Bharat Origin US Scientist Shrinivas Kulkarni Awarded 2024 Shaw Prize For Astronomical Variables & Transients
- Ananya Sharma
- May 31, 2024
- 5 min read
Hello, Everyone!
It is a proud moment for Bharaiya scientists, astronomers, and Bharatvasis. A Bharat-origin US scientist Shrinivas R.Kulkarni has been honoured with the prestigious 2024 Shaw prize{ALSO KNOWN AS NOBEL OF THE EAST} for his dedicated work and discoveries on variables and transients objects in astronomy.
Shrinivas Kulkarni is presently a professor at California Institute of Technology (Caltech)as a George Ellery Hale Professor at Caltech of subjects on Astronomy and Planetary Sciences. However, he joined Caltech in 1985.
Sir Shrinivas has dedicated his significant career to studying these variable and transient astronomical transients.
According to the award citation, he has made groundbreaking discoveries of millisecond pulsars, gamma-ray bursts, supernovae, and astronomical variables or transient celestial entities.
Pic Source: Yearbook Manorama
But what are astronomical transients and variables?
In astronomy, we call "transient " any celestial entity whose brightness changes quickly, for example, milliseconds. Also in astronomy variable star is a celestial entity whose brightness changes with time as seen from Earth.
Some examples of astronomical transients are fast radio bursts, supernovae, active galactic nuclei, Gamma Ray Bursts, and many more.
Let us understand these one by one.
Fast Radio Bursts:
These are bright and short-light or electromagnetic radiation explosions observed in radio waves. They can emit massive energy, i.e., the energy of about Sun's emissions of energy in three days but fascinatingly in thousands of a second.
Fast Radio Bursts have frequencies of about 1,400 Hz(Hertz), however, some FRBs have been traced with low frequencies of 400-800 Hz.
FRBs appear at arbitrary spots all over the sky over our Earth. According to some scientists, 10,000 FRBs occur at random sites in the sky over Earth every day.
Supernovae:
A highly potent and extremely luminous explosion of a star when it has reached its collapse or end of its life. A supernova explosion can follow a massive radiation of energy i.e. as much energy emitted by our Sun in its entire life cycle.
According to scientists, supernovas are the largest explosions in the cosmos. They are vital sources of heavy elements or metals.
Gamma Ray Bursts:
They are the most potent explosive phenomena occurring in the known universe. These are highly luminous flashes of high energy light that occur due to the universe's highly explosive phenomena such as the formation of a black hole and also as an outcome of the interaction of two neutron stars.
Black holes are particular regions in the cosmos with highly potent gravitational pull so much so that even light has no escape from it. These are collapsed cores of dying stars that have used up their fuel and mass of about twenty folds that of the Sun.
According to scientists, when the matter is attracted to a black hole two potent jets protruding outwards may trigger Gamma Ray Bursts lasting for a minimum of 2 seconds or more than 2 seconds. Scientists classify this emission as LONG BURST EMIT GAMMA RAY.
Another Gamma Ray Burst-causing phenomenon is the interaction of two neutron stars.
A neutron star is a collapsed core of a colossal star following a supernova explosion possessing a mass of about 1.4 folds of that of the Sun's mass, a radius of about 8 km and it has a density similar to a neutron.
According to scientists' estimates when two neutron stars merge, a jet of high-speed debris. This phenomenon results in short bursts of gamma rays lasting for less than 2 seconds. Scientists classify this emission as SHORT BURST EMIT GAMMA RAY.
Active Galactic Nuclei :
According to large evidence, active galactic nuclei are active supermassive black holes that emit jets of particles and gas.
Supermassive black holes are gigantic black holes having a mass of million folds to billion folds of our Sun's mass and are positioned in the center of every galaxy including its existence in our Milky Way galaxy too.
These grow by gulping cosmic matter for example Steller mass relatives i.e. black holes having mass relative to supermassive black holes
Sir Shrinivas is also lauded for exceptional leadership in establishing the Palomar Transient Factory (PTF) and its follower the Zwicky Transient Facility(ZTF) which have extensively revolutionized mankind's understanding and transcended knowledge of the time-variable optical sky.
The Shaw Prize is given annually by the Shaw Prize Foundation, which was established in 2002 by the renowned filmmaker situated in Hong Kong, who is a TV executive and philanthropist Run Run Shaw who lived from 1907 to 2014.
Sir Shrinivas will be honored by the presentation of this coveted award on 12 Nov 2024 and a monetary prize of $ 1.2 million.
The Shaw Prizes are also for remarkable work in realms of :
->Life Sciences and Medicine
-> Mathematical Sciences
Sir Shrinivas was born in Kurundwad town in Bharat's state of Maharastra. He commenced his MS in Physics from IIT Delhi, in 1978. Post completion of his MS degree, he completed his PhD in astronomy from the US in 1983 at the University of California, in Berkeley.
What is Palomar Transient Factory (PTF)?
It is a survey featured completely automated and wide-field established for systematically observing the optical transient sky.
The exploration is executed through a new camera of 8.1 degrees placed on a Samuel Oschin telescope of 48 mts at Palomar Observatory. In addition, the discovered transient's colors along with the light curves are obtained by leveraging an automated Palomar 60-inch telescope.
What is Zwicky Transient Facility?
It is a public-private alliance established for systematically studying of optical sky. Interestingly, the complete Northern Sky is scanned by a camera having a wide -field of view every 2 days.
The ZTF leverages a mosaic CCD camera which is custom-built and scans the Northern Sky by utilizing its entire focal plane of about 47 sq degrees of the P48 telescope placed in Palomar Transient Facility. This renders an aperture of more than half a meter.
While Sir Shrinivas was a PhD student, he and his team unveiled the first-millisecond pulsar i.e. a neutron star spinning at 600 times/sec.
In 1997, Sir Shrinivas and his team were pioneers in tracing the gamma-ray burst phenomenon.
According to their findings, an object that radiated rays in the distant cosmic world implies that phenomena must be of high energy radiating type.
Sir Shrinivas R.Kulkarni was also dedicated to the positioning of STARE -2 {SURVEY FOR TRANSIENT ASTRONOMICAL RADIO EMISSIONS } for the study of Fast Radio Bursts{FSBs} in our Milky Way Galaxy and it entails 3 radio telescopes which collectively study these FRBs.
Fast Radio Bursts from a Magnetrar which is an immensely magnetized neutron star were explored by STARE -2 in 2020 at Caltech which is evidence of Magnetars as a primary source of Fast Radio Bursts. A magnetar has a potent magnetic of about 10^ 9 to 10^ 11 Tesla and 10^ 13 to 10^ 15 Gauss.
Sir Shrinivas R.Kulkarni has even played a pivotal role in observing the brown dwarfs which are celestial entities having a mass intermediate of a colossal planet for instance Jupiter and of a small star.
According to scientists any cosmic entity of mass in range between 15 folds of Jupiter to 75 folds of Jupiter's mass has been classified as a brown dwarf.
As per the statement of Scott D. Tremaine committee who is a renowned astrophysicist and led this year's prize selection commitee given to the Physics World, Shrinivas R.Kulkarni should also be honored for his dedicated endeavors to standardizing astronomy by making the data accessible to the astronomers globally which is an outcome of Shrinivas's telescopes.
Conclusively, we can say that Sir Shrinivas Kulkarni has made significant endeavors to explore and study astronomical transients.
References:
Highly informative blog post highlighting the prominent work done by Shrinivas Kulkarni on Astronomical Transients and Variables...well researched...and well presented blog post😊