In 1987, Kulkarni obtained a position as faculty at the
California Institute of Technology. He discovered the first
millisecond pulsar called
PSR B1937+21 with
Donald Backer and colleagues, while he was a graduate student. In 1986, he found the first optical counterpart of binary pulsars, while he was a Millikan Fellow at California Institute of Technology. He was instrumental in discovery of the first
globular cluster pulsar in 1987 using a supercomputer. With
Dale Frail at
NRAO and Toshio Murakami and his colleagues at ISAS (predecessor of
JAXA that was led by
Yasuo Tanaka at that time), Kulkarni showed that
soft gamma-ray repeaters are
neutron stars associated with
supernova remnants. This discovery eventually led to the understanding that
neutron stars with extremely high magnetic field called
magnetars are the
soft gamma-ray repeaters.
Caltech-NRAO team which he led showed in 1997 that
gamma-ray bursts came from extra-galactic sources, and identified optical counterparts. Their research initiated the detailed studies of the sources of
gamma-ray bursts along with the European team led by
Jan van Paradijs. He was also a member of the Caltech team that observed the first irrefutable
brown dwarf in 1994 that orbited around a star called
Gliese 229. His recent work involved
Palomar Transient Factory which has succeeded in identifying the new groups of optical transients such as
superluminous supernovae,
calcium-rich supernovae, and
luminous red novae. ==Awards and honours==