Mention astronomer and the first image that pops up in your mind is probably that of someone who spends the best part of the night peering through telescopes. Serious stargazing in the 21st century, Jagadheep D. Pandian will tell you, is a whole lot more complex than that.
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Dr. Pandian, Associate Professor at the Indian Institute of Space Science and Technology (IIST) here, is one of the Indian scientists in the GLOSTAR (Global View on Star formation in the Milky Way) project, an international collaboration of astronomers that performed an extensive survey of the Milky Way.
Initial series
The team’s initial series of papers, published recently, has offered new insights into the amazing process of star formation.
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Dr. Pandian grew up in Thiruvananthapuram and studied at the Loyola School here as his father Dhanasekara Pandian, who hails from Sivakasi, worked at the Vikram Sarabhai Space Centre (VSSC), Thumba. The GLOSTAR project is expected to revolutionise our understanding of the universe, says Dr. Pandian who has been part of it since its inception in 2012.
From the earth, stars—except for our own star the sun—are those twinkling little things up in the sky. In reality, they are enormous celestial factories where things happen on an unbelievably grand scale. Yet, why study them at all?
“They are bits and pieces of a big puzzle. They are one of the fundamental building blocks of any galaxy. You have a cycle of stars forming and stars dying and that gas going back into the stellar medium, eventually forming the next generation of stars. Everything that you see around us, from sand to the components in our body, metals, everything, are formed in some way or the other in processes related to stars,” says Dr. Pandian, who graduated in electrical engineering from IIT-Madras and did his MS and PhD in astronomy at Cornell University.
There are certain aspects of star formation that are little understood.
For example, how exactly do high-mass stars form? “Some of them live only for a few million years, which is short on a galactic time scale,” he says.
The GLOSTAR project used two powerful radio telescopes, the Karl G Jansky Very Large Array (VLA) at the National Radio Astronomy Observatory (NRAO), US, and the Effelsberg 100-metre radio telescope operated by the Max Planck Institute for Radio Astronomy (MPIfR), Germany.
The VLA data alone revealed 80 new supernova remnant (SNR) candidates and more are expected from the combined data from both telescopes.
“A lot of people, when they find out that professional astronomers never look through a telescope in the old way, they are surprised,” says Dr. Pandian whose research areas include observational astronomy, high-mass star formation, galactic structures, and radio astronomy instrumentation. He was a postdoctoral fellow at MPIfR, and SMA fellow, Institute for Astronomy, University of Hawaii, before joining IIST.
Two aspects
There are two groundbreaking aspects to the GLOSTAR survey, according to him. Usually surveys study the Milky Way at a very high-angular resolution or at a very low-angular resolution. Any one by itself will not give you a complete picture. However, the present survey combines both.
“The second aspect where the survey is expected to make significant contributions is in terms of frequency coverage. Earlier instruments allowed you to study the early stages of high-mass star formation alone or the late stages. Because the frequency coverage was limited. This survey has a wide frequency coverage, and looks at both simultaneously,” he said.