Abstract

How dust impacts galaxy evolution in the early universe is largely unconstrained due to under sampling in the rest-frame far-IR. New detections of optically dark galaxies (galaxies that have no rest-frame optical counterparts) have shown that there is a population of galaxies that have largely gone undetected due to this under sampling. CHAMPS (PI: A. Faisst) is designed to study how dust impacts galaxy evolution in the early universe by complimenting MIRI and NIRCam observations from JWST in COSMOS-Web and PRIMER with new ALMA observations focused at 1.2 mm (ν = 250 GHz). This thesis presents the data reduction and source detection of observations taken by CHAMPS, the largest ALMA blank-field program of its kind, spanning 0.18 deg2 in the COSMOS field. The reduction of CHAMPS was subdivided into sections to optimize our computing time, a full reduction mosaic is currently ongoing. We used two methods for source detection, blindly detecting Gaussian peaks in our data above a peak pixel value of SNR ≥ 5, and a deeper observation method using MIRI priors to target detections. This has left us with two catalogs: a blind catalog with 916 sources detected, and a targeted, MIRI prior catalog with 1,113 sources that have been detected above an integrated SNR > 3. Using these two catalogs, we identified 381 sources overlapping between our two detection methods, suggesting them to be real extragalactic objects. Furthermore, we identified 32 AGN detected in CHAMPS by cross matching with already known objects. A bias has been detected in our source detection due to an issue affecting our synthesis beam sizes resulting from our reduction. This has caused a bias against detecting faint and diffuse sources with a blind search and caused an increase of false detections in our targeted MIRI prior catalog. The redshift distribution for the confirmed sources (those identified by both detection methods) identified 99 galaxies at z < 2, 168 galaxies at 2 < z < 4, and 75 galaxies at z > 4.

Library of Congress Subject Headings

Galaxies--Evolution; Galaxies--Observations; Dust--Analysis

Publication Date

8-2025

Document Type

Thesis

Student Type

Graduate

Degree Name

Astrophysical Sciences and Technology (MS)

Department, Program, or Center

Physics and Astronomy, School of

College

College of Science

Advisor

Jeyhan Kartaltepe

Advisor/Committee Member

Andrew Robinson

Campus

RIT – Main Campus

Plan Codes

ASTP-MS

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