The rise and fall of an extraordinary Ca-rich transient -- The discovery of ATLAS19dqr/SN 2019bkc

Abstract

This work presents the observations and analysis of ATLAS19dqr/SN 2019bkc, an extraordinary rapidly evolving transient event located in an isolated environment, tens of kiloparsecs from any likely host. Its light curves rise to maximum light in $5-6$ d and then display a decline of $\Delta m_{15}\sim 5$ mag. With such a pronounced decay, it has one of the most rapidly evolving light curves known for a stellar explosion. The early spectra show similarities to normal and `ultra-stripped' type Ic SNe, but the early nebular phase spectra, which were reached just over two weeks after explosion, display prominent calcium lines, marking SN 2019bkc as a Ca-rich transient. The Ca emission lines at this phase show an unprecedented and unexplained blueshift of 10,000 -- 12,000 km/s. Modelling of the light curve and the early spectra suggests that the transient had a low ejecta mass of $0.2-0.4$ M${}_{\odot }$ and a low kinetic energy of $(2-4)\times 10^{50}$ erg, giving a specific kinetic energy $\sim 1$ [$10^{51}$ erg]/M${}_{\odot }$. The origin of this event cannot be unambiguously defined. While the abundance distribution used to model the spectra marginally favours a progenitor of white dwarf origin through the tentative identification of \ArII, the specific kinetic energy, which is defined by the explosion mechanism, is found to be more similar to an ultra-stripped core-collapse events. SN 2019bkc adds to the diverse range of physical properties shown by Ca-rich events.

arXiv commentAccepted for publication in Astronomy & Astrophysics. Minor changes to section 4.3, some minor discussion added regarding opacities and line identification

References in corpus (94)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• Overview of the DESI Legacy Imaging Surveys
• The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
• ATLAS: A High-Cadence All-Sky Survey System
• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• A kilonova as the electromagnetic counterpart to a gravitational-wave source
• Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis
• Automated data reduction workflows for astronomy
• The metamorphosis of SN1998bw
• GROND - a 7-channel imager
• Rapidly-Evolving and Luminous Transients from Pan-STARRS1
• PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
• A faint type of supernova from a white dwarf with a helium-rich companion
• Sub-Chandrasekhar Mass Models For Type Ia Supernovae
• Three-dimensional neutrino-driven supernovae: Neutron star kicks, spins, and asymmetric ejection of nucleosynthesis products
• Optical Photometry and Spectroscopy of the SN 1998bw-like Type Ic Supernova 2002ap
• The Broad-lined Type Ic SN 2003jd
• The Cow: discovery of a luminous, hot and rapidly evolving transient
• The 2175 A dust feature in a Gamma Ray Burst afterglow at redshift 2.45
• Calcium-rich gap transients in the remote outskirts of galaxies
• Ultra-stripped Type Ic supernovae from close binary evolution
• Optical Spectra of 73 Stripped-Envelope Core-Collapse Supernovae
• Collisions of white dwarfs as a new progenitor channel for type Ia supernovae
• A Spectroscopic Analysis of the Energetic Type Ic `Hypernova' SN 1997ef
• The Carnegie Supernova Project I: analysis of stripped-envelope supernova light curves
• Thermonuclear .Ia Supernovae from Helium Shell Detonations: Explosion Models and Observables
• Nebular emission-line profiles of Type Ib/c Supernovae - probing the ejecta asphericity
• The nebular spectra of SN 2012aw and constraints on stellar nucleosynthesis from oxygen emission lines
• Late-Time Spectroscopy of SN 2002cx: The Prototype of a New Subclass of Type Ia Supernovae
• Hubble Space Telescope spectra of the type Ia supernova SN2011fe: a tail of low-density, high-velocity material with Z<Zsolar
• The bolometric light curves and physical parameters of stripped-envelope supernovae
• Observational and Physical Classification of Supernovae
• Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh
• Rapidly evolving transients in the Dark Energy Survey
• 2D simulations of the double-detonation model for thermonuclear transients from low-mass carbon-oxygen white dwarfs
• Rapidly Decaying Supernova 2010X: A Candidate ".Ia" Explosion
• Rotation-supported Neutrino-driven Supernova Explosions in Three Dimensions and the Critical Luminosity Condition
• Investigating the properties of stripped-envelope supernovae, what are the implications for their progenitors?
• The properties of the "standard" type Ic supernova 1994I from spectral models
• An Unusually Fast-Evolving Supernova
• Helium Shell Detonations on Low Mass White Dwarfs as a Possible Explanation for SN 2005E
• The Fast and Furious Decay of the Peculiar Type Ic Supernova 2005ek
• Nuclear-dominated accretion and subluminous supernovae from the merger of a white dwarf with a neutron star or black hole
• A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary
• Lower limits on the Hubble Constant from models of Type Ia Supernovae
• Optical Thermonuclear Transients From Tidal Compression of White Dwarfs as Tracers of the Low End of the Massive Black Hole Mass Function
• Nebular spectra and abundance tomography of the type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core
• Nebular Spectra and Explosion Asymmetry of Type Ia Supernovae
• Illuminating Massive Black Holes With White Dwarfs: Orbital Dynamics and High Energy Transients from Tidal Interactions
• Physics of Luminous Transient Light Curves: A New Relation Between Peak Time and Luminosity
• Light-curve and spectral properties of ultra-stripped core-collapse supernovae leading to binary neutron stars
• Atypical Thermonuclear Supernovae from Tidally Crushed White Dwarfs
• Using late-time optical and near-infrared spectra to constrain Type Ia supernova explosion properties
• Time dependent models of accretion disks with nuclear burning following the tidal disruption of a white dwarf by a neutron star
• The Type Ic SN 2007gr: a census of the ejecta from late-time optical-infrared spectra
• A GRB and Broad-lined Type Ic Supernova from a Single Central Engine
• Two New Calcium-Rich Gap Transients in Group and Cluster Environments
• Environment-derived constraints on the progenitors of low-luminosity type I supernovae
• Hubble Space Telescope and Ground-Based Observations of the Type Iax Supernovae SN 2005hk and SN 2008A
• PESSTO monitoring of SN 2012hn: further heterogeneity among faint type I supernovae
• Nebular-phase spectra of superluminous supernovae: physical insights from observational and statistical properties
• Kinematics and Host-Galaxy Properties Suggest a Nuclear Origin for Calcium-Rich Supernova Progenitors
• [OI] 6300,6364 in the nebular spectrum of a subluminous Type Ia supernova
• SN 2017ens: The Metamorphosis of a Luminous Broad-lined Type Ic Supernova into an SN IIn
• A physically motivated classification of stripped-envelope supernovae
• The progenitors of calcium-rich transients are not formed in situ
• SN 2016coi/ASASSN-16fp: An example of residual helium in a type Ic supernova?
• Modelling the Type Ic SN 2004aw: a Moderately Energetic Explosion of a Massive C+O Star without a GRB
• Photometric and spectroscopic observations, and abundance tomography modelling of the type Ia supernova SN 2014J located in M82
• On the Ca-strong 1991bg-like type Ia supernova 2016hnk: evidence for a Chandrasekhar-mass explosion
• Calcium-Rich Gap Transients: Tidal Detonations of White Dwarfs?
• One-dimensional non-LTE time-dependent radiative transfer of an He-detonation model and the connection to faint and fast-decaying supernovae
• Supernova Discoveries 2010-2011: Statistics and Trends
• Probing Intermediate Mass Black Holes With Optical Emission Lines from Tidally Disrupted White Dwarfs
• Light curves for off-centre ignition models of type Ia supernovae
• The nebular spectrum of the type Ia supernova 2003hv: evidence for a non-standard event
• iPTF15eqv: Multi-wavelength Exposé of a Peculiar Calcium-rich Transient
• iPTF 16hgs: A double-peaked Ca-rich gap transient in a metal poor, star forming dwarf galaxy
• Locations of Peculiar Supernovae as a Diagnostic of Their Origins
• The volumetric rate of calcium-rich transients in the local universe
• Hubble Space Telescope observations of the host galaxies and environments of calcium-rich supernovae
• Calcium-rich Gap Transients: Solving the Calcium Conundrum in the Intracluster Medium
• OGLE-2013-SN-079: a lonely supernova consistent with a helium shell detonation
• Relativistic Tidal Disruption and Nuclear Ignition of White Dwarf Stars by Intermediate Mass Black Holes
• The nebular spectra of the transitional Type Ia Supernovae 2007on and 2011iv: broad, multiple components indicate aspherical explosion cores
• Tidal Disruption of a White Dwarf by a Black Hole: The Diversity of Nucleosynthesis, Explosion Energy, and the Fate of Debris Streams
• The Most Rapidly Declining Type I Supernova 2019bkc/ATLAS19dqr
• Average opacity calculation for core-collapse supernovae
• Early-type host galaxies of Type II and Ib Supernovae
• Stellar binaries incident on supermassive black hole binaries: implications for double tidal disruption events, calcium-rich transients, and hypervelocity stars
• Chandra X-ray Constraints on the Candidate Ca-rich Gap Transient SN 2016hnk

