- ID:
- ivo://CDS.VizieR/J/ApJ/899/62
- Title:
- Stellar parameters from the 1st release of the MaSTar
- Short Name:
- J/ApJ/899/62
- Date:
- 14 Mar 2022 07:12:49
- Publisher:
- CDS
- Description:
- We report the stellar atmospheric parameters for 7503 spectra contained in the first release of the Mapping Nearby Galaxies at Apache Point Observatory survey (MaNGA) stellar library (MaStar) in Sloan Digital Sky Survey DR15. The first release of MaStar contains 8646 spectra measured from 3321 unique stars, each covering the wavelength range 3622-10354{AA} with a resolving power of R~1800. In this work, we first determined the basic stellar parameters: effective temperature (Teff), surface gravity (logg), and metallicity ([Fe/H]), which best fit the data using an empirical interpolator based on the Medium-resolution Isaac Newton Telescope library of empirical spectra (MILES), as implemented by the University of Lyon Spectroscopic analysis Software package. While we analyzed all 8646 spectra from the first release of MaStar, since MaStar has a wider parameter-space coverage than MILES, not all of these fits are robust. In addition, not all parameter regions covered by MILES yield robust results, likely due to the nonuniform coverage of the parameter space by MILES. We tested the robustness of the method using the MILES spectra itself and identified a proxy based on the local density of the training set. With this proxy, we identified 7503 MaStar spectra with robust fitting results. They cover the range from 3179 to 20517K in effective temperature (Teff), from 0.40 to 5.0 in surface gravity (logg), and from -2.49 to +0.73 in metallicity ([Fe/H]).
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/581/A28
- Title:
- Stellar X-ray flares from the 2XMM catalog
- Short Name:
- J/A+A/581/A28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a uniform, large-scale survey of X-ray flare emission, based on the XMM-Newton Serendipitous Source Catalogue and its associated data products. Our survey comprises both XMM-targeted active stars and those observed serendipitously in the field-of-view of each observation. The 2XMM Catalogue and the associated time-series ('light-curve') data products have been used as the basis for the survey of X-ray flares from cool stars in the Hipparcos Tycho-2 catalogue. Our sample contains ~130 flares with well-observed profiles; they originate from ~70 stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/725/480
- Title:
- Stellar X-ray sources in the COSMOS survey
- Short Name:
- J/ApJ/725/480
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the X-ray properties of a sample of solar- and late-type field stars identified in the Chandra Cosmic Evolution Survey (COSMOS), a deep (160ks) and wide (~0.9deg^2^) extragalactic survey. The sample of 60 sources was identified using both morphological and photometric star/galaxy separation methods. We determine X-ray count rates, extract spectra and light curves, and perform spectral fits to determine fluxes and plasma temperatures. Complementary optical and near-IR photometry is also presented and combined with spectroscopy for 48 of the sources to determine spectral types and distances for the sample. We find distances ranging from 30pc to ~12kpc, including a number of the most distant and highly active stellar X-ray sources ever detected. Overall the sample is typically more luminous than the active Sun, representing the high-luminosity end of the disk and halo X-ray luminosity functions. The halo population appears to include both low-activity spectrally hard sources that may be emitting through thermal bremsstrahlung, as well as a number of highly active sources in close binaries.
- ID:
- ivo://CDS.VizieR/II/218
- Title:
- Sternberg Supernova Catalogue
- Short Name:
- II/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue presents the main data on 1362 extragalactic supernovae (SNe) discovered up to July 13, 1998 and on their parent galaxies. SNe are ordered by Right Ascension of their parent galaxies. Data for parent galaxies were compiled from the following catalogues: RC3 (de Vaucouleurs et al., 1991, Cat. <VII/155>); UGC (Nilson, 1973. Cat. <VII/26>); PGC (Paturel et al., 1989, Cat. <VII/119>); MCG (Vorontsov-Velyaminov et al., 1962-1968, Cat. <VII/62>, <VII/100>); ESO (Lauberts, 1982, Cat. <VII/34>); CfA (Huchra et al., 1994, see Cat <VII/193>), and from van den Bergh (1994, Cat. <J/ApJS/92/219>). Main source of morphological types, major diameters and axial ratios was the RC3; the data from other sources have been reduced to the system of RC3. Photographic magnitudes of galaxies were adopted from the UGC and the PGC together with individual data from the literature. The sources of recession velocities or cz values were the RC3, the CfA, the PGC and IAU Circulars. Position angles were taken from the RC3, UGC and the ESO catalogues, and inclination angles were mainly derived from data in RC3 according to Holmberg (1958MeLu2.136....1H). Some data for SNe and parent galaxies were adopted from GCVS (Samus et al., 1995, Cat. <II/205>)
- ID:
- ivo://CDS.VizieR/II/256
- Title:
- Sternberg Supernova Catalogue, 2004 version
- Short Name:
- II/256
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the Sternberg Astronomical Institute (SAI) catalog of supernovae. We show that the radial distributions of type-Ia, type-Ibc and type-II supernovae differ in the central parts of spiral galaxies and are similar in their outer regions, while the radial distribution of type-Ia supernovae in elliptical galaxies differs that in spiral and lenticular galaxies. We give a list a supernovae that are farthest from the galactic centers, estimate their relative expulsion rate, and discuss their possible origins.
