AstroWIT (noun): mental sharpness and inventiveness in astrophysics; keen intelligence.
Postdoctoral Researchers
Dr. Massissilia Hamadouche
Postdoctoral Researcher
Massi (she/her) is an expert in studying the star formation histories, stellar populations, and dynamics of quiescent galaxies at cosmic noon. Here at UMass, she is leading the JWST Deep Dive Project, a Cycle 2 program targeting 11 massive quiescent galaxies at z>3. With this premiere data set, we are reducing and modeling the spectrophotometry in collaboration with PI Francesco Valentino (faculty at the Cosmic Dawn Center in Copenhagen) to constrain the timescales of their rapid star formation, metal enrichment, and quenching.
Professional Webpage: https://massi-hamadouche.carrd.co
Dr. Samantha Berek
NSF Astronomy & Astrophysics postdoctoral Fellow
Sam (she/her) is an expert in globular clusters and dwarf galaxies. Her research focuses on understanding large, clustered star formation in the early universe through both direct high redshift observations and analysis of evolved star clusters in the local universe. At UMass, she is working to expand globular cluster and stellar clump datasets across redshift while developing comprehensive empirical models to link these data into an evolutionary sequence of massive star cluster formation from high redshift stellar clumps to local globular clusters.
Professional Webpage: https://samberek.github.io/samberek/index.html
PhD Students
Sarah Bodansky
PHD Thesis
Sarah (she/her) is a 4th year graduate student working on studying the evolution of dust mass in galaxies out to cosmic noon. Using data from the upcoming Toltec/LMT Ultra Deep Survey, Sarah will help us understand if the lack of evolution in the mean dust obscuration fraction (i.e., the ratio of the obscured star formation rate to total star formation rate in galaxies) with stellar mass and redshift is related to a lack of evolution in their dust masses. Alternatively, it may be that the dust geometry is complex. A careful analysis of this data will have us build a more complete empirical picture. Sarah is also interested in understanding the cold dust properties of quiescent galaxies across cosmic time using the same data set. Sarah completed an Independent Research Project with myself and Prof. Alex Pope working on this same topic. Sarah is also a former Astrobites writer; check out some of her work below!
Astrobites Articles: https://astrobites.org/author/sbodansky/
Aidan Cloonan
INDEPENDENT RESEARCH PROJECT
Aidan (he/they) is a 2nd year graduate student, co-advised by Dr. Sinclaire Manning, working with data from the JWST PANORAMIC Survey (PIs: Christina Williams and Pascal Oesch). Among some of the most puzzling early discoveries from JWST is the population of extremely red, often compact, galaxies ubiquitous in otherwise relatively small extragalactic deep field pointings. These red galaxies comprise a grab bag of interesting astrophysical objects: star-forming galaxies with such extreme column densities of dust that were previously invisible to surveys with the Hubble Space Telescope, actively accreting supermassive black holes within the first billion years of the Big Bang, the first ‘red and dead’ quiescent galaxies’, and some of the most distant known galaxies. The goal of this project is to first identify an exciting list of red objects, and then focus in on one of these populations to understand their physical properties in greater detail.
Professional Webpage: https://sites.google.com/view/apcloonan
Sam Cutler
phd thesis
Sam (he/him) is 6th year graduate student playing a leading role in the JWST PRIMER large survey by generating NIRCam photometric catalogs for the team. He is an expert at working with the HST and JWST photometry to improve our ability to control for the point spread functions of the telescopes, testing and developing Python-based algorithms optimized for JWST data. Scientifically, Sam is interested in understanding the morphologies of low-mass quiescent galaxies and the interplay between structure and formation scenarios. Sam is also leading the effort in generating and vetting a Hubble Space Telescope near-infrared morphological catalog in the 3D-DASH 1.7 square degree region. This follows his earlier work on the pilot COSMOS-DASH program (Cutler et al. 2022). With the 3D-DASH data set, Sam is currently working on a project studying the color gradients of massive galaxies.
Professional Webpage: https://samecutler.github.io/
Aubrey Medrano
Independent Research Project
Aubrey (she/her) is a 3rd year graduate student working together with myself and Prof. Mauro Giavalisco on measuring the spatially resolved properties of galaxies selected from the James Webb Space Telescope PRIMER survey. Aubrey will join the Pirate collaboration (PI: Erica Nelson), where we are developing a Bayesian framework to fit spatially resolved stellar populations of multi-wavelength photometric data sets. She comes with vast experience from her time working within the CEERS collaboration with Prof. Steve Finkelstein, and will continue to develop her working knowledge of data from NASA’s current flagship mission.
