I am a Postdoctoral Fellow at the Oskar Klein Center at Stockholm University and Nordita Institute where I was previously a Nordita Fellow. I work on several aspects of gravitational-wave multi-messenger astrophysics, neutron stars, and transients more broadly. I did my PhD at Monash working under the supervision of Paul Lasky and Greg Ashton which was conferred in October 2021. I am a member of the LIGO Scientific Collaboration (LSC), the Australian Research Council Centre of Excellence for gravitational-wave discovery, OzGrav, the Zwicky Transient Facility (ZTF) and the upcoming Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST).

Recent News

• November 12th: Li et al. 2024 - The Nature of Optical Afterglows Without Gamma-ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling submitted to ApJ. Check it out on arXiv.
• November 7th: Andreoni et al. 2024 - Rubin ToO 2024: Envisioning the Vera C. Rubin Observatory LSST Target of Opportunity program submitted to ApJS. Check it out on arXiv.
• October 21-October 27th: This week I am in Liverpool, where I am giving an invited seminar on neutron star mergers and a talk on redback.
• October 15-18th: Now in Southampton, visiting the University of Southampton. I am giving a couple of talks here on neutron stars and redback.
• October 14-15th: I am now in Oxford, where I am giving an invited SPIMAX Seminar series talk and a talk on redback.
• October 11th: Magnall et al. 2024 - Directly inferring cosmology and the neutron-star equation of state from gravitational-wave mergers submitted to PRD. Check it out on arXiv.
• September 30th - October 11th: Visiting Cambridge for the next two weeks, find me at the Kavli Institute for Cosmology or at the Institute of Astronomy.
• September 27th: van-dalen et al. 2024 - The Einstein Probe transient EP240414a: Linking Fast X-ray Transients, Gamma-ray Bursts and Luminous Fast Blue Optical Transients submitted to ApJ. Check it out on arXiv.
• September 25th: Gkini et al. 2024 - Eruptive mass-loss less than a year before the explosion of superluminous supernovae: I. The cases of SN 2020xga and SN 2022xgc submitted to A&A. Check it out on arXiv.
• September 16-20th: This week I am in Paris, attending the Astrocolibri workshop on multi-messenger astrophysics. I am giving an invited talk on Redback.
• September 13th: Wallace and Sarin 2024 - A detailed dive into fitting strategies for GRB afterglows with contamination: A case study with kilonovae submitted to MNRAS. Check it out on arXiv. This is Wendy’s first paper, which she did as part of her masters’s project with me. Congratulations Wendy!
• September 3rd: Schulze et al. 2024 - A cosmic formation site of silicon and sulphur revealed by a new type of supernova explosion submitted to Nature. Check it out on arXiv.
• August 28th: Srinivasaragavan et al. 2024 - Optical and Radio Analysis of Systemically Classified Broad-lined Type Ic Supernovae from the Zwicky Transient Facility submitted to ApJ. Check it out on arXiv.
• August 28th: Sarin et al. 2024 - The origin of the coherent radio flash potentially associated with GRB 201006A accepted in ApJL. Check it out on arXiv.
• August 25th: Sarin and Rosswog 2024 - Cautionary tales on heating-rate prescriptions in kilonovae accepted in ApJL. Check it out on arXiv.
• August 6th: Clarke et al. 2024 - Quantifying the coincidence between gravitational waves and fast radio bursts from neutron star–black hole mergers submitted to PRD. Check it out on the arXiv
• July 22-24th: This week I am in London, attending the PAX meeting on gravitational waves
• July 3rd: Sarin et al. 2024 - Measuring the nuclear equation of state with neutron star-black hole mergers accepted in PRD. Check it out on the arXiv
• June 10-15th: This week I am attending the ZTF meeting and the Transient Symposium at the Royal Academy of Sciences. I am giving a talk on Redback.
• June 3: Today, I am at the Royal Swedish Academy of Sciences, giving an invited talk on the future of multi-messenger astronomy.
• May 30th: Candidate strongly-lensed Type Ia supernovae in the Zwicky Transient Facility archive submitted. Check it out on arXiv.
• May 30th: Today I am in Uppsala, giving an invited seminar on neutron star mergers.
• May 12-16th: This week I am in Toronto, attending the hotwiring conference. I will be giving a talk on Redback.
