- ID:
- ivo://CDS.VizieR/J/AJ/157/35
- Title:
- The population of pulsating variable stars in Sextans
- Short Name:
- J/AJ/157/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large extension of the Sextans dwarf spheroidal galaxy, 7 deg^2^, has been surveyed for variable stars using the Dark Energy Camera at the Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile. We report seven anomalous Cepheids, 199 RR Lyrae stars, and 16 dwarf Cepheids in the field. This is only the fifth extragalactic system in which dwarf Cepheids have been systematically searched. Henceforth, the new stars increase the census of stars coming from different environments that can be used to asses the advantages and limitations of using dwarf Cepheids as standard candles in populations for which the metallicity is not necessarily known. The dwarf Cepheids found in Sextans have a mean period of 0.066 day and a mean g amplitude of 0.87 mag. They are located below the horizontal branch, spanning a range of 0.8 mag: 21.9<g<22.7. The number of dwarf Cepheids in Sextans is low compared with other galaxies such as Carina, which has a strong intermediate-age population. On the other hand, the number and ratio of RR Lyrae stars to dwarf Cepheids are quite similar to those of Sculptor, a galaxy which, as Sextans, is dominated by an old stellar population. The dwarf Cepheid stars found in Sextans follow a well-constrained period-luminosity relationship with an rms=0.05 mag in the g band, which was set up by anchoring to the distance modulus given by the RR Lyrae stars. Although the majority of the variable stars in Sextans are located toward the center of the galaxy, we have found two RR Lyrae stars and one anomalous Cepheid in the outskirts of the galaxy that may be extratidal stars and suggest that this galaxy may be undergoing tidal destruction. These possible extratidal variable stars share the same proper motions as Sextans, as seen by recent Gaia measurements. Two additional stars that we initially classified as foreground RR Lyrae stars may actually be other examples of Sextans extratidal anomalous Cepheids, although radial velocities are needed to prove that scenario.
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- ID:
- ivo://CDS.VizieR/J/ApJS/230/28
- Title:
- The populations of Carina. II. Abundances
- Short Name:
- J/ApJS/230/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chemical abundances are presented for 19 elements in a sample of 63 red giants in the Carina dwarf spheroidal galaxy (dSph), based on homogeneous 1D/LTE model atmosphere analyses of our own observations (32 stars) and data available in the literature (a further 31 independent stars). The (Fe) metallicity and [{alpha}/Fe] distribution functions have mean values and dispersions of -1.59 and 0.33dex ([Fe/H] range: -2.68 to -0.64) and 0.07 and 0.13dex ([{alpha}/Fe] range: -0.27 to 0.25), respectively. We confirm the finding of Venn+ (2012, J/ApJ/751/102) that a small percentage (some 10% in the present investigation) of the sample shows clear evidence for significant enrichment by Type Ia supernova (SN Ia) ejecta. Calcium, with the most accurately determined abundance of the {alpha}-elements, shows an asymmetric distribution toward smaller values of [Ca/Fe] at all [Fe/H], most significantly over -2.0<[Fe/H]<-1.0, suggestive of incomplete mixing of the ejecta of SNe Ia with the ambient medium of each of Carina's generations. Approximate color-magnitude diagram age estimates are presented for the sample, and together with our chemical abundances, compared with the results of our previous synthetic color-magnitude diagram analysis, which reported the details of Carina's four well-defined populations. We searched for the Na-O anticorrelation universally reported in the Galaxy's globular clusters and confirm that this phenomenon does not exist in Carina. We also found that one of the 32 stars in our sample has an extremely enhanced lithium abundance-A(Li)_NLTE_=+3.36, consistent with membership of the ~1% group of Li-rich stars in dSph described by Kirby+ (2012ApJ...752L..16K).
3793. The PPMXL Catalog
- ID:
- ivo://CDS.VizieR/I/317
- Title:
- The PPMXL Catalog
- Short Name:
- I/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- USNO-B1.0 (Cat. I/284) and 2MASS (Cat. II/246) are the most widely used full-sky surveys. However, 2MASS has no proper motions at all, and USNO-B1.0 published only relative, not absolute (i.e. on ICRS) proper motions. We performed a new determination of mean positions and proper motions on the ICRS system by combining USNO-B1.0 and 2MASS astrometry. This catalog is called PPMXL, and it aims to be complete from the brightest stars down to about V=20 full-sky. PPMXL contains about 900 million objects, some 410 million with 2MASS photometry, and is the largest collection of ICRS proper motions at present. As representative for the ICRS we chose PPMX. The recently released UCAC3 (Cat. I/315) could not be used because we found plate-dependent distortions in its proper motion system north of -20{deg} declination. UCAC3 served as an intermediate system for {demta}<-20{deg}. The resulting typical individual mean errors of the proper motions range from 4mas/yr to more than 10mas/yr depending on observational history. The mean errors of positions at epoch 2000.0 are 80 to 120 mas, if 2MASS astrometry could be used, 150 to 300 mas else. We also give correction tables to convert USNO-B1.0 observations of e.g. minor planets to the ICRS system.
