- ID:
- ivo://CDS.VizieR/J/ApJ/902/127
- Title:
- Bright Gaia white dwarfs with unWISE photometry
- Short Name:
- J/ApJ/902/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of excess infrared radiation around white dwarfs provide important constraints on the evolution of planetary systems and low-mass companions beyond the main-sequence stage. In this paper series, we focus on identifying and characterizing bright white dwarfs with an infrared excess. Here, we present 188 infrared excess candidates from Gaia and unWISE, 147 of which are new discoveries. Further characterization of this sample can significantly increase the current list of white dwarf debris disks and white dwarfs with low-mass companions.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/2018
- Title:
- 6 bright Galactic Cepheids data
- Short Name:
- J/MNRAS/430/2018
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of photometric and spectroscopic data of six bright Galactic Cepheids: GH Carinae, V419 Centauri, V898 Centauri, AD Puppis, AY Sagittarii and ST Velorum. Based on new radial velocity data (in some cases supplemented with earlier data available in the literature), these Cepheids have been found to be members in spectroscopic binary systems. V898 Cen turned out to have one of the largest orbital radial velocity amplitude (>40km/s) among the known binary Cepheids. The data are insufficient to determine the orbital periods nor other orbital elements for these new spectroscopic binaries. These discoveries corroborate the statement on the high frequency of occurrence of binaries among the classical Cepheids, a fact to be taken into account when calibrating the period-luminosity relationship for Cepheids. We have also compiled all available photometric data that revealed that the pulsation period of AD Pup, the longest period Cepheid in this sample, is continuously increasing with {Delta}P=0.004567d/century, likely to be caused by stellar evolution. The wave-like pattern superimposed on the parabolic O-C graph of AD Pup may well be caused by the light-time effect in the binary system. ST Vel also pulsates with a continuously increasing period. The other four Cepheids are characterized with stable pulsation periods in the last half century.
- ID:
- ivo://CDS.VizieR/J/AJ/138/251
- Title:
- Bright Galactic stars with 24um excesses
- Short Name:
- J/AJ/138/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optically bright Galactic stars (V<~13mag) having f_nu_(24um)>1mJy are identified in Spitzer mid-infrared surveys within 8.2deg^2^ for the Bootes field of the NOAO Deep Wide-Field Survey and within 5.5deg^2^ for the First Look Survey (FLS). One hundred and twenty-eight stars are identified in Bootes and 140 in the FLS, and their photometry is given. (K-[24]) colors are determined using K magnitudes from the Two Micron All Sky Survey for all stars in order to search for excess 24um luminosity compared to that arising from the stellar photosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/339/34
- Title:
- Bright galaxies from the WENSS minisurvey
- Short Name:
- J/A+A/339/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for bright galaxies associated with radio sources from the Westerbork Northern Sky Survey (WENSS) minisurvey has been carried out. A galaxy counterpart was found for 402 of almost 10,000 radio sources. Of these a radio and optically complete sample, with a flux density limit at 325MHz of 30mJy and a limiting red magnitude of 16, can be constructed, which contains 119 galaxies. This paper is the first step of a more general study, in which we aim to derive a bright galaxy sample from the entire WENSS survey (which is now available in the public domain) and thus to construct practically definitive local radio luminosity functions of elliptical and spiral galaxies. We briefly describe the WENSS minisurvey, and the steps that are needed for the optical identification of its radio sources. Due to the large numbers of sources involved (over 200,000) completely automated procedures are obviously needed and we discuss these in some detail. It is shown that with modern utilities projects as described here have become quite feasible. Some results (e.g. a preliminary determination of the local radio luminosity function) are presented.
- ID:
- ivo://CDS.VizieR/J/A+A/487/453
- Title:
- Bright galaxies in 5 medium redshift clusters. I.
- Short Name:
- J/A+A/487/453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from five clusters of galaxies within the redshift range 0.15<=z<=0.25, imaged with the Nordic Optical Telescope (NOT) in the central ~1Mpc^2^ in very good seeing conditions, we have performed an exhaustive inspection of their bright galaxy population. That range of redshift, where only a small amount of data with the required resolution and quality is available, is particularly important for the understanding of the formation and evolution of clusters of galaxies. We have inspected the color-magnitude relation (CMR) for those clusters and measured the blue fraction of galaxies in their cores to check for evidence of evolution as found in other works. Visual classification of the galaxy morphology has been performed and the morphology-radius relation examined.
