- ID:
- ivo://CDS.VizieR/J/ApJ/900/42
- Title:
- CARMENES obs. of the binary system LB-1
- Short Name:
- J/ApJ/900/42
- Date:
- 21 Mar 2022 09:26:37
- Publisher:
- CDS
- Description:
- The mass, origin, and evolutionary stage of the binary system LB-1 have been intensely debated, following the claim that it hosts an ~70M_{sun}_ black hole, in stark contrast with the expectations for Galactic remnants. We conducted a high-resolution, phase-resolved spectroscopic study of its Paschen lines, using the Calar Alto 3.5m telescope. We find that Pa{beta} and Pa{gamma} (after subtraction of the stellar absorption component) are well fitted with a standard double-peaked disk profile. We measured the velocity shifts of the red and blue peaks at 28 orbital phases: the line center has an orbital motion in perfect antiphase with the secondary, and the radial velocity amplitude ranges from 8 to 13km/s, for different methods of profile modeling. We interpret this curve as proof that the disk traces the orbital motion of the primary, ruling out the circumbinary disk and the hierarchical triple scenarios. The phase-averaged peak-to-peak half-separation (a proxy for the projected rotational velocity of the outer part of the disk) is ~70km/s, larger than the orbital velocity of the secondary and inconsistent with a circumbinary disk. From those results, we infer a primary mass 4-8 times higher than the secondary mass. Moreover, we show that the intensity ratio of the blue and red peaks has a sinusoidal behavior in phase with the secondary, which we attribute to external irradiation of the outer part of the disk. Finally, we discuss our findings in the context of competing scenarios proposed for LB-1. Further astrometric Gaia data will test between alternative solutions.
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- ID:
- ivo://CDS.VizieR/J/ApJ/742/54
- Title:
- CASH project II. 14 extremely metal-poor stars
- Short Name:
- J/ApJ/742/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive abundance analysis of 20 elements for 16 new low-metallicity stars from the Chemical Abundances of Stars in the Halo (CASH) project. The abundances have been derived from both Hobby-Eberly Telescope High Resolution Spectrograph snapshot spectra (R~15000) and corresponding high-resolution (R~35000) Magellan Inamori Kyocera Echelle spectra. The stars span a metallicity range from [Fe/H] from -2.9 to -3.9, including four new stars with [Fe/H]<-3.7. We find four stars to be carbon-enhanced metal-poor (CEMP) stars, confirming the trend of increasing [C/Fe] abundance ratios with decreasing metallicity. Two of these objects can be classified as CEMP-no stars, adding to the growing number of these objects at [Fe/H]<-3. We also find four neutron-capture-enhanced stars in the sample, one of which has [Eu/Fe] of 0.8 with clear r-process signatures. These pilot sample stars are the most metal-poor ([Fe/H]<~-3.0) of the brightest stars included in CASH and are used to calibrate a newly developed, automated stellar parameter and abundance determination pipeline. This code will be used for the entire ~500 star CASH snapshot sample. We find that the pipeline results are statistically identical for snapshot spectra when compared to a traditional, manual analysis from a high-resolution spectrum.
- ID:
- ivo://CDS.VizieR/J/ApJ/814/121
- Title:
- CASH project. III. The CEMP star HE0414-0343
- Short Name:
- J/ApJ/814/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed abundance analysis of 23 elements for a newly discovered carbon-enhanced metal-poor (CEMP) star, HE0414-0343, from the Chemical Abundances of Stars in the Halo Project. Its spectroscopic stellar parameters are T_eff_=4863K, logg=1.25, {xi}=2.20km/s, and [Fe/H]=-2.24. Radial velocity measurements covering seven years indicate HE 0414-0343 to be a binary. HE0414-0343 has [C/Fe]=1.44 and is strongly enhanced in neutron-capture elements but its abundances cannot be reproduced by a solar-type s-process pattern alone. Traditionally, it could be classified as a "CEMP-r/s" star. Based on abundance comparisons with asymptotic giant branch (AGB) star nucleosynthesis models, we suggest a new physically motivated origin and classification scheme for CEMP-s stars and the still poorly understood CEMP-r/s. The new scheme describes a continuous transition between these two so-far distinctly treated subgroups: CEMP-sA, CEMP-sB, and CEMP-sC. Possible causes for a continuous transition include the number of thermal pulses the AGB companion underwent, the effect of different AGB star masses on their nucleosynthetic yields, and physics that is not well approximated in 1D stellar models such as proton ingestion episodes and rotation. Based on a set of detailed AGB models, we suggest the abundance signature of HE 0414-0343 to have arisen from a >1.3M_{sun}_ mass AGB star and a late-time mass transfer that transformed HE 0414-0343 into a CEMP-sC star. We also find that the [Y/Ba] ratio well parametrizes the classification and can thus be used to easily classify any future such stars.
- ID:
- ivo://CDS.VizieR/III/164
- Title:
- Catalog of Eq.Widths of Interstellar 217nm Band
- Short Name:
- III/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (from CDS Inf. Bull. 40, 31) The main task of the catalogue consists in a comprehensive collection of equivalent widths of the 217nm band derived from both spectrophotometric and filterphotometric measurements obtained with TD-1, OAO-2 and ANS satellites. These data concern reddened O, B stars with color excesses E(B-V) >= 0.02 mag. The extinction curve is approximated by the empirical formula introduced by Guertler et al. (1982AN....303..105G) e({lambda}) = A(i/{lambda} - 1/{lambda}o)^n^ + B + C {kappa}({lambda}) The relative errors amount to about {delta}A/A = +/- 0.10, {delta}B/B = +/- 0.02 and {delta}C/C = +/- 0.03.