- ID:
- ivo://CDS.VizieR/J/ApJS/199/3
- Title:
- The quasars MMT-BOSS pilot survey
- Short Name:
- J/ApJS/199/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10000deg^2^, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations (BAOs) in the distribution of Ly{alpha} absorption from the spectra of a sample of ~150000 z>2.2 quasars. Along with measuring the angular diameter distance at z~2.5, BOSS will provide the first direct measurement of the expansion rate of the universe at z>2. One of the biggest challenges in achieving this goal is an efficient target selection algorithm for quasars in the redshift range 2.2<z<3.5, where their colors tend to overlap those of the far more numerous stars. During the first year of the BOSS survey, quasar target selection (QTS) methods were developed and tested to meet the requirement of delivering at least 15 quasars/deg^2^ in this redshift range, with a goal of 20 out of 40 targets/deg^2^ allocated to the quasar survey. To achieve these surface densities, the magnitude limit of the quasar targets was set at g<=22.0 or r<=21.85. We have defined a uniformly selected subsample of 20 targets/deg^2^, for which the selection efficiency is just over 50% (~10 z>2.20 quasars/deg^2^). This "CORE" subsample will be fixed for Years Two through Five of the survey. In this paper, we describe the evolution and implementation of the BOSS QTS algorithms during the first two years of BOSS operations (through 2011 July), in support of the science investigations based on these data, and we analyze the spectra obtained during the first year. During this year, 11263 new z>2.20 quasars were spectroscopically confirmed by BOSS, roughly double the number of previously known quasars with z>2.20. Our current algorithms select an average of 15 z>2.20 quasars/deg^2^ from 40 targets/deg^2^ using single-epoch SDSS imaging.
- ID:
- ivo://CDS.VizieR/J/A+A/339/165
- Title:
- The red spectrum of HD 101065
- Short Name:
- J/A+A/339/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wavelength list for Przybylski's star (a rapidly rotation Ap star) including a measurement of the line depths.
- ID:
- ivo://CDS.VizieR/J/AJ/161/233
- Title:
- The revised TESS habitable zone catalog
- Short Name:
- J/AJ/161/233
- Date:
- 20 Jan 2022
- Publisher:
- CDS
- Description:
- In the search for life in the cosmos, NASA's Transiting Exoplanet Survey Satellite (TESS) mission has already monitored about 74% of the sky for transiting extrasolar planets, including potentially habitable worlds. However, TESS only observed a fraction of the stars long enough to be able to find planets like Earth. We use the primary mission data-the first two years of observations-and identify 4239 stars within 210pc that TESS observed long enough to see three transits of an exoplanet that receives similar irradiation to Earth: 738 of these stars are located within 30pc. We provide reliable stellar parameters from the TESS Input Catalog that incorporates Gaia DR2 and also calculate the transit depth and radial velocity semiamplitude for an Earth-analog planet. Of the 4239 stars in the Revised TESS HZ Catalog, 9 are known exoplanet hosts-GJ1061, GJ1132, GJ3512, GJ685, Kepler-42, LHS1815, L98-59, RRCae, and TOI700-around which TESS could identify additional Earth-like planetary companions. Thirty-seven additional stars host yet unconfirmed TESS Objects of Interest: three of these orbit in the habitable-zone TOI203, TOI715, and TOI2298. For a subset of 614 of the 4239 stars, TESS has observed the star long enough to be able to observe planets throughout the full temperate, habitable zone out to the equivalent of Mars orbit. Thus, the Revised TESS Habitable Zone Catalog provides a tool for observers to prioritize stars for follow-up observation to discover life in the cosmos. These stars are the best path toward the discovery of habitable planets using the TESS mission data.
