J/MNRAS/491/5524 Discovering Large-Scale Structure in ORELSE Survey (Hung+ 2020)
Establishing a new technique for discovering large-scale structure using the
ORELSE survey.
Hung D., Lemaux B.C., Gal R.R., Tomczak A.R., Lubin L.M., Cucciati O.,
Pelliccia D., Shen L., Le Fevre O., Wu P.-F., Kocevski D.D., Mei S.,
Squires G.K.
<Mon. Not. R. Astron. Soc. 491, 5524 (2020)>
=2020MNRAS.491.5524H 2020MNRAS.491.5524H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; Galaxies, optical ; Spectroscopy ; Redshifts
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: groups: general - galaxies: high-redshift -
techniques: spectroscopic - techniques: photometric
Abstract:
The Observations of Redshift Evolution in Large-Scale Environments
(ORELSE) survey is an ongoing imaging and spectroscopic campaign
initially designed to study the effects of environment on galaxy
evolution in high-redshift (z∼1) large-scale structures. We use its
rich data in combination with a powerful new technique, Voronoi
tessellation Monte-Carlo (VMC) mapping, to search for serendipitous
galaxy overdensities at 0.55<z<1.37 within 15 ORELSE fields, a
combined spectroscopic footprint of ∼1.4 square degrees. Through
extensive tests with both observational data and our own mock galaxy
catalogs, we optimize the method's many free parameters to maximize
its efficacy for general overdensity searches. Our overdensity search
yielded 402 new overdensity candidates with precisely measured
redshifts and an unprecedented sensitivity down to low total
overdensity masses Mtot>5*1013M☉). Using the mock
catalogs, we estimated the purity and completeness of our overdensity
catalog as a function of redshift, total mass, and spectroscopic
redshift fraction, finding impressive levels of both 0.92/0.83 and
0.60/0.49 for purity/completeness at z=0.8 and z=1.2, respectively,
for all overdensity masses at spectroscopic fractions of ∼20%. With
VMC mapping, we are able to measure precise systemic redshifts,
provide an estimate of the total gravitating mass, and maintain high
levels of purity and completeness at z∼1 even with only moderate
levels of spectroscopy. Other methods (e.g., red-sequence
overdensities and hot medium reliant detections) begin to fail at
similar redshifts, which attests to VMC mapping's potential to be a
powerful tool for current and future wide-field galaxy evolution
surveys at z∼1 and beyond.
Description:
Parameters for all 402 new overdensity candidates found across 15
ORELSE fields with their redshifts, transverse positions, fitted
masses, and spectroscopic fractions. The parameters given in this file
are ORELSE field, field ID number, number of points used in the
Gaussian fit, redshift mean and dispersion and associated errors,
equatorial coordinates, estimated total mass and associated errors,
and spectroscopic fraction. The candidates were cut by spectroscopic
fraction such that only those with a spectroscopic fraction of 0.05
were included. All logarithms are base 10.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
candid.dat 86 402 All Overdensity Candidates found in 15 ORELSE
fields
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Byte-by-byte Description of file: candid.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 ---- Field Name of the field the overdensity candidate
is in
9- 12 I4 ---- Id ID number of the overdensity candidate in
the given field
14- 15 I2 ---- Points Number of points used in the Gaussian fit,
i.e., the number of redshift slices the
candidate appears in
17- 22 F6.4 ---- z Mean redshift of the overdensity candidate
24- 29 F6.4 ---- e_z 1 sigma redshift uncertainty
31- 36 F6.4 ---- sigma Redshift dispersion of the overdensity
candidate, described by the width of the
Gaussian fit
38- 43 F6.4 ---- e_sigma 1 sigma redshift dispersion uncertainty
45- 53 F9.5 deg RAdeg Right ascension (J2000.0)
55- 62 F8.5 deg DEdeg Declination (J2000.0)
64- 68 F5.2 [Msun] logMass Total mass
70 A1 --- --- [+]
71- 74 F4.2 [Msun] E_logMass 1 sigma positive uncertainty on logMass
76 A1 --- --- [-]
77- 80 F4.2 [Msun] e_logMass 1 sigma negative uncertainty on logMass
82- 86 F5.3 ---- SpecFrac Fraction of spectroscopic members in
overdensity candidate
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Acknowledgements:
Denise Hung, hungd(at)hawaii.edu
Hung D, Lemaux BC, Gal RR, et al, Establishing a New Technique for
Discovering Large-Scale Structure Using the ORELSE Survey, Monthly
Notices of the Royal Astronomical Society 2019, 1-32,
doi:10.1093/mnras/stz3164. Reprinted by permission of Oxford
University Press on behalf of the Royal Astronomical Society. (c) 2019
The Author(s). All rights reserved. For permissions, please email
This table is not distributed under the
open access license of this publication.
(End) Denise Hung [IfA, Honolulu], Patricia Vannier [CDS] 09-Dec-2019