Cited by in corpus (20)

• The Zwicky Transient Facility Census of the Local Universe I: Systematic search for Calcium rich gap transients reveal three related spectroscopic sub-classes
• A Search for Extragalactic Fast Blue Optical Transients in ZTF and the Rate of AT2018cow-like Transients
• Supernovae Ia in 2019 (review): a rising demand for spherical explosions
• GRB 211211A: a Neutron Star$-$White Dwarf Merger?
• The Progenitors of Calcium-Strong Transients
• AT2018kzr: the merger of an oxygen-neon white dwarf and a neutron star or black hole
• PS15cey and PS17cke: prospective candidates from the Pan-STARRS Search for Kilonovae
• Calcium-rich Transient SN 2019ehk in A Star-Forming Environment: Yet Another Candidate for An Ultra-Stripped Envelope Supernova
• Wind-Reprocessed Transients from Stellar-mass Black Hole Tidal Disruption Events
• Panning for gold, but finding helium: discovery of the ultra-stripped supernova SN2019wxt from gravitational-wave follow-up observations
• Are stripped envelope supernovae really deficient in ${}^{56}$Ni?
• Radiative diffusion in a time-dependent outflow: a model for fast blue optical transients
• The Carnegie Supernova Project-I. Optical spectroscopy of stripped-envelope supernovae
• Results from the Pan-STARRS Search for Kilonovae: Contamination by Massive Stellar Outbursts
• SN 2023zaw: an ultra-stripped, nickel-poor supernova from a low-mass progenitor
• Modeling the fast optical transient SN 2019bkc/ATLAS19dqr with a central engine and implication for its origin
• Building spectral templates and reconstructing parameters for core collapse supernovae with CASTOR
• A real-time search for Type Ia Supernovae with late-time CSM interaction in ZTF
• Gravitational waves associated with the r-mode instability from neutron star-white dwarf mergers
• A multiwavelength view of the nearby Calcium-Strong Transient SN 2025coe in the X-Ray, Near-Infrared, and Radio Wavebands