Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at 1<z<4
Abstract
In this dissertation, I aim to improve our knowledge of galaxy evolution during the first half of cosmic history. To do so I use a sample of ∼ 7000 high signal-to-noise galaxies from the FourStar Galaxy Evolution Survey, which provides multi-wavelength imaging and accurate redshifts, allowing analysis of these galaxies’ physical properties. I also employ several statistical grouping methods to classify galaxies and build composite spectral energy distributions based on these classifications.
To begin, I analyze galaxies that fall between the blue star-forming cloud and the red quiescent sequence in color space, known as the ‘green valley’. Thought to be in the process of shutting down star formation, these galaxies hold the keys to understanding the mechanisms which cause the cessation of star formation, a key point in a galaxy’s evolution. I find that such galaxies reside between the star-forming and quiescent populations not only in color and star formation rate, but also in size, Sérsic index, and Hα equivalent width. This suggests that the quenching processes responsible produce changes in these parameters on similar timescales. Additionally, the number density of these green valley galaxies increased by more than a factor of ten from z = 3 to z = 1, while post-starburst galaxies remain at a roughly constant number density over the same time span.
I then explore the bluest, most vigorously star-forming galaxies, representing the other extreme of galaxy histories. These galaxies appear much more frequently at z ∼ 3 than in the local universe and show extreme nebular emission features, consistent with their proposed role in cosmic reionization. I also find that they are clustered around an overdensity at z = 3.47, in contrast to locally, where galaxies in clusters are preferentially found to be quenched.
Lastly, I investigate the effects of dust attenuation and reddening on galaxy observations at redshifts 1 < z < 3. This enables improved constraints on intrinsic galaxy properties such as star formation rate. I find that the average dust properties do not change drastically from z ∼ 0 to z ∼ 2, closely replicating a starburst type dust law.
Subject
galaxies: evolutiongalaxies: formation
galaxies: high-redshift
galaxies: starburst
large-scale structure of universe
ultraviolet: galaxies
dust extinction
Citation
Forrest, Benjamin W (2018). Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at 1<z<4. Doctoral dissertation, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /173400.
Related items
Showing items related by title, author, creator and subject.
-
Cohn, Jonathan Hall (2022-07-12)In this dissertation, I investigate the formation and evolution of galaxies by studying two extreme populations — young, highly star forming galaxies (SFGs) at z > 2, and old, quiescent galaxies in the local Universe that ...
-
Tomczak, Adam R.; Quadri, Ryan F.; Tran, Kim-Vy H.; Labbé, Ivo; Straatman, Caroline M. S.; Papovich, Casey; Glazebrook, Karl; Allen, Rebecca; Brammer, Gabriel B.; Kacprzak, Glenn G.; Kawinwanichakij, Lalitwadee; Kelson, Daniel D.; McCarthy, Patrick J.; Mehrtens, Nicola; Monson, Andrew J.; Persson, S. Eric; Spitler, Lee R.; Tilvi, Vithal; van Dokkum, Pieter (The Astrophysical Journal, 2014)
-
Kwan, J.; Sánchez, C.; Clampitt, J.; Blazek, J.; Crocce, M.; Jain, B.; Zuntz, J.; Amara, A.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; DeRose, J.; Dodelson, S.; Eifler, T. F.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Hartley, W. G.; Kacprzak, T.; Kirk, D.; Krause, E.; MacCrann, N.; Miquel, R.; Park, Y.; Ross, A. J.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Troxel, M. A.; Wechsler, R. H.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R. (Monthly Notices of the Royal Astronomical Society, 2017)