- ID:
- ivo://CDS.VizieR/J/MNRAS/444/2251
- Title:
- G0-G3 main-sequence stars with V<15
- Short Name:
- J/MNRAS/444/2251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The basic stellar atmospheric parameters (effective temperature, surface gravity and global metallicity) were determined simultaneously for a sample of 233 stars, limited in magnitude (V<15), with spectral types between G0 and G3 and luminosity class V (main sequence). The analysis was based on spectroscopic observations collected at the Observatorio Astrofisico Guillermo Haro and using a set of Lick-like indices defined in the spectral range 3800-4800{AA}. An extensive set of indices computed in a grid of theoretical spectra was used as a comparison tool in order to determine the photospheric parameters. The method was validated by matching the results from spectra of the asteroids Vesta and Ceres with the Sun parameters. The main results were as follows: (i) the photospheric parameters were determined for the first time for 213 objects in our sample and (ii) a sample of 20 new super-metal-rich star candidates was found.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/635/A12
- Title:
- GG Tau A ALMA ^13^CO and C^18^O(3-2) maps
- Short Name:
- J/A+A/635/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- GG Tau A is the prototype of a young triple T Tauri star that is surrounded by a massive and extended Keplerian outer disk. The central cavity is not devoid of gas and dust and at least GG Tau Aa exhibits its own disk of gas and dust emitting at millimeter wavelengths. Its observed properties make this source an ideal laboratory for investigating planet formation in young multiple solartype stars. We used new ALMA ^13^CO and C^18^O(3-2) observations obtained at high angular resolution (~0.2") together with previous CO(3-2) and (6-5) ALMA data and continuum maps at 1.3 and 0.8mm in order to determine the gas properties (temperature, density, and kinematics) in the cavity and to a lesser extent in the outer disk. By deprojecting, we studied the radial and azimuthal gas distribution and its kinematics. We also applied a new method to improve the deconvolution of the CO data and in particular better quantify the emission from gas inside the cavity. We perform local nonlocal thermodynamic equilibrium studies in order to determine the excitation conditions and relevant physical parameters inside the ring and in the central cavity. Residual emission after removing a smooth-disk model indicates unresolved structures at our angular resolution, probably in the form of irregular rings or spirals. The outer disk is cold, with a temperature <20K beyond 250au that drops quickly ({prop.to}r^-1^). The kinematics of the gas inside the cavity reveals infall motions at about 10% of the Keplerian speed. We derive the amount of gas in the cavity, and find that the brightest clumps, which contain about 10% of this mass, have kinetic temperatures 40-80K, CO column densities of a few 10^17^cm^-2^, and H_2_ densities around 10^7^cm^-3^. Although the gas in the cavity is only a small fraction of the disk mass, the mass accretion rate throughout the cavity is comparable to or higher than the stellar accretion rate. It is accordingly sufficient to sustain the circumstellar disks on a long timescale.
- ID:
- ivo://CDS.VizieR/J/MNRAS/388/500
- Title:
- GHASP: H{alpha} data cubes for 108 galaxies
- Short Name:
- J/MNRAS/388/500
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Fabry-Perot observations obtained for a new set of 108 galaxies in the frame of the Gassendi H{alpha} survey of SPirals (GHASP). The GHASP survey consists of 3D H{alpha} data cubes for 203 spiral and irregular galaxies, covering a large range in morphological types and absolute magnitudes, for kinematics analysis. The new set of data presented here completes the survey. The GHASP sample is by now the largest sample of Fabry-Perot data ever published. The analysis of the whole GHASP sample will be done in forthcoming papers. Using adaptive binning techniques based on Voronoi tessellations, we have derived H{alpha} data cubes from which are computed H{alpha} maps, radial velocity fields as well as residual velocity fields, position-velocity diagrams, rotation curves and the kinematical parameters for almost all galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/466
- Title:
- GHASP: H{alpha} data cubes for 97 galaxies
- Short Name:
- J/MNRAS/390/466
