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251. EPOCH Project. EROS-2 LMC periodic variables
ID:
ivo://CDS.VizieR/J/A+A/566/A43
Title:
EPOCH Project. EROS-2 LMC periodic variables
Short Name:
J/A+A/566/A43
Date:
21 Oct 2021
Publisher:
CDS
Description:
The EPOCH (EROS-2 periodic variable star classification using machine learning) project aims to detect periodic variable stars in the EROS-2 light curve database. In order to classify these variables, we first build a training set by compiling known variables in the Large Magellanic Could area from the OGLE and MACHO surveys. We crossmatch these variables with the EROS-2 sources and extract 22 variability features from 28,392 light curves of the corresponding EROS-2 sources. We then use Random Forests to classify the EROS-2 sources in the training set. We design the model to separate not only Delta Scuti stars, RR Lyraes, Cepheids, eclipsing binaries and long-period variables, the "superclasses", but also their subclasses, such as RRab, RRc, RRd and RRe for RR Lyraes, and similarly for the other variable types. We apply the trained model to the entire EROS-2 LMC database containing about 29 million sources and find 117,234 periodic variable candidates. Out of these 117,234 periodic variables, 55,285 have not been discovered by either OGLE or MACHO variability studies. This set comprises 1906 Delta Scuti stars, 6,607 RR Lyraes, 638 Cepheids, 178 Type II Cepheids, 34,562 eclipsing binaries and 11,394 long-period variables.
252. Epsilon Indi Ba and Bb IR spectra
ID:
ivo://CDS.VizieR/J/A+A/510/A99
Title:
Epsilon Indi Ba and Bb IR spectra
Short Name:
J/A+A/510/A99
Date:
21 Oct 2021
Publisher:
CDS
Description:
The discovery of epsilon Indi Ba, Bb, a binary brown dwarf system very close to the Sun, makes possible a concerted campaign to characterise the physical parameters of two T dwarfs. Recent observations suggest substellar atmospheric and evolutionary models may be inconsistent with observations, but there have been few conclusive tests to date. We therefore aim to characterise these benchmark brown dwarfs to place constraints on such models. We have obtained high angular resolution optical, near-infrared, and thermal-infrared imaging and medium-resolution (up to R~5000) spectroscopy of epsilon Indi Ba, Bb with the ESO VLT and present VRIzJHKL'M' broad-band photometry and 0.63-5.1 micron spectroscopy of the individual components. The photometry and spectroscopy of the two partially blended sources were extracted with a custom algorithm. Furthermore, we use deep AO-imaging to place upper limits on the (model-dependent) mass of any further system members. We derive luminosities of log L/L_{sun}=-4.699+/-0.017 and -5.232+/-0.020 for epsilon Indi Ba, Bb, respectively, and using the dynamical system mass and COND03 evolutionary models predict a system age of 3.7-4.3Gyr, in excess of previous estimates and recent predictions from observations of these brown dwarfs. Moreover, the effective temperatures of 1352-1385K and 976-1011K predicted from the COND03 evolutionary models, for epsilon Indi Ba and Bb respectively, are in disagreement with those derived from the comparison of our data with the BT-Settl atmospheric models where we find effective temperatures of 1300-1340K and 880-940K, for epsilon Indi Ba and Bb respectively, with surface gravities of logg=5.25 and 5.50. Finally, we show that spectroscopically determined effective temperatures and surface gravities for ultra-cool dwarfs can lead to underestimated masses even where precise luminosity constraints are available.
253. Equivalent widths of cool stars
ID:
ivo://CDS.VizieR/J/A+A/549/A129
Title:
Equivalent widths of cool stars
Short Name:
J/A+A/549/A129
Date:
21 Oct 2021
Publisher:
CDS
Description:
The near-infrared (NIR) wavelength range offers some unique spectral features, and it is less prone to the extinction than the optical one. Recently, the first flux calibrated NIR library of cool stars from the NASA Infrared Telescope Facility (IRTF) have become available, and it has not been fully exploited yet. We want to develop spectroscopic diagnostics for stellar physical parameters based on features in the wavelength range 1-5um. In this work we test the technique in the I and K bands. The study of the Y, J, H, and L bands will be presented in the following paper. An objective method for semi-empirical definition of spectral features sensitive to various physical parameters is applied to the spectra. It is based on sensitivity map - i.e., derivative of the flux in the spectra with respect to the stellar parameters at a fixed wavelength. New optimized indices are defined and their equivalent widths (EWs) are measured.
