209 citations · 2.5k across the 85 of their papers we have counts for
89 papers
The shell around VY Canis Majoris in SPHEREx is likely an artifact
Viraj Karambelkar, Yashvi Sharma, Kishalay De
Recently, the presence of a large shell around the bright hypergiant star VY Canis Majoris was reported in images from the SPHEREx mission. We report similar shells around other br…
A data processing pipeline for the WINTER near-infrared surveyor using the framework
Viraj Karambelkar, Robert Stein, Danielle Frostig +18
We present the data reduction and transient detection pipeline for the Wide-field Infrared Transient Explorer (WINTER) surveyor and report its on-sky performance. The WINTER camera…
Multi-Wavelength Identification of a Luminous Mid-Infrared Supernova Powered by Circumstellar Interaction with Binary-Driven Pre-supernova Mass Loss
Kohki Uno, Kishalay De, Geoffrey Mo +6
Terminal mass-loss in massive stars is commonly reconstructed from observations of circumstellar interaction in core-collapse supernovae (CCSNe); however, such signatures can be ea…
SPIRITS 19q: Dust Production by a Subsolar-metallicity Carbon-rich Wolf-Rayet Star in NGC 2403
Sam Rose, Ryan M. Lau, Jacob E. Jencson +20
We present JWST/NIRSpec IFU observations of SPIRITS 19q, the highly dust-producing carbon-rich (WC) binary candidate located in a subsolar-metallicity region of the nearby spiral g…
Ghosts of eruptions past: Searching for historical Galactic supernovae using variable thermal dust echoes and machine learning
Justin Vega, Kishalay De, Ashish Mahabal +4
The Galactic core-collapse supernova (SN) rate is estimated at per century; however, no optically visible SN has been discovered in the past 400 years. Although recor…
Fading into darkness: A weak mass ejection and low-efficiency fallback accompanying black hole formation in M31-2014-DS1
Kishalay De, Morgan MacLeod, Jacob E. Jencson +10
Stellar-mass black holes (BHs) can form from the near-complete collapse of massive stars, causing them to abruptly disappear. The star M31-2014-DS1 in the Andromeda galaxy was repo…
SPHEREx as a frontier for infrared transients: Classification of new Galactic FU Ori outbursts and classical novae
Viraj Karambelkar, Kishalay De, Lynne A. Hillenbrand +3
We demonstrate proof-of-concept of a new strategy for studying infrared (IR) transients enabled by the newly launched SPHEREx space mission, by leveraging its synergy with the NEOW…
Dynamical binary interactions in the 2040s
Nadejda Blagorodnova, Ondřej Pejcha, Tomek Kamiński +15
Dynamical binary interactions such as common envelope (CE) evolution or stellar mergers are a critical phase in the formation of a wide variety of binary phenomena, ranging from bl…
The WINTER Observatory: A One-Degree InGaAs Survey Camera to study the Transient Infrared Sky
Danielle Frostig, Nathan Lourie, Viraj Karambelkar +20
The Wide-field Infrared Transient Explorer (WINTER) is a near-infrared time-domain survey instrument operating on a dedicated 1-meter robotic telescope at Palomar Observatory. The…
GRB 230204B: GIT Discovery of a Fast Fading Afterglow Associated with an Energetic GRB from a Massive-Star Progenitor
Vishwajeet Swain, Varun Bhalerao, Harsh Kumar +19
We present a comprehensive multi-wavelength study of a bright gamma-ray burst GRB 230204B, analyzing both prompt and afterglow emissions. This GRB is highly energetic, with an isot…
ZTF25abjmnps (AT2025ulz) and S250818k: A Candidate Superkilonova from a Sub-threshold Sub-Solar Gravitational Wave Trigger
Mansi M. Kasliwal, Tomas Ahumada, Robert Stein +61
On August 18, 2025, the LIGO-Virgo-KAGRA collaboration reported gravitational waves from a sub-threshold binary neutron star merger. If astrophysical, this event would have a surpr…
The nature of ASASSN-24fw's occultation: modelling the event as dimming by optically thick rings around a sub-stellar companion
Sarang Shah, Jonathan P. Marshall, Carlos del Burgo +12
ASASSN-24fw is a main-sequence F-type star that experienced a rapid and long-lasting dimming event beginning in late 2024 and continuing until mid 2025. Its pre-dimming spectral en…
