Related papers: ZTF25abjmnps (AT2025ulz) and S250818k: A Candidate…

Identification of a Radio Counterpart to SN 2025ulz in the S250818k Localization Area

On 2025 August 18, the LIGO-Virgo-KAGRA collaboration reported S250818k, a sub-threshold gravitational-wave (GW) candidate consistent with a binary neutron star (NS) merger potentially involving a sub-solar-mass NS. Optical follow-up by the…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Tanner O'Dwyer , Alessandra Corsi , Deepika Yadav , Kunal P. Mooley , Raphael Baer-Way , Poonam Chandra , Gregg Hallinan , Mansi M. Kasliwal , Lauren Rhodes , Oleg M. Smirnov , Davide Lazzati , Joeri van Leeuwen , Adam Deller , Pikky Atri , Tanazza Khanam

Electromagnetic Follow-up of the Sub-Solar Mass Gravitational Wave Candidate S251112cm: Kilonova Constraints and a Coincident IIb Supernova

On November 12th, 2025 the LIGO--Virgo--KAGRA (LVK) collaboration reported gravitational waves (GWs) from a compact object merger candidate (S251112cm) with at least one sub-solar mass component. Using the Dark Energy Camera (DECam), the…

High Energy Astrophysical Phenomena · Physics 2026-05-12 Xander J. Hall , Tomas Ahumada , Julius Gassert , Antonella Palmese , Brian D. Metzger , Mansi M. Kasliwal , Mattia Bulla , Daniel Gruen , Robert Stein , Christoffer Fremling , Shreya Anand , Igor Andreoni , Malte Busmann , Tomás Cabrera , Ryan Christinzio , James Freeburn , Ignacio Magaña Hernandez , Lei Hu , Brendan O'Connor , Ji-an Jiang , Zhengyan Liu , Wen Zhao , Eric C. Bellm , David Cook , Michael W. Coughlin , Richard Dekany , Matthew Graham , Russ R. Laher

AT2025ulz and S250818k: Leveraging DESI spectroscopy in the hunt for a kilonova associated with a sub-solar mass gravitational wave candidate

On August 18th, 2025, the LIGO--Virgo--KAGRA collaboration reported a sub-threshold gravitational wave candidate detection consistent with a sub-solar-mass neutron star merger, denoted S250818k. An optical transient, AT2025ulz, was…

High Energy Astrophysical Phenomena · Physics 2025-10-29 Xander J. Hall , Antonella Palmese , Brendan O'Connor , Daniel Gruen , Malte Busmann , Julius Gassert , Lei Hu , Ignacio Magana Hernandez , Jessica Nicole Aguilar , Ariel Amsellem , Steven Ahlen , John Banovetz , Segev BenZvi , Davide Bianchi , David Brooks , Francisco Javier Castander , Todd Claybaugh , Andrei Cuceu , Arjun Dey , Peter Doel , Jennifer Faba-Moreno , Simone Ferraro , Andreu Font-Ribera , Jaime E. Forero-Romero , Gaston Gutierrez , Laurent Le Guillou , Dick Joyce , Theodore Kisner , Anthony Kremin , Ofer Lahav , Claire Lamman , Martin Landriau , Michael Levi , Axel de la Macorra , Marc Manera , Aaron Meisner , Ramon Miquel , John Moustakas , Seshadri Nadathur , Francisco Prada , Ignasi Perez-Rafols , Graziano Rossi , Eusebio Sanchez , David Schlegel , Michael Schubnell , David Sprayberry , Gregory Tarle , Benjamin Alan Weaver , Rongpu Zhou , Hu Zou

ENGRAVE follow-up of a type IIb supernova spatially coincident with the sub-threshold gravitational wave trigger S250818k

The candidate gravitational wave (GW) event S250818k was one of only three non-retracted LIGO-Virgo-KAGRA public alerts issued during the fourth observing run of the network (O4) with a binary neutron star (BNS) merger classification…

