People

Prof. Fiona Harrison

NuSTAR and UVEX PI

Prof. Fiona Harrison is the California Institute of Technology (Caltech) Benjamin M. Rosen Professor of Physics, and the Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy. Prof. Harrison’s research is focused on the study of energetic phenomena ranging from gamma-ray bursts, black holes on all mass scales, to neutron stars and supernovae. Currently she is principal investigator for NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR). She received her Ph.D. in physics from the University of California, Berkeley, and went to Caltech in 1993 as a Robert A. Millikan Prize Fellow in Experimental Physics.

• fiona[at]srl[dot]caltech[dot]edu

• Fiona's Website

Staff Scientist

I am a staff scientist at the NuSTAR Science Operations Center, part of the team that operates and maintains the NuSTAR telescope. My current research interest is in X-ray transients. These are sources of X-rays that come and go that could be black holes or neutron stars undergoing a brief period of accretion, the merger of two neutron stars, supernovae, or flares from stars in our Galaxy.

• murray[at]srl[dot]caltech[dot]edu

NuSTAR Project Scientist

Hannah's primary research interest is in ultraluminous X-ray sources and other accreting X-ray binaries in nearby galaxies. They are also part of the team responsible for calibration and upkeep of the NuSTAR telescope.

• hpearn[at]caltech[dot]edu

Manager, NuSTAR Science Operations Center

Karl supervises the operation of the NuSTAR space telescope, ensuring that scientists around the world obtain the observations requested for their investigations, often leading coordination with other telescopes in space and on the ground.

• krl[at]srl[dot]caltech[dot]edu

• Karl's Website

Research Scientist

Brian works on hardware and mission development as well high energy astronomy. He is one of the principal mission scientists for NuSTAR and leads the calibration efforts. He is also the payload manager for the Ultraviolet Explorer (UVEX) NASA MIDEX responsible for delivering the wide-field UV telescope and its cameras. He uses telescopes to study a wide range of astrophysical phenomena, from the leftover remnants of exploding stars to flares from the Sun and high energy emission from X-ray binaries.

• bwgref[at]srl[dot]caltech[dot]edu

• Brian's Website

Senior Staff Scientist

I am a detector scientist for NuSTAR CZT detector as well as many other radiation detectors. I have been studying CZT/CdTe solid-state pixel detectors for NASA’s future high-energy X-ray missions as part of an APRA program. I have also participate to develop the particles detector for NASA’s STEREO and Parker Solar Probe mission. I am currently working on to develop the detector readout system for the SPHEREx mission.

• miyasaka[at]srl[dot]caltech[dot]edu

Research Scientist and Instruments System Engineer

I am a solid-state physicist working on the UVEX mission. My role encompasses detector related fabrications and characterization setups development.

• mashhadi[at]caltech[dot]edu

NuSTAR Deputy PI

I primarily study extreme supermassive black holes at a variety of wavelengths, including very distant ones, heavily enshrouded ones, and ones that are rapidly changing in brightness.

• daniel[dot]k[dot]stern[at]gmail[dot]com

Postdoctoral Research Associate

I analyze X-ray data to investigate the connection between spectral states and the geometry of accretion flows in black hole X-ray binaries (BHXBs) during outbursts, with a particular focus on the influence of mass accretion rate on this relationship. My research also explores the physics of outflows, disk winds, and obscuration commonly observed in highly inclined BHXBs, which are often transient or state-dependent phenomena. Additionally, I am deeply interested in the multi-wavelength variability characteristics of active galactic nuclei (AGN).

• oadegoke[at]caltech[dot]edu

Postdoctoral Research Associate

I am a black hole astronomer. I study how black holes grow, evolve, and shape the universe. My focus is on the supermassive ones that power the centers of active galaxies. I investigate their behavior, ranging from the innermost regions - exceptional laboratories for studying gravity at its glory - to the more extended regions where black holes inject power and matter into their host galaxies, altering their evolution. In my research, I combine observational and modeling techniques to understand the multi-wavelength spectral and timing properties of black holes.

• ekammoun[at]caltech[dot]edu

• Elias's Website

Postdoctoral Research Associate

My main focus of research is compact objects, particularly black holes and neutron stars. I enjoy working with observations and theory, aiming to bridge the two to deepen our understanding of physics and the universe. Some particular areas I am passionate about are: accretion physics, AGN and black hole variability, multi-wavelength astronomy, jets, magnetars, and studying compact objects and transient phenomena through spectral-timing analysis, imaging and polarimetry. Most of the time I am working on developing novel timing methodologies for astronomy and applying them on accreting black holes to study time lags and variability. When I’m not doing that, I’m working on spectropolarimetry and imaging of supernova remnants, magnetars and X-ray binaries, or running simulations for upcoming high time/spectral /spatial resolution and high effective area missions, exploring their applications to physics and instrumentation design.

