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Autores principales: Craig, Peter, Chakrabarti, Sukanya, Pettitt, Alexander R., Sanderson, Robyn, Rosolowsky, Erik
Formato: Preprint
Publicado: 2025
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Acceso en línea:https://arxiv.org/abs/2506.05575
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author Craig, Peter
Chakrabarti, Sukanya
Pettitt, Alexander R.
Sanderson, Robyn
Rosolowsky, Erik
author_facet Craig, Peter
Chakrabarti, Sukanya
Pettitt, Alexander R.
Sanderson, Robyn
Rosolowsky, Erik
contents For more than fifty years, astronomers have mapped the neutral hydrogen gas in the Galaxy assuming kinematically derived distances. We employ the distances of nearby young stars, which trace the gas from which they formed, in longitude-latitude-velocity space to map this gas without using kinematic distances. We denote this new method "pattern matching". Analysis of simulated spiral galaxies indicates that our pattern matching distances are 24% more accurate than kinematic distances for gas within 15 kpc of the Sun. The two methods provide similar agreement with parallaxes towards these masers, although the kinematic method shows a small systematic offset in the distance that is not present in the pattern matching distance. Using parallaxes and velocities for masers, we show that this novel method, when matched with nearby Cepheids, performs well compared to kinematics. This analysis is restricted to sources that have a reasonably good match with a member of our Cepheid sample. The distances derived here, and the associated map, have broad utility - from improving our understanding of star formation and the dynamical structure of the Galaxy, to informing 3-D dust maps.
format Preprint
id arxiv_https___arxiv_org_abs_2506_05575
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A map of the outer gas disk of the Galaxy with direct distances from young stars
Craig, Peter
Chakrabarti, Sukanya
Pettitt, Alexander R.
Sanderson, Robyn
Rosolowsky, Erik
Astrophysics of Galaxies
For more than fifty years, astronomers have mapped the neutral hydrogen gas in the Galaxy assuming kinematically derived distances. We employ the distances of nearby young stars, which trace the gas from which they formed, in longitude-latitude-velocity space to map this gas without using kinematic distances. We denote this new method "pattern matching". Analysis of simulated spiral galaxies indicates that our pattern matching distances are 24% more accurate than kinematic distances for gas within 15 kpc of the Sun. The two methods provide similar agreement with parallaxes towards these masers, although the kinematic method shows a small systematic offset in the distance that is not present in the pattern matching distance. Using parallaxes and velocities for masers, we show that this novel method, when matched with nearby Cepheids, performs well compared to kinematics. This analysis is restricted to sources that have a reasonably good match with a member of our Cepheid sample. The distances derived here, and the associated map, have broad utility - from improving our understanding of star formation and the dynamical structure of the Galaxy, to informing 3-D dust maps.
title A map of the outer gas disk of the Galaxy with direct distances from young stars
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2506.05575