Will Jarvis
Independent Research Project
Will (he/him) is a 1st year graduate student working together with myself and Prof. Alexandra Pope on completing a systematic search for globular clusters in early massive quiescent galaxies in the James Webb Space Telescope MINERVA Treasury Program. In the context of the hierarchical merger paradigm, globular cluster populations give us important information to distinguish in-situ formation channels form ex-situ mergers and and accretion. Such an independent measure of the star formation history is invaluable when compared to the properties of the host galaxies, giving us important clues about the formation and assembly of massive galaxies.
Undergraduate Researchers
*Member of AstroTROUP during the 2023/2024, 2024/2025 , and 2025/2026 Academic Years
**Currently a post-bac research assistant
***Primarily supervised by Dr. Massi Hamadouche
Affiliated Postdoctoral Researchers
Dr. Jacqueline Antwi-Danso
Banting postdoctoral fellow
Jacqueline (she/her) is an expert on the stellar populations and chemical properties of the first massive, quiescent galaxies. Jacqueline is PI of a Cycle 2 JWST program to acquire spectroscopic follow-up of a premier sample of quiescent galaxy candidates at z>3 using JWST/NIRSpec multi-object spectroscopy. She has a full-time position at the University of Toronto through the prestigious Banting Fellowship, spending roughly 25% of her time visiting UMass Amherst, with a joint affiliation.
Professional Webpage: https://antwi-danso.carrd.co/
Other Academic Family Members
** otherwise known as former Astrowhit group members
Postdoctoral Scholars
Dr. Sinclaire Manning (UMass Amherst 2021-2025; NASA Hubble Postdoctoral Fellow) - current Assistant Professor at UMass Amherst
Dr. John Weaver (UMass Amherst 2022-2025; Photometric Catalog lead for the JWST UNCOVER Survey) - current Brinson Prize Postdoctoral Fellow at MIT
Dr. Mimi Song (UMass Amherst 2019-2023; Lead of the 3D-Herschel NASA/ADAP program)
Graduate Students
Yanzhe (Jenny) Zhang (UMass Amherst, 2022-2024, Independent Research Project co-advised with Prof. Houjun Mo)
Joyce Caliendo (UMass Amherst, 2021-2022, Independent Research Project co-advised with Prof. Alex Pope)
Maike Clausen (Exchange student from MPIA, 2021-2022) — current PhD student at the University of Edinburgh
Roxana Popescu (UMass Amherst, 2019-2022, 2nd year project) — current UMass graduate student
Dr. Mohammad Akhshik (University of Connecticut, 2016-2022, PhD Thesis) — Senior Quantitative Analyst in Finance/Energy at Quant in Baltimore MD
Jonathan Mercedes Feliz (University of Connecticut, 2018-2019) — current UConn graduate student
Undergraduate Students
David Marroquin (UMass Fall 2023 - Spring 2025; AstroTROUP)
Zachary Webb (UMass Spring 2020 - Spring 2024; Honors Thesis) - Lab Technician at Spectral Solutions Inc.
Lillian Wright (UMass Fall 2019 - Spring 2023) - current SNU graduate student
Ananya Sreelekha (UMass, Spring 2022-Spring 2023; Honors Independent Project) - current UToledo graduate student
Seth Martin (UMass, Spring 2022-Spring 2023; Honors Thesis)
Leonardo Drake (UMass, Spring 2022 - Summer 2022) - current UMass Physics masters student
Joyce Caliendo (University of Connecticut, 2018-2021)
Tyler Metivier (University of Connecticut, 2016-2020) — current UNH graduate student
Sam Cutler (University of Connecticut, 2016-2019) — current UMass Amherst graduate student
Alexandra Cain (University of Connecticut, 2018-2019)
Rochelle Horanzy (University of Connecticut, 2016-2018)
Mohammad Ashas (University of Connecticut, 2016-2018) — science teacher at Fairmont Private Schools, finishing a masters degree at Cal State Long Beach
Warren Sharpp (UMass Amherst/FCAD Internship, June-August 2016)
Daniel Lange-Vagle (Tufts University, 2014 - 2016)
Michael Alburger (NASA/GSFC Summer Internship, June-August 2014)
Recent Papers led by Team Members
Sam Cutler (6th year PhD candidate and current member of the group) recently published a paper in the Astrophysical Journal Letters exploring the morphological properties of low-mass quiescent galaxies at cosmic noon, finding evidence for two distinct formation pathways.
