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6801. The SEGUE K giant survey. III. Galactic halo
ID:
ivo://CDS.VizieR/J/ApJ/816/80
Title:
The SEGUE K giant survey. III. Galactic halo
Short Name:
J/ApJ/816/80
Date:
21 Oct 2021
Publisher:
CDS
Description:
We statistically quantify the amount of substructure in the Milky Way stellar halo using a sample of 4568 halo K giant stars at Galactocentric distances ranging over 5-125kpc. These stars have been selected photometrically and confirmed spectroscopically as K giants from the Sloan Digital Sky Survey's Sloan Extension for Galactic Understanding and Exploration (SEGUE) project. Using a position-velocity clustering estimator (the 4distance) and a model of a smooth stellar halo, we quantify the amount of substructure in the halo, divided by distance and metallicity. Overall, we find that the halo as a whole is highly structured. We also confirm earlier work using blue horizontal branch (BHB) stars which showed that there is an increasing amount of substructure with increasing Galactocentric radius, and additionally find that the amount of substructure in the halo increases with increasing metallicity. Comparing to resampled BHB stars, we find that K giants and BHBs have similar amounts of substructure over equivalent ranges of Galactocentric radius. Using a friends-of-friends algorithm to identify members of individual groups, we find that a large fraction (~33%) of grouped stars are associated with Sgr, and identify stars belonging to other halo star streams: the Orphan Stream, the Cetus Polar Stream, and others, including previously unknown substructures. A large fraction of sample K giants (more than 50%) are not grouped into any substructure. We find also that the Sgr stream strongly dominates groups in the outer halo for all except the most metal-poor stars, and suggest that this is the source of the increase of substructure with Galactocentric radius and metallicity.
6802. The Seven Sisters DANCe. I. Pleiades
ID:
ivo://CDS.VizieR/J/A+A/577/A148
Title:
The Seven Sisters DANCe. I. Pleiades
Short Name:
J/A+A/577/A148
Date:
21 Oct 2021
Publisher:
CDS
Description:
The DANCe survey provides photometric and astrometric (position and proper motion) measurements for approximately 2 millions unique sources in a region encompassing approximately 80deg^2^ centered around the Pleiades cluster. We aim at deriving a complete census of the Pleiades, and measure the mass and luminosity function of the cluster. Using the probabilistic selection method described in Sarro et al. (2014A&A...563A..45S, Cat. J/A+A/563/A45), we identify high probability members in the DANCe (i>14mag) and Tycho-2 (V<12mag) catalogues, and study the properties of the cluster over the corresponding luminosity range. We find a total of 2109 high probability members, of which 812 are new, making it the most extensive and complete census of the cluster to date. The luminosity and mass functions of the cluster are computed from the most massive members down to 0.025M_{sun}_. The size, sensitivity and quality of the sample result in the most precise luminosity and mass functions observed to date for a cluster. Our census supersedes previous studies of the Pleiades cluster populations, both in terms of sensitivity and accuracy.
6803. The short period binary CSPN of M 3-1
ID:
ivo://CDS.VizieR/J/MNRAS/482/L75
Title:
The short period binary CSPN of M 3-1
Short Name:
J/MNRAS/482/L75
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery of a 3h5m orbital-period binary star at the heart of the planetary nebula M 3-1 - the shortest period photometrically variable central star known and second only to V458 Vul, in general. Combined modelling of light and radial velocity curves reveals both components to be close to Roche lobe filling, strongly indicating that the central star will rapidly evolve to become a cataclysmic variable, perhaps experiencing a similar evolution to V458 Vul resulting in a nova eruption before the planetary nebula has fully dissipated. While the short orbital period and near Roche lobe filling natures of both components make the central binary of M 3-1 an important test case with which to constrain the formation processes of cataclysmic variables, novae, and perhaps even supernovae type Ia.
