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Predicting Hα emission-line galaxy counts for future galaxy redshift surveys

Merson, Alexander I. and Wang, Yun and Benson, Andrew and Faisst, Andreas and Masters, Daniel and Kiessling, Alina and Rhodes, Jason (2018) Predicting Hα emission-line galaxy counts for future galaxy redshift surveys. Monthly Notices of the Royal Astronomical Society, 474 (1). pp. 177-196. ISSN 0035-8711. doi:10.1093/mnras/stx2649.

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Knowledge of the number density of Hα emitting galaxies is vital for assessing the scientific impact of the Euclid and Wide Field Infrared Survey Telescope (WFIRST) missions. In this work, we present predictions from a galaxy formation model, GALACTICUS, for the cumulative number counts of Hα-emitting galaxies. We couple GALACTICUS to three different dust attenuation methods and examine the counts using each method. A χ^2 minimisation approach is used to compare the model predictions to observed galaxy counts and calibrate the dust parameters. We find that weak dust attenuation is required for the GALACTICUS counts to be broadly consistent with the observations, though the optimum dust parameters return large values for χ2, suggesting that further calibration of GALACTICUS is necessary. The model predictions are also consistent with observed estimates for the optical depth and the Hα luminosity function. Finally, we present forecasts for the redshift distributions and number counts for two Euclid-like and one WFIRST-like surveys. For a Euclid-like survey with redshift range of 0.9 ≤ z ≤ 1.8 and Hα+[NII] blended flux limit of 2 × 10^(−16) erg s^(−1) cm^(−2), we predict a number density between 3900 and 4800 galaxies per square degree. For a WFIRST-like survey with redshift range of 1 ≤ z ≤ 2 and blended flux limit of 1 × 10^(−16) erg s^(−1) cm^(−2), we predict a number density between 10 400 and 15 200 galaxies per square degree.

Item Type:Article
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URLURL TypeDescription Paper
Benson, Andrew0000-0001-5501-6008
Faisst, Andreas0000-0002-9382-9832
Masters, Daniel0000-0001-5382-6138
Rhodes, Jason0000-0002-4485-8549
Additional Information:© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 October 6. Received 2017 October 6; in original form 2017 May 4. We thank James Colbert, Ivano Baronchelli, Shoubaneh Hemmati and Kirsten Larson for many helpful conversations. We also thank the anonymous referee for their valuable and constructive comments that helped greatly improve the manuscript. AM acknowledges sponsorship of a NASA Postdoctoral Program Fellowship. AM, AK and JR were supported by JPL, which is run under contract by California Institute of Technology for NASA. This work was supported by NASA ROSES grant 12-EUCLID12-0004 and by NASA grant 15-WFIRST15-0008 “Cosmology with the High Latitude Survey” WFIRST Science Investigation Team (SIT).
Funding AgencyGrant Number
NASA Postdoctoral FellowshipUNSPECIFIED
Subject Keywords:methods: numerical, galaxies: formation, galaxies: statistics, large-scale structure of Universe
Issue or Number:1
Record Number:CaltechAUTHORS:20180301-081149157
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Official Citation:Alexander Merson, Yun Wang, Andrew Benson, Andreas Faisst, Daniel Masters, Alina Kiessling, Jason Rhodes; Predicting Hα emission-line galaxy counts for future galaxy redshift surveys, Monthly Notices of the Royal Astronomical Society, Volume 474, Issue 1, 11 February 2018, Pages 177–196,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85024
Deposited By: Ruth Sustaita
Deposited On:01 Mar 2018 18:45
Last Modified:15 Nov 2021 20:25

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