S. Cutler, K.E. Whitaker, J.R. Weaver, B. Wang, R. Pan, R. Bezanson, L. Furtak, I. Labbé, J. Leja, S. Price, Y. Cheng, M., Clausen, F. Cullen, P. Dayal, A. De Graaf, M. Dickinson, J. Dunlop, R. Feldmann, M. Franx, M. Giavalisco, K. Glazebrook, J. Greene, N. Grogin, G. Illingworth, A. Koekemoer, V. Kokorev, D. Marchesini, M. Maseda, T. Miller, T. Nanayakkara, E. Nelson, D. Setton, H. Shipley, K. Suess, F. Valentino, “Two Distinct Classes of Quiescent Galaxies at Cosmic Noon Revealed by JWST PRIMER and UNCOVER”, 2024, ApJ, 967, 23.
Lillian Wright (undergraduate group member from 2019-2023) recently published a paper in the Astrophysical Journal Letters detailing her study of the morphology of the first quiescent galaxies at z>3 using JWST imaging from the CEERS program. Lily is now a PhD student at SNU.
L. Wright, K.E. Whitaker, J.R. Weaver, S. Cutler, B. Wang, A. Carnall, K. Suess, R. Bezanson, E. Nelson, T. Miller, K. Ito, F. Valentino, “Remarkably Compact Quiescent Candidates at 3<z<5 in JWST-CEERS”, 2024, ApJL, 964, 10.
Maike Clausen (former group member from 2022-2023) recently published a paper to the Astrophysical Journal studying the sizes of recently quenched galaxies relative to older quiescent galaxies in the 3D-DASH Hubble Space Telescope imaging data set. Maike is now a PhD student at the University of Edinburgh.
M. Clausen, K.E. Whitaker, I. Momcheva, S. Cutler, K. Suess, J.R. Weaver, T. Miller, A. van der Wel, S. Wuyts, D. Wake, P. van Dokkum, R. Bezanson, G. Brammer, M. Franx, E. Nelson, N. Forster-Schreiber, “3D-DASH: The evolution of size, shape, and intrinsic scatter in populations of young and old quiescent galaxies at 0.5<z<3”, 2024, ApJ, 791, 99.
John Weaver (postdoctoral group member from 2022-present) led a paper recently published a manuscript in the Astrophysical Journal describing the details of the JWST UNCOVER photometric catalogs. The catalogs are publicly available for all to use!
Weaver, J., Cutler, S., Pan, R., Whitaker, K.E., Labbé, I., Price, S., Bezanson, R., Brammer, G., Marchesini, D., Leja, J., Wang, B., Furtak, L., Zitrin, A., Atek, H., Coe, D., Dayal, P., van Dokkum, P., Feldmann, R., Forster Schreiber, N., Franx, M., Fujimoto, S., Fudamoto, Y., Glazebrook, K., de Graaff, A., Greene, J., Juneau, S., Kassin, S., Kriek, M., Khullar, G., Maseda, M., Mowla, L., Muzzin, A., Nanayakkara, T., Nelson, E., Oesch, P., Pacifici, C., Papovich, C., Setton, D., Shapley, A., Smit, R., Stefanon, M., Taylor, E., Weibel, A., Williams, C., “The UNCOVER Survey: A first-look HST+JWST catalog of 50,000 galaxies near Abell 2744 and beyond”, 2024, ApJS, 270, 7.
Jacqueline Antwi-Danso (remote postdoctoral group member from 2023-present) led the analysis of ground-based spectroscopic data from the Keck Telescope, confirming one of the most distant known quenched galaxies (with two additional probable candidates). Jacqueline has an approved Cycle 2 JWST program to follow-up these exciting targets.
Antwi-Danso, J., Papovich, C., Esdaile, J., Nanayakkara, T., Glazebrook, K., Hutchison, T., Whitaker, K., Marsan, Z. C., Diaz, R., Marchesini, D., Muzzin, A., Tran, K.-V., Setton, D., Kaushal, Y., Speagle, J., Cole, J., “The FENIKS Survey: Spectroscopic Confirmation of Massive Quiescent Galaxies at z ~ 3-5”, 2025, ApJ, 978, 90.
Mo Akhshik (former PhD student group member from 2016-2023) led the analysis of Hubble Space Telescope grism spectroscopy from the REQUIEM survey, with the survey paper being the final chapter of his PhD thesis. Mo is currently a senior analyst at Quant in Baltimore, Maryland.
Akhshik, M., Whitaker, K.E., Leja, J., Richard, J., Spilker, J., Song, M., Brammer, G., Bezanson, R., Ebeling, H., Gallazzi, A., Mahler, G., Mowla, L., Nelson, E., Pacifici, C., Sharon, K., Toft, S., Williams, C., Wright, L., Zabl, J., “REQUIEM-2D: A diversity of formation pathways in a sample of spatially-resolved massive quiescent galaxies at z~2”, 2023, ApJ, 943, 179.