A spectral library and census of near-infrared stellar large-amplitude variables from Palomar Gattini-IR
Nicholas Earley, Viraj Karambelkar, Mansi Kasliwal +9
We present a near-infrared census of stellar large-amplitude variables (LAVs) observed by the Palomar Gattini-IR (PGIR) surveyor from 2019-2021. Over the three-year time period, PG…
GRB 250704B: An Off-axis Short GRB with a Long-Lived Afterglow Plateau
Vishwajeet Swain, Tomás Ahumada, Sameer K. Patil +27
We present a detailed multi-wavelength afterglow study of the short GRB 250704B, extensively monitored in optical and near-infrared bands. Its afterglow displays an unusually long-…
Optical/infrared observations of the extraordinary GRB 250702B: a highly obscured afterglow in a massive galaxy consistent with multiple possible progenitors
Jonathan Carney, Igor Andreoni, Brendan O'Connor +31
GRB 250702B was the longest gamma-ray burst ever detected, with a duration that challenges standard collapsar models and suggests an exotic progenitor. We collected a rich set of o…
Multi-color characterization of optically invisible FU Orionis-type outbursts: Demonstration and prospects for the WINTER survey
Danielle Frostig, Kishalay De, Lynne A. Hillenbrand +8
Episodic mass accretion is the dominant mechanism for mass assembly in the proto-stellar phase. Although prior optical time-domain searches have allowed detailed studies of individ…
Hot springs and dust reservoirs: JWST reveals the dusty, molecular aftermath of extragalactic stellar mergers
Viraj Karambelkar, Mansi Kasliwal, Ryan M. Lau +7
We present James Webb Space Telescope (JWST) observations of four Luminous Red Novae (LRNe): dusty, extragalactic transients from stellar mergers following common-envelope evolutio…
A half-ring of ionized circumstellar material trapped in the magnetosphere of a white dwarf merger remnant
Andrei A. Cristea, Ilaria Caiazzo, Tim Cunningham +31
Many white dwarfs are observed in compact double white dwarf binaries and, through the emission of gravitational waves, a large fraction are destined to merge. The merger remnants…
Efficacy of Galaxy Catalogues for following up gravitational wave events
Tamojeet Roychowdhury, Harsh Choudhary, Varun Bhalerao +6
The detection of gravitational waves (GW) by the LIGO-Virgo-KAGRA (LVK) network has opened up a new era in astrophysics. The identification of the electromagnetic counterparts of G…
Twin peaks: SN 2021uvy and SN 2022hgk in the landscape of double-peaked stripped envelope supernovae
Yashvi Sharma, Jesper Sollerman, William Meynardie +25
In recent years, a class of stripped-envelope supernovae (SESNe) showing two distinct light-curve peaks has emerged, where the first peak cannot be attributed to shock cooling emis…
LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: Zwicky Transient Facility observations
Tomás Ahumada, Shreya Anand, Mattia Bulla +49
We present the searches conducted with the Zwicky Transient Facility (ZTF) in response to S250206dm, a bona fide event with a false alarm rate of one in 25 years, detected by the I…
The slow brightening of WNTR23bzdiq / WTP19aalzlk : Possible onset of common-envelope evolution in an asymptotic giant branch star?
Viraj Karambelkar, Mansi Kasliwal, Kishalay De +6
We present WNTR23bzdiq/WTP19aalzlk, a slow eruption of an early-asymptotic giant branch (AGB) star in M31 identified by the Wide-field Infrared Transient Explorer (WINTER) near-inf…
WINTER on S250206dm: A near-infrared search for an electromagnetic counterpart to a gravitational-wave event
Danielle Frostig, Viraj R. Karambelkar, Robert D. Stein +10
We present near-infrared follow-up observations of the International Gravitational Wave Network (IGWN) event S250206dm with the Wide-Field Infrared Transient Explorer (WINTER). WIN…
Cryoscope: A Cryogenic Infrared Survey Telescope in Antarctica
Mansi M. Kasliwal, Nicholas Earley, Roger Smith +58
We present Cryoscope--a new 50 deg field-of-view, 1.2 m aperture, survey telescope to be located at Dome C, Antarctica. Cryoscope has an innovative optical-thermal d…