• demet[at]caltech[dot]edu

Millikan Experimental Fellow

Guillem Megias Homar is a Millikan Experimental Fellow working on telescope instrumentation, image-quality optimization, and fast-transient discovery. He co-led Rubin Observatory’s Active Optics commissioning and investigates GLAO concepts and next-generation X-ray interferometry.

• gmegias[at]caltech[dot]edu

Postdoctoral Research Associate

I am interested in hardware and instrumentation, particularly the design and development of space missions and their scientific payloads. At SRL, my main work focuses on developing new hard X-ray detectors for the next generation of space telescopes beyond NuSTAR. These detectors aim for higher sensitivity, better count rates, improved quantum efficiency, and a wider energy band, enabling deeper studies of the X-ray universe. I also search for gamma-ray bursts in NuSTAR’s data stream through the NuSTAR-SINGS project. Previously, I completed my PhD at IIT Bombay, where I led the structural and thermal design of the proposed Daksha X-ray mission, studied GRBs and FRBs using AstroSat-CZTI, and worked on low-latency gravitational-wave alerts in the LIGO-Virgo-KAGRA collaboration.

• gauravw[at]caltech[dot]edu

• Gaurav's Website

Postdoctoral Research Associate

My research interests are high-energy astrophysics, including the X-ray origin (coronae) of the active galactic nuclei (AGN), the obscuring structure surrounding the supermassive black holes (SMBHs), and the demographics of AGN. To answer these questions, I used deep NuSTAR and soft X-ray observations both on singles sources including AGN in local Universe and high-redshifts and on the extragalactic contiguous fields.

• xiuruiz[at]caltech[dot]edu

• Xiurui's Website

Graduate Student

Black hole, neutron star…I am interested in the most powerful objects in the Universe. I have been working on X-ray binary and Active Galactic Nucleus (AGN) with X-ray satellites since I was an undergrad. My current research includes both theoretical and observational work, like modeling accretion disk reflection and studying AGN-Galaxy co-evolution with X-ray telescopes.

• yding[at]caltech[dot]edu

• Yuanze's Website

Graduate Student

I work on astronomical instrumentation, detector development, and characterization setups, with interests spanning galaxy evolution and the circumgalactic medium. As an undergraduate, I contributed to missions such as NASA’s ASPERA UV smallsat and FIREBall-2. I co-built the calibration system for FIREBall-2 and was a part of the optical alignment and flight hardware assembly teams for both missions. I also conducted observations and helped commission the CHaS IFU to study the circumgalactic medium of galaxies and HII regions. I am currently working on the UVEX mission, focusing on detector development and characterization setups.

• nkerkese[at]caltech[dot]edu

Graduate Student

I study galaxy evolution, with a focus on connecting insights from cosmological simulations to the observable nearby Universe. My work has spanned the most massive galaxies to the least, in order to better understand how properties such as morphology or environment drive evolution and quenching. I am also interested in developing the software tools needed for simulating images and spectra with space instruments, which are useful for data interpretation, performance estimation, and mission design. Presently, I am working on designing the image simulator for UVEX.

• eshread[at]caltech[dot]edu

Graduate Student

I am interested in objects that show periodicity or variability in X-ray and optical wavelengths, with a focus on magnetic cataclysmic variables (CVs). I primarily use ZTF (Zwicky Transient Facility) along with a wide range of optical and X-ray telescopes for follow-up observations. In the past I have worked on accretion around supermassive black hole systems like active galactic nuclei (AGN) and tidal disruption events (TDE).

• syun2[at]caltech[dot]edu

WAVE Student

I am a rising Junior at Harvey Mudd College majoring in physics with a focus in astronomy. Previously, I have done research at Carnegie Science doing exoplanet research. At Caltech, I am excited to learn more about AGN and instrument design.

• mburch[at]caltech[dot]edu

SURF Student

I am a rising 3rd year at Cambridge majoring in natural science, which is mostly physics, and I will focus on astrophysics in my 3rd year. Last summer, I had done a summer research on LRDs, which inspired my interests on AGNs. This summer, my research is on AGNs’ temperature variability and the correlation between AGNs’ temperature and X-ray luminosity. Of course, I am also very interested in other topics about astrophysics, such as cosmology, exoplanets, etc.

