- ID:
- ivo://CDS.VizieR/J/A+A/566/A32
- Title:
- Equivalent widths of WINGS galaxies
- Short Name:
- J/A+A/566/A32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of Equivalent Width (EW) measurements of spectra from the spectroscopic follow-up of the WIde-field Nearby Galaxy-cluster Survey (WINGS).Using the Anglo Australian Telescope (AAT) and the William Herschel Telescope (WHT), we have obtained optical spectra for about 6000 galaxies selected in fields centered on 48 local (0.04<z<0.07) X-ray selected. We apply a method we have developed to automatically measure the EW of spectral lines in a robust way even in spectra with a non optimal signal to noise. This way, we derive a spectral classification reflecting the stellar content, based on the presence and strength of the [OII] (3727) and H{delta} lines.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/380/578
- Title:
- Equiv. widths of 13 horizontal branch stars
- Short Name:
- J/A+A/380/578
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution spectra of 13 core helium-burning stars in the thick disk of the Galaxy have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 22 chemical elements. Abundances of carbon were studied using the C_2_ Swan (0, 1) band head at 5635.5{AA}. The wavelength interval 7980-8130{AA} with strong CN features was analysed in order to determine nitrogen abundances and 12C/13C isotope ratios. The oxygen abundances were determined from the [O I] line at 6300{AA}. Abundances in the investigated stars suggest that carbon is depleted by about 0.3dex, nitrogen is enhanced by more than 0.4dex and oxygen is unaltered. The 12C/13C ratios are lowered and lie between values 3 and 7 which is in agreement with "cool bottom processing" predictions (Boothroyd & Sackmann, 1999ApJ...510..232B). The C/N ratios in the investigated stars are lowered to values between 0.7 and 1.2 which is less than present day theoretical predictions and call for further studies of stellar mixing processes. Abundance ratios of O, Mg, Eu and other heavy chemical elements to iron in the investigated stars show a pattern characteristic of thick disk stars. The results provide evidence that the thick disk population has a distinct chemical history from the thin disk. The onset of the bulk of SN Ia is suggested to appear at [Fe/H]~-0.6dex.
5653. EREBOS project. I.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A80
- Title:
- EREBOS project. I.
- Short Name:
- J/A+A/630/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eclipsing post-common-envelope binaries are highly important for resolving the poorly understood, very short-lived common-envelope phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare helium-burning cores of red giants that have lost almost all of their hydrogen envelope. This mass loss is often triggered by common-envelope interactions with close stellar or even substellar companions. Cool companions to hot subdwarf stars such as late-type stars and brown dwarfs are detectable from characteristic light-curve variations - reflection effects and often eclipses. In the recently published catalog of eclipsing binaries in the Galactic Bulge and in the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey, we discovered 125 new eclipsing systems showing a reflection effect seen by visual inspection of the light curves and using a machine-learning algorithm, in addition to the 36 systems previously discovered by the Optical Gravitational Lesing Experiment (OGLE) team. The Eclipsing Reflection Effect Binaries from Optical Surveys (EREBOS) project aims at analyzing all newly discovered eclipsing binaries of the HW Vir type (hot subdwarf + close, cool companion) based on a spectroscopic and photometric follow up to derive the mass distribution of the companions, constrain the fraction of substellar companions, and determine the minimum mass needed to strip off the red-giant envelope. To constrain the nature of the primary we derived the absolute magnitude and the reduced proper motion of all our targets with the help of the parallaxes and proper motions measured by the Gaia mission and compared those to the Gaia white-dwarf candidate catalog. It was possible to derive the nature of a subset of our targets, for which observed spectra are available, by measuring the atmospheric parameter of the primary, confirming that less than 10% of our systems are not sdO/Bs with cool companions but are white dwarfs or central stars of planetary nebula. This large sample of eclipsing hot subdwarfs with cool companions allowed us to derive a significant period distribution for hot subdwarfs with cool companions for the first time showing that the period distribution is much broader than previously thought and is ideally suited to finding the lowest-mass companions to hot subdwarf stars. The comparison with related binary populations shows that the period distribution of HW Vir systems is very similar to WD+dM systems and central stars of planetary nebula with cool companions. In the future, several new photometric surveys will be carried out, which will further increase the sample of this project, providing the potential to test many aspects of common-envelope theory and binary evolution.
