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The High Latitude Spectroscopic Survey on the Nancy Grace Roman Space Telescope

Wang, Yun and Zhai, Zhongxu and Alavi, Anahita and Massara, Elena and Pisani, Alice and Benson, Andrew and Hirata, Christopher M. and Samushia, Lado and Weinberg, David H. and Colbert, James and Doré, Olivier and Eifler, Tim and Heinrich, Chen and Ho, Shirley and Krause, Elisabeth and Padmanabhan, Nikhil and Spergel, David and Teplitz, Harry I. (2022) The High Latitude Spectroscopic Survey on the Nancy Grace Roman Space Telescope. Astrophysical Journal, 928 (1). Art. No. 1. ISSN 0004-637X. doi:10.3847/1538-4357/ac4973.

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The Nancy Grace Roman Space Telescope will conduct a High Latitude Spectroscopic Survey (HLSS) over a large volume at high redshift, using the near-IR grism (1.0–1.93 μm, R = 435–865) and the 0.28 deg² wide-field camera. We present a reference HLSS that maps 2000 deg² and achieves an emission-line flux limit of 10⁻¹⁶ erg s⁻¹ cm⁻² at 6.5σ, requiring ∼0.6 yr of observing time. We summarize the flowdown of the Roman science objectives to the science and technical requirements of the HLSS. We construct a mock redshift survey over the full HLSS volume by applying a semianalytic galaxy formation model to a cosmological N-body simulation and use this mock survey to create pixel-level simulations of 4 deg² of HLSS grism spectroscopy. We find that the reference HLSS would measure ∼10 million Hα galaxy redshifts that densely map large-scale structure at z = 1–2 and 2 million [O III] galaxy redshifts that sparsely map structures at z = 2–3. We forecast the performance of this survey for measurements of the cosmic expansion history with baryon acoustic oscillations and the growth of large-scale structure with redshift-space distortions. We also study possible deviations from the reference design and find that a deep HLSS at f_(line) > 7 × 10⁻¹⁷ erg s⁻¹ cm⁻² over 4000 deg² (requiring ∼1.5 yr of observing time) provides the most compelling stand-alone constraints on dark energy from Roman alone. This provides a useful reference for future optimizations. The reference survey, simulated data sets, and forecasts presented here will inform community decisions on the final scope and design of the Roman HLSS.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wang, Yun0000-0002-4749-2984
Zhai, Zhongxu0000-0001-7984-5476
Alavi, Anahita0000-0002-8630-6435
Pisani, Alice0000-0002-6146-4437
Benson, Andrew0000-0001-5501-6008
Hirata, Christopher M.0000-0002-2951-4932
Samushia, Lado0000-0002-1609-5687
Weinberg, David H.0000-0001-7775-7261
Colbert, James0000-0001-6482-3020
Doré, Olivier0000-0002-5009-7563
Eifler, Tim0000-0002-1894-3301
Heinrich, Chen0000-0003-0426-1948
Krause, Elisabeth0000-0001-8356-2014
Spergel, David0000-0002-5151-0006
Teplitz, Harry I.0000-0002-7064-5424
Additional Information:© 2022 The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 October 5; revised 2021 December 20; accepted 2022 January 7; published 2022 March 22. This work is supported in part by NASA grant 15-WFIRST15-0008, Cosmology with the High Latitude Survey Roman Science Investigation Team. This work was done in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. We thank Jeff Kruk for cross-checking the Roman ETC and input on the Roman grism simulations, James Rhoads for communications on Reference Roman HLIS+HLSS sky background assumptions, and Lukas Wenzl for helpful comments on a draft of the paper.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:Dark energy; Cosmology
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Dark energy (351); Cosmology (343)
Record Number:CaltechAUTHORS:20220223-214616322
Persistent URL:
Official Citation:Yun Wang et al 2022 ApJ 928 1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113567
Deposited By: George Porter
Deposited On:24 Feb 2022 21:51
Last Modified:06 Apr 2022 18:57

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