Investigating the Diversity of Type Ia Supernova Spectra with the Open-Source Relational Database Kaepora

Abstract

We present a public, open-source relational database (we name kaepora) containing a sample of 4975 spectra of 777 Type Ia supernovae (SNe Ia). Since we draw from many sources, we significantly improve the spectra by inspecting these data for quality, removing galactic emission lines and cosmic rays, generating variance spectra, and correcting for the reddening caused by both MW and host-galaxy dust. With our database, we organize this homogenized dataset by 56 unique categories of SN-specific and spectrum-specific metadata. With kaepora, we produce composite spectra of subpopulations of SNe Ia and examine how spectral features correlate with various SN properties. These composite spectra reproduce known correlations with phase, light-curve shape, and host-galaxy morphology. With our large dataset, we are also able to generate fine-grained composite spectra simultaneously over both phase and light-curve shape. The color evolution of our composite spectra is consistent with other SN Ia template spectra, and the spectral properties of our composite spectra are in rough agreement with these template spectra with some subtle differences. We investigate the spectral differences of SNe Ia that occur in galaxies with varying morphologies. Controlling for light-curve shape, which is highly correlated with host-galaxy morphology, we find that SNe Ia residing in late-type and early-type galaxies have similar spectral properties at multiple epochs. However for SNe Ia in these different environments, their spectra appear to have Ca II near-infrared triplet features that have slightly different strengths. Although this is apparent in the composite spectra and there is some difference in the populations as seen by individual spectra, this difference is not large enough to indicate differences in the underlying populations.

24 pages, 38 figures, published in MNRAS. Repository: https://github.com/msiebert1/kaepora; Database and Composite Spectra: https://msiebert1.github.io/kaepora/; Documentation: https://kaepora.readthedocs.io/en/latest/index.html

References in corpus (17)

• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Improved Distances to Type Ia Supernovae with Multicolor Light Curve Shapes: MLCS2k2
• Improved Distances to Type Ia Supernovae with Two Spectroscopic Subclasses
• The Spectroscopic Diversity of Type Ia Supernovae
• The Luminous and Carbon-Rich Supernova 2006gz: A Double Degenerate Merger?
• The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?
• Optical and Near-Infrared Observations of the Highly Reddened, Rapidly Expanding Type Ia Supernova 2006X in M100
• SN 2003du: 480 days in the Life of a Normal Type Ia Supernova
• Late-Time Spectroscopy of SN 2002cx: The Prototype of a New Subclass of Type Ia Supernovae
• Anomalous extinction behaviour towards the Type Ia SN 2003cg
• Consistent estimates of (56)Ni yields for type Ia supernovae
• Spectropolarimetry of the Peculiar Type Ia SN 2005hk
• Optical and IR observations of SN 2002dj: some possible common properties of fast expanding SNe Ia
• ESC observations of SN 2005cf: II. Optical Spectroscopy and the high velocity features
• SN 2002cv: A Heavily Obscured Type Ia Supernova
• Luminosity Indicators in the Ultraviolet Spectra of Type Ia Supernovae
• Constraints on Circumstellar Material Around the Type Ia Supernova 2007af

Cited by in corpus (19)

• Cosmological Results from the RAISIN Survey: Using Type Ia Supernovae in the Near Infrared as a Novel Path to Measure the Dark Energy Equation of State
• SALT3-NIR: Taking the Open-Source Type Ia Supernova Model to Longer Wavelengths for Next-Generation Cosmological Measurements
• Supernovae and their host galaxies -- VII. The diversity of Type Ia supernova progenitors
• SN 2022ann: A type Icn supernova from a dwarf galaxy that reveals helium in its circumstellar environment
• Spectroscopic Studies of Type Ia Supernovae Using LSTM Neural Networks
• Spectroscopic observations of progenitor activity 100 days before a Type Ibn supernova
• deepSIP: Linking Type Ia Supernova Spectra to Photometric Quantities with Deep Learning
• A Probabilistic Autoencoder for Type Ia Supernovae Spectral Time Series
• A Spectroscopic Model of the Type Ia Supernova--Host Galaxy Mass Correlation from SALT3
• Late-time Hubble Space Telescope Observations of AT 2018cow. I. Further Constraints on the Fading Prompt Emission and Thermal Properties 50--60 Days Post-discovery
• Abundance stratification in type Ia supernovae -- VI: the peculiar slow decliner SN\,1999aa
• Observational properties of a bright type Iax SN 2018cni and a faint type Iax SN 2020kyg
• Propagating Uncertainties in the SALT3 Model Training Process to Cosmological Constraints
• ZTF SN Ia DR2: Improved SN Ia colors through expanded dimensionality with SALT3+
• The New Status Qvo? SN 2021qvo is Another 2003fg-like Type Ia Supernova with a Rising Light-Curve Bump
• Normal or transitional? The evolution and properties of two type Ia supernovae in the Virgo cluster
• SN 2025ogs: A Spectroscopically-Normal Type Ia Supernova at z = 2 as a Benchmark for Redshift Evolution
• Calcium versus silicon ejecta velocities and decline rates in supernovae Ia: The role of high-velocity features
• Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq