- ID:
- ivo://CDS.VizieR/J/AJ/109/543
- Title:
- Color of Bright Galaxies
- Short Name:
- J/AJ/109/543
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Total color indices (V-R)tot, (V-I)tot and effective color indices (V-R)eff, (V-I)eff in the Cousins VRI photometric system are presented for 501 mostly normal galaxies. The colors are computed using a procedure outlined in the Third Reference Catalogue of Bright Galaxies (RC3) whereby standard color curves approximated by Laplace-Gauss integrals are fitted to observed photoelectric multiaperture photometry. 11 sources of such photometry were used for our analysis, each source being assigned an appropriate weight according to a rigorous analysis of residuals of the data from the best-fitting standard color curves. Together with the integrated B-V and U-B colors provided in RC3, our analysis widens the range of wavelength of homogeneously defined colors of normal galaxies of all Hubble types. We present color-color and color-type relations that can be modeled to understand the star formation history of galaxies.
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- ID:
- ivo://CDS.VizieR/II/19
- Title:
- Colors of F and G dwarfs
- Short Name:
- II/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Synthetic spectra have been computed for F and G dwarf stars, using a number of values of chemical abundances, Doppler broadening velocity and damping constants. Filter transmission function have been convolved with thee spectra to yield color indices in 3 photometric systems.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/12
- Title:
- Colors of the Outer Solar System Origins Survey
- Short Name:
- J/ApJS/243/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Colours of the Outer Solar System Origins Survey is acquiring near-simultaneous g, r, and J photometry of unprecedented precision with the Gemini North Telescope, targeting nearly 100 trans-Neptunian objects (TNOs) brighter than m_r_=23.6mag discovered in the Outer Solar System Origins Survey. Combining the optical and near-infrared photometry with the well-characterized detection efficiency of the Colours of the Outer Solar System Origins Survey target sample will provide the first flux-limited compositional dynamical map of the outer solar system. In this paper, we describe our observing strategy and detail the data reduction processes we employ, including techniques to mitigate the impact of rotational variability. We present optical and near-infrared colors for 35 TNOs. We find two taxonomic groups for the dynamically excited TNOs, the neutral and red classes, which divide at g-r~0.75. Based on simple albedo and orbital distribution assumptions, we find that the neutral class outnumbers the red class, with a ratio of 4:1 and potentially as high as 11:1. Including in our analysis constraints from the cold classical objects, which are known to exhibit unique albedos and r-z colors, we find that within our measurement uncertainty our observations are consistent with the primordial solar system protoplanetesimal disk being neutral class dominated, with two major compositional divisions in grJ color space.
- ID:
- ivo://CDS.VizieR/J/AJ/119/1424
- Title:
- Color-temperature relations of M giants
- Short Name:
- J/AJ/119/1424
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of a project to model the integrated spectra and colors of elliptical galaxies through evolutionary synthesis, we have refined our synthetic spectrum calculations of M giants. After critically assessing three effective temperature scales for M giants, we adopted the relation of Dyck et al. for our models. Using empirical spectra of field M giants as a guide, we then calculated MARCS stellar atmosphere models (Gustafsson et al. 1975; Bell et al. 1976) and SSG synthetic spectra (Bell & Gustafsson 1978; Gustafsson & Bell 1979) of these cool stars, adjusting the band absorption oscillator strengths of the TiO bands to better reproduce the observational data. The resulting synthetic spectra are found to be in very good agreement with the K-band spectra of stars of the appropriate spectral type taken from Kleinmann & Hall (1986) as well. Spectral types estimated from the strengths of the TiO bands and the depth of the band head of CO near 2.3 {mu}m quantitatively confirm that the synthetic spectra are good representations of those of field M giants. The broadband colors of the models match the field relations of K and early-M giants very well; for late-M giants, differences between the field star and synthetic colors are probably caused by the omission of spectral lines of VO and H_2_O in the spectrum synthesis calculations. Here, we present four grids of K-band bolometric corrections and colors - Johnson U-V and B-V, Cousins V-R and V-I, Johnson-Glass V-K, J-K, and H-K, and CIT/CTIO V-K, J-K, H-K, and CO - for models having 3000 K {<=} Teff {<=} 4000 K and -0.5 {<=} log(g) {<=} 1.5.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/369
- Title:
- Colour and spectral index from the SLUGGS survey
- Short Name:
- J/MNRAS/446/369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ~90 {AA}^-1^. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the H{alpha} and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.
