- ID:
- ivo://CDS.VizieR/J/ApJS/106/1
- Title:
- EFAR cluster and galaxy selection
- Short Name:
- J/ApJS/106/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The EFAR project is a study of 736 candidate elliptical galaxies in 84 clusters lying in two regions, toward Hercules-Corona Borealis and Perseus-Pisces-Cetus, at distances cz~6000-15000km/s. In this paper (the first of a series), we present an introduction to the EFAR project and describe in detail the selection of the clusters and galaxies in our sample. Fundamental data for the galaxies and clusters are given, including accurate new positions for each galaxy and redshifts for each cluster. The galaxy selection functions are determined by using diameters measured from Schmidt sky survey images for 2185 galaxies in the cluster fields. Future papers in this series will present the spectroscopic and photometric observations of this sample, investigate the properties of the fundamental plane for elliptical galaxies, and determine the large-scale peculiar velocity fields in these two regions of the universe.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/305/259
- Title:
- EFAR galaxies redshifts & velocity dispersions
- Short Name:
- J/MNRAS/305/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the spectroscopic data for the galaxies studied in the EFAR project, which is designed to measure the properties and peculiar motions of early-type galaxies in two distant regions. We have obtained 1319 spectra of 714 early-type galaxies over 33 observing runs on 10 different telescopes. We describe the observations and data reductions used to measure redshifts, velocity dispersions and the Mgb and Mg_2_ Lick linestrength indices. Detailed simulations and intercomparison of the large number of repeat observations lead to reliable error estimates for all quantities. The measurements from different observing runs are calibrated to a common zero-point or scale before being combined, yielding a total of 706 redshifts, 676 velocity dispersions, 676 Mgb linestrengths and 582 Mg_2_ linestrengths. The median estimated errors in the combined measurements are {Delta}cz=20km/s, {Delta}sigma/sigma=9.1%, {Delta}Mgb/Mgb=7.2% and {Delta}Mg_2_=0.015mag. Comparison of our measurements with published data sets shows no systematic errors in the redshifts or velocity dispersions, and only small zero-point corrections to bring our linestrengths on to the standard Lick system. We have assigned galaxies to physical clusters by examining the line-of-sight velocity distributions based on EFAR and ZCAT redshifts, together with the projected distributions on the sky. We derive mean redshifts and velocity dispersions for these clusters, which will be used in estimating distances and peculiar velocities and to test for trends in the galaxy population with cluster mass. The spectroscopic parameters presented here for 706 galaxies combine high-quality data, uniform reduction and measurement procedures, and detailed error analysis. They form the largest single set of velocity dispersions and linestrengths for early-type galaxies published to date.
- ID:
- ivo://CDS.VizieR/J/MNRAS/292/499
- Title:
- EFAR photometric data
- Short Name:
- J/MNRAS/292/499
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present R-band CCD photometry for 776 galaxies observed in the EFAR (Elliptical FAR away) project. The photometry is compared with photoelectric data, showing that a common zero-point good to better than 1% and a precision of 0.03mag per zero-point have been achieved. We give the circularly averaged surface brightness profiles and the photometric parameters of the 762 program galaxies, D(n) diameters (at 20.5mag/arcsec^2^), half-luminosity radii Re, total magnitudes m_T_, and average effective surface brightnesses <SBe>. More than 80% of the profiles have a global S/N ratio larger than 300. The extrapolation needed to derive total magnitudes is less than 10% for 80% of the fits. More than 80% of the galaxies have mean effective surface brightness larger than the observed sky brightness. In 90% of the profiles the estimate of the contamination of the sky by the galaxy light is less than 1%. We derive total magnitudes and half-luminosity radii to better than 0.15mag and 25%, respectively, for 90% of our sample. In contrast, external comparisons show that data in the literature can be strongly affected by systematic errors due to large extrapolations, small radial range, sky subtraction errors, seeing effects, and the use of a simple R^1/4^ fit. The resulting errors can easily amount to more than 0.5mag in the total magnitudes and 50% in the half-luminosity radii.