High Energy Astrophysical Phenomena · Physics 2026-05-05 K. Ackley , M. T. Botticella , A. Boye , M. Branchesi , G. Bruni , E. Cappellaro , S. Chaty , T. -W. Chen , F. D'Ammando , V. D'Elia , F. F. De Pasquale , Dimple , R. A. J. Eyles-Ferris , M. Fraser , G. Gianfagna , J. H. Gillanders , G. Greco , M. Gromadzki , C. P. Gutièrrez , A. Hajela , L. Izzo , P. G. Jonker , S. Kobayashi , R. Kotak , G. P. Lamb , G. Leloudas , A. J. Levan , J. D. Lyman , K. Maguire , A. Martin-Carrillo , A. Melandri , M. J. Michałowski , S. R. Oates , F. Onori , B. Patricelli , E. Pian , G. Pignata , S. Piranomonte , L. Piro , Q. Pognan , M. L. Pumo , A. Rossi , R. Roy , A. Saccardi , O. S. Salafia , R. Salvaterra , N. Sarin , S. Schulze , S. J. Smartt , R. L. C. Starling , D. Steeghs , N. R. Tanvir , A. L. Thakur , S. D. Vergani , S. Yi , D. R. Young

AT2025ulz and S250818k: Investigating early time observations of a subsolar mass gravitational-wave binary neutron star merger candidate

Over the past LIGO--Virgo--KAGRA (LVK) observing runs, it has become increasingly clear that identifying the next electromagnetic counterparts to gravitational-wave (GW) neutron star mergers will likely be more challenging compared to the…

High Energy Astrophysical Phenomena · Physics 2025-10-29 Xander J. Hall , Malte Busmann , Hauke Koehn , Keerthi Kunnumkai , Antonella Palmese , Brendan O'Connor , James Freeburn , Lei Hu , Daniel Gruen , Tim Dietrich , Mattia Bulla , Michael W. Coughlin , Sarah Antier , Marion Pillas , Paul A. Price , Tomás Ahumada , Ariel Amsellem , Igor Andreoni , Jule Augustin , Tom'as Cabrera , Rasika Deshpande , Jennifer Fabà-Moreno , Julius Gassert , Sergey Karpov , Mansi Kasliwal , Ignacio Magaña Hernandez , Rachel Mandelbaum , Felipe Fontinele Nunes , Peter T. H. Pang , Julian Sommer , Robert Stein , Constantin Tabor , Pablo Vega , Thibeau Wouters , Xiaoxiong Zuo

Pan-STARRS follow-up of the gravitational-wave event S250818k and the lightcurve of SN 2025ulz

Kilonovae are the scientifically rich, but observationally elusive, optical transient phenomena associated with compact binary mergers. Only a handful of events have been discovered to date, all through multi-wavelength (gamma ray) and…

High Energy Astrophysical Phenomena · Physics 2025-11-19 J. H. Gillanders , M. E. Huber , M. Nicholl , S. J. Smartt , K. W. Smith , K. C. Chambers , D. R. Young , J. W. Tweddle , S. Srivastav , M. D. Fulton , F. Stoppa , G. S. H. Paek , A. Aamer , M. R. Alarcon , A. Andersson , A. Aryan , K. Auchettl , T. -W. Chen , T. de Boer , A. K. H. Kong , J. Licandro , T. Lowe , D. Magill , E. A. Magnier , P. Minguez , T. Moore , G. Pignata , A. Rest , M. Serra-Ricart , B. J. Shappee , I. A. Smith , M. A. Tucker , R. Wainscoat

Optimizing Kilonova Searches: A Case Study of the Type IIb SN 2025ulz in the Localization Volume of the Low-Significance Gravitational Wave Event S250818k

Kilonovae, the ultraviolet/optical/infrared counterparts to binary neutron star mergers, are an exceptionally rare class of transients. Optical follow-up campaigns are plagued by contaminating transients, which may mimic kilonovae, but do…

