IIT Hyderabad Researchers Help Find Evidence for the Humming of the Universe by Low Frequency Gravitational Waves

• IITH researchers, as part of the Indian Pulsar Timing Array (InPTA) consortium, find evidence for ultra-low frequency gravitational waves
• The results could not have been possible without the NSM (National Supercomputing Mission) facility Param Seva installed at IIT Hyderabad
• Such waves are expected to originate from a large number of dancing monster black hole pairs more than a million times more massive than the Sun.
• Link to papers: https://doi.org/10.1051/0004-6361/202346844 and https://doi.org/10.1051/0004-6361/202346842

A team of researchers from IIT Hyderabad (IITH) are part of an international team of astronomers from India, Japan, and Europe has published results from monitoring pulsars, nature’s best clocks, using six of the World's most sensitive radio telescopes, including India’s largest telescope uGMRT. These results provide a hint of evidence for the relentless vibrations of the fabric of the universe, caused by ultra-low frequency gravitational waves. Such waves are expected to originate from a large number of dancing monster black hole pairs, crores of times heavier than our Sun. The team’s results are a crucial milestone in opening a new, astrophysically-rich window in the gravitational wave spectrum.

Representative image

Such dancing monster Black Hole pairs, expected to lurk in the centres of colliding galaxies, create ripples in the fabric of our cosmos, and astronomers call them nano-hertz gravitational waves as their wavelengths can be many lakhs of crores of kilometres. The relentless cacophony of gravitational waves from a large number of supermassive black hole pairs creates a persistent humming of our universe. The team, consisting of members of the European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) consortia, published their results in two papers in the Astronomy and Astrophysics journal, and their results hint at the presence of such gravitational waves in their data set. These results include an analysis of pulsar data collected over 25 years with six of the world’s largest radio telescopes.

The IITH team which took part in this discovery consists of Dr Shantanu Desai, faculty in the Department of Physics and Department of AI, Mr Aman Srivastava, Physics PhD student, Mr Divyansh Kharbanda (2023 BTech graduate in Engineering Physics), Ms Swetha Arumugam (rising BTech senior in EE). Another B Tech student in EE, Ms Pragna Mamdipaka, is also part of InPTA and is playing an active role in ongoing InPTA efforts. IITH has been part of InPTA since 2018, and some of the past InPTA students from IITH are pursuing higher studies in Astrophysics and related industries.

Emphasizing the importance of this result and IITH’s contribution, Prof B S Murty, Director, IITH, said, “Congratulations to the InPTA collaboration and the IITH team involved in this discovery. I am delighted that the state-of-the-art NSM Param Seva computing facility at IITH has helped to create these path-breaking results. This achievement also underscores the power of collaboration in attaining scientific benchmarking results’’.

“I am elated that IITH students from both Physics and Electrical Engineering could be part of this historical discovery. These results are due to many years of painstaking efforts from many scientists. I am grateful for the support received from IITH. In particular, the results could not have been possible without the NSM (National Supercomputing Mission) facility Param Seva installed at IIT Hyderabad’’, said Prof Shantanu Desai, IITH.

The InPTA experiment involves researchers from NCRA (Pune), TIFR (Mumbai), IIT (Roorkee), IISER (Bhopal), IIT (Hyderabad), IMSc (Chennai) and RRI (Bengaluru) along with colleagues from Kumamoto University, Japan. More details about InPTA can be found at https://inpta.iitr.ac.in/

This combined IPTA data set is expected to be more sensitive, and scientists are excited about the constraints they can place on the GWB (Gravitational Wave Background) along with understanding various other phenomena that may have taken place when the Universe was in its infancy, just a few seconds old, which can also produce gravitational waves at these astronomically long wavelengths.

IITH Scientists within InPTA Paving the Way To Charting Interstellar ‘Weather’

IITH Researchers within InPTA Measuring Interstellar Weather using Radio Telescope

The InPTA collaboration is the only PTA consortia which do simultaneous dual frequency observations of millisecond pulsars over widely separated lower and higher frequency bands, which is critical for our ultra-high precision measurement of interstellar noise.

No other radio telescope among the other PTA consortia has sensitivity equal to that of InPTA at low frequencies.

The Indian Pulsar Timing Array (InPTA) recently published its first official Data Release. Prof Shantanu Desai from the Physics department of IIT Hyderabad, PhD student Aman Srivastava, B.Tech student Divyansh Kharbanda, and IITH alumnus Raghav Girgaonkar have co-authored this research article which got published recently in the Publications of the Astronomical Society of Australia. The data release stems from three and a half years of observation using the upgraded Giant Metrewave Radio Telescope (uGMRT) near Pune. The Indo-Japanese team of thirty-eight radio-astronomers measures delays in the arrival of radio pulses from special types of neutron stars called millisecond pulsars, which are crucial for the discovery of low-frequency gravitational waves. InPTA has joined hands with similar teams from the USA, Europe and Australia to detect these tiny, elusive ripples in spacetime, named nanohertz gravitational waves.

Complementing the team’s efforts, Prof B S Murty, Director, IITH, said, “The research which we are doing should motivate young students to take up careers in science and engineering. The InPTA collaboration involves both Indian and Japanese scientists working at multiple institutes and people at all levels (faculty, PhD students, postdocs, UG students, Engineers, Computing professionals etc.) who have actively contributed towards it is a such amazing example.”.

“This research helps us better understand our Universe and our role in it. However, one should remember wifi (ubiquitous) in daily life was a spin-off of research in radio astronomy while searching for radio bursts from primordial black holes. The precision measurements which we are making use state of the art electronics and communication systems and also involve the application of novel data analysis and data mining tools. These could have potential industrial applications”, added Prof Shantanu.

The authors explain, “The universe is filled with gravitational wave background holding answers to deep secrets of nature. The waves that we detect now are strong but short-lived. We are listening to large waves crashing loudly upon the seashore, whereas space-time is continually brimming with tiny ripples. Imagine a symphony where high-pitched sections blare at crescendos while bass sections play the fundamental progressions throughout. The interplay of gravitational waves in the universe is similar to a symphony played by nature. We have been eavesdropping upon the crescendos while a persistent buzz forms the basis of this cosmic melody. These waves are generated by supermassive black hole binary pairs orbiting around each other for millions of years during their courses of collision. The primary hindrance in their detection is the vast ocean of interstellar medium lying in between. The InPTA data is critical for charting this interstellar ‘weather’ and paving the way to the discovery in the near future.”

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About IIT Hyderabad

Indian Institute of Technology Hyderabad (IITH) is one of the eight new IITs established by the Government of India in 2008. In a short span of 14 years, the institute has become a top-ranker. It has 290+ full-time faculty, ~4,200 students, 18 Departments + Centre for Interdisciplinary Programs, nearly 200+ state-of-the-art laboratories, and five research and entrepreneurship centers. The institute has a strong research focus with approx. Rs ~700 crores of sanctioned research funding, with PhD scholars accounting for about 30% of total student strength. IITH has more than 8100+ research publications with 1,20,000+ Citations, 190+ Published Patents, 1,700+ sponsored/consultancy projects with 500+ running projects, and about 100+ startups.