Holismokes

Abstract

We present the HOLISMOKES programme on strong gravitational lensing of supernovae (SNe) as a probe of SN physics and cosmology. We investigate the effects of microlensing on early-phase SN Ia spectra using four different SN explosion models. We find that distortions of SN Ia spectra due to microlensing are typically negligible within ten rest-frame days after a SN explosion (< 1% distortion within the 1σ spread and ≲10% distortion within the 2σ spread). This shows the great prospects of using lensed SNe Ia to obtain intrinsic early-phase SN spectra for deciphering SN Ia progenitors. As a demonstration of the usefulness of lensed SNe Ia for cosmology, we simulate a sample of mock lensed SN Ia systems that are expected to have accurate and precise time-delay measurements in the era of the Rubin Observatory Legacy Survey of Space and Time (LSST). Adopting realistic yet conservative uncertainties on their time-delay distances and lens angular diameter distances, of 6.6% and 5%, respectively, we find that a sample of 20 lensed SNe Ia would allow us to constrain the Hubble constant (H0) with 1.3% uncertainty in the flat ΛCDM cosmology. We find a similar constraint on H0 in an open ΛCDM cosmology, while the constraint degrades to 3% in a flat wCDM cosmology. We anticipate lensed SNe to be an independent and powerful probe of SN physics and cosmology in the upcoming LSST era.

Discovering New Strong Gravitational Lenses in the DESI Legacy Imaging Surveys

“…In addition, the angular scales of our systems are typically between 1 5 and 5″ (see Figure 10), significantly larger than the typical value for previously known galaxy lensing systems (1 5). This translates to longer time delays and a smaller relative uncertainty per system for quasars and supernova events in the background galaxy, and therefore higher precision in the measurement of H 0 (e.g., Suyu et al 2020).…”

“…In recent years, strongly lensed supernovae, both core-collapse (Kelly et al 2015;Rodney et al 2016) and Type Ia (Quimby et al 2014;Goobar et al 2017), have been discovered. Time-delay H 0 measurements from multiply imaged supernovae can therefore be an important independent approach to address the discrepancy between H 0 measured locally and the value inferred from the cosmic microwave background (e.g., Goldstein & Nugent 2017;Goldstein et al 2018Goldstein et al , 2019Pierel & Rodney 2019;Wojtak et al 2019;Suyu et al 2020).…”

Holismokes

“…We focused on systems with luminous red galaxies (LRGs) acting as lenses and with image separations 0.75 , larger than the median seeing FWHMs in g, r, and i bands. Such systems are ideal for constraining the lens mass-density profiles and for finding strongly lensed supernovae for cosmography and stellar physics, which are major goals of our ongoing Highly Optimized Lensing Investigations of Supernovae, Microlensing Objects, and Kinematics of Ellipticals and Spirals (HOLISMOKES; Suyu et al 2020). To go beyond previous studies that relied on strict catalog preselections, we demonstrate that a dedicated neural network trained on a carefully constructed dataset can automatically and efficiently identify such lenses over an extended galaxy sample.…”

Holismokes

“…1 The type I and II refer to the types of lensing images, not SN types. we chose κ = 0.7 and γ = 0.7, which are the median values of type II lensing images of the OM10 catalog (Huber et al 2021;Suyu et al 2020). We adopted s = 0.5 for both cases.…”

“…With this work, which is part of Highly Optimised Lensing Investigations of Supernovae, Microlensing Objects, and Kinematics of Ellipticals and Spirals (HOLISMOKES; Suyu et al 2020), we take a closer look at SNe II for time-delay measurements that incorporate microlensing effects. Characteristic features in the light curves and spectra of SNe II could be used to conduct time-delay measurements.…”