Caltech Astronomer Receives 2017 Dan David Prize

Shrinivas (Shri) Kulkarni, the John D. and Catherine T. MacArthur Professor of Astronomy and Planetary Science and director of Caltech's Optical Observatories, has been awarded the 2017 Dan David Prize, along with the late Neil Gehrels (PhD '82) of NASA's Goddard Space Flight Center and Andrzej Udalski of the Warsaw University Astronomical Observatory.

Each year, the Dan David Prize, endowed by the Dan David Foundation, awards three prizes worth $1 million each "for achievements having an outstanding scientific, technological, cultural or social impact on our world," according to the prize website. The awards are given in three fields within three "time dimensions"—past, present, and future.

Kulkarni, Gehrels, and Udalski will split the prize for the future category. All three researchers work in the field of time-domain astronomy, in which varying astronomical objects or phenomena are studied over time.

"Much of recent astronomy has focused on the static sky. Over the past two decades, exploration of the dynamic sky—cosmic explosions, moving objects, variable stars—has blossomed and is now widely considered to be the next frontier," says Kulkarni.

Born in India and now a U.S. citizen, Kulkarni joined Caltech in 1985. He is a leading authority on exotic astrophysical phenomena such as gamma ray bursts, brown dwarfs, and millisecond pulsars, and has been associated with many of the major advances in understanding the universe that have been made over the last decade. Kulkarni is the principal investigator behind the Palomar Transient Factory, a project that used a telescope at Caltech's Palomar Observatory to regularly scan the skies for variable and exploding stars, asteroids, comets, and other changing objects. He is also the principal investigator behind the PTF's successor, the Zwicky Transient Factory, which is scheduled to begin scanning the skies in July 2017.

Gehrels, who passed away on February 6, 2017, earned his PhD from Caltech in 1982 under adviser Edward C. Stone, David Morrisroe Professor of Physics. Gehrels, a pioneer in the study of bursts of gamma rays from deep space, was principal investigator for NASA's Swift satellite. Swift and its predecessor, the Compton Gamma Ray Observatory, for which Gehrels served as the project scientist, helped reveal that many gamma ray bursts are likely caused by extremely energetic supernovas in distant galaxies.

Udalski uses a technique called gravitational microlensing to look for dim objects, such as planets, that reveal themselves when they pass in front of other more distant stars and distort the starlight. He leads a microlensing project called the Optical Gravitational Lensing Experiment, or OGLE, which makes most of its observations at Las Campanas Observatory in Chile.