Probing cosmic dawn with emission lines: predicting infrared and nebular line emission for ALMA and JWST

Harley Katz, Thomas P. Galligan, Taysun Kimm, Joakim Rosdahl, Martin G. Haehnelt, Jeremy Blaizot, Julien Devriendt, Adrianne Slyz, Nicolas Laporte, Richard Ellis

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Infrared and nebular lines provide some of our best probes of the physics regulating the properties of the interstellar medium (ISM) at high redshift. However, interpreting the physical conditions of high-redshift galaxies directly from emission lines remains complicated due to inhomogeneities in temperature, density, metallicity, ionization parameter, and spectral hardness. We present a new suite of cosmological, radiation-hydrodynamics simulations, each centred on a massive Lyman-break galaxy that resolves such properties in an inhomogeneous ISM. Many of the simulated systems exhibit transient but well-defined gaseous discs that appear as velocity gradients in [C ii] 157.6 μ m emission. Spatial and spectral offsets between [C ii] 157.6 μ m and [O iii] 88.33 μ m are common, but not ubiquitous, as each line probes a different phase of the ISM. These systems fall on the local [C ii]-SFR relation, consistent with newer observations that question previously observed [C ii] 157.6 μ m deficits. Our galaxies are consistent with the nebular line properties of observed z ∼2-3 galaxies and reproduce offsets on the BPT and mass-excitation diagrams compared to local galaxies due to higher star formation rate (SFR), excitation, and specific-SFR, as well as harder spectra from young, metal-poor binaries. We predict that local calibrations between H α and [O ii] 3727 A luminosity and galaxy SFR apply up to z > 10, as do the local relations between certain strong line diagnostics (R23 and [O iii] 5007 A /H β) and galaxy metallicity. Our new simulations are well suited to interpret the observations of line emission from current (ALMA and HST) and upcoming facilities (JWST and ngVLA).

Original languageEnglish
Pages (from-to)5902-5921
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume487
Issue number4
DOIs
Publication statusPublished - 2019 Jun 25

Bibliographical note

Funding Information:
This work was performed using the DiRAC Data Intensive service at Leicester, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility (www.dirac.ac .uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K000373/1 and ST/R002363/1 and STFC DiRAC Operations grant ST/R001014/1. DiRAC is part of the National e-Infrastructure.

Funding Information:
This work made considerable use of the open source analysis software PYNBODY (Pontzen et al. 2013). We thank the anonymous referee for their detailed revision of the manuscript. We thank Masami Ouchi, Dan Stark, Akio Inoue, Naoki Yoshida, Kana Moriwaki, Roberto Maiolino, Stefano Carniani, Rebecca Bowler, and Clotilde Laigle for discussions regarding the content of this manuscript. We thank Allison Strom for providing observational data for KBSS galaxies. HK thanks the Beecroft fellowship, the Nicholas Kurti Junior Fellowship, and Brasenose College. TK was supported by the National Research Foundation of Korea (No. 2017R1A5A1070354 and No. 2018036146). Support by ERC Advanced Grant 320596 ‘The Emergence of Structure during the Epoch of reionization’ is gratefully acknowledged by MH, HK, and TK. JB and JR acknowledge support from the ORAGE project from the Agence Nationale de la Recherche under grant ANR-14-CE33-0016-03. NL and RSE acknowledge funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 669253).

Funding Information:
This work made considerable use of the open source analysis software PYNBODY (Pontzen et al. 2013). We thank the anonymous referee for their detailed revision of the manuscript. We thank Masami Ouchi, Dan Stark, Akio Inoue, Naoki Yoshida, Kana Moriwaki, Roberto Maiolino, Stefano Carniani, Rebecca Bowler, and Clotilde Laigle for discussions regarding the content of this manuscript. We thank Allison Strom for providing observational data for KBSS galaxies. HK thanks the Beecroft fellowship, the Nicholas Kurti Junior Fellowship, and Brasenose College. TK was supported by the National Research Foundation of Korea (No. 2017R1A5A1070354 and No. 2018036146). Support by ERC Advanced Grant 320596 'The Emergence of Structure during the Epoch of reionization' is gratefully acknowledged byMH, HK, and TK. JB and JR acknowledge support from the ORAGE project from the Agence Nationale de la Recherche under grant ANR-14-CE33- 0016-03. NL and RSE acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 669253). Thisworkwas performed using the DiRACData Intensive service at Leicester, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility (www.dirac.ac .uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K000373/1 and ST/R002363/1 and STFC DiRAC Operations grant ST/R001014/1. DiRAC is part of the National e-Infrastructure.

Publisher Copyright:
© 2019 The Author(s).

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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