High Energy Astrophysical Phenomena · Physics 2025-10-28 Noah Franz , Bhagya Subrayan , Charles D. Kilpatrick , Griffin Hosseinzadeh , David J. Sand , Kate D. Alexander , Wen-fai Fong , Collin T. Christy , Jeniveve Pearson , Tanmoy Laskar , Brian Hsu , Jillian Rastinejad , Michael J. Lundquist , Edo Berger , K. Azalee Bostroem , Clecio R. Bom , Phelipe Darc , Mark Gurwell , Shelbi Hostler Schimpf , Garrett K. Keating , Phillip Noel , Conor Ransome , Ramprasad Rao , Luidhy Santana-Silva , A. Souza Santos , Manisha Shrestha , Ramya Anche , Jennifer E. Andrews , Sanchayeeta Borthakur , Nathaniel R. Butler , Deanne L. Coppejans , Philip N Daly , Kathryne J. Daniel , Paul C. Duffell , Tarraneh Eftekhari , Carl E. Fields , Alexander T. Gagliano , Walter W. Golay , Aldana Grichener , Erika T. Hamden , Daichi Hiramatsu , Harsh Kumar , Vikram Manikantan , Raffaella Margutti , Vasileios Paschalidis , Kerry Paterson , Daniel E. Reichart , Mathieu Renzo , Kali Salmas , Genevieve Schroeder , Nathan Smith , Kristine Spekkens , Jay Strader , David E. Trilling , Nicholas Vieira , Benjamin Weiner , Peter K. G. Williams

A kilonova as the electromagnetic counterpart to a gravitational-wave source

Gravitational waves were discovered with the detection of binary black hole mergers and they should also be detectable from lower mass neutron star mergers. These are predicted to eject material rich in heavy radioactive isotopes that can…

High Energy Astrophysical Phenomena · Physics 2017-10-18 S. J. Smartt , T. -W. Chen , A. Jerkstrand , M. Coughlin , E. Kankare , S. A. Sim , M. Fraser , C. Inserra , K. Maguire , K. C. Chambers , M. E. Huber , T. Kruhler , G. Leloudas , M. Magee , L. J. Shingles , K. W. Smith , D. R. Young , J. Tonry , R. Kotak , A. Gal-Yam , J. D. Lyman , D. S. Homan , C. Agliozzo , J. P. Anderson , C. R. Angus C. Ashall , C. Barbarino , F. E. Bauer , M. Berton , M. T. Botticella , M. Bulla , J. Bulger , G. Cannizzaro , Z. Cano , R. Cartier , A. Cikota , P. Clark , A. De Cia , M. Della Valle , L. Denneau , M. Dennefeld , L. Dessart , G. Dimitriadis , N. Elias-Rosa , R. E. Firth , H. Flewelling , A. Flors , A. Franckowiak , C. Frohmaier , L. Galbany , S. Gonzalez-Gaitan , J. Greiner , M. Gromadzki , A. Nicuesa Guelbenzu , C. P. Gutierrez , A. Hamanowicz , L. Hanlon , J. Harmanen , K. E. Heintz , A. Heinze , M. -S. Hernandez , S. T. Hodgkin , I. M. Hook , L. Izzo , P. A. James , P. G. Jonker , W. E. Kerzendorf , S. Klose , Z. Kostrzewa-Rutkowska , M. Kowalski , M. Kromer , H. Kuncarayakti , A. Lawrence , T. B. Lowe , E. A. Magnier , I. Manulis , A. Martin-Carrillo , S. Mattila , O. McBrien , A. Muller , J. Nordin , D. O'Neill , F. Onori , J. T. Palmerio , A. Pastorello , F. Patat , G. Pignata , Ph. Podsiadlowski , M. L. Pumo , S. J. Prentice , A. Rau , A. Razza , A. Rest , T. Reynolds , R. Roy , A. J. Ruiter , K. A. Rybicki , L. Salmon , P. Schady , A. S. B. Schultz , T. Schweyer , I. R. Seitenzahl , M. Smith , J. Sollerman , B. Stalder , C. W. Stubbs , M. Sullivan , H. Szegedi , F. Taddia , S. Taubenberger , G. Terreran , B. van Soelen , J. Vos , R. J. Wainscoat , N. A. Walton , C. Waters , H. Weiland , M. Willman , P. Wiseman , D. E. Wright , L. Wyrzykowski , O. Yaron