- ID:
- ivo://CDS.VizieR/J/A+AS/102/397
- Title:
- Colour magnitude diagram of M13
- Short Name:
- J/A+AS/102/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two overlapping regions of M13 were observed on April 24, 1989 at the Loiano Observatory with a CDCD camera. A Colour-Magnitude diagram down to the main sequence was derived, as a preliminary search for the blue Horizontal Branch stars in this cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A68
- Title:
- 3D correction in 5 photometric systems
- Short Name:
- J/A+A/611/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection. The influence of this inhomogeneity, referred to as granulation, on colours has never been investigated over a large range of effective temperatures and gravities. We aim to study, in a quantitative way, the impact of granulation on colours. We use the CIFIST (Cosmological Impact of the FIrst Stars) grid of CO5BOLD (COnservative COde for the COmputation of COmpressible COnvection in a BOx of L Dimensions, L=2,3) hydrodynamical models to compute emerging fluxes. These in turn are used to compute theoretical colours in the UBVRI, 2MASS, Hipparcos, Gaia and SDSS systems. Every CO5BOLD model has a corresponding one dimensional (1D) plane-parallel LHD (Lagrangian HydroDynamics) model computed for the same atmospheric parameters, which we used to define a "3D correction" that can be applied to colours computed from fluxes computed from any 1D model atmosphere code. As an example, we illustrate these corrections applied to colours computed from ATLAS models. The 3D corrections on colours are generally small, of the order of a few hundredths of a magnitude, yet they are far from negligible. We find that ignoring granulation effects can lead to underestimation of Teff by up to 200K and overestimation of gravity by up to 0.5dex, when using colours as diagnostics.We have identified a major shortcoming in how scattering is treated in the current version of the CIFIST grid, which could lead to offsets of the order 0.01mag, especially for colours involving blue and UV bands. We have investigated the Gaia and Hipparcos photometric systems and found that the (G-Hp),(BP-RP) diagram is immune to the effects of granulation. In addition, we point to the potential of the RVS photometry as a metallicity diagnostic. Our investigation shows that the effects of granulation should not be neglected if one wants to use colours as diagnostics of the stellar parameters of F,G,K stars. A limitation is that scattering is treated as true absorption in our current computations, thus our 3D corrections are likely an upper limit to the true effect. We are already computing the next generation of the CIFIST grid, using an approximate treatment of scattering.
- ID:
- ivo://CDS.VizieR/II/164
- Title:
- DDO Photoelectric Photometric Catalog
- Short Name:
- II/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue collects the DDO photometric data published in the astronomical literature until the end of 1988, and contains 8034 DDO measurements, concerning 6139 stars. The DDO 6-filter has the following peak wavelengths and widths: ------------------------ Filter Peak Width [nm] [nm] ------------------------ 35 346.0 38.3 38 381.5 33.0 41 416.6 8.3 42 425.7 7.3 45 451.7 7.6 48 488.6 18.6 51 (*) 513.0 13.4 ------------------------ (*) additional to DDO.
- ID:
- ivo://CDS.VizieR/J/AZh/77/619
- Title:
- Energy distributions in giants and supergiants
- Short Name:
- J/AZh/77/619
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Normal spectral energy distributions for early-type subgiants, giants and supergiants are derived.
- ID:
- ivo://CDS.VizieR/J/ApJS/252/23
- Title:
- E(V-I) reddening map of MCs from OGLE-IV RC stars
- Short Name:
- J/ApJS/252/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the most extensive and detailed reddening maps of the Magellanic Clouds (MCs) derived from the color properties of Red Clump (RC) stars. The analysis is based on the deep photometric maps from the fourth phase of the Optical Gravitational Lensing Experiment (OGLE-IV), covering approximately 670deg^2^ of the sky in the Magellanic System region. The resulting maps provide reddening information for 180deg^2^ in the Large Magellanic Cloud (LMC) and 75deg^2^ in the Small Magellanic Cloud (SMC), with a resolution of 1.7'x1.7' in the central parts of the MCs, decreasing to approximately 27'x27' in the outskirts. The mean reddening is E(V-I)=0.100+/-0.043mag in the LMC and E(V-I)=0.047+/-0.025mag in the SMC. We refine methods of calculating the RC color to obtain the highest possible accuracy of reddening maps based on RC stars. Using spectroscopy of red giants, we find the metallicity gradient in both MCs, which causes a slight decrease of the intrinsic RC color with distance from the galaxy center of ~0.002mag/deg in the LMC and between 0.003 and 0.009mag/deg in the SMC. The central values of the intrinsic RC color are 0.886 and 0.877mag in the LMC and SMC, respectively.
