TY - JOUR
T1 - Interpreting the Si ii and C ii Line Spectra from the COS Legacy Archive Spectroscopic SurveY Using a Virtual Galaxy from a High-resolution Radiation-hydrodynamic Simulation
AU - Gazagnes, Simon
AU - Mauerhofer, Valentin
AU - Berg, Danielle A.
AU - Blaizot, Jeremy
AU - Verhamme, Anne
AU - Garel, Thibault
AU - Erb, Dawn K.
AU - Arellano-Córdova, Karla Z.
AU - Brinchmann, Jarle
AU - Chisholm, John
AU - Hayes, Matthew
AU - Henry, Alaina
AU - James, Bethan L.
AU - Jaskot, Anne
AU - Jurlin, Nika
AU - Martin, Crystal L.
AU - Maseda, Michael
AU - Scarlata, Claudia
AU - Skillman, Evan D.
AU - Wilkins, Stephen M.
AU - Wofford, Aida
AU - Xu, Xinfeng
N1 - Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/8/1
Y1 - 2023/8/1
N2 - Observations of low-ionization state metal lines provide crucial insights into the interstellar medium (ISM) of galaxies, yet, disentangling the physical processes responsible for the emerging line profiles is difficult. This work investigates how mock spectra generated using a single galaxy in a radiation-hydrodynamical simulation can help us interpret observations of a real galaxy. We create 22,500 C ii and Si ii spectra from the virtual galaxy at different times and through multiple lines of sight and compare them with the 45 observations of low-redshift star-forming galaxies from the COS Legacy Spectroscopic SurveY (classy). We find that the mock profiles provide accurate replicates of the observations of 38 galaxies with a broad range of stellar masses (106-109 M ⊙) and metallicities (0.02-0.55 Z ⊙). Additionally, we highlight that aperture losses explain the weakness of the fluorescent emission in several classy spectra and must be accounted for when comparing simulations to observations. Overall, we show that the evolution of a single simulated galaxy can produce a large diversity of spectra whose properties are representative of galaxies of comparable or smaller masses. Building upon these results, we explore the origin of the continuum, residual flux, and fluorescent emission in the simulation. We find that these different spectral features all emerge from distinct regions in the galaxy’s ISM, and their characteristics can vary as a function of the viewing angle. While these outcomes challenge simplified interpretations of down-the-barrel spectra, our results indicate that high-resolution simulations provide an optimal framework to interpret these observations.
AB - Observations of low-ionization state metal lines provide crucial insights into the interstellar medium (ISM) of galaxies, yet, disentangling the physical processes responsible for the emerging line profiles is difficult. This work investigates how mock spectra generated using a single galaxy in a radiation-hydrodynamical simulation can help us interpret observations of a real galaxy. We create 22,500 C ii and Si ii spectra from the virtual galaxy at different times and through multiple lines of sight and compare them with the 45 observations of low-redshift star-forming galaxies from the COS Legacy Spectroscopic SurveY (classy). We find that the mock profiles provide accurate replicates of the observations of 38 galaxies with a broad range of stellar masses (106-109 M ⊙) and metallicities (0.02-0.55 Z ⊙). Additionally, we highlight that aperture losses explain the weakness of the fluorescent emission in several classy spectra and must be accounted for when comparing simulations to observations. Overall, we show that the evolution of a single simulated galaxy can produce a large diversity of spectra whose properties are representative of galaxies of comparable or smaller masses. Building upon these results, we explore the origin of the continuum, residual flux, and fluorescent emission in the simulation. We find that these different spectral features all emerge from distinct regions in the galaxy’s ISM, and their characteristics can vary as a function of the viewing angle. While these outcomes challenge simplified interpretations of down-the-barrel spectra, our results indicate that high-resolution simulations provide an optimal framework to interpret these observations.
UR - http://www.scopus.com/inward/record.url?scp=85166510570&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/acda2c
DO - 10.3847/1538-4357/acda2c
M3 - Article
AN - SCOPUS:85166510570
SN - 0004-637X
VL - 952
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 164
ER -