Ultraviolet extinction correlation with 3D dust maps using white dwarfs

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Main Authors: Sahu, Snehalata, Tremblay, Pier-Emmanuel, Lallement, Rosine, Redfield, Seth, Gaensicke, Boris T.
Format: Preprint
Published: 2024
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author Sahu, Snehalata
Tremblay, Pier-Emmanuel
Lallement, Rosine
Redfield, Seth
Gaensicke, Boris T.
author_facet Sahu, Snehalata
Tremblay, Pier-Emmanuel
Lallement, Rosine
Redfield, Seth
Gaensicke, Boris T.
contents Accurate astrometric and photometric measurements from Gaia have led to the construction of 3D dust extinction maps which can now be used for estimating the integrated extinctions of Galactic sources located within 5 kpc. These maps based on optical observations may not be reliable for use in the ultraviolet (UV) which is more sensitive to reddening. Past studies have focused on studying UV extinction using main-sequence stars but lack comparison with 3D dust maps. White dwarfs with well-modeled hydrogen-dominated (DA) atmospheres provide an advantage over main-sequence stars affected by magnetic activity. In this work, we study the variation of UV extinction with 3D dust maps utilising HST and GALEX observations of DA white dwarfs located within 300 pc. We used HST COS spectroscopic data of 76 sight lines to calculate the optical extinction from Si II column densities and validate our results with the kinematic model predictions of the local interstellar medium. Also, we combined GALEX and Gaia photometric observations of 1158 DA white dwarfs to study UV reddening by comparing observed and modeled colour-colour relations. We calculated GALEX non-linearity corrections and derived reddening coefficients (R(NUV-G) = 6.52 +/- 1.53 and R(FUV-G) = 6.04 +/- 2.41) considering their variations with optical extinction (Av < 0.1 mag), and found them to be in good agreement with known extinction laws. HST analysis suggests a positive bias of 0.01-0.02 mag in the optical extinction from 3D maps depending on the Galactic latitude. These results independently confirm the validity of 3D dust maps to deredden the optical and UV observations of white dwarfs.
format Preprint
id arxiv_https___arxiv_org_abs_2410_10358
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ultraviolet extinction correlation with 3D dust maps using white dwarfs
Sahu, Snehalata
Tremblay, Pier-Emmanuel
Lallement, Rosine
Redfield, Seth
Gaensicke, Boris T.
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Accurate astrometric and photometric measurements from Gaia have led to the construction of 3D dust extinction maps which can now be used for estimating the integrated extinctions of Galactic sources located within 5 kpc. These maps based on optical observations may not be reliable for use in the ultraviolet (UV) which is more sensitive to reddening. Past studies have focused on studying UV extinction using main-sequence stars but lack comparison with 3D dust maps. White dwarfs with well-modeled hydrogen-dominated (DA) atmospheres provide an advantage over main-sequence stars affected by magnetic activity. In this work, we study the variation of UV extinction with 3D dust maps utilising HST and GALEX observations of DA white dwarfs located within 300 pc. We used HST COS spectroscopic data of 76 sight lines to calculate the optical extinction from Si II column densities and validate our results with the kinematic model predictions of the local interstellar medium. Also, we combined GALEX and Gaia photometric observations of 1158 DA white dwarfs to study UV reddening by comparing observed and modeled colour-colour relations. We calculated GALEX non-linearity corrections and derived reddening coefficients (R(NUV-G) = 6.52 +/- 1.53 and R(FUV-G) = 6.04 +/- 2.41) considering their variations with optical extinction (Av < 0.1 mag), and found them to be in good agreement with known extinction laws. HST analysis suggests a positive bias of 0.01-0.02 mag in the optical extinction from 3D maps depending on the Galactic latitude. These results independently confirm the validity of 3D dust maps to deredden the optical and UV observations of white dwarfs.
title Ultraviolet extinction correlation with 3D dust maps using white dwarfs
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2410.10358