AT2025ulz and S250818k: zooming in with the Hubble Space Telescope

AT2025ulz is an optical/near-infrared transient discovered during follow-up of the candidate gravitational wave (GW) event S250818k. Its young age ($\lesssim$1 d), rapid decline and strong color evolution over the first 48 hr classify it as…

High Energy Astrophysical Phenomena · Physics 2025-12-18 Yu-Han Yang , Eleonora Troja , Marko Ristić , Muskan Yadav , Massine El Kabir , Rubén Sánchez-Ramírez , Rosa L. Becerra , Chris L. Fryer , Brendan O'Connor , Simone Dichiara , Alberto J. Castro-Tirado , Camila Angulo-Valdez , Josefa Becerra González , José A. Font , Ori Fox , Lei Hu , Youdong Hu , William H. Lee , Margarita Pereyra , Alicia M. Sintes , Alan M. Watson , K. Océlotl C. López Mendoza

Analyzing GW231109_235456 and understanding its potential implications for population studies, nuclear physics, and multi-messenger astronomy

We study the gravitational-wave trigger GW231109_235456, a sub-threshold binary neutron star merger candidate observed in the first part of the fourth observing run of the LIGO-Virgo-KAGRA collaboration. Assuming the trigger is of…

High Energy Astrophysical Phenomena · Physics 2025-10-28 Thibeau Wouters , Anna Puecher , Peter T. H. Pang , Tim Dietrich

AT2025ulz and S250818k: Deep X-ray and radio limits on off-axis afterglow emission and prospects for future discovery

The first joint electromagentic (EM) and gravitational wave (GW) detection, known as GW170817, marked a critical juncture in our collective understanding of compact object mergers. However, it has now been 8 years since this discovery, and…

High Energy Astrophysical Phenomena · Physics 2025-10-30 Brendan O'Connor , Roberto Ricci , Eleonora Troja , Antonella Palmese , Yu-Han Yang , Geoffrey Ryan , Hendrik van Eerten , Muskan Yadav , Xander J. Hall , Ariel Amsellem , Rosa L. Becerra , Malte Busmann , Tomas Cabrera , Simone Dichiara , Lei Hu , Ravjit Kaur , Keerthi Kunnumkai , Ignacio Magana Hernandez

The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars

We report the discovery and monitoring of the near-infrared counterpart (AT2017gfo) of a binary neutron-star merger event detected as a gravitational wave source by Advanced LIGO/Virgo (GW170817) and as a short gamma-ray burst by Fermi/GBM…

High Energy Astrophysical Phenomena · Physics 2017-10-17 N. R. Tanvir , A. J. Levan , C. Gonzalez-Fernandez , O. Korobkin , I. Mandel , S. Rosswog , J. Hjorth , P. D'Avanzo , A. S. Fruchter , C. L. Fryer , T. Kangas , B. Milvang-Jensen , S. Rosetti , D. Steeghs , R. T. Wollaeger , Z. Cano , C. M. Copperwheat , S. Covino , V. D'Elia , A. de Ugarte Postigo , P. A. Evans , W. P. Even , S. Fairhurst , R. Figuera Jaimes , C. J. Fontes , Y. I. Fujii , J. P. U. Fynbo , B. P. Gompertz , J. Greiner , G. Hodosan , M. J. Irwin , P. Jakobsson , U. G. Jorgensen , D. A. Kann , J. D. Lyman , D. Malesani , R. G. McMahon , A. Melandri , P. T. O'Brien , J. P. Osborne , E. Palazzi , D. A. Perley , E. Pian , S. Piranomonte , M. Rabus , E. Rol , A. Rowlinson , S. Schulze , P. Sutton , C. C. Thoene , K. Ulaczyk , D. Watson , K. Wiersema , R. A. M. J. Wijers

