Ultraviolet Properties of Multiphase Gas toward the Inner Galaxy

We present a systematic study of the multiphase interstellar gas in the inner Galaxy using Hubble Space Telescope/STIS absorption spectroscopy of 16 massive stars located at spectroscopic distances between 1.3 and 10 kpc in the region −30° ≲  l  ≲ +30° and −15° ≲  b  ≲ +15°. These sight lines probe...

Full description

Saved in:
Bibliographic Details
Main Authors: Frances H. Cashman, Andrew J. Fox, Debopam Som, Bart P. Wakker, Robert A. Benjamin, Dhanesh Krishnarao, David M. French, Rongmon Bordoloi, Felix J. Lockman
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/add69b
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present a systematic study of the multiphase interstellar gas in the inner Galaxy using Hubble Space Telescope/STIS absorption spectroscopy of 16 massive stars located at spectroscopic distances between 1.3 and 10 kpc in the region −30° ≲  l  ≲ +30° and −15° ≲  b  ≲ +15°. These sight lines probe gas above and below the Sagittarius Carina, Scutum Crux-Centaurus, Norma, and Near 3-kpc spiral arms in a range of z -height from 0 to 1.5 kpc. Along the 16 sight lines, we measure velocity centroids for 800 UV absorption-line components across multiple gas phases (molecular CO, neutral, low ion, and high ion). We find that 619/800 components have velocities that are consistent with a simple model of corotation with the disk, indicating that multiphase gas with disk-like kinematics extends at least 1 kpc into the halo. We present a database of absorption-line parameters that can be used for kinematic modeling of gas flows into and out of the Galactic disk.
ISSN:1538-4357