- ID:
- ivo://CDS.VizieR/J/A+A/392/1
- Title:
- Spectrophotometry of simulated Stellar Populations
- Short Name:
- J/A+A/392/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new set of evolutionary synthesis spectra are presented for Simple Stellar Populations (SSPs) covering ranges in metallicity from 0.02<=Z/Z_{sun}_<=2.5 and ages from 4*10^6^yr<=t<=16Gyr. They are based on the most recent isochrones from the Padova group that extend earlier models by the inclusion of the thermal pulsing AGB phase for stars in the mass range 2M_{sun}_<=m<=7M_{sun}_ in accordance with the fuel consumption theorem. We show that with respect to earlier models, inclusion of the TP-AGB phase leads to significant changes in the (V-I) and (V-K) colors of SSPs in the age range from 10^8^ to >~10^9^yr. Using model atmosphere spectra from Lejeune et al. (1997, Cat. <J/A+AS/125/229>, 1998, Cat. <J/A+AS/130/65>), we calculate the spectral evolution of single burst populations of various metallicities covering the wavelength range from 90{AA} through 160{mu}m. Isochrone spectra are convolved with filter response functions to describe the time evolution of luminosities and colors in Johnson, Thuan & Gunn, Koo, HST, Washington and Stroemgren filters. The models and their results are not only intended for use in the interpretation of star clusters but also for combination with any kind of dynamical galaxy formation and/or evolution model that contains a star formation criterion. Moreover, the evolution of these single burst single metallicity stellar populations is readily folded with any kind of star formation -- and eventually chemical enrichment -- history to describe the evolutionary spectral synthesis of composite stellar populations like galaxies of any type with continuous or discontinuous star formation. For these latter purposes we also present the time evolution of ejection rates for gas and metals for two different Initial Mass Functions (IMFs) as well as cosmological and evolutionary corrections for all the filters as a function of redshift for 0<=z<=5 and two different cosmologies.
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- ID:
- ivo://CDS.VizieR/J/AJ/117/2308
- Title:
- Spectroscopy of hot stars in the halo
- Short Name:
- J/AJ/117/2308
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss a spectroscopic and photometric technique that enables the identification and classification of field horizontal-branch (FHB) and other A-type stars, even from relatively low signal-to-noise ratio medium-resolution spectra. This technique makes use of broadband UBV colors predicted from model atmosphere calculations and Balmer line profiles and Ca II K equivalent widths determined from synthetic spectra to estimate the physical parameters T_eff_, log(g), and [Fe/H] for stars in the effective temperature range 6000 - 10,000 K.
- ID:
- ivo://CDS.VizieR/J/AJ/160/130
- Title:
- SpT & NIR color excess of Solar-type stars
- Short Name:
- J/AJ/160/130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although solar-analog stars have been studied extensively over the past few decades, most of these studies have focused on visible wavelengths, especially those identifying solar-analog stars to be used as calibration tools for observations. As a result, there is a dearth of well-characterized solar analogs for observations in the near-infrared, a wavelength range important for studying solar system objects. We present 184 stars selected based on solar-like spectral type and V-J and V-K colors whose spectra we have observed in the 0.8-4.2{mu}m range for calibrating our asteroid observations. Each star has been classified into one of three ranks based on spectral resemblance to vetted solar analogs. Of our set of 184 stars, we report 145 as reliable solar-analog stars, 21 as solar analogs usable after spectral corrections with low-order polynomial fitting, and 18 as unsuitable for use as calibration standards owing to spectral shape, variability, or features at low to medium resolution. We conclude that all but five of our candidates are reliable solar analogs in the longer wavelength range from 2.5 to 4.2{mu}m. The average colors of the stars classified as reliable or usable solar analogs are V-J=1.148, V-H=1.418, and V-K= 1.491, with the entire set being distributed fairly uniformly in R.A. across the sky between -27{deg} and +67{deg} in decl.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A11
- Title:
- STAGGER-grid of 3D stellar models. V.
- Short Name:
- J/A+A/611/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have calculated spectra from 1000 to 200000{AA} with a constant resolving power of {lambda}/{Delta}{lambda}=20000 and from 8470 and 8710{AA} (Gaia Radial Velocity Spectrometer - RVS - spectral range) with a constant resolving power of {lambda}/{Delta}{lambda}=300000. This for the Stagger-grid 3D stellar atmosphere models in the ranges: Teff from 4000 to 7000K, logg from 1.5 to 5.0, and [Fe/H], from -4.0 to +0.5. We used synthetic spectra to compute theoretical colours in the Johnson-Cousins UBV(RI)C, SDSS, 2MASS, Gaia, SkyMap- per, Stroemgren systems, and HST-WFC3.
