Numerous studies show that galaxies in dense environments often exhibit a decline in their star formation rates (SFR) which can be observed in the SFR-density relation, referred to as "environmental quenching." However, at redshift z > 1, there exists tension among different studies regarding the evolution of the SFR-density relation. One source of this uncertainty arises from the lack of spectroscopy of galaxies at z > 1, which can result in inaccurately estimating the environmental density of galaxies in extragalactic fields. To address this issue, we present the CANDELS-Herschel Environmental Spectroscopic Survey (CHESS) designed to increase the spectroscopic completeness in CANDELS COSMOS, UDS, and EGS fields at the redshift range of 0.5 < z < 1.7. This spectroscopic catalog focuses on the Herschel-selected galaxies with stellar masses M* > 10^{10} solar masses to accurately measure SFR for those sources and ensure an unbiased spectroscopic sampling at our redshift range. From the CHESS observation program, we obtained 677 new high-quality spectroscopic redshifts in the COSMOS, UDS, and EGS fields, including serendipitous objects. By combining our new spectroscopic catalog with the existing archival spectroscopic redshifts, we are able to construct improved overdensity maps of galaxies in all five CANDELS fields using the Monte Carlo Voronoi tessellation method. With our new CHESS catalog, we are able to detect new overdensity regions in CANDELS COSMOS, UDS, and EGS fields as well as generate an updated SFR-density relation. This new dataset allows us to probe deeper into the large-scale structure at $0.5 < z < 1.7$, and offer us new insights into the evolution of SFR with varying redshifts.

Library of Congress Subject Headings

Stars--Formation; Galaxies--Evolution; Galaxies--Clusters; Red shift; Astronomical spectroscopy

Publication Date


Document Type


Student Type


Degree Name

Astrophysical Sciences and Technology (MS)

Department, Program, or Center

School of Physics and Astronomy (COS)


Jeyhan Kartaltepe

Advisor/Committee Member

Andrew Robinson

Advisor/Committee Member

Joshua Faber


RIT – Main Campus

Plan Codes