Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Erik C. Kool
Joel Johansson
Jesper Sollerman
Javier Moldón
Takashi J. Moriya
Steve Schulze
Laura Chomiuk
Chelsea Harris
Miguel Pérez-Torres
Seppo Mattila
Peter Lundqvist
Matthew Graham
Sheng Yang
Daniel A. Perley
Nora Linn Strotjohann
Christoffer Fremling
Avishay Gal-Yam
Jeremy Lezmy
Kate Maguire
Conor Omand
Abstract： Type Ia supernovae are thought to be carbon-oxygen white dwarf stars that explode after accreting material from a companion star, but despite extensive studies the nature of the companion star is still poorly understood, as is the explosion mechanism. In the single degenerate scenario, the companion is a non-degenerate star that loses material through winds and/or binary interaction, and a few Type Ia supernovae have shown evidence for hydrogen-rich circumstellar material. We present here the study of SN 2020eyj, a unique Type Ia supernova showing delayed interaction with helium-rich, but hydrogen-poor, circumstellar material. This material surrounding SN 2020eyj is revealed by its unusual light curve and infrared emission, narrow helium emission lines and, for the first time ever in a Type Ia supernova, also a radio counterpart. The circumstellar material likely originates from the companion star, providing the first direct evidence for a, so far hypothesized, single degenerate progenitor system composed of a white dwarf and a helium donor star.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Hung-Jin Huang
Tim Eifler
Rachel Mandelbaum
Gary M. Bernstein
Anqi Chen
Ami Choi
Juan García-Bellido
Dragan Huterer
Elisabeth Krause
Eduardo Rozo
Sukhdeep Singh
Sarah Bridle
Joseph DeRose
Jack Elvin-Pole
Xiao Fang
Oliver Friedrich
Marco Gatti
Enrique Gaztanaga
Daniel Gruen
Will Hartley
Abstract： Measurements of large-scale structure are interpreted using theoretical predictions for the matter distribution, including potential impacts of baryonic physics. We constrain the feedback strength of baryons jointly with cosmology using weak lensing and galaxy clustering observables (3$\times$2pt) of Dark Energy Survey (DES) Year 1 data in combination with external information from baryon acoustic oscillations (BAO) and Planck cosmic microwave background polarization. Our baryon modeling is informed by a set of hydrodynamical simulations that span a variety of baryon scenarios; we span this space via a Principal Component (PC) analysis of the summary statistics extracted from these simulations. We show that at the level of DES Y1 constraining power, one PC is sufficient to describe the variation of baryonic effects in the observables, and the first PC amplitude ($Q_1$) generally reflects the strength of baryon feedback. With the upper limit of $Q_1$ prior being bound by the Illustris feedback scenarios, we reach $\sim 20\%$ improvement in the constraint of $S_8=\sigma_8(\Omega_{\rm m}/0.3)^{0.5}=0.788^{+0.018}_{-0.021}$ compared to the original DES 3$\times$2pt analysis. This gain is driven by the inclusion of small-scale cosmic shear information down to 2.5 arcmin, which was excluded in previous DES analyses that did not model baryonic physics. We obtain $S_8=0.781^{+0.014}_{-0.015}$ for the combined DES Y1+Planck EE+BAO analysis with a non-informative $Q_1$ prior. In terms of the baryon constraints, we measure $Q_1=1.14^{+2.20}_{-2.80}$ for DES Y1 only and $Q_1=1.42^{+1.63}_{-1.48}$ for DESY1+Planck EE+BAO, allowing us to exclude one of the most extreme AGN feedback hydrodynamical scenario at more than $2 \sigma$.
Peer Review Status:Awaiting Review
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