Hamid Hassani

PhD candidate at the University of Alberta

I study how stars, stellar clusters, and the ISM evolve across cosmic time using JWST, HST, and VLA data within PHANGS, and I developed Neloura, a platform for astronomical image visualization, cataloging, SED inspection, and interactive source finding designed for the next generation of datasets such as SKA.

Hamid Hassani smiling in a colorful setting

Research focus

I am currently focused on multi-wavelength diagnostics that connect dust physics, stellar clusters, and the ISM across nearby galaxies, combining infrared, optical, ultraviolet, millimeter, and radio observations with advanced visualization tools to uncover how stellar clusters evolve and how feedback, dust, and environment shape their emission.

Observational programs

  • AstroSat/UVIT: PHANGS–AstroSat–Color Survey (PI; 12 hr)
  • AstroSat/UVIT: PHANGS–AstroSat–Dwarfs Survey (PI; 15 hr)
  • JWST: PHANGS–JWST Treasury (Co-I; 150 hr total)
  • JWST: Massive star formation in galactic centres (Co-I; 62 hr)
  • HST: Cycles 31–32 cluster & dust mapping (Co-I; 288 orbits)
  • HST: HST+JWST+ALMA Treasury survey (Co-I; 169 orbits)
  • ALMA: The 10 pc Survey of Molecular Clouds & Feedback (Co-I; 600+ hr)
  • MeerKAT: PHANGS dwarf-galaxy atomic gas mapping (Co-PI; 60 hr)
Neloura interface showing multi-panel FITS workflows Neloura catalog overlays and diagnostics Neloura catalog overlays and diagnostics Neloura catalog overlays and diagnostics
Next-gen astronomical image visualization and analysis.

Neloura

Powered by Python and JavaScript, Neloura delivers in-browser visualization of large astronomical mosaics, catalogs, SEDs, and interactive source finding—no installation required. It is designed for the massive datasets expected from SKA, Roman, and other next-generation missions.

Advocacy & representation

Student governance roles that keep my research accountable to people first.

    From 2023 to 2024, I served in several leadership and advocacy roles dedicated to strengthening the voice of graduate and post-secondary students at institutional, municipal, and provincial levels. As Vice President External of the Graduate Students’ Association (GSA), I led advocacy efforts on behalf of more than 10,000 graduate students, working closely with municipal and provincial decision-makers. In parallel, I co-chaired the Alberta Graduate Provincial Advocacy Council (ab-GPAC), coordinating province-wide policy initiatives representing over 20,000 graduate students across Alberta. My advocacy extended to the city level as Vice-Chair of the Edmonton Student Alliance (ESA), where I represented nearly 100,000 post-secondary students in discussions with city leadership. I also served as a Graduate Student Representative on the University of Alberta Alumni Council, contributing student perspectives to institutional policy discussions. More recently, I have continued to support academic community building and governance as an Ambassador for the Graduate Physics Student Association (GPSA).

Current research

I focus on how stars and stellar clusters emerge from dust, and how environment shapes their earliest phases—connecting JWST imaging to multi-wavelength tracers of feedback and star formation.

Current project · 2025 (PhD)

The radio–mid‑infrared signature of cluster evolution

We investigate how 3 GHz radio continuum and mid-infrared (21 µm) emission jointly trace the life cycle of massive stars and stellar clusters, from their dust-embedded formation to feedback-dominated evolutionary stages, across nearby galaxies.

Traditionally, radio and infrared star-formation tracers have been calibrated using integrated galaxy measurements, where diverse regions are spatially blended and the underlying physics is effectively averaged. Establishing the radio–mid-infrared connection on the scale of individual star-forming regions and stellar clusters is therefore essential, as it enables phase-resolved tracking of cluster evolution (from embedded to exposed), isolates environmental dependencies, and provides dust-insensitive diagnostics in regimes where optical tracers break down.

NGC 4254 VLA+Effelsberg 8 GHz map NGC 4254 VLA 3 GHz map
New VLA 3GHZ
VLA+Effelsberg 8GHz
Hassani et al. in prep 2025
K.T. Chyzy, M. Ehle, R. Beck 2007 A&A.

Published papers as first author

Recent lead-author work using multi-wavelength data from JWST, HST, ALMA, and AstroSat, with each entry noting the analysis or tools I led.