- ID:
- ivo://CDS.VizieR/J/ApJ/727/9
- Title:
- The RR Lyrae population of NGC 6101
- Short Name:
- J/ApJ/727/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use V-band time-series data to analyze the RR Lyrae (RRL) population of the Galactic globular cluster NGC 6101. Using template fitting, we have discovered seven new RRL stars and confirmed 10 candidates. We find unusually long mean periods for the RRL of <P_ab_>=0.803 days and <P_c_>=0.393 days, and an atypically high ratio of n(c)/n(ab+c)=0.82. Based on our derived mean properties of the RRL, NGC 6101 is Oosterhoff type II, consistent with the cluster metallicity but intriguing with respect to its kinematics.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A112
- Title:
- The Sco OB2 population from Gaia DR2 data
- Short Name:
- J/A+A/623/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Sco OB2 association is the nearest OB association, extending over approximately 2000 square degrees on the sky. Only its brightest and most massive members are already known (from HIPPARCOS) across its entire size, while studies of its lower mass population refer only to small portions of its extent. In this work we exploit the capabilities of Gaia DR2 measurements to search for Sco OB2 members across its entire size and down to the lowest stellar masses. We used both Gaia astrometric (proper motions and parallaxes) and photometric measurements (integrated photometry and colors) to select association members, using minimal assumptions derived mostly from the HIPPARCOS studies. Gaia resolves small details in both the kinematics of individual Sco OB2 subgroups and their distribution with distance from the Sun. We developed methods to explore the 3D kinematics of a stellar population covering large sky areas. We find nearly 11000 pre-main-sequence (PMS) members of Sco OB2 (with less than 3% field-star contamination), plus ~3600 main-sequence (MS) candidate members with a larger (10-30%) field-star contamination. A higher confidence subsample of ~9200 PMS (and ~1340 MS) members is also selected (<1% contamination for the PMS), however this group is affected by larger (~15%) incompleteness. We separately classify stars in compact and diffuse populations. Most members belong to one of several kinematically distinct diffuse populations, whose ensemble clearly outlines the shape of the entire association. Upper Sco is the densest region of Sco OB2. It is characterized by a complex spatial and kinematical structure and has no global pattern of motion. Other dense subclusters are found in Lower Centaurus-Crux and in Upper Centaurus-Lupus; the richest example of the latter, which has been recently identified, is coincident with the group near V1062 Sco. Most of the clustered stars appear to be younger than the diffuse PMS population, suggesting star formation in small groups that rapidly disperse and are diluted, reaching space densities lower than field stars while keeping memory of their original kinematics. We also find that the open cluster IC 2602 has a similar dynamics to Sco OB2, and its PMS members are currently evaporating and forming a diffuse (size~10{deg}) halo around its double-peaked core.
- ID:
- ivo://CDS.VizieR/VII/260
- Title:
- The SDSS-DR7 quasar catalog
- Short Name:
- VII/260
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the fifth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog, which is based upon the SDSS Seventh Data Release. The catalog, which contains 105783 spectroscopically confirmed quasars, represents the conclusion of the SDSS-I and SDSS-II quasar survey. The catalog consists of the SDSS objects that have luminosities larger than M_i_=-22.0 (in a cosmology with H_0_=70km/s/Mpc, {Omega}_M_=0.3, and {Omega}_{Lambda}=0.7), have at least one emission line with FWHM larger than 1000km/s or have interesting/complex absorption features, are fainter than i~15.0, and have highly reliable redshifts. The catalog covers an area of ~9380deg^2^. The quasar redshifts range from 0.065 to 5.46, with a median value of 1.49; the catalog includes 1248 quasars at redshifts greater than 4, of which 56 are at redshifts greater than 5. The catalog contains 9210 quasars with i<18; slightly over half of the entries have i<19. For each object the catalog presents positions accurate to better than 0.1"rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200{AA} at a spectral resolution of ~2000; the spectra can be retrieved from the SDSS public database using the information provided in the catalog. Over 96% of the objects in the catalog were discovered by the SDSS. We also include a supplemental list of an additional 207 quasars with SDSS spectra whose archive photometric information is incomplete.
3800. The SDSS extended PSFs
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/5317
- Title:
- The SDSS extended PSFs
- Short Name:
- J/MNRAS/491/5317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A robust and extended characterization of the Point Spread Function (PSF) is crucial to extract the photometric information produced by deep imaging surveys. Here we present the extended PSFs of the Sloan Digital Sky Survey (SDSS), one of the most productive astronomical surveys of all time. By stacking ~1000 images of individual stars with different brightness, we obtain the bidimensional SDSS PSFs extending over 8 arcmin in radius for all the SDSS filters (u, g, r, i, z). This new characterization of the SDSS PSFs is near a factor of 10 larger in extension than previous PSFs characterizations of the same survey. We found asymmetries in the shape of the PSFs caused by the drift scanning observing mode. The flux of the PSFs is larger along the drift scanning direction. Following a reproducible science philosophy, we make all the PSF models and the used tools publicly available. Finally, we illustrate with an example how the PSF models can be used to remove the scattered light field produced by the brightest stars in the Coma Cluster central region. This particular example shows the huge importance of PSFs in the study of the low surface brightness Universe, especially with the upcoming of ultra-deep surveys such as the Large Synoptic Survey Telescope (LSST).