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Gassendi HAlpha survey of SPirals survey (GHASP) consists of 3D H{alpha} data cubes for 203 spiral and irregular galaxies, covering a large range in morphological types and absolute magnitudes, for kinematics analysis. It is the largest sample of Fabry-Perot data published up to now. In order to provide an homogenous sample, reduced and analysed using the same procedure, we present in this paper the new reduction and analysis for a set of 97 galaxies already published in previous papers but now using the new data reduction procedure adopted for the whole sample. The GHASP survey is now achieved and the whole sample is reduced using the adaptive binning techniques based on Voronoi tessellations. We have derived H{alpha} data cubes from which are computed H{alpha} maps, radial velocity fields as well as residual velocity fields, position-velocity diagrams, rotation curves and kinematical parameters for almost all galaxies. The rotation curves, the kinematical parameters and their uncertainties are computed homogeneously using the new method based on the power spectrum of the residual velocity field. This paper provides the kinematical parameters for the whole sample. For the first time, the integrated H{alpha} profiles have been computed and are presented for the whole sample. The total H{alpha} fluxes deduced from these profiles have been used in order to provide a flux calibration for the 203 GHASP galaxies. This paper confirms the conclusions already drawn from half the sample concerning (i) the increased accuracy of position angles measurements using kinematical data, (ii) the difficulty to have robust determinations of both morphological and kinematical inclinations in particular for low-inclination galaxies and (iii) the very good agreement between the Tully-Fisher relationship derived from our data and previous determinations found in the literature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/401/2113
- Title:
- GHASP: H{alpha} data cubes for 153 galaxies
- Short Name:
- J/MNRAS/401/2113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Due to their large distances, high-redshift galaxies are observed at a very low spatial resolution. In order to disentangle the evolution of galaxy kinematics from low-resolution effects, we have used Fabry-Perot 3D H{alpha} data cubes of 153 nearby isolated galaxies selected from the Gassendi H{alpha} survey of SPirals (GHASP) to simulate data cubes of galaxies at redshift z=1.7 using a pixel size of 0.125" and a 0.5" seeing. We have derived H{alpha} flux, velocity and velocity dispersion maps.
- ID:
- ivo://CDS.VizieR/J/ApJ/901/123
- Title:
- Ghostly damped Ly{alpha} systems in SDSS DR14
- Short Name:
- J/ApJ/901/123
- Date:
- 18 Feb 2022 09:18:37
- Publisher:
- CDS
- Description:
- We report the discovery of 59 new ghostly absorbers from the Sloan Digital Sky Survey Data Release 14. These absorbers, with z_abs_~z_QSO_, reveal no Ly{alpha} absorption, and they are mainly identified through the detection of strong metal absorption lines in the spectra. The number of such previously known systems is 30. The new systems are found with the aid of machine-learning algorithms. The spectra of 41 (out of total of 89) absorbers also cover the Ly{beta} spectral region. By fitting the damping wings of the Ly{beta} absorption in the stacked spectrum of 21 (out of 41) absorbers with relatively stronger Ly{beta} absorption, we measured an HI column density of log N(HI)=21.50. This column density is 0.5dex higher than that of the previous work. We also found that the metal absorption lines in the stacked spectrum of the 21 ghostly absorbers with stronger Ly{beta} absorption have similar properties as those in the stacked spectrum of the remaining systems. This circumstantial evidence strongly suggests that the majority of our ghostly absorbers are indeed DLAs.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/85
- Title:
- Ghostly strong Lya absorbers in SDSS DR12
- Short Name:
- J/ApJ/888/85
- Date:
- 25 Oct 2021 10:15:53
- Publisher:
- CDS
- Description:
- We have searched the Sloan Digital Sky Survey Data Release 12 for ghostly strong Ly{alpha} (DLA) systems. These systems, located at the redshift of the quasars, show strong absorption from low-ionization atomic species but reveal no HI Ly{alpha} absorption. Our search has, for the first time, resulted in a sample of 30 homogeneously selected ghostly absorbers with z_QSO_>2.0. Thirteen of the ghostly absorbers exhibit absorption from other HI Lyman series lines. The lack of Ly{alpha} absorption in these absorbers is consistent with them being dense and compact with projected sizes smaller than the broad-line region of the background quasar. Although uncertain, the estimated median HI column density of these absorbers is logN(HI)~21.0. We compare the properties of ghostly absorbers with those of eclipsing DLAs that are high-column-density absorbers, located within 1500km/s of the quasar emission redshift and showing strong Ly{alpha} emission in their DLA trough. We discover an apparent sequence in the observed properties of these DLAs, with ghostly absorbers showing wider HI kinematics, stronger absorptions from high-ionization species, CII and SiII excited states, and a higher level of dust extinction. Since we estimate that all these absorbers have similar metallicities, logZ/Z_{sun}_~-1.0, we conclude that ghostly absorbers are part of the same population as eclipsing DLAs, except that they are denser and located closer to the central active galactic nuclei.
