Signatures of anti-social mass-loss in the ordinary Type II SN 2024bch -- A non-interacting supernova with early high-ionisation features

Abstract

In this paper we analyse the spectro-photometric properties of the Type II supernova 2024bch, exploded in NGC 3206 at a distance of $19.9\mathrm{Mpc}$. Its early spectra are characterised by narrow high-ionisation emission lines, often interpreted as signatures of ongoing interaction between rapidly expanding ejecta and a confined dense circumstellar medium. However, we provide a model for the bolometric light curve of the transient that does not require sources of energy different than radioactive decays and H recombination. Our model can reproduce the bolometric light curve of SN 2024bch adopting an ejected mass of $M_{bulk}\simeq 5{\mathrm{M}}_{\odot }$ surrounded by an extended envelope of only $0.2{\mathrm{M}}_{\odot }$ with an outer radius $R_{env}=7.0\times 10^{13}\mathrm{cm}$. An accurate modelling focused on the radioactive part of the light curve, which accounts for incomplete $\gamma -$ray trapping, gives a ${}^{56}\mathrm{Ni}$ mass of $0.048{\mathrm{M}}_{\odot }$. We propose narrow lines to be powered by Bowen fluorescence induced by scattering of He II Ly$\alpha$ photons, resulting in the emission of high-ionisation resonance lines. Simple light travel time calculations based on the maximum phase of the narrow emission lines place the inner radius of the H-rich, un-shocked shell at a radius $\simeq 4.4\times 10^{15}\mathrm{cm}$, compatible with an absence of ejecta-CSM interaction during the first weeks of evolution. Possible signatures of interaction appear only $\sim 69\mathrm{days}$ after explosion, although the resulting conversion of kinetic energy into radiation does not seem to contribute significantly to the total luminosity of the transient.

