Kishalay De

Cosmic fireworks from compact stellar binaries

I am an Assistant Professor in the Department of Astronomy at Columbia Univeristy and Associate Research Scientist at the Center for Computational Astrophysics, Flatiron Institute in New York City. I work with wide-field imaging surveys on the ground and in space to discover cosmic fireworks from stellar binaries in our Galaxy and in the distant Universe. Using panchromatic follow-up facilities, I try to understand the role of stellar cataclysms in shaping the unvierse as we "see" it in light and "hear" it in gravitational waves. You can find more details of my recent work here.

I was previously a NASA Einstein Fellow and Kavli Institute Fellow at the Massachusetts Institute of Technology, and a Postdoctoral affiliate at the Institute for Theory and Computation at Harvard University. I obtained my PhD in Astrophysics from the California Institute of Technology in 2021, under the supervision of Mansi Kasliwal. As part of my thesis, I served as the data pipeline lead and helped commission Palomar Gattini-IR, the first wide-field infrared time domain survey to study dust obscured eruptions in the Milky Way. Using the Zwicky Transient Facility wide-field optical time domain survey, I helped construct the largest volume-limited sample of nearby supernovae to study faint and fleeting explosions from the eruptions of helium shells on white dwarfs and births of neutron stars in compact binary systems. Previously, I obtained my undergraduate degree in Physics from the Indian Institute of Science in 2016, working with Yashwant Gupta and Prateek Sharma on high time resolution studies of radio pulsars. You can find a copy of my CV here.

• The Galactic locations of PGIR discovered novae (colored stars) compared to previous optical samples (colored circles). The grayscale map shows the typical dust extinction along the line of sight, while the symbol colors show the estimated extinction towards the novae. The PGIR sample has unveiled a population of heavily obscured outbursts near the central plane that are missed in the optical bands.

Ongoing work

I am currently working with data from several time domain surveys to discover transient phenomena from compact stellar binaries in the Galactic plane. I am leading a large funded project to characterize the transient mid-infrared sky using nearly 15 years of archival data from NASA's WISE space telescope. As part of a team of more than a dozen reseachers, we are discovering infrared outbursts associated with stellar mergers and planetary engulfment events in the nearby universe, novae and X-ray binaries in the dusty Galactic plane and enshrouded accretion flares from supermassive black holes across the universe (see WISE publication Library). Using the Palomar Gattini-IR survey, I systematically search for large amplitude transients in the Milky Way, which has revealed a population of heavily obscured novae that are missed in the optical bands, dust enshrouded young stars in outburst and reddened microlensing events. The infrared sensitivity of PGIR also makes it ideally suited to study counterparts of dust obscured Galactic X-ray sources to enable systematic characterization of the donors and evolutionary states of X-ray binaries. With the Wide Field Infrared Transient Explorer (WINTER) coming online in 2022, we will be able to carry out unprecedented characterization of infrared variability in Galactic accreting sources. As part of my research, I also develop pipelines for processing large imaging datasets from public time domain surveys to develop a panchromatic view of the transient sky.