Hi! I'm Eric.

I'm an astrophysicist.


I am a Postdoctoral Scholar in Astronomy at Caltech.

I develop and exploit new optical and X-ray instruments to better understand the physics of compact objects like neutron stars and black holes.

Eric Bellm


I am the Project Scientist for the Zwicky Transient Facility (ZTF), a next-generation optical time-domain survey based on the Palomar Transient Factory (PTF). With the benefit of a new camera with a 47 square degree field of view and faster readout, ZTF will survey more than an order of magnitude faster than PTF and conduct an unprecedented high cadence, wide area survey.

ZTF will discover a young supernovae every night, identify rare classes of transients, and produce an all-sky variability catalog averaging 300 epochs per year. First light is expected in 2017.

ZTF Cryostat

Repeated optical imaging of the Galactic Plane can probe Galactic Structure with variable star populations and identify rare outbursting sources, but crowded fields makes automated photometry difficult.

With the benefit of a new PSF image-differencing pipeline, we are conducting a variability survey of the entire Northern Galactic Plane. Data obtained in 2013 and 2014 are already world-leading in epochs × areal coverage × depth.

I am particularly interested in using these data to identify new compact binaries as part of a larger project to classify unidentified X-ray sources with optical variability.

Galactic Plane

NuSTAR's high-sensitivity and continuous energy coverage enables some of the best spectroscopy of X-ray binaries. My analysis of the cyclotron line in the Be/X-ray binary GRO J1008-57 confirmed its high magnetic field.

Fermi has discovered many millisecond pulsars eclipsing and ablating low-mass companions--"Black Widow" systems. I am conducting photometric and radial-velocity followup to model these systems and measure the masses of the neutron stars.

Compact Binary

Increasingly sensitive measurements of gamma-ray bursts continue to reveal new complexity in the emission mechanisms.

With NuSTAR, I discovered an unusual extra component in the late-time X-ray afterglow of the ultra-long GRB130925A. In contrast, NuSTAR data for the bright nearby GRB130427A was consistent with emission by a single mechanism.

In my dissertation, I evaluated multi-component "quasi-thermal" spectral models of the GRB prompt emission using RHESSI and Swift.


As part of my dissertation work, I participated in two campaigns of the balloon-borne gamma-ray Nuclear Compton Telescope. I calibrated its effective area and polarization response for future observations of GRBs. My campaign blog chronicled these adventures.

Balloon launch


Postdoctoral Scholar, Caltech 2011-
Ph.D., Physics, U.C. Berkeley 2011
A.B., Physics & Astronomy, Harvard2005


My papers on ADS.

Complete CV (pdf).


Office:Cahill 216
MC 249-17
1200 E. California Blvd.
Pasadena, CA 91125


Email:ebellm ∝ caltech.edu