- ID:
- ivo://CDS.VizieR/J/other/Sci/350.64
- Title:
- 51 Eri b near-infrared spectrum
- Short Name:
- J/other/Sci/350.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric composition and luminosity, which is influenced by their formation mechanism. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20Myr-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water vapor absorption. Modeling of the spectra and photometry yields a luminosity of L/LS=1.6-4.0x10^-6^ and an effective temperature of 600-750K. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold- start" core accretion process that may have formed Jupiter.
- ID:
- ivo://CDS.VizieR/J/A+A/603/A57
- Title:
- 51 Eri b SPHERE/IFS spectra & atmosphere models
- Short Name:
- J/A+A/603/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 51 Eridani b is an exoplanet around a young (20Myr) nearby (29.4pc) F0-type star, which was recently discovered by direct imaging. It is one of the closest direct imaging planets in angular and physical separation (~0.5", ~13AU) and is well suited for spectroscopic analysis using integral field spectrographs. We aim to refine the atmospheric properties of the known giant planet and to constrain the architecture of the system further by searching for additional companions. We used the extreme adaptive optics instrument SPHERE at the Very Large Telescope (VLT) to obtain simultaneous dual-band imaging with IRDIS and integral field spectra with IFS, extending the spectral coverage of the planet to the complete Y- to H-band range and providing additional photometry in the K12-bands (2.11, 2.25 micron). We present the first spectrophotometric measurements in the Y and K bands for the planet and revise its J-band flux to values 40% fainter than previous measurements. Cloudy models with uniform cloud coverage provide a good match to the data. We derive the temperature, radius, surface gravity, metallicity, and cloud sedimentation parameter fsed. We find that the atmosphere is highly super-solar ([Fe/H]~1.0), and the low fsed~1.26 value is indicative of a vertically extended, optically thick cloud cover with small sized particles. The model radius and surface gravity estimates suggest higher planetary masses of M_gravity_=9.1^+4.9^_-3.3_. The evolutionary model only provides a lower mass limit of >2M_jupiter_ (for pure hot-start). The cold-start model cannot explain the luminosity of the planet. The SPHERE and NACO/SAM detection limits probe the 51 Eri system at solar system scales and exclude brown-dwarf companions more massive than 20M_jupiter_ beyond separations of ~2.5AU and giant planets more massive than 2M_jupiter_ beyond 9 au.
- ID:
- ivo://CDS.VizieR/J/A+A/495/249
- Title:
- EROS-2 beat Cepheids in Magellanic Clouds
- Short Name:
- J/A+A/495/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a systematic search of Beat Cepheids (BC) in the Magellanic Clouds from the EROS-2 database. Observations were carried out on the MARLY telescope (ESO La Silla, Chile) between July 1996 and March 2003. A specific pipeline was developed to extract periodic light curves from the photometric data obtained with the PEIDA package (Ansari, 1996VA.....40..519A). Two different populations are identified in each Cloud: the BCs pulsating on the fundamental and first overtone modes (FO/F objects) simultaneously, and those pulsating on the first and second overtones (SO/FO objects). A Fourier analysis was performed on each light curve. We derived lower, higher and mean values of metallicities for the FO/F objects, using linear nonadiabatic convective stellar models.
- ID:
- ivo://CDS.VizieR/J/A+A/500/1027
- Title:
- EROS CMD towards 4 Galactic spiral arms fields
- Short Name:
- J/A+A/500/1027
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The EROS-2 project has been designed to search for microlensing events towards any dense stellar field. The densest parts of the Galactic spiral arms have been monitored to maximize the microlensing signal expected from the stars of the Galactic disk and bulge. 12.9 million stars have been monitored during 7 seasons towards 4 directions in the Galactic plane, away from the Galactic center.