• May 12th: Sarin et al. 2024 - Redback: A Bayesian inference software package for electromagnetic transients. Accepted in MNRAS. Check it out on arXiv and GitHub.
• April 15th: Sarin et al. 2024 - The origin of the coherent radio flash potentially associated with GRB 201006A submitted to ApJL. Check it out on arXiv.
• April 12th: Sarin and Rosswog 2024 - Cautionary tales on heating-rate prescriptions in kilonovae submitted to ApJL. Check it out on arXiv.
• Feb 8th: Rosswog et al. 2024 - Mergers of double neutron stars with one high-spin component: brighter kilonovae and fallback accretion, weaker gravitational waves accepted in MNRAS. Check it out on arXiv.
• Feb 5th-8th: At ANU this week, On Tuesday, I am giving the joint CGA-RSAA seminar on neutron star mergers
• January 29th-4th: Attending the TDU conference where I am giving a talk on Redback
• January 18th 2024: Sarin and Metzger 2024 - Tidal Disruption Events through the Lens of the Cooling Envelope Model Accepted in ApJL. Check it out on arXiv.
• November 14th-17th: At the OzGrav retreat in Adelaide!
• November 13th: Sarin et al. 2023 - Measuring the nuclear equation of state with neutron star-black hole mergers submitted to PRL. Check it out on the arXiv
• November 7th: Travelling to Australia! Will be spending the summer here and attending a few conferences.
• November 1st-3rd: In Lund this week, where I am giving an invited talk on r-process nucleosynthesis in kilonovae
• October 31st: Today I gave the OKC seminar.
• October 16th-19th: Back in Stockholm for the OKC15 conference. I will be talking about what we learnt and expect to learn from direct GW and indirect EM observations of BNS mergers.
• October 9th-13th: This week I am in Nijmegen, visiting Radboud University. On Monday I gave an invited colloquium on EM transients.
• October 3-5th: This week I am in Hamburg, visiting the beautiful Hamburg Observatory and Prof. Stephan Rosswog, I will be giving an invited colloquium on the 4th on the observational implications of merging neutron star binaries.
• September 4-8th: This week I am attending a workshop on kilonovae. I will be giving a talk on what theoretical/observational developments are needed to make the most of our kilonovae observations.
• Aug 24th: Omand and Sarin 2023 - A Generalized Semi-Analytic Model for Magnetar-Driven Supernovae submitted to MNRAS. Check it out on the arXiv.
• Aug 24th: Sarin et al. 2023 - Super excited to finally submit the paper for Redback, Redback: A Bayesian inference software package for electromagnetic transients. Check it out on arXiv and GitHub.
• July 27th: Sarin and Metzger 2023 - Tidal Disruption Events through the Lens of the Cooling Envelope Model submitted to ApJL. Check it out on arXiv.
• July 5th: Levan et al. 2023 - JWST detection of heavy neutron capture elements in a compact object merger. Submitted to Nature. Check it out on the arXiv
• July 3rd: Sarin et al. 2023 - Confronting the neutron star population with inverse cascades accepted in ApJL. Check it out on the arXiv.
• June 29th: I gave an invited talk at the Engrave Webinar on Redback.
• June 14-June 28th: Contributing as a mentor/supervisor for high school students for Rays. The students will be working with me to learn about EM transients.
• May 23: Sarin et al. 2023 - Confronting the neutron star population with inverse cascades submitted to ApJL. Check it out on the arXiv.
• May 9th: Schulze et al. 2023 - 1100 Days in the Life of the Supernova 2018ibb – the Best Pair-Instability Supernova Candidate, to date submitted to A&A, check it out on the arXiv.
• May 8th-12th: This week I am in Berlin attending the Ready Set Go workshop and ZTF meeting link. I gave an invited talk on EM transients and was on a panel discussion on the challenges for EM follow-up of GW events.
• April 1st: Starting a new project with a Master’s student on kilonovae and GW.
• March 1st: Looking forward to working with a new master’s student, Antoine on optimizing follow-up of GW events
• February 20th: Anand et al. 2023 - Collapsars as Sites of r-process Nucleosynthesis: Systematic Near-Infrared Follow-up of Type Ic-BL Supernovae submitted to ApJ. Check it out on the arXiv.