- ID:
- ivo://CDS.VizieR/J/MNRAS/466/1019
- Title:
- Bright HMXBs in THINGS galaxies
- Short Name:
- J/MNRAS/466/1019
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a spectral analysis of bright Chandra X-ray sources located in 27 nearby galaxies and maps of star-formation rate (SFR) and ISM surface densities for these galaxies, we constructed the intrinsic X-ray luminosity function (XLF) of luminous high-mass X-ray binaries (HMXBs), taking into account absorption effects and the diversity of HMXB spectra. The XLF per unit SFR can be described by a power law dN/dlogL=2.0(L/10^39^erg/s)^(-0.6)^(M_{sun}_/yr)^-1^ from L=10^38^ to 10^40.5^erg/s, where L is the unabsorbed luminosity at 0.25-8 keV. The intrinsic number of luminous HMXBs per unit SFR is a factor of ~2.3 larger than the observed number reported before. The intrinsic XLF is composed of hard, soft and supersoft sources (defined here as those with the 0.25-2keV to 0.25-8keV flux ratio of <0.6, 0.6-0.95 and >0.95, respectively) in ~2:1:1 proportion. We also constructed the intrinsic HMXB XLF in the soft X-ray band (0.25-2keV). Here, the numbers of hard, soft and supersoft sources prove to be nearly equal. The cumulative present-day 0.25-2 keV emissivity of HMXBs with luminosities between 10^38^ and 10^40.5^erg/s is ~5x10^39^erg/s(M_{sun}_/yr)^-1^, which may be relevant for studying the X-ray preheating of the early Universe.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A159
- Title:
- Bright Lyman-alpha emitters in MUSE/COSMOS field
- Short Name:
- J/A+A/633/A159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search for the presence of bright Ly-alpha emitters among Spitzer SMUVS galaxies at z>2.9 making use of homogeneous MUSE spectroscopic data. Although these data only cover a small region of COSMOS, MUSE has the unique advantage of providing spectral information over the entire field, without the need of target pre-selection. This results in an unbiased detection of all the brightest Ly-alpha emitters among the SMUVS sources, which by design are stellar-mass selected galaxies. Within the studied area, ~14% of the SMUVS galaxies at z>2.9 have Ly-alpha fluxes F_{lambda}_>~7x10^-18^erg/s/cm^2^. These Ly-alpha emitters are characterized by three types of emission, 47% show a single line profile, 19% present a double peak or a blue bump and 31% show a red tail. One object (3%) shows both a blue bump and a red tail. We also investigate the spectral energy distribution (SED) properties of the SMUVS galaxies which are MUSE detected and which are not. After stellar-mass matching both populations, we find that the MUSE detected galaxies have generally lower extinction than SMUVS-only objects, while there is no clear intrinsic difference in the mass and age distributions of the two samples. For the MUSE-detected SMUVS galaxies, we compare the instantaneous SFR lower limit obtained from the Ly-alpha line with its past average derived from SED fitting, and find evidence for rejuvenation in some of our oldest objects. In addition, we study the spectra of those Ly-alpha emitters which are not detected in SMUVS in the same field. We find that the emission line profile shown are 67% a single line, 3% a blue bump and 20% a red tail profile. The difference in profile distribution could be ascribed to the fainter Ly-alpha luminosities of the MUSE sources not detected in SMUVS and an intrinsically different mass distribution. Finally, we search for the presence of galaxy associations using the spectral redshifts. MUSE's integral coverage reveals that these associations are 20 times more likely than what is derived from all the other existing spectral data in COSMOS, which is biased by target pre-selection.