- ID:
- ivo://CDS.VizieR/II/119
- Title:
- Stellar Distribution near the South Galactic Pole
- Short Name:
- II/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a field of 2.8 square degrees centered on Kapteyn Selected Area 141 (l=245, b=-86). The center of field was near SAO 166815 (Bok I 174 B) at 01 05 11 -29 33 12 (1950). The covered ranges were 01 01 30 < RA < 01 09 30 and -30 20 < Dec < -28 35 (1950). Photographic V magnitudes and B-V colors of 640 stars were measured in Region I. Data were card punched at the Australian National University on an Univac 1100/82. The coordinates were determined by Kavan U. Ratnatunga from PDS scans of the region on UKSTU Schmidt plate J6657S (taken on 03-Jan-1981) and visual cross identifications were given with the published finding chart. The coordinate calibration used the positions of SAO stars. Estimated rms accuracies for the following measurements are: Visual Magnitude: 0.03 mag B-V colors : 0.05 mag Positions : 1 arc second
- ID:
- ivo://CDS.VizieR/J/ApJ/867/108
- Title:
- Stellar masses and rest-frame u-g colors of SNIa
- Short Name:
- J/ApJ/867/108
- Date:
- 03 Dec 2021 00:48:50
- Publisher:
- CDS
- Description:
- Recent analyses suggest that distance residuals measured from Type Ia supernovae (SNe Ia) are correlated with local host galaxy properties within a few kiloparsecs of the SN explosion. However, the well-established correlation with global host galaxy properties is nearly as significant, with a shift of 0.06mag across a low to high mass boundary (the mass step). Here, with 273 SNe Ia at z<0.1, we investigate whether the stellar masses and rest-frame u-g colors of regions within 1.5kpc of the SN Ia explosion site are significantly better correlated with SN distance measurements than global properties or properties measured at random locations in SN hosts. At >~2{sigma} significance, local properties tend to correlate with distance residuals better than properties at random locations, though despite using the largest low-z sample to date, we cannot definitively prove that a local correlation is more significant than a random correlation. Our data hint that SNe observed by surveys that do not target a pre-selected set of galaxies may have a larger local mass step than SNe from surveys that do, an increase of 0.071+/-0.036mag (2.0{sigma}). We find a 3{sigma} local mass step after global mass correction, evidence that SNe Ia should be corrected for their local mass, but we note that this effect is insignificant in the targeted low-z sample. Only the local mass step remains significant at >2{sigma} after global mass correction, and we conservatively estimate a systematic shift in H0 measurements of -0.14km/s/Mpc with an additional uncertainty of 0.14km/s/Mpc, ~10% of the present uncertainty.
- ID:
- ivo://CDS.VizieR/II/46
- Title:
- Strong cyanogen stars
- Short Name:
- II/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A cyanogen index for late-type giants, insensitive to surface gravity but sensitive to metallicity, is presented in the David Dunlap Observatory (DDO) photometric system. Observations were made using conventional single-channel photometers with 1P21 photomultiplier tubes on the 40cm and 90cm telescopes of Kitt Peak National Observatory. The original DDO filter set C was used (see Paper I, 1968AJ.....73..313M). Table 1 contains DDO photometry on 52 bright late-type giants for calibration. Most G8 to M0 stars, luminosity class III, V<4.0mag, north of {delta}=-10{deg}, supplement the original stars from Paper I. Table 4 includes both DDO and UBV photometry for stars from Schmitt (1967 thesis, Univ. Michigan, Ann Arbor) and Spinrad and Taylor (1967AJ.....72S.320S). Reddening values were computed using the method of McClure and Racine (1969AJ.....74.1000M).
- ID:
- ivo://CDS.VizieR/J/MNRAS/253/686
- Title:
- Survey of faint compact objects
- Short Name:
- J/MNRAS/253/686
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a low-resolution (73A) spectroscopic survey of faint compact objects conducted with the Low Dispersion Survey Spectrograph at the Anglo-Australian Telescope. The sample is a random subset of all compact sources with 22.5<=b_j_<=23.5 in three high-latitude fields. Additional data on compact sources with 21<=b_j_<=22.5 have been selected from the higher resolution (13A) survey previously published by Colless et al. (1990), and a subset of these brighter objects has been studied at both dispersions.
- ID:
- ivo://CDS.VizieR/J/AJ/159/273
- Title:
- Taurus members & nonmembers with K2 data
- Short Name:
- J/AJ/159/273
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of K2 light curves (LCs) from Campaigns 4 and 13 for members of the young (~3Myr) Taurus association, in addition to an older (~30Myr) population of stars that is largely in the foreground of the Taurus molecular clouds. Out of 156 of the highest-confidence Taurus members, we find that 81% are periodic. Our sample of young foreground stars is biased and incomplete, but nearly all stars (37/38) are periodic. The overall distribution of rotation rates as a function of color (a proxy for mass) is similar to that found in other clusters: the slowest rotators are among the early M spectral types, with faster rotation toward both earlier FGK and later M types. The relationship between period and color/mass exhibited by older clusters such as the Pleiades is already in place by Taurus age. The foreground population has very few stars but is consistent with the USco and Pleiades period distributions. As found in other young clusters, stars with disks rotate on average slower, and few with disks are found rotating faster than ~2days. The overall amplitude of the LCs decreases with age, and higher-mass stars have generally lower amplitudes than lower-mass stars. Stars with disks have on average larger amplitudes than stars without disks, though the physical mechanisms driving the variability and the resulting LC morphologies are also different between these two classes.
- ID:
- ivo://CDS.VizieR/J/ApJ/469/355
- Title:
- Teff, B-V and BC relation
- Short Name:
- J/ApJ/469/355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table provides improved numerical relations between effective temperatures of stars, their B-V colors, and their bolometric corrections (BC) for the purpose of comparing theoretical stellar evolutionary calculations to color-magnitude diagrams of star clusters. Temperature and bolometric correction measurements for 335 stars from the literature form the observational basis for the transformations. Measured temperatures range from 2900 to 52500K.