6804. The simultaneous optical-to-X-ray SED of AGNs
ID:
ivo://CDS.VizieR/J/ApJS/187/64
Title:
The simultaneous optical-to-X-ray SED of AGNs
Short Name:
J/ApJS/187/64
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report Swift observations of a sample of 92 bright soft X-ray selected active galactic nuclei (AGNs). This sample represents the largest number of AGNs observed to study the spectral energy distribution (SED) of AGNs with simultaneous optical/UV and X-ray data. The principal motivation of this study is to understand the SEDs of AGNs in the optical/UV to X-ray regime and to provide bolometric corrections which are important in determining the Eddington ratio L/L_Edd_. In particular, we rigorously explore the dependence of the UV-EUV contribution to the bolometric correction on the assumed EUV spectral shape. We find strong correlations of the spectral slopes {alpha}_X_ and {alpha}_UV_ with L/L_Edd_.
6805. The SkyMapper DR3 SSOs
ID:
ivo://CDS.VizieR/J/A+A/658/A109
Title:
The SkyMapper DR3 SSOs
Short Name:
J/A+A/658/A109
Date:
22 Feb 2022
Publisher:
CDS
Description:
The populations of small bodies of the Solar System (asteroids, comets, and Kuiper Belt objects) are used to constrain the origin and evolution of the Solar System. Their orbital distribution and composition distribution are both required to track the dynamical pathway from their formation regions to their current locations. We aim to increase the sample of Solar System objects (SSOs) that have multifilter photometry and compositional taxonomy. Methods. We searched for moving objects in the SkyMapper Southern Survey. We used the predicted SSO positions to extract photometry and astrometry from the SkyMapper frames. We then applied a suite of filters to clean the catalog from false-positive detections. We finally used the near-simultaneous photometry to assign a taxonomic class to objects. We release a catalog of 880,528 individual observations, consisting of 205515 known and unique SSOs. The catalog completeness is estimated to be about 97% down to V=18mag and the purity is higher than 95% for known SSOs. The near-simultaneous photometry provides either three, two, or a single color that we use to classify 117356 SSOs with a scheme consistent with the widely used Bus-DeMeo taxonomy. The present catalog contributes significantly to the sample of asteroids with known surface properties (about 40% of main-belt asteroids down to an absolute magnitude of 16). We will release more observations of SSOs with future SkyMapper data releases.
6806. The Sloan Lens ACS (SLACS) Survey. IX.
ID:
ivo://CDS.VizieR/J/ApJ/705/1099
Title:
The Sloan Lens ACS (SLACS) Survey. IX.
Short Name:
J/ApJ/705/1099
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the current photometric data set for the Sloan Lens ACS (SLACS) Survey, including Hubble Space Telescope (HST) photometry from Advanced Camera for Surveys, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade "A" (certain) lens systems, bringing the number of SLACS grade "A" lenses to 85; including 13 grade "B" (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade "A" systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous data set of galaxy-scale lenses to date. The ensemble properties of the SLACS lens galaxies, e.g., stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M_*_>~10^11^M_{sun}_, and are therefore an ideal data set to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z~0.5.
6807. The solar neighborhood. XLIII. New nearby stars
ID:
ivo://CDS.VizieR/J/AJ/156/49
Title:
The solar neighborhood. XLIII. New nearby stars
Short Name:
J/AJ/156/49
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have conducted a novel search of most of the southern sky for nearby red dwarfs having low proper motions, with specific emphasis on those with {mu}<0.18"/yr, the lower cutoff of Luyten's classic proper-motion catalog. We used a tightly constrained search of the SuperCOSMOS database and a suite of photometric distance relations for photographic BRI and 2MASS JHK_s_ magnitudes to estimate distances to more than 14 million red dwarf candidates. Here we discuss 29 stars in 26 systems estimated to be within 25 pc, all of which have {mu}<0.18"/yr, that we have investigated using milliarcsecond astrometry, VRI photometry, and low-resolution spectroscopy. In total, we present the first parallaxes of 20 star systems, 9 of which are within 25 pc. We have additionally identified 14 young M dwarfs, of which 3 are new members of the nearby young moving groups, and 72 new giants, including two new carbon stars. We also present the entire catalog of 1215 sources we have identified by this means.