254. Equivalent widths of two post-AGB stars
ID:
ivo://CDS.VizieR/J/A+A/417/269
Title:
Equivalent widths of two post-AGB stars
Short Name:
J/A+A/417/269
Date:
21 Oct 2021
Publisher:
CDS
Description:
In an effort to extend the still limited sample of s-process enriched post-AGB stars, high-resolution, high signal-to-noise VLT+UVES spectra of the optical counterparts of the infrared sources IRAS 06530-0213 and IRAS 08143-4406 were analysed.
255. 51 Eri b near-infrared spectrum
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.
256. 51 Eri b SPHERE/IFS spectra & atmosphere models
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.
257. 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.
258. ESO 1D reduced spectra
ID:
ivo://eso.org/ssap
Title:
ESO 1D reduced spectra
Short Name:
ESO SSAP
Date:
29 Mar 2022 09:14:37
Publisher:
European Southern Observatory
Description:
The ESO Simple Spectral Access service provides access to the 1D reduced spectra generated either by the principal investigators of ESO observations, or by an unattended ESO processing-pipeline that makes use of certified master calibrations. The spectra are FITS files adhering to the ESO Science Data Product standard, based on the Virtual Observatory Spectral Data Model standard (v1.0 for some spectra, and v2.0 for some others, use the VOCLASS FITS keyword to discern the two).
259. ESO TAP_CAT: a TAP service to query the astronomical catalogs generated by ESO observers, including the catalogs of the ESO Public Surveys.
ID:
ivo://eso.org/tap_cat
Title:
ESO TAP_CAT: a TAP service to query the astronomical catalogs generated by ESO observers, including the catalogs of the ESO Public Surveys.
Short Name:
ESO TAP_CAT
Date:
26 Jun 2024 14:26:53
Publisher:
European Southern Observatory
Description:
TAP_CAT is the ESO Science Archive service that provides programmatic access onto the astronomical catalogues produced by the principal investigators of ESO programmes. The Table Access Protocol (TAP) lets you execute queries against our astronomical catalogues. The queries must adhere to the Astronomical Data Query Language (ADQL, IVOA standard). Table Upload is not currently supported, though it is foreseen for a next release. This service provides limited support for spatial queries; only CONTAINS and CIRCLE are supported, as in this example: CONTAINS(point('', catalog_rightascension, catalog_declination), CIRCLE('', user_defined_rightascension, user_defined_declination, userdefined_radius))= 1. Please note that CONTAINS(...)=0 is not supported. A sister service (Catalog Facility: https://www.eso.org/qi) provides a web interface to the same collection of catalogues; the web interface implements a well-defined but limited query model, while instead TAP_CAT provides full ADQL support, allowing users to build their own query constraints using expressions, combining different columns, or using boolean operators (NOT, OR, etc.). A sibling service (TAP_OBS, endpoint: http://archive.eso.org/tap_obs) exists and can be used to query the raw and reduced data, and the atmospheric measurements taken at the La Silla Paranal Observatory (including APEX).
260. ESO TAP_OBS: a TAP service to browse and access raw and reduced data, and to query the ambient measurements, of the La Silla Paranal Observatory.
ID:
ivo://eso.org/tap_obs
Title:
ESO TAP_OBS: a TAP service to browse and access raw and reduced data, and to query the ambient measurements, of the La Silla Paranal Observatory.
Short Name:
ESO TAP_OBS
Date:
27 Nov 2024 10:24:04
Publisher:
European Southern Observatory
Description:
TAP_OBS is the ESO Science Archive TAP endpoint for observations (raw and reduced data) and ambient measurements (atmospheric seeing, turbulence, water vapour, relative humidity, air pressure, etc.) taken at the La Silla Paranal Observatory, including the Chajnantor (APEX) data. The Table Access Protocol (TAP) lets you execute queries against our database tables, and inspect various metadata. Table Upload is not currently supported, though it is foreseen for a next release. The IVOA ObsCore standard service is also provided (table name: ivoa.ObsCore), but currently only for reduced data. Other tables exposed are the dbo.raw describing all the LPO observations, the ambient tables (in the asm schema), plus the provenance table to close the loop between the raw and the reduced data, but also to describe the relationships between reduced data (e.g. a source table originating from a reduced image, etc.). A sibling service (TAP_CAT, endpoint: https://archive.eso.org/tap_cat) exists and can be used to query the astronomical catalogs produced by the principal investigators of ESO programmes (ESO public surveys included).