- ID:
- ivo://CDS.VizieR/J/ApJ/879/105
- Title:
- Effective temperatures of low-mass stars
- Short Name:
- J/ApJ/879/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution, near-infrared spectra will be the primary tool for finding and characterizing Earth-like planets around low-mass stars. Yet, the properties of exoplanets cannot be precisely determined without accurate and precise measurements of the host star. Spectra obtained with the Immersion Grating Infrared Spectrometer simultaneously provide diagnostics for most stellar parameters, but the first step in any analysis is the determination of the effective temperature. Here we report the calibration of high-resolution H-band spectra to accurately determine the effective temperature for stars between 4000 and 3000K (~K8-M5) using absorption line-depths of FeI, OH, and Al I. The field star sample used here contains 254 K and M stars with temperatures derived using BT-Settl synthetic spectra. We use 106 stars with precise temperatures in the literature to calibrate our method, with typical errors of about 140K, and systematic uncertainties less than ~120K. For the broadest applicability, we present Teff-line-depth-ratio relationships, which we test on 12 members of the TW Hydrae Association and at spectral resolving powers between ~10000 and 120000. These ratios offer a simple but accurate measure of effective temperatures in cool stars that are distance and reddening independent.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A116
- Title:
- EG And Halpha line fluxes and radial velocities
- Short Name:
- J/A+A/646/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Structure of the wind from the cool giants in symbiotic binaries carries important information for understanding the wind mass transfer to their white dwarf companions, its fuelling, and thus the path to different phases of symbiotic-star evolution. In this paper we indicate a non-spherical distribution of the neutral wind zone around the red giant (RG) in the symbiotic binary star EG And. In particular, its focusing towards the orbital plane and the asymmetry alongside the orbital motion of the RG. We achieved this aim by analysing the periodic orbital variations of fluxes and radial velocities of individual components of the H_alpha and [OIII] lambda 5007 lines observed on our high-cadence medium (R~11000) and high-resolution (R~38000) spectra. The asymmetric shaping of the neutral wind zone at the near-orbital-plane region is indicated by: (i) the asymmetric course of the Halpha core emission fluxes along the orbit, (ii) the presence of their secondary maximum around the orbital phase phi=0.1 possibly caused by the refraction effect, and (iii) the properties of the H_alpha broad wing emission originating by Raman scattering on H^0^ atoms. The wind is substantially compressed from polar directions to the orbital plane as constrained by the location of the [OIII] lambda 5007 line emission zones in the vicinity of the RG at/around its poles. The corresponding mass-loss rate from the polar regions of <~10^-8^M_{sun}_/yr is a factor of >~10 lower than the average rate of ~10^-7^M_{sun}_/yr derived from nebular emission of the ionized wind from the RG, and it is two orders of magnitude lower than that measured in the near-orbital-plane region from Rayleigh scattering. The startling properties of the nebular [OIII] lambda 5007 line in EG And provides an independent indication of the wind focusing towards the orbital plane -- the key to understanding the efficient wind mass transfer in symbiotic binary stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/97/141
- Title:
- Einstein sample multiparametric analysis. I.
- Short Name:
- J/ApJS/97/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted bivariate and multivariate statistical analysis of data measuring the luminosity and interstellar medium of the Einstein sample of early-type galaxies (presented by Fabbiano, Kim & Trinchiere =1992ApJS...80..531F).
- ID:
- ivo://CDS.VizieR/J/A+A/620/A87
- Title:
- Ejection processes in NGC 2264
- Short Name:
- J/A+A/620/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of forbidden [OI]6300{AA} emission line profiles in classical T Tauri stars in the young, open cluster NGC 2264. We separate each of these profiles into up to four features via Gaussian decomposition: narrow and broad low-velocity components and blue- and redshifted high-velocity components. We study the luminosities and kinematic properties of these components along with known stellar and accretion parameters, in order to investigate their origins.
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/2039
- Title:
- Elemental abundances of {alpha} Cir
- Short Name:
- J/MNRAS/386/2039
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Sydney University Stellar Interferometer to measure the angular diameter of alpha Cir. This is the first detailed interferometric study of a rapidly oscillating A (roAp) star, alpha Cir being the brightest member of its class. We used the new and more accurate Hipparcos parallax to determine the radius to be 1.967+/-0.066R_{sun}_. We have constrained the bolometric flux from calibrated spectra to determine an effective temperature of 7420+/-170K . This is the first direct determination of the temperature of an roAp star. Our temperature is at the low end of previous estimates, which span over 1000K and were based on either photometric indices or spectroscopic methods. In addition, we have analysed two high-quality spectra of alpha Cir, obtained at different rotational phases and we find evidence for the presence of spots.
- ID:
- ivo://CDS.VizieR/J/A+A/364/237
- Title:
- Elemental abundances of Deneb
- Short Name:
- J/A+A/364/237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study presents a detailed model atmosphere abundance analysis of Deneb which was performed using Kurucz LTE ATLAS9 model atmospheres. The atmospheric parameters were determined from Mg I/II and Fe I/II equilibrium, and by fitting the H{gamma} profile and optical region spectrophotometry. The compromise values which best satisfy these criteria are T_eff_ = 9000 K and log g = 1.45. The Mg I, Mg II, Si II, Ti II, Cr II, Fe I, and Fe II lines yield microturbulences of 3.60, 6.50, 8.50, 8.00, 11.90, 3.60, and 10.40 km/s, respectively. An average microturbulence of 7 km/s was used for the other atomic species.
- ID:
- ivo://CDS.VizieR/J/ApJ/787/154
- Title:
- Elemental abundances of solar sibling candidates
- Short Name:
- J/ApJ/787/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high-resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD 162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible but instead from identifying and carefully measuring the abundances of those elements that show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.
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