Panning for gold, but finding helium: discovery of the ultra-stripped supernova SN2019wxt from gravitational-wave follow-up observations

We present the results from multi-wavelength observations of a transient discovered during the follow-up of S191213g, a gravitational wave (GW) event reported by the LIGO-Virgo Collaboration as a possible binary neutron star merger in a low…

High Energy Astrophysical Phenomena · Physics 2023-07-26 I. Agudo , L. Amati , T. An , F. E. Bauer , S. Benetti , M. G. Bernardini , R. Beswick , K. Bhirombhakdi , T. de Boer , M. Branchesi , S. J. Brennan , M. D. Caballero-García , E. Cappellaro , N. Castro Rodríguez , A. J. Castro-Tirado , K. C. Chambers , E. Chassande-Mottin , S. Chaty , T. -W. Chen , A. Coleiro , S. Covino , F. D'Ammando , P. D'Avanzo , V. D'Elia , A. Fiore , A. Flörs , M. Fraser , S. Frey , C. Frohmaier , L. Galbany , C. Gall , H. Gao , J. García-Rojas , G. Ghirlanda , S. Giarratana , J. H. Gillanders , M. Giroletti , B. P. Gompertz , M. Gromadzki , K. E. Heintz , Y. -D. Hu , M. E. Huber , A. Inkenhaag , L. Izzo , Z. P. Jin , P. G. Jonker , D. A. Kann , E. C. Kool , R. Kotak , G. Leloudas , A. J. Levan , C. -C. Lin , J. D. Lyman , E. A. Magnier , K. Maguire , I. Mandel , B. Marcote , D. Mata Sánchez , S. Mattila , A. Melandri , M. J. Michałowski , J. Moldon , M. Nicholl , A. Nicuesa Guelbenzu , S. R. Oates , F. Onori , M. Orienti , R. Paladino , Z. Paragi , M. Perez-Torres , E. Pian , G. Pignata , S. Piranomonte , J. Quirola-Vásquez , F. Ragosta , A. Rau , S. Ronchini , A. Rossi , R. Sánchez-Ramírez , O. S. Salafia , S. Schulze , S. J. Smartt , K. W. Smith , J. Sollerman , S. Srivastav , R. L. C. Starling , D. Steeghs , H. F. Stevance , V. Testa , M. A. P. Torres , S. D. Vergani , D. Vescovi , R. Wainscost , D. Watson , K. Wiersema , Ł. Wyrzykowski , J. Yang , S. Yang , D. R. Young

Eccentricity as a signature of hierarchical subsolar-mass mergers in collapsar disks

In this work, we investigate gravitational-wave signatures of a proposed subsolar-mass merger scenario resulting from fragmentation inside a collapsar accretion disk. This scenario has gained recent interest with the electromagnetic…

High Energy Astrophysical Phenomena · Physics 2026-05-29 Jiaxi Wu , Elias R. Most , Nils L. Vu , Nils Deppe , Lawrence E. Kidder , Kyle C. Nelli , William Throwe

GW170817/GRB 170817A/AT2017gfo association: some implications for physics and astrophysics

On 17 August 2017, a gravitational wave event (GW170817) and an associated short gamma-ray burst (GRB 170817A) from a binary neutron star merger had been detected. The followup optical/infrared observations also identified the…

High Energy Astrophysical Phenomena · Physics 2017-12-20 Hao Wang , Fu-Wen Zhang , Yuan-Zhu Wang , Zhao-Qiang Shen , Yun-Feng Liang , Xiang Li , Neng-Hui Liao , Zhi-Ping Jin , Qiang Yuan , Yuan-Chuan Zou , Yi-Zhong Fan , Da-Ming Wei

Implications of the search for optical counterparts during the first six months of the Advanced LIGO's and Advanced Virgo's third observing run: possible limits on the ejecta mass and binary properties