- ID:
- ivo://CDS.VizieR/J/MNRAS/480/707
- Title:
- Stripe 82 1-2 GHz VLA Snapshot Survey
- Short Name:
- J/MNRAS/480/707
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have combined spectroscopic and photometric data from the Sloan Digital Sky Survey with 1.4GHz radio observations, conducted as part of the Stripe 82 1-2GHz Snapshot Survey using the Karl G. Jansky Very Large Array, which covers ~100 sq deg, to a flux limit of 88uJy rms. Cross-matching the 11768 radio source components with optical data via visual inspection results in a final sample of 4794 cross-matched objects, of which 1996 have spectroscopic redshifts and 2798 objects have photometric redshifts. Three previously undiscovered giant radio galaxies were found during the cross-matching process, which would have been missed using automated techniques. For the objects with spectroscopy, we separate radio-loud active galactic nuclei (AGN) and star-forming galaxies (SFGs) using three diagnostics and then further divide our radio-loud AGN into the high and low excitation radio galaxy (HERG and LERG) populations. A control-matched sample of HERGs and LERGs, matched on stellar mass, redshift, and radio luminosity, reveals that the host galaxies of LERGs are redder and more concentrated than HERGs. By combining with near-infrared data, we demonstrate that LERGs also follow a tight K-z relationship. These results imply the LERG populations are hosted by population of massive, passively evolving early-type galaxies. We go on to show that HERGs, LERGs, quasars, and SFGs in our sample all reside in different regions of a Wide-field Infrared Survey Explorer colour-colour diagram. This cross-matched sample bridges the gap between previous 'wide but shallow' and 'deep but narrow' samples and will be useful for a number of future investigations.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/17
- Title:
- Strong DES lens candidates from neural networks
- Short Name:
- J/ApJS/243/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search Dark Energy Survey (DES) Year 3 imaging for galaxy-galaxy strong gravitational lenses using convolutional neural networks, extending previous work with new training sets and covering a wider range of redshifts and colors. We train two neural networks using images of simulated lenses, then use them to score postage-stamp images of 7.9 million sources from DES chosen to have plausible lens colors based on simulations. We examine 1175 of the highest-scored candidates and identify 152 probable or definite lenses. Examining an additional 20000 images with lower scores, we identify a further 247 probable or definite candidates. After including 86 candidates discovered in earlier searches using neural networks and 26 candidates discovered through visual inspection of blue-near-red objects in the DES catalog, we present a catalog of 511 lens candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/894/78
- Title:
- Strong gravitational lenses from DECaLS
- Short Name:
- J/ApJ/894/78
- Date:
- 03 Dec 2021 00:50:48
- Publisher:
- CDS
- Description:
- We perform a semi-automated search for strong gravitational lensing systems in the 9000 deg2 Dark Energy Camera Legacy Survey (DECaLS), part of the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys. The combination of the depth and breadth of these surveys are unparalleled at this time, making them particularly suitable for discovering new strong gravitational lensing systems. We adopt the deep residual neural network architecture developed by Lanusse+ (2018MNRAS.473.3895L) for the purpose of finding strong lenses in photometric surveys. We compile a training sample that consists of known lensing systems in the Legacy Surveys and the Dark Energy Survey as well as non-lenses in the footprint of DECaLS. In this paper we show the results of applying our trained neural network to the cutout images centered on galaxies typed as ellipticals in DECaLS. The images that receive the highest scores (probabilities) are visually inspected and ranked. Here we present 335 candidate strong lensing systems, identified for the first time.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/185
- Title:
- Strong-lensing systems from 4 surveys
- Short Name:
- J/ApJ/806/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we assemble a catalog of 118 strong gravitational lensing systems from the Sloan Lens ACS Survey (SLACS), BOSS emission-line lens survey (BELLS), Lens Structure and Dynamics (LSD), and Strong Lensing Legacy Survey (SL2S) and use them to constrain the cosmic equation of state. In particular, we consider two cases of dark energy phenomenology: the XCDM model, where dark energy is modeled by a fluid with constant w equation-of-state parameter, and in the Chevalier-Polarski-Linder (CPL) parameterization, where w is allowed to evolve with redshift, w(z)=w_0_+w_1_(z/1+z). We assume spherically symmetric mass distribution in lensing galaxies, but we relax the rigid assumption of the SIS model in favor of a more general power-law index {gamma}, also allowing it to evolve with redshifts {gamma}(z). Our results for the XCDM cosmology show agreement with values (concerning both w and {gamma} parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with {gamma}(z). The resulting confidence regions for the parameters are much better than those obtained with a similar method in the past. They are also showing a trend of being complementary to the Type Ia supernova data. Our analysis demonstrates that strong gravitational lensing systems can be used to probe cosmological parameters like the cosmic equation of state for dark energy. Moreover, they have a potential to judge whether the cosmic equation of state evolved with time or not.
- ID:
- ivo://CDS.VizieR/J/ApJ/739/L44
- Title:
- Structural data for galaxies between 0.2<z<2.7
- Short Name:
- J/ApJ/739/L44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the size growth seen in early-type galaxies over 10Gyr of cosmic time. Our analysis is based on a homogeneous synthesis of published data from 16 spectroscopic surveys observed at similar spatial resolution, augmented by new measurements for galaxies in the Gemini Deep Deep Survey. In total, our sample contains structural data for 465 galaxies (mainly early-type) in the redshift range 0.2<z<2.7. The size evolution of passively evolving galaxies over this redshift range is gradual and continuous, with no evidence for an end or change to the process around z~1, as has been hinted at by some surveys which analyze subsets of the data in isolation. The size growth appears to be independent of stellar mass, with the mass-normalized half-light radius scaling with redshift as R_e_{propto}(1+z)^-1.62+/-0.34^. Surprisingly, this power law seems to be in good agreement with the recently reported continuous size evolution of UV-bright galaxies in the redshift range z~0.5-3.5. It is also in accordance with the predictions from recent theoretical models.
