The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with GRANDMA

Abstract

We present the Global Rapid Advanced Network Devoted to the Multi-messenger Addicts (GRANDMA). The network consists of 21 telescopes with both photometric and spectroscopic facilities. They are connected together thanks to a dedicated infrastructure. The network aims at coordinating the observations of large sky position estimates of transient events to enhance their follow-up and reduce the delay between the initial detection and the optical confirmation. The GRANDMA program mainly focuses on follow-up of gravitational-wave alerts to find and characterise the electromagnetic counterpart during the third observational campaign of the Advanced LIGO and Advanced Virgo detectors. But it allows for any follow-up of transient alerts involving neutrinos or gamma-ray bursts, even with poor spatial localisation. We present the different facilities, tools, and methods we developed for this network, and show its efficiency using observations of LIGO/Virgo S190425z, a binary neutron star merger candidate. We furthermore report on all GRANDMA follow-up observations performed during the first six months of the LIGO-Virgo observational campaign, and we derive constraints on the kilonova properties assuming that the events' locations were imaged by our telescopes.

Implications of the search for optical counterparts during the second part of the Advanced LIGO’s and Advanced Virgo’s third observing run: lessons learned for future follow-up observations

“…For example, GW190425 (Abbott et al 2020a) brought stringent limits on potential counterparts from a number of teams, including GROWTH (Coughlin et al 2019d) and MMT/SOAR (Hosseinzadeh et al 2019). GW190814, as a potential, well-localized BHNS candidate, also had extensive follow-up from a number of teams, including GROWTH (Andreoni et al 2020a), ENGRAVE (Ackley et al 2020), GRANDMA (Antier et al 2020a), and Magellan (Gomez et al 2019). S190521g brought the first strong candidate counterpart to a BBH merger Graham et al (2020).…”

“…1 Amongst the wide field-of-view telescopes, ATLAS (McBrien et al 2019a;Smartt et al 2019a, b;Srivastav et al 2019), ASAS-SN (Shappee et al 2019), CNEOST (Li et al 2019;Xu et al 2019b, c), Dabancheng/HMT (Xu et al 2019d), DESGW-DECam (Soares-Santos et al 2019), DDOTI/OAN (Dichiara et al 2019;Pereyra et al 2019;Watson et al 2019b), GOTO (Ackley et al 2019a, b;Steeghs et al 2019a, b;Gompertz et al 2020), GRANDMA (Antier et al 2020a;Antier et al 2020b), GRAWITA-VST (Grado et al 2019a, b), GROWTH-DECAM (Andreoni et al 2019a;Goldstein et al 2019), GROWTH-Gattini-IR (De et al 2019;Hankins et al 2019a, b), GROWTH-INDIA (Bhalerao et al 2019), HSC (Yoshida et al 2019), J-GEM (Niino et al 2019), KMTNet (Im et al 2019;Kim et al 2019), MASTERnetwork (Lipunov et al 2019a, b, c, d, e, f, g, h), MeerLICHT (Groot et al 2019), Pan-STARRS (Smith et al 2019;Smartt et al 2019a), SAGUARO (Lundquist et al 2019), SVOM-GWAC (Wei et al 2019), Swope (Kilpatrick et al 2019), Xinglong-Schmidt (Xu et al 2019a;Zhu et al 2019), and the Zwicky Transient Facility (Anand et al 2019;Coughlin et al 2019d;Kasliwal et al 2019a, b;Kool et al 2019;Singer et al 2019;…”

The H.E.S.S. gravitational wave rapid follow-up program

“…Therefore we conclude that PGW-in-FoV performance is superior to The 3D algorithms were developed to provide the best possible coverage efficiency of the most promising nearby GW events. The galaxy-targeted Best-galaxy is typically used by small FoV instruments like the GRANDMA collaboration telescopes with F oV < 1deg 2 [26] and Magellan [27]. The PGalinFoV and PGalinFoV-PixRegion algorithms are FoV-targeted and are best adapted for medium and large FoV instruments in order to take advantage of the relatively large FoV.…”

Updated parameter estimates for GW190425 using astrophysical arguments and implications for the electromagnetic counterpart

“…They quickly released a three-dimensional probability map of the location of the GW emission with a two-dimensional 90th-percentile localization region of 10,183 deg 2 which was revised about a day later to having a size of 7,461 deg 2 (Ligo Scientific Collaboration & VIRGO Collaboration 2019b); the final map released in 2020 January has a 8,284 deg 2 two-dimensional 90th-percentile localization region (LVC20). Although this region covers ∼1/5 of the entire sky, several groups searched for an EM counterpart (e.g., Antier et al 2019;Coughlin et al 2019;Hosseinzadeh et al 2019;Lundquist et al 2019). Collectively, ∼50% of the twodimensional localization area was observed in the days following the merger.…”