GW170817 showed that neutron star mergers not only emit gravitational waves but also can release electromagnetic signatures in multiple wavelengths. Within the first half of the third observing run of the Advanced LIGO and Virgo detectors,…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Michael W. Coughlin , Tim Dietrich , Sarah Antier , Mattia Bulla , Francois Foucart , Kenta Hotokezaka , Geert Raaijmakers , Tanja Hinderer , Samaya Nissanke

Constraining the Kilonova Rate with Zwicky Transient Facility Searches Independent of Gravitational Wave and Short Gamma-ray Burst Triggers

The first binary neutron star merger, GW170817, was accompanied by a radioactivity-powered optical/infrared transient called a kilonova. To date, no compelling kilonova has been found during optical surveys of the sky, independent of…

High Energy Astrophysical Phenomena · Physics 2020-12-09 Igor Andreoni , Erik C. Kool , Ana Sagues Carracedo , Mansi M. Kasliwal , Mattia Bulla , Tomas Ahumada , Michael W. Coughlin , Shreya Anand , Jesper Sollerman , Ariel Goobar , David L. Kaplan , Tegan T. Loveridge , Viraj Karambelkar , Jeff Cooke , Ashot Bagdasaryan , Eric C. Bellm , S. Bradley Cenko , David O. Cook , Kishalay De , Richard Dekany , Alexandre Delacroix , Andrew Drake , Dmitry A. Duev , Christoffer Fremling , V. Zach Golkhou , Matthew J. Graham , David Hale , S. R. Kulkarni , Thomas Kupfer , Russ R. Laher , Ashish A. Mahabal , Frank J. Masci , Ben Rusholme , Roger M. Smith , Anastasios Tzanidakis , Angela Van Sistine , Yuhan Yao

Investigating GW190425 with numerical-relativity simulations

The third observing run of the LIGO-Virgo collaboration has resulted in about hundred gravitational-wave triggers including the binary neutron star merger GW190425. However, none of these events have been accompanied with an electromagnetic…

High Energy Astrophysical Phenomena · Physics 2021-09-20 Reetika Dudi , Ananya Adhikari , Bernd Brügmann , Tim Dietrich , Kota Hayashi , Kyohei Kawaguchi , Kenta Kiuchi , Koutarou Kyutoku , Masaru Shibata , Wolfgang Tichy

Prospects for kilonova signals in the gravitational-wave era

The binary neutron star merger gravitational-wave signal GW170817 was followed by three electromagnetic counterparts, including a kilonova arising from the radioactivity of freshly synthesized $r$-process elements in ejecta from the merger.…

High Energy Astrophysical Phenomena · Physics 2021-07-21 Robert Mochkovitch , Frédéric Daigne , Raphaël Duque , Hannachi Zitouni

LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: Zwicky Transient Facility observations

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 International Gravitational Wave Network (IGWN). Although the…

High Energy Astrophysical Phenomena · Physics 2025-07-02 Tomás Ahumada , Shreya Anand , Mattia Bulla , Vaidehi Gupta , Mansi Kasliwal , Robert Stein , Viraj Karambelkar , Eric C. Bellm , Theophile Jegou du Laz , Michael W. Coughlin , Igor Andreoni , Smaranika Banerjee , Aleksandra Bochenek , K-Ryan Hinds , Lei Hu , Antonella Palmese , Daniel Perley , Natalya Pletskova , Anirudh Salgundi , Avinash Singh , Jesper Sollerman , Vishwajeet Swain , Avery Wold , Varun Bhalerao , S. Bradley Cenko , David O. Cook , Chris Copperwheat , Matthew Graham , David L. Kaplan , Leo P. Singer , Niharika Sravan , Malte Busmann , Julius Gassert , Daniel Gruen , Julian Sommer , Yajie Zhang , Ariel Amsellem , Tomás Cabrera , Xander J. Hall , Keerthi Kunnumkai , Brendan O'Connor , Tyler Barna , Felipe Fontinele Nunes , Andrew Toivonen , Argyro Sasli , Frank J. Masci , Tracy X. Chen , Richard Dekany , Josiah Purdum , Antoine Le-Calloch , G. C. Anupama , Sudhanshu Barway