• November 22nd: I am advertising masters projects at Stockholm University, if you are interested in applying please contact me.
• November 22nd: Sarin et al. 2023 - Missed opportunities: GRB 211211A and the case for continual gravitational-wave coverage with a single observatory. accepted in MNRAS. Check it out on arXiv
• October 26th: Sarin et al. 2023 - Missed opportunities: GRB 211211A and the case for continual gravitational-wave coverage with a single observatory. submitted to MNRAS. Check it out on arXiv
• October 14th: I gave an invited seminar at the Center for Gravitation, Cosmology & Astrophysics University of Wisconsin–Milwaukee.
• September 9th: Sarin et al. 2022 - On the diversity of magnetar-driven kilonovae published in MNRAS. Check it out on the arXiv.
• July 12-August 26th: Back in Melbourne, Australia. I gave seminars at Monash, University of Melbourne, Swinburne University; and received the Vice Chancellor’s prize for thesis excellence in person!
• July 6th-11: Back in Stockholm after a productive US trip, attending the ZTF-DES Supernova meeting.
• June 26th-July 5th: I spent the week in New York, giving three talks, two at the Flatiron Institute and a THEA Seminar at Columbia University
• June 12th-June 26th: I am now in Aspen, attending a workshop on next generation gravitational-wave instruments!
• June 4th: My paper with Paul Lasky on Multimessenger astronomy with a kHz-band gravitational-wave observatory was announced as an Editor’s Pick from the Journal’s Featured Article Collection.
• June 3rd-June 12th: This week I am in California, visiting UC Berkeley.
• May 31st: Sarin et al. 2022 - On the diversity of magnetar-driven kilonovae submitted to MNRAS. Check it out on the arXiv.
• 28th May 2022: I was awarded the 2021 Vice-Chancellor’s Commendation for Doctoral Thesis Excellence! One prize is awarded across the Science Faculty at Monash. Incredibly grateful to my supervisors, mentors and colleagues.
• 10-20th May 2022: I visited the GSSI Institute in L’Aquila and later attended the PHAROS conference in Rome. Really enjoyed the first in person conference since the Pandemic. Nice to see lots of familiar faces!
• 6th May 2022: I was awarded the Robert Street Doctoral Prize for best PhD thesis at Monash!
• 28th March 2022: Sarin et al. 2022 - Linking the rates of neutron star binaries and short gamma-ray bursts accepted in Phys Review D. Check it out on the arXiv.
• 17th March 2022: Today, we released the alpha version of redback, a bayesian inference software package for electromagnetic transients. If you are interested in fitting and interpreting the observations of electromagnetic transients, check it out on github and consider contributing!
• 3rd March 2022: Sarin et al. 2022 - Low-efficiency long gamma-ray bursts: A case study with AT2020blt published in to MNRAS. Check it out on arXiv.
• January 24th 2022: Sarin et al. 2022 - Linking the rates of neutron star binaries and short gamma-ray bursts submitted to Phys Review D. Check it out on the arXiv.
• January 22-28th 2022: This week I am in Switzerland attending the Saas-fee winter school on gravitational waves and multi-messenger astronomy. And Skiing!
• December 2021: Sarin & Lasky 2022 - Multimessenger astronomy with a kHz-band gravitational-wave observatory accepted in PASA. Check it out on arXiv.
• October 21st 2021: Sarin & Lasky 2022 - Multimessenger astronomy with a kHz-band gravitational-wave observatory submitted to PASA. Check it out on arXiv.
• October 8th 2021: I did an interview on the highs and lows of my PhD with LIGO-India. Check it out on Youtube or the press release here
• October 8th 2021: I am now officially Dr Nikhil Sarin!
• July 18-23rd 2021: This week I am attending the AMALDI meeting. I will be giving a talk on the multimessenger signatures of binary neutron star mergers.
• July 15th 2021: Today I submitted my PhD thesis titled The observational signatures of nascent neutron stars!! Hoping for a smooth review!
• July 12-16th 2021: I am attending the Annual ASA meeting this week (in hybrid format). Looking forward to listening to all the exciting science happening across Australia.