- ID:
- ivo://nasa.heasarc/mdwarfasc
- Title:
- Bright M Dwarf All-Sky Catalog
- Short Name:
- MDWARFASC
- Date:
- 25 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains an all-sky catalog of M dwarf stars with apparent infrared magnitude J < 10. The 8889 stars are selected from the ongoing SUPERBLINK survey of stars with proper motion mu > 40 mas yr<sup>-1</sup>, supplemented on the bright end with the Tycho-2 catalog. Completeness tests which account for kinematic (proper motion) bias suggest that this catalog represents ~75% of the estimated ~11,900 M dwarfs with J < 10 expected to populate the entire sky. The catalog is, however, significantly more complete for the northern sky (~90%) than it is for the south (~60%). Stars are identified as cool, red M dwarfs from a combination of optical and infrared color cuts, and are distinguished from background M giants and highly reddened stars using either existing parallax measurements or, if such measurements are lacking, using their location in an optical-to-infrared reduced proper motion diagram. These bright M dwarfs are all prime targets for exoplanet surveys using the Doppler radial velocity or transit methods; the combination of low-mass and bright apparent magnitude should make possible the detection of Earth-size planets on short-period orbits using currently available techniques. Parallax measurements, when available, and photometric distance estimates are provided for all stars, and these place most systems within 60 pc of the Sun. Spectral type estimated from V-J color shows that most of the stars range from K7 to M4, with only a few late M dwarfs, all within 20 pc. Proximity to the Sun also makes these stars good targets for high-resolution exoplanet imaging searches, especially if younger objects can be identified on the basis of X-ray or UV excess. For that purpose, we include X-ray flux from ROSAT and FUV/NUV ultraviolet magnitudes from GALEX for all stars for which a counterpart can be identified in those catalogs. Additional photometric data include optical magnitudes from Digitized Sky Survey plates and infrared magnitudes from the Two Micron All Sky Survey. This table was first created by the HEASARC in October 2011 based on electronic versions of Tables 1 and 2 from the reference paper which were obtained from the AJ web site. A slightly revised version based on corrected versions of the input tables received from the author was ingested in December 2011. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/ApJ/652/1585
- Title:
- Bright metal-poor stars from HES survey
- Short Name:
- J/ApJ/652/1585
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 1777 bright (9<B<14) metal-poor candidates selected from the Hamburg/ESO Survey (HES). Despite saturation effects present in the red portion of the HES objective-prism spectra, the data were recoverable and quantitative selection criteria could be applied to select the sample. Analyses of medium-resolution (~2{AA}) follow-up spectroscopy of the entire sample, obtained with several 24m class telescopes, yielded 145 new metal-poor stars with metallicity [Fe/H]<-2.0, of which 79 have [Fe/H]<-2.5 and 17 have [Fe/H]<-3.0. We also obtained C/Fe estimates for all of these stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/81
- Title:
- Bright metal-poor stars from HES Survey. II.
- Short Name:
- J/ApJ/835/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtain estimates of stellar atmospheric parameters for a previously published sample of 1777 relatively bright (9<B<14) metal-poor candidates from the Hamburg/ESO Survey. The original Frebel+ (2006, J/ApJ/652/1585; Paper I) analysis of these stars was able to derive estimates of [Fe/H] and [C/Fe] only for a subset of the sample, due to limitations in the methodology then available. A new spectroscopic analysis pipeline has been used to obtain estimates of T_eff_, logg, [Fe/H], and [C/Fe] for almost the entire data set. This sample is very local-about 90% of the stars are located within 0.5kpc of the Sun. We consider the chemodynamical properties of these stars in concert with a similarly local sample of stars from a recent analysis of the Bidelman and MacConnell "weak metal" candidates by Beers+ (2014, J/ApJ/794/58). We use this combined sample to identify possible members of the halo stream of stars suggested by Helmi+ (1999Natur.402...53H) and Chiba & Beers (2000AJ....119.2843C), as well as stars that may be associated with stripped debris from the putative parent dwarf of the globular cluster Omega Centauri, suggested to exist by previous authors. We identify a clear increase in the cumulative frequency of carbon-enhanced metal-poor (CEMP) stars with declining metallicity, as well as an increase in the fraction of CEMP stars with distance from the Galactic plane, consistent with previous results. We also identify a relatively large number of CEMP stars with kinematics consistent with the metal-weak thick-disk population, with possible implications for its origin.