6808. The solar neighborhood. XLII. New nearby subdwarfs
ID:
ivo://CDS.VizieR/J/AJ/154/191
Title:
The solar neighborhood. XLII. New nearby subdwarfs
Short Name:
J/AJ/154/191
Date:
21 Oct 2021
Publisher:
CDS
Description:
Parallaxes, proper motions, and optical photometry are presented for 51 systems consisting of 37 cool subdwarf and 14 additional high proper motion systems. Thirty-seven systems have parallaxes reported for the first time, 15 of which have proper motions of at least 1"/yr. The sample includes 22 newly identified cool subdwarfs within 100 pc, of which three are within 25 pc, and an additional five subdwarfs from 100 to 160 pc. Two systems-LSR 1610-0040 AB and LHS 440 AB-are close binaries exhibiting clear astrometric perturbations that will ultimately provide important masses for cool subdwarfs. We use the accurate parallaxes and proper motions provided here, combined with additional data from our program and others, to determine that effectively all nearby stars with tangential velocities greater than 200 km/s are subdwarfs. We compare a sample of 167 confirmed cool subdwarfs to nearby main sequence dwarfs and Pleiades members on an observational Hertzsprung-Russell diagram using M_V_ versus (V-K_s_) to map trends of age and metallicity. We find that subdwarfs are clearly separated for spectral types K5-M5, indicating that the low metallicities of subdwarfs set them apart in the H-R diagram for (V-K_s_)=3-6. We then apply the tangential velocity cutoff and the subdwarf region of the H-R diagram to stars with parallaxes from Gaia Data Release 1 and the MEarth Project to identify a total of 29 new nearby subdwarf candidates that fall clearly below the main sequence.
6809. The solar neighborhood. XLIV. RECONS discoveries
ID:
ivo://CDS.VizieR/J/AJ/155/265
Title:
The solar neighborhood. XLIV. RECONS discoveries
Short Name:
J/AJ/155/265
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe the 44 systems discovered to be within 10 pc of the Sun by the RECONS team, primarily via the long-term astrometry program at the CTIO/SMARTS 0.9 m that began in 1999. The systems-including 41 with red dwarf primaries, 2 white dwarfs, and 1 brown dwarf-have trigonometric parallaxes greater than 100 mas, with errors of 0.4-2.4 mas in all but one case. We provide updated astrometric, photometric (VRIJHK magnitudes), spectral type, and multiplicity information here. Among these are 14 systems that are new entries to the 10 pc sample, including the first parallaxes for 9 systems and new values for 5 systems that had previous parallaxes with errors greater than 10 mas or values placing them beyond 10 pc. We also provide new data for 22 systems known to lie within 10 pc and 9 systems reported to be closer than that horizon but for which new parallaxes place them further away, bringing the total to 75 systems. The 44 systems added by RECONS comprise one of every 7 systems known within 10 pc. We illustrate the evolution of the 10 pc sample from the 191 systems known when the final Yale Parallax Catalog was published in 1995 to the 317 systems known today. Even so close to the Sun, additional discoveries of white, red, and brown dwarfs are possible, both as primaries and secondaries, although we estimate that at least 90% of the stellar systems closer than 10 pc have now been identified.
6810. The solar neighborhood.XLVI. New M dwarf binaries
ID:
ivo://CDS.VizieR/J/AJ/160/215
Title:
The solar neighborhood.XLVI. New M dwarf binaries
Short Name:
J/AJ/160/215
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use 20yr of astrometric data from the REsearch Consortium On Nearby Stars (RECONS) program on the Cerro Tololo Inter-American Observatory/SMARTS 0.9m telescope to provide new insight into multiple star systems in the solar neighborhood. We provide new and updated parallaxes for 210 systems and derive nine high-quality astrometric orbits with periods of 2.49-16.63yr. Using a total of 542 systems parallaxes from RECONS, we compare systems within 25pc to Gaia DR2 to define criteria for selecting unresolved astrometric multiples from the DR2 results. We find that three out of four unresolved multistar red dwarf systems within 25pc in DR2 have parallax_error >=0.32mas, astrometric_gof_al>=56, astrometric_excess-noise_sig>=108.0, ruwe>=2.0, and parallaxes more than ~10% different from the long-term RECONS results. These criteria have broad applications to any work targeting nearby stars, from studies seeking binary systems to efforts targeting single stars for planet searches.