The Circumstellar Environments of Double-Peaked, Calcium-strong Supernovae 2021gno and 2021inl
Creators: name: Jacobson-Galán, Wynn
name: Venkatraman, Padma
name: Margutti, Raffaella
name: Khatami, David
name: Terreran, Giacomo
name: Foley, Ryan J.
name: Angulo, Rodrigo
name: Angus, Charlotte R.
name: Auchettl, Katie
name: Blanchard, Peter K.
name: Bobrick, Alexey
name: Bright, Joe S.
name: Couch, Cirilla D.
name: Coulter, David A.
name: Clever, Karoli
name: Davis, Kyle W.
name: de Boer, Thomas
name: DeMarchi, Lindsay
name: Dodd, Sierra A.
name: Jones, David O.
name: Johnson, Jessica
name: Kilpatrick, Charles D.
name: Khetan, Nandita
name: Lai, Zhisen
name: Langeroodi, Danial
name: Lin, Chien-Cheng
name: Magnier, Eugene A.
name: Milisavljevic, Dan
name: Perets, Hagai B.
name: Pierel, Justin D. R.
name: Raymond, John
name: Rest, Sofia
name: Rest, Armin
name: Ridden-Harper, Ryan
name: Shen, Ken J.
name: Siebert, Matthew R.
name: Smith, Carli
name: Taggart, Kirsty
name: Tinyanont, Samaporn
name: Valdes, Frank
name: Villar, Victoria A.
name: Wang, Qinan
name: Yadavalli, S. Karthik
name: Zenati, Yossef
name: Zenteno, Alfredo
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present panchromatic observations and modeling of calcium-strong supernovae (SNe) 2021gno in the star-forming host galaxy NGC 4165 (D = 30.5 Mpc) and 2021inl in the outskirts of elliptical galaxy NGC 4923 (D = 80 Mpc), both monitored through the Young Supernova Experiment (YSE) transient survey. The multi-color light curves of both SNe show two peaks, the former peak being derived from shock cooling emission (SCE) and/or shock interaction with circumstellar material (CSM). The primary peak in SN 2021gno is coincident with luminous, rapidly decaying X-ray emission ($L_x = 5 \times 10^{41}$ erg s$^{-1}$) detected by Swift-XRT at $δt = 1$ day after explosion, this observation being the second ever detection of X-rays from a calcium-strong transient. We interpret the X-ray emission from SN 2021gno in the context of shock interaction with dense CSM that extends to $r &lt; 3 \times 10^{14}$ cm. Based on modeling of the SN 2021gno X-ray spectrum, we calculate a CSM mass range of $M_{\rm CSM} = (0.3 - 1.6) \times 10^{-3}$ M$_{\odot}$ and particle densities of $n = (1-4) \times 10^{10}$ cm$^{-3}$. Radio non-detections of SN 2021gno indicate a low-density environment at larger radii ($r &gt; 10^{16}$ cm) and a progenitor mass loss rate of $\dot{M} &lt; 10^{-4}$ M$_{\odot}$ yr$^{-1}$, for $v_w = 500$ km s$^{-1}$. For radiation derived from SCE, modeling of the primary light curve peak in both SNe indicates an extended progenitor envelope mass and radius of $M_e = 0.02 - 0.05$ M$_{\odot}$ and $R_e = 30 - 230$ R$_{\odot}$. The explosion properties of SNe 2021gno and 2021inl suggest progenitor systems containing either a low-mass massive star or a white dwarf (WD), the former being unlikely for either object given the lack of star formation at both explosion sites. Furthermore, the progenitor environments of both SNe are consistent with explosion models for low-mass hybrid He/C/O WD + C/O WD binaries.
description: 33 pages, 19 figures. Submitted to ApJ. Comments welcome!