Dust star-forming galaxies across cosmic time
File(s)
Author(s)
Parmar, Ayushi
Type
Thesis
Abstract
While significant progress has been made in studying dusty star-forming galaxies (DSFGs), many questions remain regarding their physical properties, environments, and evolution. Future advances will depend on high-resolution, multiwavelength observations from current and upcoming facilities, enabling precise measurements of DSFG redshifts, morphologies, and kinematics to clarify their role in cosmic structure formation and stellar mass build-up. To begin with, we investigate the number counts and infrared luminosity functions (IRLFs) for the
far-infrared (FIR) extension of the Euclid mock galaxy catalogue, MAMBO. We find good agreement between our results and the literature. However, applying Euclid and SPIRE/PACS
limits and exploring environmental dependencies reveals that a significantly larger mock sample (∼ 30 times bigger) is required to draw robust conclusions about the IRLF’s environmental
trends for a near-IR/FIR-selected population. We also present a SCUBA-2 analysis of the Herschel -SPIRE Dark Field (SDF), currently the deepest FIR field. We detect 36 sources at 850μm and cross-identify them with ancillary data, identifying 20 as SPIRE-dropouts; candidate high-redshift galaxies. Photometric redshift estimates place the SPIRE-detected sources primarily at 2 < z < 3, while SPIRE-dropouts lie at z > 3. FIR/submillimetre SED fitting suggests the stacked SPIRE-dropouts contribute ∼ 15% to the cosmic star formation rate density (CSFRD) at z = 6.7. The SPIRE-detected sources show a CSFRD excess at z ∼ 1, possibly hinting at large-scale structure in the SDF. Finally, we present SMA follow-up of 12 SPIRE-dropouts across various fields. Photometric analysis identifies optical/NIR counterparts for four sources, including a multiple system and a potential lens. Four remain without optical/NIR counterparts, and four are undetected with the SMA. FIR/millimetre SED fitting estimates an average redshift of z = 7.4 for the SMA sample. In closing, we discuss the implications of these results and the future avenues of research produced by this work.
far-infrared (FIR) extension of the Euclid mock galaxy catalogue, MAMBO. We find good agreement between our results and the literature. However, applying Euclid and SPIRE/PACS
limits and exploring environmental dependencies reveals that a significantly larger mock sample (∼ 30 times bigger) is required to draw robust conclusions about the IRLF’s environmental
trends for a near-IR/FIR-selected population. We also present a SCUBA-2 analysis of the Herschel -SPIRE Dark Field (SDF), currently the deepest FIR field. We detect 36 sources at 850μm and cross-identify them with ancillary data, identifying 20 as SPIRE-dropouts; candidate high-redshift galaxies. Photometric redshift estimates place the SPIRE-detected sources primarily at 2 < z < 3, while SPIRE-dropouts lie at z > 3. FIR/submillimetre SED fitting suggests the stacked SPIRE-dropouts contribute ∼ 15% to the cosmic star formation rate density (CSFRD) at z = 6.7. The SPIRE-detected sources show a CSFRD excess at z ∼ 1, possibly hinting at large-scale structure in the SDF. Finally, we present SMA follow-up of 12 SPIRE-dropouts across various fields. Photometric analysis identifies optical/NIR counterparts for four sources, including a multiple system and a potential lens. Four remain without optical/NIR counterparts, and four are undetected with the SMA. FIR/millimetre SED fitting estimates an average redshift of z = 7.4 for the SMA sample. In closing, we discuss the implications of these results and the future avenues of research produced by this work.
Version
Open Access
Date Issued
2025-08-08
Date Awarded
01/02/2026
License URL
Advisor
Clements, Dave
Sponsor
Particle Physics and Astronomy Research Council (Great Britain)
Grant Number
ST/T506151/1
ST/V506734/1
ST/W507519/1
Publisher Department
Department of Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)