PIB TrackerRadio survey uncovers a hidden population of faint, weakly active black holes in nearby galaxies
An international team including an Indian Institute of Astrophysics scientist used the UK's e-MERLIN radio array to survey 280 nearby galaxies, detecting compact radio emission — and hidden, weakly accreting supermassive black holes — at the centres of nearly one-quarter of them.
What happened
- A high-resolution radio survey has revealed a hidden population of weakly active supermassive black holes in nearby galaxies.
- The international team included Dr. Aru Beri of the Indian Institute of Astrophysics (IIA), an autonomous institution under the Department of Science and Technology (DST).
- Using the UK's e-MERLIN radio array, they observed 280 nearby galaxies from the Palomar sample on parsec scales, detecting compact radio emission at the centres of nearly one-quarter of them.
- X-ray data from NASA's Chandra X-ray Observatory confirmed the emission is from accreting black holes, not star formation, supernova remnants or X-ray binaries.
- The results suggest faint, low-level activity may be the dominant mode of black hole growth in today's Universe; the study appeared in the Monthly Notices of the Royal Astronomical Society (MNRAS).
For Prelims
- Indian Institute of Astrophysics (IIA): A Bengaluru-based autonomous institute under the DST; runs observatories including Kodaikanal and the high-altitude Hanle (Ladakh) site.
- Supermassive black hole (SMBH): A black hole of millions–billions of solar masses at a galaxy's centre; an actively feeding SMBH powers an Active Galactic Nucleus (AGN).
- Radio interferometry: Linking many radio dishes to act as one giant telescope for high resolution; e-MERLIN links seven telescopes across the UK, run from Jodrell Bank.
- Accretion: Matter spiralling into a black hole heats up and radiates — the way otherwise-invisible black holes are detected (via radio, X-ray, etc.).
- Chandra X-ray Observatory: A NASA space telescope for X-ray astronomy — used here to cross-confirm the radio detections.
- India's own radio facility: The Giant Metrewave Radio Telescope (GMRT/uGMRT) near Pune, run by NCRA–TIFR — India's flagship radio interferometer.
For UPSC: A prelims-friendly science story: use it to anchor black-hole/AGN accretion, radio interferometry, and the institutional map of Indian astronomy (IIA under DST; GMRT under NCRA-TIFR). For Mains it illustrates India's participation in global 'big science' collaborations and the value of publicly funded basic research and international observatory access.
What it is NOT: This is fundamental astrophysics led by a UK-based array (e-MERLIN) with an Indian co-author — not an Indian-built instrument or an India-specific mission. The black holes are 'faint' and weakly accreting, not newly formed; 'hidden monsters' is descriptive, not a new class of object.
For Mains
Syllabus: GS3.13 · GS3.11 · Linkage L2
Anchor
Basic science and international collaboration — India's astronomers contributing to frontier astrophysics through shared global observatories and publicly funded research.
Substantiation (data)
e-MERLIN survey of 280 nearby galaxies (Palomar sample) with IIA's Dr. Aru Beri; compact radio emission at the centres of ~25% of galaxies; Chandra X-ray confirmation; published in MNRAS.
Exemplification
Radio interferometry (e-MERLIN; India's GMRT/uGMRT) and multi-wavelength astronomy (radio + X-ray) as the toolkit for detecting weakly accreting supermassive black holes.
Problematisation
Frontier astronomy needs sustained funding, access to large international facilities and skilled human capital — areas where India must keep investing to remain a research partner, not just a user.
Way-forward
Deepen participation in global collaborations, expand indigenous facilities (uGMRT, upcoming instruments), and strengthen the pipeline of researchers and data infrastructure.
Position
India's stance: publicly funded basic research and international scientific cooperation are strategic investments in knowledge and capability.
Deploys into: Awareness in the field of space, IT and biotechnology (GS3.13 — astronomy/space science) · science and technology developments and their applications (GS3.11) · Indian scientific institutions (IIA under DST, GMRT under NCRA-TIFR) and India in global 'big science' collaborations.
Ministry of Science & Technology · 2026-07-06 · PRID 2281654 · PIB source ↗