- ID:
- ivo://CDS.VizieR/III/29
- Title:
- Catalog of H{gamma} measures
- Short Name:
- III/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of equivalent widths of H{gamma} measured by R.M. Petrie in the spectra of 1171 stars is presented. The catalogue represents a compilation of all the published and unpublished values available to us. It is shown that no systematic differences exist between the equivalent widths by Petrie and those currently being derived at the Dominion Astrophysical Observatory.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A67
- Title:
- Catalog of strong MgII absorbers
- Short Name:
- J/A+A/546/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A significantly higher incidence of strong (rest equivalent width Wr>1{AA}) intervening MgII absorption is observed along gamma-ray burst (GRB) sight-lines relative to those of quasar sight-lines. A geometrical explanation for this discrepancy has been suggested: the ratio of the beam size of the source to the characteristic size of an MgII absorption system can influence the observed MgII equivalent width, if these two sizes are comparable. We investigate whether the differing beam sizes of the continuum source and broad-line region of Sloan Digital Sky Survey (SDSS) quasars produce a discrepancy between the incidence of strong MgII absorbers illuminated by the quasar continuum region and those of absorbers illuminated by both continuum and broad-line region light.
- ID:
- ivo://CDS.VizieR/J/AJ/153/95
- Title:
- Catalog of Suspected Nearby Young Stars
- Short Name:
- J/AJ/153/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new nearby young moving group (NYMG) kinematic membership analysis code, LocAting Constituent mEmbers In Nearby Groups (LACEwING), a new Catalog of Suspected Nearby Young Stars, a new list of bona fide members of moving groups, and a kinematic traceback code. LACEwING is a convergence-style algorithm with carefully vetted membership statistics based on a large numerical simulation of the Solar Neighborhood. Given spatial and kinematic information on stars, LACEwING calculates membership probabilities in 13 NYMGs and three open clusters within 100 pc. In addition to describing the inputs, methods, and products of the code, we provide comparisons of LACEwING to other popular kinematic moving group membership identification codes. As a proof of concept, we use LACEwING to reconsider the membership of 930 stellar systems in the Solar Neighborhood (within 100 pc) that have reported measurable lithium equivalent widths. We quantify the evidence in support of a population of young stars not attached to any NYMGs, which is a possible sign of new as-yet-undiscovered groups or of a field population of young stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/1
- Title:
- Catalog of Type-1 AGNs from SDSS-DR7
- Short Name:
- J/ApJS/219/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have recently identified a substantial number of type 1 active galactic nuclei (AGNs) featuring weak broad-line regions (BLRs) at z<0.2 from detailed analysis of galaxy spectra in the Sloan Digital Sky Survey Data Release 7. These objects predominantly show a stellar continuum but also a broad H{alpha} emission line, indicating the presence of a low-luminosity AGN oriented so that we are viewing the central engine directly without significant obscuration. These accreting black holes have previously eluded detection due to their weak nature. The newly discovered BLR AGNs have increased the number of known type 1 AGNs by 49%. Some of these new BLR AGNs were detected with the Chandra X-ray Observatory, and their X-ray properties confirm that they are indeed type 1 AGNs. Based on our new and more complete catalog of type 1 AGNs, we derived the type 1 fraction of AGNs as a function of [OIII]{lambda}5007 emission luminosity and explored the possible dilution effect on obscured AGNs due to star formation. The new type 1 AGN fraction shows much more complex behavior with respect to black hole mass and bolometric luminosity than has been suggested previously by the existing receding torus model. The type 1 AGN fraction is sensitive to both of these factors, and there seems to be a sweet spot (ridge) in the diagram of black hole mass and bolometric luminosity. Furthermore, we present the possibility that the Eddington ratio plays a role in determining opening angles.
- ID:
- ivo://CDS.VizieR/III/245
- Title:
- Catalogue of H line profiles of 235 B-F stars
- Short Name:
- III/245
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- There are given 1064 profiles of the hydrogen lines H{gamma} and H{delta} for 235 B,A,F-stars obtained at the Main Stellar Spectrograph of the 6-m telescope in 1978-1986 in the course of several large observing projects. Optical density close to D=1.0 was reached for all spectra on Kodak IIaO photographic plates. The profiles are presented as smoothed intensity normalized to the level of local continuum for different distances from lines core, in {AA}. The blue and red wings of H{gamma} and H{delta} lines are averaged.
- ID:
- ivo://CDS.VizieR/J/MNRAS/371/495
- Title:
- Catalogue of 1806 MgII absorbers from SDSS DR3
- Short Name:
- J/MNRAS/371/495
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the mean halo mass of z=~0.5 MgII absorbers using the cross-correlation (over comoving scales 0.05-13h^-1^Mpc) between 1806 MgII quasar absorption systems and ~250000 luminous red galaxies (LRGs), both selected from the Sloan Digital Sky Survey Data Release 3.