- ID:
- ivo://CDS.VizieR/J/ApJ/731/100
- Title:
- 148GHz ACT extragalactic sources catalog
- Short Name:
- J/ApJ/731/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on extragalactic sources detected in a 455deg^2^ map of the southern sky made with data at a frequency of 148GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15mJy to 1500mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low-redshift X-ray-selected galaxy clusters. Estimates of the radio to millimeter-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (>50mJy) 148GHz selected sample with complete cross-identifications from the Australia Telescope 20GHz survey, we observe an average steepening of the spectra between 5, 20, and 148GHz with median spectral indices of {alpha}_5-20_=-0.07+/-0.06, {alpha}_20-148_=-0.39+/-0.04, and {alpha}_5-148_=-0.20+/-0.03. When the measured spectral indices are taken into account, the 148GHz differential source counts are consistent with previous measurements at 30GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20mJy is C^Sync^=(2.8+/-0.3)x10^-6^{mu}K^2^.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/27
- Title:
- 15GHz and jet properties of MOJAVE blazars
- Short Name:
- J/ApJ/742/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the Fermi Large Area Telescope {gamma}-ray and 15GHz Very Long Baseline Array radio properties of a joint {gamma}-ray and radio-selected sample of active galactic nuclei (AGNs) obtained during the first 11 months of the Fermi mission (2008 August 4-2009 July 5). Our sample contains the brightest 173 AGNs in these bands above declination -30{deg} during this period, and thus probes the full range of {gamma}-ray loudness ({gamma}-ray to radio band luminosity ratio) in the bright blazar population. The latter quantity spans at least 4 orders of magnitude, reflecting a wide range of spectral energy distribution (SED) parameters in the bright blazar population. The BL Lac objects, however, display a linear correlation of increasing {gamma}-ray loudness with synchrotron SED peak frequency, suggesting a universal SED shape for objects of this class.
- ID:
- ivo://CDS.VizieR/J/ApJ/740/59
- Title:
- 1.4GHz and X-ray sources in 12 clusters of galaxies
- Short Name:
- J/ApJ/740/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Chandra imaging spectroscopy and Very Large Array (VLA) L-band radio maps, we have identified radio sources at P_1.4GHz_>=5x10^23^W/Hz and X-ray point sources (XPSs) at L_0.3-8keV_>=5x10^42^erg/s in L>L* galaxies in 12 high-redshift (0.4<z<1.2) clusters of galaxies. The radio galaxies and XPSs in this cluster sample, chosen to be consistent with Coma Cluster progenitors at these redshifts, are compared to those found at low-z analyzed in Hart et al. (Paper I, 2009ApJ...705..854H). Within a projected radius of 1Mpc of the cluster cores, we find 17 cluster radio galaxies (11 with secure redshifts, including one luminous FR II radio source at z=0.826, and six more with host galaxy colors similar to cluster ellipticals). Within this same projected radius, we identify seven spectroscopically confirmed cluster XPSs, all with cluster red-sequence (CRS) host galaxy colors. Consistent with the results from Martini et al. (2009ApJ...701...66M), we estimate a minimum X-ray active fraction of 1.4%+/-0.8% for cluster red-sequence galaxies in high-z clusters, corresponding to an approximate 10-fold increase from 0.15%+/-0.15% at low-z. Although complete redshift information is lacking for several XPSs in z>0.4 cluster fields, the increased numbers and luminosities of the CRS radio galaxies and XPSs suggest a substantial (9-10-fold) increase in the heat injected into high-redshift clusters by AGNs compared to the present epoch.