• wchen9[at]caltech[dot]edu

SURF Student

I’m a rising fourth year student at Penn State majoring in Astronomy and Astrophysics. I am interested in X-ray reflection modeling of black hole accretion disks, and this summer I am working on exploring systematic biases in black hole spin measurements. Outside of research I like drawing, reading, and trying new foods.

• mxd5974[at]psu[dot]edu

SURF Student

I’m a rising junior at Caltech majoring in Physics, with particular interests in general relativity and cosmology. Outside the classroom, I’m a pitcher on Caltech’s baseball team and enjoy playing tennis, chess, and poker in my free time. I’m recovering from an ACL injury this summer, so I may not be as active around campus. However, I’m looking forward to exploring more of LA once I’m more mobile.

• kfarrell[at]caltech[dot]edu

SURF Student

I’m a rising senior at UIUC majoring in Astrophysics + Data Science. Currently, I am interested in everything about time-domain and astrophysical transient research. At UIUC, I am working with Prof. K. Decker French on radio variability in poststarburst galaxies. I was also a SURF student last year with Dr. Wynn Jacobson-Galan and Prof. Mansi Kasliwal on X-ray supernovae, particularly SN 2024ggi. Now, I am working with Dr. Murray Brightman on X-ray transients in NuSTAR or Swift-XRT Data! Outside research, I like to swim and underwater hockey! (Yes it’s a real sport, check it out or talk to me).

• ff10[at]illinois[dot]edu

SURF Student

I am a rising sophomore at Caltech majoring in Physics and considering Applied Physics, though I am also interested in astrophysics! This summer, I’ll be analyzing AGN X-ray emissions collected primarily by NuSTAR and XMM-Newton to analyze AGN coronal temperatures. I hope to learn more from my mentor and peers about their research and ultimately get a better idea of the specific topics of astrophysics I may want to pursue in the future.

• zgranado[at]caltech[dot]edu

SURF Student

I am a rising junior studying physics and mathematics at UCLA. I am deeply interested in the fundamental theoretical frameworks that govern the universe across all scales, from quantum mechanics to cosmology. In the High Energy Astrophysics Group, I study complex astrophysical objects, such as AGNs, using X-ray reverberation techniques to probe and map their inner geometry. Outside of research, I love windsurfing (the even better kind of surfing) and singing in an a cappella group.

SURF Student

I'm a rising junior at UC San Diego majoring in Physics with a minor in Mathematics. At UCSD, I've worked at Rare Labs helping build a radon counter chamber, assembling and testing chamber electronics, and I’m also currently working in a heliophysics research group. This summer, I’m investigating a serendipitous NuSTAR source in the Kepler field to identify its nature and characterize its properties. I'm excited to learn more about high-energy astrophysics and am hoping that this project helps me better understand which area of astronomy I’m interested in. Outside of research, I enjoy hiking, working out, watching sports, movies, and TV shows.

• snasri@[at]ucsd[dot]edu

WAVE Student

I’m a rising junior at Harvard concentrating in Physics and Astrophysics. I’m especially interested in studying AGN, black holes, and other high-energy phenomena. I’ve spent three summers working at the U.S. Naval Observatory, where I’ve studied binary stars and intermediate-mass black holes. At Harvard, I’m involved with research in the High Energy Division studying distant quasars. At Caltech, I’ll be studying the disk wind properties of black hole x-ray binaries. Outside of the classroom, I love to read and explore new coffee shops.

• Sarahpinto[at]college[dot]harvard[dot]edu

WAVE Student

I’m a rising junior at UC San Diego majoring in Astrophysics and minoring in Math. At UCSD, I work in the Optical and Infrared Laboratory, specifically designing and developing Liger, an adaptive optics­ fed integral field spectrograph for the W. M. Keck Observatory. In addition to instrumentation, I’m very interested in High Energy Astrophysics and am excited to study the variability of AGN with the newly released SPHEREx data at Caltech. Outside of astrophysics, I enjoy playing volleyball, going to the beach, and playing guitar.

• aerajab[at]gmail[dot]com

SURF Student

I’m a rising junior at Middlebury College majoring in Physics and Math, with interests in high-energy astrophysics, compact objects, and time-domain X-ray observations. At Middlebury, I have worked with Professor Brumback on timing analysis of the neutron-star X-ray binary SMC X-1, using NuSTAR and Swift/BAT observations to study its variability and superorbital behavior. This summer at Caltech, I’m working with the HEA group on accretion flow properties of the black hole X-ray binary. Outside of research, I enjoy lifting weights.

• yuchiz[at]middlebury[dot]edu