I am leading the development of major portions of two new large optical time-domain surveys. I am the Alert Production Science Lead for the Large Synoptic Survey Telescope as well as Survey Scientist for the Zwicky Transient Facility.
I use optical variability data to classify high-energy sources, particularly compact binaries. My research includes observation, instrumentation, and large-scale data analysis.
I lead the team at the University of Washington building the LSST real-time data processing pipelines. LSST will generate about 15 terabytes of images each night. Our software will rapidly process these images, subtract them from templates derived from past LSST images, identify and characterize all of the moving and varying objects, and package and distribute these alerts to the world--all within 60 seconds of the shutter closing!
Meeting LSST's stringent performance targets requires us to extend the state of the art in algorithms for calibration, astrometry, image differencing, atmospheric characterization, and more. I am responsible for ensuring that the LSST data products will be suitable for the broad range of cutting-edge time-domain science that we expect LSST to enable.
I am particularly involved in the development of the LSST alert stream, a real-time feed of the ten million moving, varying, or exploding objects LSST will detect each night.
ZTF achieved first light in October 2017 and is now in routine survey operations. It is regularly discovering young supernovae, rare classes of transients, variable stars, and solar system objects.
Forty percent of the ZTF observing time is used for public surveys. Since June 2018, UW is using prototype LSST tools to forward alerts from these surveys to community brokers in near real time. Bulk public access to these alerts is also available.
ZTF's Galactic Plane surveys provide fertile ground for identifying new compact binaries through their optical variability. I am conducting large-scale searches for these systems using powerful new data-mining tools.
Fermi has discovered many millisecond pulsars eclipsing and ablating low-mass companions--"Black Widow" and "redback" systems. I have used conducting photometric and radial-velocity followup to model these systems, measure the masses of the neutron stars, and understand their evolutionary history.
My study of the unique redback MSP binary PSR J2129-0429 revealed that it has a heavy neutron star of 1.7 solar masses as well as an unexpected optical dimming on a timescale of years. The system sits in an unusual region of binary evolution phase space, exactly at the bifurcation period between converging and diverging binaries.
Increasingly sensitive measurements of gamma-ray bursts continue to reveal new complexity in the emission mechanisms.
ZTF's wide-area, high-cadence survey is well-suited to identifying relativistic transients (GRBs, orphan afterglows, and related phenomena) independent of their high-energy triggers.
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.
As part of my dissertation work, I participated in two campaigns of the balloon-borne gamma-ray Nuclear Compton Telescope. I maintained the flight control software and calibrated its effective area and polarization response for future observations of GRBs.
Our 2009 New Mexico flight yielded the first image of the Crab Nebula by a compact Compton telescope. I led our 2010 Alice Springs campaign, directing shipping logistics, field operations, and interfaces with NASA and the media.
My campaign blog chronicled these adventures.