{\it Gaia} DR2 giants in the Galactic dust -- I. Reddening across the whole dust layer and some properties of the giant clump

Abstract

We consider a complete sample of 101810 giants with Gaia DR2 parallaxes $\varpi$ within the red clump domain of the Hertzsprung-Russell diagram in the space cylinder with a radius of 700 pc around the Sun and a height of $|Z|=1800$ pc. We use the Gaia DR2 $G_{\mathrm{BP}}$, $G_{\mathrm{RP}}$ and WISE $W3$ photometry. We describe the spatial variations of the modes of the observables $G_{\mathrm{BP}}-G_{\mathrm{RP}}$, $G_{\mathrm{RP}}-W3$, $G_{\mathrm{BP}}+5+5{\log }_{10}\varpi$, $G_{\mathrm{RP}}+5+5{\log }_{10}\varpi$, and $W3+5+5{\log }_{10}\varpi$ by extinction and reddening in combination with linear vertical gradients of the intrinsic colours and absolute magnitudes of the red giant clump. The derived clump median absolute magnitude in $W3$ agrees with its recent literature estimates. The clump median intrinsic colours and absolute magnitudes in $G_{\mathrm{BP}}$ and $G_{\mathrm{RP}}$ are derived for the first time at a precision level of 0.01 mag. We confirm the reliability of the derived clump absolute magnitudes, intrinsic colours, and their vertical gradients by comparing them with the theoretical predictions from PARSEC, MIST and BaSTI isochrones. This leads us to the median age and [Fe/H] of the clump within $|Z|<1.7$ kpc from the Galactic mid-plane as $(2.3\pm 0.5)+(3.2\pm 1.6)|Z|$ Gyr and $(-0.08\pm 0.08)-(0.16\pm 0.07)|Z|$ dex, respectively, where $Z$ is expressed in kpc. These results agree with recent empirical and theoretical estimates. Moreover, all the models give similar age-metallicity relations by use of our results in the optical range. The derived extinctions and reddenings across the whole dust half-layer below or above the Sun converge to the reddening $E(B-V)=0.06$ mag by use of the most reliable extinction laws.

accepted to MNRAS

References in corpus (21)

• Modules for Experiments in Stellar Astrophysics (MESA)
• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• Gaia-2MASS 3D maps of Galactic interstellar dust within 3 kpc
• Vertical distribution of Galactic disk stars IV - AMR and AVR from clump giants
• The Tycho-Gaia astrometric solution. How to get 2.5 million parallaxes with less than one year of Gaia data
• A Multi-Band Catalog of 10978 Star Clusters, Associations and Candidates in the Milky Way
• Modeling Thermal Dust Emission with Two Components: Application to the Planck HFI Maps
• Empirical photometric calibration of the Gaia Red Clump: colours, effective temperature and absolute magnitude
• Red clump stars and Gaia: Calibration of the standard candle using a hierarchical probabilistic model
• The SDSS-2MASS-WISE Ten Dimensional Stellar Color Locus
• 3D Stellar Reddening Map from 2MASS Photometry: An Improved Version
• 3D Interstellar Extinction Map within the Nearest Kiloparsec
• Variations of the Interstellar Extinction Law within the Nearest Kiloparsec
• Galactic Globular and Open Cluster Fiducial Sequences in the Pan-STARRS1 Photometric System
• Red Giant Clump in the Tycho-2 Catalogue
• Spatial Distribution and Kinematics of OB Stars
• Interstellar Extinction
• Local Stellar Kinematics from RAVE data - VII. Metallicity Gradients from Red Clump Stars
• Isochrone fitting of Galactic globular clusters -- II. NGC6205 (M13)
• Using the reduced proper motions of Tycho-2 stars with B-V from 0.75 to 1.25: Monte Carlo simulations
• On the Properties of the Galactic Dust Layer within 700 pc of the Sun

Cited by in corpus (9)

• The structure of the Milky Way based on unWISE 3.4$\mu$m integrated photometry
• Isochrone fitting of Galactic globular clusters -- III. NGC\,288, NGC\,362, and NGC\,6218 (M12)
• 3D Parameter Maps of Red Clump Stars in the Milky Way -- Absolute Magnitudes and Intrinsic Colors
• New Interstellar Extinction Maps Based on Gaia and Other Sky Surveys
• Gaia DR2 giants in the Galactic dust -- II. Application of the reddening maps and models
• Models for Metal-Poor Stars with Different Initial Abundances of C, N, O, Mg, and Si. III. Grids of Isochrones for $-2.5\le$ [Fe/H] $\le -0.5$ and Helium Abundances $Y=0.25$ and $0.29$ at Each Metallicity
• A Three-Dimensional Analytical Model of the Interstellar Extinction within the Nearest Kiloparsec
• Spectral Evidence of Solar Neighborhood Analogs in CALIFA Galaxies
• Interstellar Extinction in Galactic Cirri in SDSS Stripe 82