Maximizing the Detection Probability of Kilonovae Associated With Gravitational Wave Observations

Abstract

Estimates of the source sky location for gravitational wave signals are likely span areas ranging up to hundreds of square degrees or more, making it very challenging for most telescopes to search for counterpart signals in the electromagnetic spectrum. To boost the chance of successfully observing such counterparts, we have developed an algorithm which optimizes the number of observing fields and their corresponding time allocations by maximizing the detection probability. As a proofof-concept demonstration, we optimize follow-up observations targeting kilonovae using telescopes including CTIO-Dark Energy Camera, Subaru-HyperSuprimeCam, Pan-STARRS and Palomar Transient Factory. We consider three simulated gravitational wave events with 90% credible error regions spanning areas from ∼30 deg 2 to ∼300 deg 2 . Assuming a source at 200 Mpc, we demonstrate that to obtain a maximum detection probability, there is an optimized number of fields for any particular event that a telescope should observe. To inform future telescope design studies, we present the maximum detection probability and corresponding number of observing fields for a combination of limiting magnitudes and fields-of-view over a range of parameters. We show that for large gravitational wave error regions, telescope sensitivity rather than field-of-view, is the dominating factor in maximizing the detection probability.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

“…We detailed our plan to automatically notify the astronomical community of event candidates, starting in O3. This information will help to optimize multi-messenger follow-up and source identification, to plan instrument operation and projects, and to evaluate joint detections in order to maximize the science return of each GW detection (e.g., Abadie et al 2012b;Aasi et al 2014a;Kasliwal and Nissanke 2014;Singer et al 2014;Cannon et al 2012;Evans et al 2016a;Gehrels et al 2016;Ghosh et al 2016;Chan et al 2017;Rana et al 2017;Patricelli et al 2016;Salafia et al 2017;Patricelli et al 2018;Coughlin et al 2018;Vinciguerra et al 2019).…”

Strategies for the follow-up of gravitational wave transients with the Cherenkov Telescope Array

“…In these cases, CTA will need to cover as much of the GW sky localization region as possible. There have been multiple studies discussing optimal strategies for covering the broad GW sky localization regions and maximizing the probability of detecting transient counterparts (e.g., Chan et al 2017;Coughlin & Stubbs 2016;Ghosh et al 2016;Salafia et al 2017). All of these studies highlight that the probability of detecting a counterpart transient can be boosted by factors of a few if the sky location is tiled efficiently and the time allocation per sky location is optimized for each telescope's sensitivity and the skymap probability.…”

“…Additionally, the probability of counterpart detection can be boosted if observing strategies target galaxies within the GW sky localization region (Chan et al 2017;Gehrels et al 2016;Singer et al 2016). A good example for this strategy is that followed by the Swope Telescope which was the first to discover the optical counterpart of GW170817 despite its small telescope size (Coulter et al 2017).…”