iPTF15eqv: Multi-wavelength Exposé of a Peculiar Calcium-rich Transient

Abstract

The progenitor systems of the class of "Ca-rich transients" is a key open issue in time domain astrophysics. These intriguing objects exhibit unusually strong calcium line emissions months after explosion, fall within an intermediate luminosity range, are often found at large projected distances from their host galaxies, and may play a vital role in enriching galaxies and the intergalactic medium. Here we present multi-wavelength observations of iPTF15eqv in NGC 3430, which exhibits a unique combination of properties that bridge those observed in Ca-rich transients and Type Ib/c supernovae. iPTF15eqv has among the highest [Ca II]/[O I] emission line ratios observed to date, yet is more luminous and decays more slowly than other Ca-rich transients. Optical and near-infrared photometry and spectroscopy reveal signatures consistent with the supernova explosion of a < 10 solar mass star that was stripped of its H-rich envelope via binary interaction. Distinct chemical abundances and ejecta kinematics suggest that the core collapse occurred through electron capture processes. Deep limits on possible radio emission made with the Jansky Very Large Array imply a clean environment ($n<$ 0.1 cm${}^{-3}$) within a radius of $\sim 10^{17}$ cm. Chandra X-ray Observatory observations rule out alternative scenarios involving tidal disruption of a white dwarf by a black hole, for masses > 100 solar masses). Our results challenge the notion that spectroscopically classified Ca-rich transients only originate from white dwarf progenitor systems, complicate the view that they are all associated with large ejection velocities, and indicate that their chemical abundances may vary widely between events.

24 pages, 16 figures. Closely matches version published in The Astrophysical Journal

References in corpus (32)

• Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity
• Mass loss from hot massive stars
• The effect of massive binaries on stellar populations and supernova progenitors
• Circumstellar Emission from Type Ib and Ic Supernovae
• Kinematics of the Local Universe XIII. 21-cm line measurements of 452 galaxies with the Nançay radiotelescope, JHK Tully-Fisher relation and preliminary maps of the peculiar velocity field
• Asphericity in Supernova Explosions from Late-Time Spectroscopy
• The Broad-lined Type Ic SN 2003jd
• The Unique Type Ib Supernova 2005bf at Nebular Phases: A Possible Birth Event of A Strongly Magnetized Neutron Star
• The Status of Multi-Dimensional Core-Collapse Supernova Models
• Optical Spectra of 73 Stripped-Envelope Core-Collapse Supernovae
• Photometric and spectroscopic evolution of the type IIP supernova SN 2004et
• Luminous Blue Variables as the progenitors of supernovae with quasi-periodic radio modulations
• Unstable Helium Shell Burning on Accreting White Dwarfs
• Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh
• From Spitzer Galaxy Photometry to Tully-Fisher Distances
• Constraining supernova models using the hot gas in clusters of galaxies
• Double-peaked Oxygen Lines Are not Rare in Nebular Spectra of Core-Collapse Supernovae
• No X-rays from the very nearby Type Ia SN2014J: constraints on its environment
• Nebular spectra and abundance tomography of the type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core
• Illuminating Massive Black Holes With White Dwarfs: Orbital Dynamics and High Energy Transients from Tidal Interactions
• The Broad-Lined Type Ic SN 2012ap and the Nature of Relativistic Supernovae Lacking a Gamma-ray Burst Detection
• Atypical Thermonuclear Supernovae from Tidally Crushed White Dwarfs
• Two New Calcium-Rich Gap Transients in Group and Cluster Environments
• Nebular phase observations of the type-Ib supernova iPTF13bvn favour a binary progenitor
• Nebular Phase Observations of the Type Ib Supernova 2008D/X-ray Transient 080109: Side-Viewed Bipolar Explosion
• Origin of central abundances in the hot intra-cluster medium - II. Chemical enrichment and supernova yield models
• MMT & Magellan Infrared Spectrograph
• The progenitors of calcium-rich transients are not formed in situ
• 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
• Data Reduction Pipeline for the MMT and Magellan Infrared Spectrograph
• A pair of CO + He white dwarfs as the progenitor of 2005E-like supernovae?

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• Spatially Resolved X-ray Study of Supernova Remnant G306.3$-$0.9 with Unusually High Calcium Abundance
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• Characterizing the host galaxies and delay times of Ca-rich gap transients vs 91bg-like SNe and normal Type Ia SNe
• A multiwavelength view of the nearby Calcium-Strong Transient SN 2025coe in the X-Ray, Near-Infrared, and Radio Wavebands
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