The Optical Two- and Three-dimensional Fundamental Plane Correlations for Nearly 180 Gamma-Ray Burst Afterglows with Swift/UVOT, RATIR, and the Subaru Telescope

Abstract

Gamma-ray bursts (GRBs) are fascinating events due to their panchromatic nature. We study optical plateaus in GRB afterglows via an extended search into archival data. We comprehensively analyze all published GRBs with known redshifts and optical plateaus observed by many ground-based telescopes (e.g., Subaru Telescope, RATIR) around the world and several space-based observatories such as the Neil Gehrels Swift Observatory. We fit 500 optical light curves, showing the existence of the plateau in 179 cases. This sample is 75% larger than the previous one, and it is the largest compilation so far of optical plateaus. We discover the 3D fundamental plane relation at optical wavelengths using this sample. This correlation is between the rest-frame time at the end of the plateau emission, T opt * , its optical luminosity, L opt, and the peak in the optical prompt emission, L peak,opt, thus resembling the three-dimensional (3D) X-ray fundamental plane (the so-called 3D Dainotti relation). We correct our sample for redshift evolution and selection effects, discovering that this correlation is indeed intrinsic to GRB physics. We investigate the rest-frame end-time distributions in X-rays and optical ( T opt * , T X * ), and conclude that the plateau is achromatic only when selection biases are not considered. We also investigate if the 3D optical correlation may be a new discriminant between optical GRB classes and find that there is no significant separation between the classes compared to the Gold sample plane after correcting for evolution.

The Closure Relations in Optical Afterglow of Gamma-Ray Bursts

“…We take our sample of 82 GRBs from a larger sample of 99 GRBs in Dainotti et al (2022a). The GRBs have been observed in optical wavelengths by satellites such as Swift and the Ultraviolet/Optical Telescope (UVOT), as well as groundbased detectors such as the Subaru Telescope, the MITSuME, the reionization and Transients InfraRed telescope (RATIR), and the Gamma-Ray Burst Optical/Near-IR Detector (GROND).…”

“…Due to the difficulty of gathering a large sample of spectral indices at the specific time T a , we take the β parameter from the literature and assume a constant value throughout the LC for all GRBs in our sample. For 30 GRBs in which no optical spectral index could be found in the literature, Dainotti et al (2022a) extrapolate the spectral index from the photon index Γ in X-ray (given in the Swift XRT repository, Evans et al (2009)) by assuming β = Γ − 1. However, it cannot always be guaranteed that the X-ray and optical LCs fall in the same region of the spectral energy distribution (SED), therefore, for these GRBs, we compare the temporal index found in the optical fitting to the corresponding temporal index found in the X-ray fitting (Srinivasaragavan et al 2020).…”

“…Previous studies have shown that Swift X-ray LCs have complex features beyond a simple power-law decay (Tagliaferri et al 2005;Nousek et al 2006;O'Brien et al 2006;Zhang et al 2006bZhang et al , 2007aZhang et al , 2007bZhang et al , 2007cSakamoto et al 2007;Zhang 2007;Zhao et al 2019;Fraija et al 2019c). A plateau feature or a flattening of the LC immediately following the prompt emission and preceding the afterglow decay, has been found in all wavelengths of the GRB afterglow, including X-ray (Nousek et al 2006;O'Brien et al 2006;Zhang et al 2006b;Sakamoto et al 2007;Evans et al 2009), optical (Dainotti et al 2020b(Dainotti et al , 2022a, and radio (Levine et al 2022) wavelengths. These plateaus typically last from on the order of 10 2 -10 5 s, and are thought to result from continuous energy injection from a central engine (Dai & Lu 1998;Rees & Mészáros 1998;Sari & Mészáros 2000;Zhang & Mészáros 2001;Zhang et al 2006b;Liang et al 2007)-either the fall-back accretion of matter onto a black hole (Kumar et al 2008;Cannizzo & Gehrels 2009;Cannizzo et al 2011;Metzger et al 2018) or the spin-down luminosity from a newborn magnetar (Zhang & Mészáros 2001;Toma et al 2007;Troja et al 2007;Dall'Osso et al 2011;Rowlinson et al 2013Rowlinson et al , 2014…”

“…This plateau has been used to develop a correlation between the rest-frame end time of the plateau in X-rays and its correspondent luminosity at that time, called the 2D Dainotti correlation in X-rays (Dainotti et al 2008(Dainotti et al , 2010(Dainotti et al , 2011(Dainotti et al , 2013b(Dainotti et al , 2017aDel Vecchio et al 2016;Zhang et al 2018). This correlation has been extended to optical (Dainotti et al 2020b(Dainotti et al , 2022a and radio afterglows (Levine et al 2022). It has been proposed as a possible method of standardizing the varied sample of GRBs to use it as a cosmological tool (Cardone et al 2009(Cardone et al , 2010Dainotti et al 2013aDainotti et al , 2022bDainotti et al , 2022cDainotti et al , 2022dPostnikov et al 2014;Cao et al 2022aCao et al , 2022b.…”

“…It has been proposed as a possible method of standardizing the varied sample of GRBs to use it as a cosmological tool (Cardone et al 2009(Cardone et al , 2010Dainotti et al 2013aDainotti et al , 2022bDainotti et al , 2022cDainotti et al , 2022dPostnikov et al 2014;Cao et al 2022aCao et al , 2022b. Dainotti et al (2016); Dainotti & Del Vecchio (2017); Dainotti et al (2020aDainotti et al ( , 2022a analyze an extension of this 2D correlation to the 3Dl fundamental plane both in X-rays and optical, which describes a correlation between the rest-frame end time of the plateau, the luminosity at that time, and the peak prompt luminosity.…”