JWST mid-infrared composite of nearby galaxies Source catalog overlays from the Hidden Life of Stars paper Source catalog overlays from the Hidden Life of Stars paper
Assembly of young, optically bright stellar clusters traced by strong 21 µm emission in nearby galaxies.
Dusty, embedded stellar clusters that are faint in Hα, revealed by bright 21 µm emission in nearby galaxies.
Spectral energy distribution of a rare dusty stellar cluster with little/no bright Hα emission, observed with JWST and HST.
2025 · arXiv e-prints

The Hidden Life of Stars: Embedded Beginnings to AGB Endings in the PHANGS-JWST Sample. I. Catalog of Mid-IR Sources

My research with JWST has defined a new framework for tracing how stellar clusters evolve from their dusty, embedded birth to their exposed and evolved stages across nearby galaxies. I led the first systematic censuses of compact mid-infrared sources using JWST imaging, identifying and characterizing tens of thousands of stellar clusters spanning the full evolutionary sequence—from deeply embedded stellar clusters to red-supergiant and AGB-dominated populations.

Read on arXiv →
AstroSat ultraviolet atlas montage
AstroSat/UVIT observations of 31 nearby galaxies in 9 filters from 1480 Å to 2790 Å.
2024 · ApJS

The PHANGS-AstroSat Atlas of Nearby Star-forming Galaxies

Using AstroSat/UVIT, I calibrated over 150 maps of 31 nearby galaxies at ~1.4″ (25–160 pc) resolution, providing the sharpest wide-field UV images across 9 filters from 1480 Å to 2790 Å. Combined with MUSE Hα and ALMA CO(2–1) data, these maps reveal that the FUV/Hα ratio varies by nearly two dex, decreasing in high-pressure centers and bars—evidence that clusters clear their natal gas more rapidly in dense environments. After correcting for attenuation and controlling for stellar mass and metallicity, FUV/Hα increases with stellar population age, tracing cluster emergence as H II regions fade. We also identified extended ultraviolet disks—faint, outer-disk structures marking recent star formation beyond the optical radius.

Read the paper → Data→
21 micron compact source population visualization
A strong correlation between L21 µm and dust-corrected L holds over >5 orders of magnitude in stellar clusters of nearby galaxies, linking mid‑infrared dust emission to the optically bright phase of stellar clusters.
2023 · ApJL

PHANGS-JWST First Results: The 21 µm Compact Source Population

My research asks how long massive clusters remain hidden in their dusty, embedded phase before emerging as feedback-dominated systems. I find that such regions are rare in nearby galaxies, implying a short lifetime of only a few million years. Combining mid-infrared and optical diagnostics, I show that 21 µm emission robustly traces nascent (< 5 Myr) clusters and correlates tightly with Hα emission over five orders of magnitude

Read the letter →
Spectral energy distribution fit for the Magellanic Clouds
First resolved magnetic-field strength maps of the LMC and SMC.
2022 · MNRAS

The Role of Thermal and Non-thermal Processes in the ISM of the Magellanic Clouds

Using single-dish and interferometric observations spanning three frequency bands from 0.16 to 4.8 GHz—including GLEAM/MWA (166 MHz) as the low-frequency SKA precursor, and ATCA and Parkes data—I combined multi-band radio maps with de-reddened Hα emission to produce the spatially resolved thermal and non-thermal component maps of the Magellanic Clouds. Whereas previous studies have established that cosmic-ray electrons steepen their synchrotron spectra as they propagate, and that magnetic-field strength correlates with the star formation rate, my study goes further. Using resolved radio continuum maps of these metal-poor galaxies, I demonstrate for the first time across ISM phases that non-thermal (cosmic-ray + magnetic-field) energy dominates the ISM under equipartition, and that magnetic-field amplification and cosmic-ray feedback are tightly coupled to the star formation rate even in low-metallicity regimes.

Read on MNRAS →

Featured talks & outreach

Public talks and interviews highlighting how infrared and JWST observations reveal the hidden life of stars and star-forming regions.

Unveiling Hidden Stars & Star-Forming Regions with JWST

Invited talk at AURORA (Astronomy Union for Reading, Outreach, and Research Activities), University of California, Riverside, highlighting how the PHANGS-JWST survey uses infrared diagnostics to uncover embedded stellar clusters and dusty star formation.

In Dust We Trust: Illuminating the Cosmos with Infrared Observations

Public outreach talk at the Zeidler Star Theater, Telus World of Science (Edmonton, Alberta), delivered as part of the RASC Edmonton Centre regular monthly meeting in October 2024, exploring how infrared astronomy reveals obscured star formation.

Contact me

Email hhassani@ualberta.ca