arXiv comment14 pages, 14 figures, 4 tables, accepted for publication on A&A

References in corpus (81)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• How Massive Single Stars End their Life
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• K-corrections and filter transformations in the ultraviolet, optical, and near infrared
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• Progenitors of core-collapse supernovae
• Nucleosynthesis in Massive Stars With Improved Nuclear and Stellar Physics
• HyperLEDA. III. The catalogue of extragalactic distances
• The Zwicky Transient Facility: Science Objectives
• Cosmicflows-3
• An extremely luminous X-ray outburst at the birth of a supernova
• Confined Dense Circumstellar Material Surrounding a Regular Type II Supernova: The Unique Flash-Spectroscopy Event of SN 2013fs
• Characterizing the V-band light-curves of hydrogen-rich type II supernovae
• The diversity of Type II supernova versus the similarity in their progenitors
• A Wolf-Rayet-like progenitor of supernova SN 2013cu from spectral observations of a wind
• Design and operation of the ATLAS Transient Science Server
• Generalized Semi-Analytical Models of Supernova Light Curves
• From Shock Breakout to Peak and Beyond: Extensive Panchromatic Observations of the Type Ib Supernova 2008D associated with Swift X-ray Transient 080109
• Evidence for Asphericity in the Type IIn Supernova 1998S
• Nucleosynthesis in Type II Supernovae
• High Density Circumstellar Interaction in the Luminous Type IIn SN 2010jl: The first 1100 days
• The type IIn supernova 1994W: evidence for the explosive ejection of a circumstellar envelope
• The progenitor mass of the Type IIP supernova SN 2004et from late-time spectral modeling
• Towards Characterization of the Type IIP Supernova Progenitor Population: a Statistical Sample of Light Curves from Pan-STARRS1
• Broad emission lines from opaque electron-scattering environment of SN 1998S
• Optical and Infrared Spectroscopy of the type IIn SN 1998S : Days 3-127
• Ultraviolet Light Curves of Supernovae with Swift Uvot
• Carnegie Supernova Project: Observations of Type IIn supernovae
• The nebular spectra of SN 2012aw and constraints on stellar nucleosynthesis from oxygen emission lines
• Photometric and Spectroscopic Properties of Type II-P Supernovae
• Interacting Supernovae: Types IIn and Ibn
• PTF11iqb: Cool supergiant mass loss that bridges the gap between Type IIn and normal supernovae
• A large fraction of hydrogen-rich supernova progenitors experience elevated mass loss shortly prior to explosion
• Optical and Infrared photometry of the type IIn SN 1998S:Days 11-146
• Supernovae from Red Supergiants with Extensive Mass Loss
• Caltech Core-Collapse Project (CCCP) Observations of Type II Supernovae: Evidence for Three Distinct Photometric Subtypes
• A Sample of Type II-L Supernovae
• Optical and Ultraviolet Spectroscopy of SN 1995N: Evidence for Strong Circumstellar Interaction
• Final Moments I: Precursor Emission, Envelope Inflation, and Enhanced Mass loss Preceding the Luminous Type II Supernova 2020tlf
• SN 2006bp: Probing the Shock Breakout of a Type II-P Supernova
• The early detection and follow-up of the highly obscured Type II supernova 2016ija/DLT16am
• The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet Evolution
• The Young Supernova Experiment: Survey Goals, Overview, and Operations
• Quantitative spectroscopic analysis of and distance to SN1999em
• Supernova Interaction with a Circumstellar Medium
• Early Emission from the Type IIn Supernova 1998S at High Resolution
• Short-Lived Circumstellar Interaction in the Low-Luminosity Type IIP SN 2016bkv
• The prevalence and influence of circumstellar material around hydrogen-rich supernova progenitors
• H-alpha Spectral diversity of type II supernovae
• The multi-faceted Type II-L supernova 2014G from pre-maximum to nebular phase
• The Type IIP Supernova 2012aw in M95: hydrodynamical modelling of the photospheric phase from accurate spectrophotometric monitoring
• Supernova Shock Breakout Through a Wind
• Massive stars exploding in a He-rich circumstellar medium - IX. SN 2014av, and characterization of Type Ibn SNe
• Models of interacting supernovae and their spectral diversity
• Shock Breakout in Type II Plateau Supernovae: Prospects for High Redshift Supernova Surveys
• Spectra of supernovae in the nebular phase
• On the photometric and spectroscopic diversity of Type II supernovae
• Constraining the physical properties of Type II-P supernovae using nebular phase spectra
• Supersolar Ni/Fe production in the Type IIP SN 2012ec
• A Shock Flash Breaking Out of a Dusty Red Supergiant
• Type II supernova spectral diversity II: Spectroscopic and photometric correlations
• A two-component model for fitting light-curves of core-collapse supernovae
• The Early Phases of Supernova 2020pni: Shock-Ionization of the Nitrogen-Enriched Circumstellar Material
• High-Energy Neutrinos and Gamma-Rays from Non-Relativistic Shock-Powered Transients
• A semi-analytical light curve model and its application to type IIP supernovae
• The long-lived Type IIn SN 2015da: Infrared echoes and strong interaction within an extended massive shell
• The early discovery of SN 2017ahn: signatures of persistent interaction in a fast declining Type II supernova
• New Observations of the Very Luminous Supernova 2006gy: Evidence for Echoes
• Electron scattering wings on lines in interacting supernovae
• MASTER: The Mobile Astronomical System of Telescope-Robots
• The Carnegie Supernova Project II. The shock wave revealed through the fog: The strongly interacting Type IIn SN 2013L
• Optical follow-up of the tidal disruption event iPTF16fnl: new insights from X-shooter observations
• The Iron Yield of Normal Type II Supernovae
• The He II Fowler lines and the O III and N III Bowen fluorescence lines in the symbiotic nova RR Tel
• LSQ13fn: A type II-Plateau supernova with a possibly low metallicity progenitor that breaks the standardised candle relation
• Probing Explosion Geometry of Core-collapse Supernovae with Light Curves of the Shock Breakout
• A Spectroscopic Study of Nuclear Processing and Production of Anomalously Strong Lines in the Crab Nebula
• Optically Informed Searches of High-Energy Neutrinos from Interaction-Powered Supernovae
• Extended supernova shock breakout signals from inflated stellar envelopes
• A study in scarlet -- I. Photometric properties of a sample of Intermediate Luminosity Red Transients
• Hidden shock powering the peak of SN 2020faa