• 4th June 2021: Sarin et al. 2021 - Low-efficiency long gamma-ray bursts: A case study with AT2020blt submitted to MNRAS. Check it out on arXiv.
• 1st June 2021: Sarin & Lasky 2021 - The evolution of binary neutron star post-merger remnants: a review accepted in General Relativity and Gravitation. Check it out on arXiv.
• 24th May 2021: Sarin et al. 2021 - CDF XT1: The off-axis afterglow of a neutron star merger at z = 2.23 submitted to ApJL. Check it out on arXiv.
• 23-26 March 2021: I gave a virtual talk at the THESEUS conference. See slides here
• February 2021: Pleased to finally announce that I have accepted a postdoctoral fellowship at NORDITA. Looking forward to moving to Sweden in November.
• January 2021: I passed my pre-submission milestone for my PhD! This is the last milestone before I submit my thesis in mid July.
• November 27th 2020: Sarin & Lasky 2021 - The evolution of binary neutron star post-merger remnants: a review submitted to General Relativity and Gravitation. Check it out on arXiv.
• November 23rd-27th 2020: This week I am attending the annual OzGrav retreat.
• 16th November 2020: Today I am giving an invited talk at Caltech.
• September 2020: Sarin et al. 2020 - Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars accepted in MNRAS.
• August 2020: I gave a couple more remote talks this month. One at the Flatiron Institute, and another at the University of California, Berkeley.
• August 2020: Submitted Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars to MNRAS. Check it out on arXiv.
• July 2020: Over the last month I have given several talks remotely, this remote adventure concludes this week with talks at the University of Bath, Leicester, Gran Sasso and Swinburne. Pleased to be able to present my work at so many different places, unfortunate downside that it had to be remotely.
• 3rd June 2020: Romero-Shaw et al. 2020 - Bayesian inference for compact binary coalescences with BILBY: Validation and application to the first LIGO–Virgo gravitational-wave transient catalogue submitted to MNRAS. Check it out on arXiv
• 8th March 2020: Sarin et al. 2020 - Gravitational waves or deconfined quarks: what causes the premature collapse of neutron stars born in short gamma-ray bursts? accepted in PRD.
• 4th March 2020: My recent paper is in the news! see article here on the Monash website and here on OzGrav!
• January 16th 2020: Sarin et al. 2020 - Gravitational waves or deconfined quarks: what causes the premature collapse of neutron stars born in short gamma-ray bursts? submitted to PRD. Check it out on arXiv. This paper took a long time but it was well worth it.
• November 17th-22nd November: This week I am in Lorne, Victoria for the Annual OzGrav retreat and ECR workshop.
• November 8th: After a long productive trip in Japan my visit comes a conclusion. Met heaps of amazing people, started several collaborations, lots of exciting science to come.
• October 27th-3rd November: This week, I am the Yamada meeting on gamma-ray-bursts in the beautiful city of Yokohama. I am presenting a couple of posters on my work on the population properties of long-lived neutron star merger remnants and extension of millisecond-magnetar models to include radiative losses.
• September 24 - October 25th: This month, I am in Kyoto attending the Yukawa institute long-term workshop on Multi-messenger astrophysics in the gravitational-wave era
• July 7-12th: Attended the ASA conference at the University of Queensland, Brisbane.
• May 3: Conference proceedings of the Xiamen-Custipen workshop submitted (Lasky et al. 2019) Neutron Star Merger Remnants: Braking Indices, Gravitational Waves, and the Equation Of State
• April: LIGO-Virgo Collaboration paper, Search for Gravitational Waves from a Long-lived Remnant of the Binary Neutron Star Merger GW170817 published in ApJ.
• April: Bilby paper published in ApJS
• February 18-22: Attended the LIGO Parameter Estimation group face-to-face meeting at Monash. Getting infrastructure ready for O3.
• February 4-8: Attended the annual ANITA workshop and school at Swinburne. Presented work on X-ray afterglows.
• December 18: X-ray afterglows of short gamma-ray bursts: Magnetar or fireball? accepted in ApJ.
• December 4: At the Annual OzGrav retreat and ECR Workshop.
• November 7: Bilby paper (Ashton et al. 2018) submitted to ApJS.
• September 25: Submitted paper to ApJ, X-ray afterglows of short gamma-ray bursts: Magnetar or fireball?