Abstract
We present calculations of ultraviolet spectra resulting from the scattering of photons by gas infalling onto an isotropically emitting source of radiation. The model is based on an adaptation of the semianalytical line transfer (SALT) code of Scarlata & Panagia, and designed to interpret the inverse P Cygni profiles observed in the spectra of partially ionized galactic inflows. In addition to presenting the model, we explore the parameter space of the inflowing SALT model and recreate various physically motivated scenarios including spherical inflows, inflows with covering fractions less than unity, and galactic fountains (i.e., galactic systems with both an inflowing and outflowing component). The resulting spectra from inflowing gas show spectral features that could be misinterpreted as interstellar medium features in low resolution spectroscopy (σ ≈ 120 km s−1), suggesting that the total number of galactic systems with inflows is undercounted. Our models suggest that observations at medium resolution (R = 6000 or σ ≈ 50 km s−1) that can be obtained with 8 m class telescopes will be able to resolve the characteristic inverse P Cygni profiles necessary to identify inflows.
| Original language | English (US) |
|---|---|
| Article number | 47 |
| Journal | Astrophysical Journal |
| Volume | 939 |
| Issue number | 1 |
| DOIs | |
| State | Published - Nov 1 2022 |
Bibliographical note
Funding Information:The authors would like to thank Jacob Miller for graciously helping to create the figures in this work. The authors would also like to thank the anonymous referee for their thorough reading of the manuscript and for providing further insight into parameter constraints. Support for this work was provided by NASA through grant No. HST-GO-15626 from the Space Telescope Science Institute.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.