- ID:
- ivo://CDS.VizieR/J/A+A/389/149
- Title:
- EROS II periodic stars towards Galactic spiral arm
- Short Name:
- J/A+A/389/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for variable stars in a photometric survey of a six square degree region along the Galactic plane at (l=305{deg}, b=-0.8{deg}) and (l=330{deg}, b=-2.5{deg}). This survey was performed in the framework of the EROS II (Experience de Recherche d'Objets Sombres) microlensing program. The variable stars were found among 1913576 stars that were monitored between April and June 1998 in two passbands, with an average of 60 measurements. For the periodicity search, a new method is proposed well suited when the photometric data are unevenly distributed in time, as is our case. 1362 objects whose luminosity varies were selected. Among them we identified 9 Cepheids, 19 RR Lyrae, 34 Miras, 176 eclipsing binaries and 266 Semi-Regular stars. Most of them are newly identified objects. The cross-identification with known catalogues has been performed. Our catalogue and light curves are available from our Web site (http://www.lal.in2p3.fr/recherche/eros/GSA/EROS2-GSA-periodic.html)
5659. EROs in Groth Strip
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/2246
- Title:
- EROs in Groth Strip
- Short Name:
- J/MNRAS/414/2246
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalogue of EROs from the Groth Strip and study the relation between their morphology and mass. With a selection criterion F814W-Ks>=4 and Ks<=21.0 we find 102 EROs, over a survey area of 155 arcmin2, leading to a surface density of 0.66arcmin^-2^. The photometric data include U, B, F606W, F814W, J, Ks bands. Morphologies are based on a by eye classification and we distinguish between three basic classes: compact objects, targets with a disc and/or a bulge component and irregular or merger candidates. An additional group consists of the few objects which could not be classified.
- ID:
- ivo://nasa.heasarc/erass1hard
- Title:
- eROSITA All-Sky Survey (First 6 Months) Three-Band (2.3-5.0 keV) Source Catalog
- Short Name:
- ERASS1HARD
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The eROSITA telescope array aboard the Spektrum Roentgen Gamma (SRG) satellite began surveying the sky in December 2019, with the aim of producing all-sky X-ray source lists and sky maps of an unprecedented depth. The authors present catalogs of both point-like and extended sources using the data acquired in the first six months of survey operations (eRASS1; completed June 2020) over the half sky whose proprietary data rights lie with the German eROSITA Consortium. This catalog contains all X-ray sources detected in the 2.3-5 keV band with detection likelihood > 12. The 5466 sources detected in the less sensitive but harder 2.3-5 keV band is the result of the first true imaging survey of the entire sky above 2 keV. The eRASS1 main catalog, <a href="/W3Browse/erosita/erass1main.html">eRASS1MAIN</a>, contains nearly 930000 entries detected in the most sensitive 0.2-2.3 keV energy range and the sources (only the strongly associated ones) from the main catalog have been linked to eRASS1MAIN in this catalog. The reference paper presents methods to identify and flag potential spurious sources in the catalogs, which were applied for this work, and the authors tested and validated the astrometric accuracy via cross-comparison with other X-ray and multi-wavelength catalogs. The catalogs form part of the first data release (DR1) of the SRG/eROSITA all-sky survey. Beyond the X-ray catalogs, DR1 contains all detected and calibrated event files, source products (light curves and spectra), and all-sky maps. The data files are linked to the table and also accessible from the <a href="/docs/srg/erosita/">HEASARC eROSITA</a> and <a href="https://erosita.mpe.mpg.de/dr1/">eROSITA-DE ERASS1</a> websites. The catalog uses the following designation for indicating the bands for the different measurement: <pre> Band Energy range (keV) 0 0.2 - 5.0 1 0.2 - 0.6 2 0.6 - 2.3 3 2.3 - 5.0 </pre> This database table was ingested by the HEASARC in June 2024 and is based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/682/A34">CDS Catalog J/A+A/682/A34</a> file erass1-h.dat. In some cases, the HEASARC has altered the original field names, as per HEASARC conventions, and provides the original field names in square brackets. This is a service provided by NASA HEASARC .