excess, V-[25]>=8mag. AS 78 is recognized as a photometric variable for the first time. A large near-IR excess radiation is detected in AS 78 and confirmed by new, higher-quality, data for MWC 657. Significant variations in the Balmer line profiles are detected for both objects. Modelling of the Balmer line profiles of AS 78 obtained in 1994 yields the following parameters of the star and its wind: T_eff_~17000K, logL_bol_/L_{sun}_~4.0, dM/dt~10^-6^M_{sun}_/yr. The photometric and new spectroscopic data indicate that the star's T_eff_ increases with time, while the stellar wind changes its structure. Distances towards both objects are estimated on the basis of their radial velocities and the galactic rotation curve. Consideration of different options about the nature and evolutionary state of both objects leads us to suggest that they are binary systems containing a B-type intermediate-luminosity star and a gaseous disk around the less luminous component.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/872
- Title:
- A spectropolarimetric analysis of WASP-12
- Short Name:
- J/ApJ/720/872
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The knowledge of accurate stellar parameters is paramount in several fields of stellar astrophysics, particularly in the study of extrasolar planets, where often the star is the only visible component and therefore used to infer the planet's fundamental parameters. Another important aspect of the analysis of planetary systems is the stellar activity and the possible star-planet interaction. Here, we present a self-consistent abundance analysis of the planet-hosting star WASP-12 and a high-precision search for a structured stellar magnetic field on the basis of spectropolarimetric observations obtained with the ESPaDOnS spectropolarimeter. Our results show that the star does not have a structured magnetic field, and that the obtained fundamental parameters are in good agreement with what was previously published. In addition, we derive improved constraints on the stellar age (1.0-2.65Gyr), mass (1.23-1.49M/M_{sun}_), and distance (295-465pc). WASP-12 is an ideal object in which to look for pollution signatures in the stellar atmosphere. We analyze the WASP-12 abundances as a function of the condensation temperature and compare them with those published by several other authors on planet-hosting and non-planet-hosting stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/251/482
- Title:
- A spectroscopic survey of faint QSOs
- Short Name:
- J/MNRAS/251/482
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/679/239
- Title:
- Associated MgII absorbers
- Short Name:
- J/ApJ/679/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied a sample of 415 associated (z_abs_~z_em_; relative velocity with respect to QSO in units of c, {beta}<0.01) MgII absorption systems with 1.0<=z_abs_<=1.86, in the spectra of SDSS DR3 QSOs, to determine the dust content and ionization state in the absorbers. We also compared these properties to those of a similarly selected sample of 809 intervening systems ({beta}>0.01), so as to understand their origin. Normalized, composite spectra were derived for absorption line measurements, for the full sample and for several subsamples, chosen on the basis of the line strengths and other absorber and QSO properties. From these, and from the equivalent widths in individual spectra, we conclude that the associated MgII absorbers have higher ionization (higher ratios of the strengths of CIV and MgII lines), than the intervening absorbers. The ionization decreases with increasing {beta}. Average extinction curves were obtained for the subsamples by comparing their geometric mean QSO spectra with those of matching (in z_em_ and i magnitude) samples of QSOs without absorption lines. There is clear evidence for SMC-like dust attenuation in these systems; the 2175{AA} absorption feature is absent. The extinction is almost twice that observed in intervening systems. We reconfirm that QSOs with nonzero FIRST radio flux are intrinsically redder than the QSOs with no detection in the FIRST survey.
