The MOSDEF survey: towards a complete census of the z ∼2.3 star-forming galaxy population

Jordan N. Runco, Alice E. Shapley, Ryan L. Sanders, Mariska Kriek, Naveen A. Reddy, Alison L. Coil, Bahram Mobasher, Brian Siana, Michael W. Topping, William R. Freeman, Irene Shivaei, Mojegan Azadi, Sedona H. Price, Gene C.K. Leung, Tara Fetherolf, Laura De Groot, Tom Zick, Francesca M. Fornasini, Guillermo Barro

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We analyse the completeness of the MOSDEF survey, in which z ∼ 2 galaxies were selected for rest-optical spectroscopy from well-studied HST extragalactic legacy fields down to a fixed rest-optical magnitude limit (HAB = 24.5). The subset of z ∼ 2 MOSDEF galaxies with high signal-to-noise (S/N) emission-line detections analysed in previous work represents a small minority (<10 per cent) of possible z ∼ 2 MOSDEF targets. It is therefore crucial to understand how representative this high S/N subsample is, while also more fully exploiting the MOSDEF spectroscopic sample. Using spectral-energy distribution (SED) models and rest-optical spectral stacking, we compare the MOSDEF z ∼ 2 high S/N subsample with the full MOSDEF sample of z ∼ 2 star-forming galaxies with redshifts, the latter representing an increase in sample size of more than a factor of three. We find that both samples have similar emission-line properties, in particular in terms of the magnitude of the offset from the local star-forming sequence on the [N ii] BPT diagram. There are small differences in median host galaxy properties, including the stellar mass (M∗), star formation rate (SFR) and specific SFR (sSFR), and UVJ colours; however, these offsets are minor considering the wide spread of the distributions. Using SED modelling, we also demonstrate that the sample of z ∼ 2 star-forming galaxies observed by the MOSDEF survey is representative of the parent catalog of available such targets. We conclude that previous MOSDEF results on the evolution of star-forming galaxy emission-line properties were unbiased relative to the parent z ∼ 2 galaxy population.

Original languageEnglish
Pages (from-to)4337-4354
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Dec 1 2022

Bibliographical note

Funding Information:
We acknowledge support from NSF AAG grants AST1312780, 1312547, 1312764, 1313171, 2009313, 2009085, 2009278, grant AR-13907 from the Space Telescope Science Institute, and grant NNX16AF54G from the NASA ADAP program. We also ac- knowledge a NASA contract supporting the 'WFIRST Extragalactic Potential Observations (EXPO) Science Investigation Team' (15- WFIRST15-0004), administered by GSFC. Support for this work was also provided through the NASA Hubble Fellowship grant # HST - HF2-51469.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. We thank the 3D- HST collaboration, who provided spectroscopic and photometric catalogs used to select MOSDEF targets and to derive stellar population parameters. We acknowledge the First Carnegie Symposium in Honor of Leonard Searle for useful information and discussions that benefited this work. This research made use of ASTROPY, 2 a community-developed core PYTHON package for ASTRONOMY (Astropy Collaboration 2013, 2018). Finally, we wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W.M. Keck Foundation.

Publisher Copyright:
© 2022 The Author(s).


  • galaxies: ISM
  • galaxies: evolution
  • galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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