A 2 month Galaxy-targeted Near-infrared Follow-up of the Sub-solar-mass Gravitational-wave Candidate S251112cm: Probing Electromagnetic Counterpart Scenarios
Year: 2026
Type: article
Abstract: S251112cm is a nearby (93 ± 27 Mpc) compact-binary merger candidate with a high inferred probability that at least one component is below 1 M ⊙ . This event provides a rare test case for electromagnetic follow-up of a theoretically predicted but unconfirmed sub-solar-mass merger candidate. Motivated by scenarios predicting near-infrared (NIR)-bright emission over weeks to months, we carried out a deep galaxy-targeted UKIRT J -band campaign over approximately 2 months, prioritizing host candidates by a ranking that combines the three-dimensional localization probability with Wide-field Infrared Survey Explorer (WISE) W1 luminosity as a stellar-mass proxy. Of ∼9000 candidate hosts, we monitored 59, corresponding to 7.7% of the cumulative weighted host prior. Difference imaging reveals no convincing transient down to typical depths of J ∼ 22–23 mag (AB). At this distance, both a Type Ic-BL supernova template and an AT 2017gfo-like kilonova (KN) template—including time-shifted variants up to Δ t ∼ 60 days—would have remained above our median depth for multiple epochs within the monitored hosts. Comparison with a canonical KN model grid, summarized through conditional weighted consistent-fraction maps, shows that bright configurations with high dynamical and wind-ejecta masses are strongly disfavored, while less luminous configurations remain largely permissible. While these constraints are host limited and do not constitute an event-wide exclusion, this campaign provides the first empirical case study of long-baseline, deep NIR follow-up for a sub-solar-mass merger gravitational-wave (GW) class and demonstrates a host-weighted framework applicable to future galaxy-targeted campaigns.
Source: The Astrophysical Journal
Institutions: University of Hawaiʻi at Mānoa, University of Hawaii System
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Awards: NEO DISCOVERY AND CHARACTERIZATION WITH THE PAN-STARRS PS1 TELESCOPE. WE WILL USE THE PAN-STARRS PS1 TELESCOPE SYSTEM TO RAPIDLY SURVEY LARGE AREAS O, Graduate Research Fellowship Program (GRFP), THE POWER OF THE PAN-STARRS1 TELESCOPE TO DISCOVER NEOS HAS BEEN AMPLY DEMONSTRATED WITH THE CURRENT 11% DEDICATED ALLOCATION OF OBSERVING TIME SUPPO, A NEO SEARCH PROGRAM USING THE PAN-STARRS PS1 TELESCOPETHE GOAL OF THE PROPOSED RESEARCH IS TO USE T, Graduate Research Fellowship Program (GRFP), G8380168758, THE OBJECTIVE OF THIS PROPOSAL IS TO SIGNIFICANTLY UPGRADE THE PAN-STARRS TELESCOPE SYSTEM ON HALEAKALA, MAUI BY COMPLETING THE INSTRUMENTATION AND C, WE PROPOSE TO CONTINUE OUR SURVEY TO DISCOVER NEAR EARTH OBJECTS (NEOS) WITH THE PAN-STARRS SYSTEM EXPANDED TO INCLUDE THE PAN-STARRS2 OBSERVATORY (PS2) TOGETHER WITH THE PAN-STARRS1 OBSERVATORY (PS1). SINCE THE START OF DEDICATED USE OF PAN- STARRS FOR NEO DISCOVERY IN SPRING OF 2014 PS1 HAS DISCOVERED OVER 40% OF ALL NEOS AND OVER 50% OF THE LARGER NEOS AND POTENTIALLY HAZARDOUS ASTEROIDS. PS1 IS ALSO THE LEADING DISCOVERY TELESCOPE FOR NEOS LARGER THAN 1 KM IN DIAMETER. WITH PS2 WE WILL AT LEAST DOUBLE OUR RAW SURVEY POWER. THE PAN-STARRS2 OBSERVATORY IS COMPLETE AND WE EXPECT TO COMPLETE ITS CAMERA (GPC2) SOON AND ADD SCIENCE OPERATIONS WITH PS2 TO THE ONGOING PS1 SURVEY. PS2 WILL BE IN FULL SCIENCE OPERATIONS BY THE START OF THE PERIOD OF PERFORMANCE OF THIS PROPOSAL. THE PS2 OPTICS ARE SUPERIOR TO THOSE OF PS1 AND WE HAVE ELIMINATED THE CAUSE OF CORRELATED READ NOISE THAT AFFLICTS FAINT OBJECTS IN THE CAMERA ON PS1. THUS WE EXPECT PS2 TO BE SLIGHTLY SUPERIOR TO PS1 IN DISCOVERING NEOS. THE PAN-STARRS SYSTEM WITH BOTH PS1 AND PS2 WILL CHANGE THE LANDSCAPE OF NEO DISCOVERY. WE CAN DOUBLE THE AREA SURVEYED OR PERFORM SELF FOLLOW-UP OBSERVATIONS WHICH WILL SIGNIFICANTLY DECREASE THE NUMBER OF OBJECTS LOST DUE TO AN ABSENCE OF FOLLOW-UP. MORE SELF-FOLLOW-UP WILL ALSO AVOID BIASES INTRODUCED BY THE DIGEST SCORE AND PROVIDE A MORE SYSTEMATIC SURVEY. WE WILL INVESTIGATE WIDE AREA SURVEY STRATEGIES RANGING BETWEEN THESE TWO EXTREMES TO OPTIMIZE FOR THE MOST COMPLETE NEO SURVEY AND TO REDUCE LOSSES OF RARE OR CAMOUFLAGED NEOS THAT WE ARE CURRENTLY UNDER-SAMPLING. IN ADDITION TO BRINGING THE SURVEY POWER OF PS2 ON LINE WE HAVE IDENTIFIED PROMISING AVENUES WHERE WE CAN IMPROVE OUR DISCOVERY RATE BY ADVANCES IN SOFTWARE INCLUDING IMPROVED DE-TRENDING ASTROMETRY OBJECT DETECTION IMAGE SUBTRACTION AND MACHINE LEARNING TECHNIQUES. FINALLY WE HAVE AN EXPERIENCED TEAM WITH A PROVEN RECORD OF SUCCESS.
OpenAlex ID: W7221797025