The millimeter-wavelength source catalog from the third-generation South Pole Telescope survey

The South Pole Telescope (SPT) is at the frontier of measuring the cosmic microwave background (CMB) and surveying the millimeter sky. The third generation SPT camera (SPT-3G) observed a 1,696 square degree patch of sky during the austral winters of 2019-2023, resulting in high-resolution CMB maps with a factor of six improved noise levels over the first generation SPT survey. The SPT-3G camera’s observing frequencies are centered roughly at 90, 150, and 220 GHz (3.3, 2, and 1.4 mm), which results in data suitable for large-angular-scale science including CMB studies as well as comparatively small-scale discoveries of individual galaxies, galaxy clusters, and transient objects including flaring stars and active galactic nuclei (AGN). In this thesis, I present the point-source-finding pipeline for the SPT-3G survey; the static, emissive point source catalog; and differential source counts from five years of data. This work is the first point source catalog data release for the aforementioned survey. I detected 28,736 objects with signal-to-noise of at least five in one or more bands, corresponding to 1.24, 1.44, and 4.57 mJy at 90, 150, and 220 GHz, respectively, with approximately arcminute resolution. Comparisons to external catalogs in radio, infrared, and millimeter frequencies leave 14,565 SPT-3G sources (51% of the whole catalog) without counterparts at other wavelengths or already cataloged in a previous millimeter survey. The spectral indices of these sources reveal two distinct populations: flat- and falling-spectrum sources indicating synchrotron radiation and rising-spectrum sources corresponding to thermal emission. The synchrotron sources are AGN while the thermal sources are dust- enshrouded galaxies, which are bright at millimeter wavelengths due to the reprocessing of starlight by dust. Many of the dusty galaxies are expected to be at high redshift (z>1) in a subpopulation of submillimeter galaxies (SMGs), which may also be strongly gravitationally lensed. The catalog comprises 12,464 synchrotron sources and 16,272 dusty sources (4,303 of which are strong SMG candidates). The SPT-3G point source catalog in the millimeter sky probes a high mean redshift of objects, enabling the future study of the early universe’s galaxies and structure formation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Astronomy

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Archipley, Melanie Ann

Contributors dc:contributor

• Vieira, Joaquin
• Crawford, Thomas
• Holder, Gil
• Menanteau, Felipe
• Fields, Brian

• Observations
• Galaxies
• Cosmic Microwave Background (cmb)
• Millimeter Wave Astronomy
• High Redshift Galaxies
• Submillimeter Galaxies
• Active Galactic Nuclei (agn)
• Cosmology
• Synchrotron Radiation
• Dust
• Astronomy
• Catalogs
• Surveys

Statement dc:rights

• Copyright 2024 Melanie Ann Archipley

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/125711

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F125711