- ID:
- ivo://CDS.VizieR/J/ApJ/870/115
- Title:
- Reddening, distance modulus & Fe/H of RRLs in w Cen
- Short Name:
- J/ApJ/870/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We developed a new approach to provide accurate estimates of the metal content, reddening, and true distance modulus of RR Lyrae stars (RRLs). The method is based on homogeneous optical (BVI) and near-infrared (JHK) mean magnitudes and on predicted period-luminosity-metallicity relations (IJHK) and absolute mean magnitude-metallicity relations (BV). We obtained solutions for three different RRL samples in {omega}Cen: first overtone (RRc, 90), fundamental (RRab, 80), and global (RRc+RRab) in which the period of first overtones were fundamentalized. The metallicity distribution shows a well defined peak at [Fe/H]~-1.98 and a standard deviation of {sigma}=0.54dex. The spread is, as expected, metal-poor ([Fe/H]<=-2.3) objects. The current metallicity distribution is ~0.3dex more metal-poor than similar estimates for RRLs available in the literature. The difference vanishes if the true distance modulus we estimated is offset by -0.06/-0.07mag in true distance modulus. We also found a cluster true distance modulus of {mu}=13.720{+/-}0.002{+/-}0.030mag, where the former error is the error on the mean and the latter is the standard deviation. Moreover, we found a cluster reddening of E(B-V)=0.132{+/-}0.002{+/-}0.028mag and spatial variations of the order of a few arcmin across the body of the cluster. Both the true distance modulus and the reddening are slightly larger than similar estimates available in the literature, but the difference is within 1{sigma}. The metallicity dependence of distance diagnostics agrees with theory and observations, but firm constraints require accurate and homogeneous spectroscopic measurements.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/430/421
- Title:
- Reddening in LMC bar region
- Short Name:
- J/A+A/430/421
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- E(V-I) reddening values for 1123 locations in the bar region of the Large Magellanic Cloud are presented. V, I photometry of red clump stars identified in the Optical Gravitational Lensing Experiment II (OGLE-II) catalogue of LMC were used to estimate reddening. E(V-I) values were estimated as the difference between observed and the characteristic values of (V-I) for the red clump population in a given region. It is found that most of the regions in the bar have reddening values less than 0.1mag with only a few locations having values more than 0.2mag. The eastern side of the bar is found to be more reddened when compared to the western side, with similar and relatively small values for differential reddening as in most parts of the bar. Increased reddening in the eastern end of the bar could be caused by a small fraction of the H I clouds in the line of sight. A high density of HI clouds located in the eastern end of the bar should have caused very high reddening in these regions, whereas only a relatively small increase in the reddening is estimated. This indicates that most of the H I clouds in this direction are likely to be located behind the bar.
- ID:
- ivo://CDS.VizieR/J/A+A/359/347
- Title:
- Reddening in open and globular clusters
- Short Name:
- J/A+A/359/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper compares reddening values E(B-V) derived from the stellar content of 103 old open clusters and 147 globular clusters of the Milky Way with those derived from DIRBE/IRAS 100{mu}m dust emission in the same directions. Star clusters at |b|>20{deg} show comparable reddening values between the two methods, in agreement with the fact that most of them are located beyond the disk dust layer. For very low galactic latitude lines of sight, differences occur in the sense that DIRBE/IRAS reddening values can be substantially larger, suggesting effects due to the depth distribution of the dust. The differences appear to arise from dust in the background of the clusters consistent with a dust layer where important extinction occurs up to distances from the Plane of =~300pc. For 3% of the sample a significant background dust contribution might be explained by higher dust clouds. We find evidence that the Milky Way dust lane and higher dust clouds are similar to those of several edge-on spiral galaxies recently studied in detail by means of CCD imaging.
- ID:
- ivo://CDS.VizieR/J/AJ/149/203
- Title:
- Reddening of ~35000 quasars from SDSS
- Short Name:
- J/AJ/149/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the extinction/reddening of ~35000 uniformly selected quasars with 0<z{<=}5.3 in order to better understand their intrinsic optical/ultraviolet (UV) spectral energy distributions. Using rest-frame optical-UV photometry taken from the Sloan Digital Sky Survey's (SDSS) 7th data release, cross-matched to WISE in the mid-infrared, 2MASS and UKIDSS in the near-infrared, and GALEX in the UV, we isolate outliers in the color distribution and find them well described by an SMC-like reddening law. A hierarchical Bayesian model with a Markov Chain Monte Carlo sampling method was used to find distributions of power law indices and E(B-V) consistent with both the broad absorption line (BAL) and non-BAL samples. We find that, of the ugriz color-selected type 1 quasars in SDSS, 2.5% (13%) of the non-BAL (BAL) sample are consistent with E(B-V)>0.1 and 0.1% (1.3%) with E(B-V)>0.2. Simulations show both populations of quasars are intrinsically bluer than the mean composite, with a mean spectral index ({alpha}_{lambda}_) of -1.79 (-1.83). The emission and absorption-line properties of both samples reveal that quasars with intrinsically red continua have narrower Balmer lines and stronger high-ionization emission lines, the latter indicating a harder continuum in the extreme-UV and the former pointing to differences in black hole mass and/or orientation.
