Barnali Das
| Name | Barnali Das |
|---|---|
| Post | Reader |
| barnali [at] ncra.tifr.res.in | |
| Office Phone | 02025719255 Extn: 9255 |
| Office Room | F205 |
| Website | Personal Webpage |
| HQ | Pune |
| Address |
National Centre for Radio Astrophysics |
Main Research Areas: Magnetospheric emission from massive stars; Unifying model for radio production in large-scale stellar magnetospheres; Binary magnetospheric interactions; Stellar transients; Radio stars.
Biography:
I completed my B.Sc. (Hons.), Physics, from Hans Raj College, University of Delhi in 2014, and my M.Sc. (Physics) from IIT-Kanpur in 2016. Following this, I joined NCRA-TIFR as a research scholar, working with Professor Poonam Chandra on coherent radio emission
from hot magnetic stars for my Ph.D. thesis. After completing my Ph.D. in 2021, I joined the University of Delaware, USA, as a postdoctoral researcher, and then CSIRO, Australia, in 2023 as a Bolton research scientist. I joined NCRA-TIFR as a Reader in 2025.
Research Description:
My primary research interest lies in magnetic massive stars (OBA stars) that are unique in terms of their unusually stable and simple (mostly dipolar) magnetic fields. My research aims to fully characterize their magnetospheric emission (radio, optical, X-ray) so as to
use them as celestial laboratories. In addition, I am also interested in exploring a range of similarities that these objects exhibit in their radio emission with totally disparate objects, and what they tell us about the underlying physics of large-scale magnetospheres.
Coherent radio emission from magnetic massive stars
A subset of magnetic massive stars produce coherent radio emission via electron cyclotron maser emission (ECME) in the form of periodic radio pulses. We call such stars ‘Main sequence Radio Pulse emitters’ (MRPs). Though first discovered in 2000, the number of known MRPs has increased significantly recently, mostly due to our targetted searches with the uGMRT. Using the uGMRT, we have been able to identify more than 70% of the current MRP sample. Yet the number of MRPs remains small (<25), which makes it difficult to characterize the phenomenon. I am currently using the uGMRT, VLA, ASKAP, ATCA, and MeerKAT telescopes, to both expand the sample and acquire wideband observations, which are necessary for their characterization.
Modelling stellar magnetospheres
While there has been a lot of work on how we can model the wind-magnetic field interplay
in massive stars using optical (Halpha) emission, we are yet to fully incorporate the
information provided by radio into these models. We are working on overcoming this
limitation by developing a new theoretical/numerical framework and also taking inputs
from other wavebands. The ultimate goal is to develop a magnetospheric model that will
consistently explain magnetospheric emission across the electromagnetic spectrum.
Binary magnetospheric interactions
Binary magnetospheric interactions refer to interactions between two objects with at least
one of them being magnetic. Such interactions become much more complex (interesting)
when both objects are magnetic, and harbour stable magnetospheres. I am interested in
understanding the consequences of such interactions in main-sequence stars with the
help of radio and X-ray observations.
1. ‘VAST-MeMeS: Characterising non-thermal radio emission from magnetic massive stars using the Australian SKA Pathfinder’, B. Das et al. 2025, PASA, 42, 147.
2. ‘The effect of collisional cooling of energetic electrons on radio emission from the centrifugal magnetospheres of magnetic hot stars’, B. Das & S. Owocki 2025, PASA, 42, 138
3. ‘Coherent Radio Emission from "Main-sequence Radio Pulse Emitters": A New Stellar Diagnostic to Probe 3D Magnetospheric Structures’, B. Das, P. Chandra & V. Petit 2024, ApJ, 974, 267
4. ‘Discovery of extraordinary X-ray emission from magnetospheric interaction in the unique binary stellar system ε Lupi’, B. Das et al. 2023, MNRAS, 522, 5805
5. ‘Discovery of Eight "Main-sequence Radio Pulse Emitters" Using the GMRT: Clues to the Onset of Coherent Radio Emission in Hot Magnetic Stars’, B. Das et al. 2022, ApJ, 925, 125