English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Rapid variability before and near the maximum brightness of supernovae hasthe potential to provide a better understanding of nearly every aspect ofsupernovae, from the physics of the explosion up to their progenitors and thecircumstellar environment. Thanks to modern time-domain optical surveys, whichare discovering supernovae in the early stage of their evolution, we have theunique opportunity to capture their intraday behavior before maximum. Wepresent high-cadence photometric monitoring (on the order of seconds-minutes)of the optical light curves of three Type Ia and two Type II SNe over severalnights before and near maximum light, using the fast imagers available on the2.3~m Aristarchos telescope at Helmos Observatory and the 1.2~m telescope atKryoneri Observatory in Greece. We applied differential aperture photometrytechniques using optimal apertures and we present reconstructed light curvesafter implementing a seeing correction and the Trend Filtering Algorithm(TFA).TFA yielded the best results, achieving a typical precision between0.01-0.04~mag. We did not detect significant bumps with amplitudes greater than0.05~mag in any of the SNe targets in the VR-, R-, and I- bands light curvesobtained. We measured the intraday slope for each light curve, which rangesbetween -0.37-0.36 mag/day in broadband VR, -0.19-0.31 mag/day in R band, and-0.13-0.10 mag/day in I band. We used SNe light curve fitting templates for SN2018gv, SN 2018hgc and SN 2018hhn to photometrically classify the light curvesand to calculate the time of maximum. We provide values for the maximum of SN2018zd after applying a low-order polynomial fit and SN 2018hhn for the firsttime. We suggest monitoring early supernovae light curves in hotter (bluer)bands with a cadence of hours as a promising way of investigating thepost-explosion photometric behavior of the progenitor stars.

First systematic high-precision survey of bright supernovae I. Methodology for identifying early bumps