- ID:
- ivo://CDS.VizieR/J/AJ/135/631
- Title:
- Reddenings for the MACHO bulge RR0 Lyrae stars
- Short Name:
- J/AJ/135/631
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present mean reddenings toward 3525 RR0 Lyrae stars from the Galactic bulge fields of the MACHO Survey. These reddenings are determined using the color at minimum V-band light of the RR0 Lyrae stars themselves and are found to be in general agreement with extinction estimates at the same location obtained from other methods.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/1336
- Title:
- Reddenings of FGK supergiants & Cepheids
- Short Name:
- J/MNRAS/389/1336
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate and homogeneous atmospheric parameters (Teff, logg, Vt, [Fe/H]) are derived for 74 FGK non-variable supergiants from high-resolution, high signal-to-noise ratio, echelle spectra. Extremely high precision for the inferred effective temperatures (10-40K) is achieved by using the line-depth ratio method. The new data are combined with atmospheric values for 164 classical Cepheids, observed at 675 different pulsation phases, taken from our previously published studies.
- ID:
- ivo://CDS.VizieR/J/AJ/153/204
- Title:
- RR Lyrae stars from the PS1 3{pi} survey
- Short Name:
- J/AJ/153/204
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RR Lyrae stars may be the best practical tracers of Galactic halo (sub-)structure and kinematics. The PanSTARRS1 (PS1) 3{pi} survey offers multi-band, multi-epoch, precise photometry across much of the sky, but a robust identification of RR Lyrae stars in this data set poses a challenge, given PS1's sparse, asynchronous multi-band light curves (<~12 epochs in each of five bands, taken over a 4.5yr period). We present a novel template fitting technique that uses well-defined and physically motivated multi-band light curves of RR Lyrae stars, and demonstrate that we get accurate period estimates, precise to 2s in >80% of cases. We augment these light-curve fits with other features from photometric time-series and provide them to progressively more detailed machine-learned classification models. From these models, we are able to select the widest (three-fourths of the sky) and deepest (reaching 120kpc) sample of RR Lyrae stars to date. The PS1 sample of ~45000 RRab stars is pure (90%) and complete (80% at 80kpc) at high galactic latitudes. It also provides distances that are precise to 3%, measured with newly derived period-luminosity relations for optical/near-infrared PS1 bands. With the addition of proper motions from Gaia and radial velocity measurements from multi-object spectroscopic surveys, we expect the PS1 sample of RR Lyrae stars to become the premier source for studying the structure, kinematics, and the gravitational potential of the Galactic halo. The techniques presented in this study should translate well to other sparse, multi-band data sets, such as those produced by the Dark Energy Survey and the upcoming Large Synoptic Survey Telescope Galactic plane sub-survey.
78. S Dor variables
- ID:
- ivo://CDS.VizieR/J/A+A/366/508
- Title:
- S Dor variables
- Short Name:
- J/A+A/366/508
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The goal in writing this paper is five fold: (1) to summarize the scientific achievements in the 20th century on S Dor variables (or LBVs); (2) to present an inventory of these variables in the Galaxy and the Magellanic Clouds with a description of their physical state and instability properties; (3) to emphasize the photometric achievements of the various types of instabilities. Generally this seems to be a neglected item resulting in a number of misunderstandings continuously wandering through literature; (4) to investigate the structure of the S Dor-area on the HR-diagram; (5) to estimate the total numbers of S Dor variables in the three stellar systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/786/59
- Title:
- SED fitting results of HETDEX pilot survey
- Short Name:
- J/ApJ/786/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use broadband photometry extending from the rest-frame UV to the near-IR to fit the individual spectral energy distributions of 63 bright (L(Ly{alpha})>10^43^ erg/s) Ly{alpha} emitting galaxies (LAEs) in the redshift range 1.9<z<3.6. We find that these LAEs are quite heterogeneous, with stellar masses that span over three orders of magnitude, from 7.5<log M/M_{sun}_<10.5. Moreover, although most LAEs have small amounts of extinction, some high-mass objects have stellar reddenings as large as E(B-V)~0.4. Interestingly, in dusty objects the optical depths for Ly{alpha} and the UV continuum are always similar, indicating that Ly{alpha} photons are not undergoing many scatters before escaping their galaxy. In contrast, the ratio of optical depths in low-reddening systems can vary widely, illustrating the diverse nature of the systems. Finally, we show that in the star-formation-rate-log-mass diagram, our LAEs fall above the "main-sequence" defined by z~3 continuum selected star-forming galaxies. In this respect, they are similar to submillimeter-selected galaxies, although most LAEs have much lower mass.
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/323
- Title:
- Simulated UVEX colors with reddening
- Short Name:
- J/MNRAS/399/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The UV-Excess survey of the northern Galactic plane images a 10{deg}x185{deg} wide band, centred on the Galactic equator using the 2.5-m Isaac Newton Telescope in four bands (U, g, r, HeI 5875) down to ~21-22mag (~20 in HeI 5875). The setup and data reduction procedures are described. Simulations of the colours of main-sequence stars, giant, supergiants, DA and DB white dwarfs and AM Canum Venaticorum stars are made, including the effects of reddening. A first look at the data of the survey (currently 30 per cent complete) is given.
