Magnetar Engines in Fast Blue Optical Transients and Their Connections with SLSNe, SNe Ic-BL, and lGRBs

Abstract

We fit the multiband lightcurves of 40 fast blue optical transients (FBOTs) with the magnetar engine model. The mass of the FBOT ejecta, the initial spin period, and the polar magnetic field of the FBOT magnetars are respectively constrained to M ej = 0.11 − 0.09 + 0.22 M ⊙ , P i = 9.1 − 4.4 + 9.3 ms , and B p = 11 − 7 + 18 × 10 14 G . The wide distribution of the value of B p spreads the parameter ranges of the magnetars from superluminous supernovae (SLSNe) to broad-line Type Ic supernovae (SNe Ic-BL; some are observed to be associated with long-duration gamma-ray bursts), which are also suggested to be driven by magnetars. Combining FBOTs with the other transients, we find a strong universal anticorrelation of P i ∝ M ej − 0.41 , indicating they could share a common origin. To be specific, it is suspected that all of these transients originate from the collapse of extremely stripped stars in close binary systems, but with different progenitor masses. As a result, FBOTs distinguish themselves by their small ejecta masses with an upper limit of ∼1 M ⊙, which leads to an observational separation in the rise time of the lightcurves of ∼10 days. In addition, FBOTs together with SLSNe can be separated from SNe Ic-BL by an empirical line in the M peak–t rise plane corresponding to an energy requirement of the mass of 56Ni of ∼0.3M ej, where M peak is the peak absolute magnitude of the transients and t rise is the rise time.

Linear and Circular Polarimetry of the Optically Bright Relativistic Tidal Disruption Event AT 2022cmc

“…While these objects, primarily found in quiescent or poststarburst galaxies (Arcavi et al 2014;French et al 2020), constitute the most numerous and homogeneous class among TDEs, there exist a number of other transients that have been proposed to be due to tidal disruptions. These include objects found through their X-ray emission (Saxton et al 2020); objects found in active galactic nuclei (AGNs; explicitly excluded by the criteria of van Velzen et al 2020), such as PS16dtm (Blanchard et al 2017); objects found in luminous infrared galaxies often suffering considerable extinction (Tadhunter et al 2017;Mattila et al 2018); unique objects such as the superluminous ASASSN-15lh (Leloudas et al 2016), some of which are often debated to be of supernova or AGN origin (see Zabludoff et al 2021); or fast blue optical transients (FBOTs), such as AT 2018cow, whose nature is also debated (e.g., Kuin et al 2019;Perley et al 2019;Kremer et al 2021;Liu et al 2022;Metzger 2022).…”

Linear and circular polarimetry of the optically bright relativistic Tidal Disruption Event AT 2022cmc

“…Nowadays, the majority of TDEs are found by wide-field optical surveys and a distinct class of objects has been discovered where the optical/UV emission is dominated by a thermal component with black-body temperatures 2 − 4 × 10 4 K (van Velzen et al 2020). While these objects, primarily found in quiescent or post-starburst galaxies (Arcavi et al 2014;Kuin et al 2019;Kremer et al 2021;Metzger 2022;Liu et al 2022).…”

An environmental analysis of the fast transient AT2018cow and implications for its progenitor and late-time brightness

“…Liu et al 2018;Kuin et al 2019;Perley et al 2019;Metzger 2022), while the second category regards FBOTs as arising from the core collapse of massive stars. To power the rapid evolution, the collapsar models require ★ E-mail: n.sun@sheffield.ac.uk some special energy input by, e.g., magnetar (Prentice et al 2018;Fang et al 2019;Liu et al 2022), jets (Gottlieb, Tchekhovskoy, & Margutti 2022;Soker 2022), or the strong interaction between ejecta and circumstellar material (CSM; Fox & Smith 2019;Leung et al 2020;Xiang et al 2021). Many observational studies (Ho et al 2021;Xiang et al 2021) reveal the similarities in the light curves and spectra between FBOTs and the Type Ibn SNe (i.e.…”