Ryan Wollaeger
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View article: Kilonova light-curve interpolation with neural networks
Kilonova light-curve interpolation with neural networks Open
Kilonovae are the electromagnetic transients created by the radioactive decay of freshly synthesized elements in the environment surrounding a neutron star merger. To study the fundamental physics in these complex environments, kilonova mo…
View article: Light Curves and Spectra from Kilonova Models [Poster]
Light Curves and Spectra from Kilonova Models [Poster] Open
White dwarf-neutron star merger simulations show a Ca IR line feature in spectra, pointing to Ca-rich transients as a possible observation (Kaltenborn et al 2024, Gillanders et al 2024). Supernova and new/old kilonova (KN) models have been…
View article: On a Spectral Method for β-particle Bound Excitation Collisions in Kilonovae
On a Spectral Method for β-particle Bound Excitation Collisions in Kilonovae Open
The interaction of β -particles with the weakly ionized plasma background is an important mechanism for powering the kilonova (KN) transient signal from neutron star mergers. For this purpose, we present an implementation of the approximat…
View article: The Effect of the Velocity Distribution on Kilonova Emission
The Effect of the Velocity Distribution on Kilonova Emission Open
The electromagnetic emission from the nonrelativistic ejecta launched in neutron star mergers (either dynamically or through a disk wind) has the potential to probe both the total mass and composition of this ejecta. These observations are…
View article: On a spectral method for $β$-particle bound excitation collisions in kilonovae
On a spectral method for $β$-particle bound excitation collisions in kilonovae Open
The interaction of $β$-particles with the weakly ionized plasma background is an important mechanism for powering the kilonova transient signal from neutron star mergers. For this purpose, we present an implementation of the approximate fa…
View article: The Effect of the Velocity Distribution on Kilonova Emission
The Effect of the Velocity Distribution on Kilonova Emission Open
The electromagnetic emission from the nonrelativistic ejecta launched in neutron star mergers (either dynamically or through a disk wind) has the potential to probe both the total mass and composition of this ejecta. These observations are…
View article: SuperNu Version 4.x
SuperNu Version 4.x Open
We seek to release SuperNu, Version 4.x, as a continuation of development for the open source SuperNu software. The SuperNu, Version 3.x Monte Carlo radiative transfer code for astrophysical transients was released with GPLv3 copyright, as…
View article: The Effect of the Velocity Distribution on Kilonova Emission
The Effect of the Velocity Distribution on Kilonova Emission Open
The electromagnetic emission from the non-relativistic ejecta launched in neutron star mergers (either dynamically or through a disk wind) has the potential to probe both the total mass and composition of this ejecta. These observations ar…
View article: Interpolated kilonova spectra models: Examining the effects of a phenomenological, blue component in the fitting of AT2017gfo spectra
Interpolated kilonova spectra models: Examining the effects of a phenomenological, blue component in the fitting of AT2017gfo spectra Open
In this paper, we present a simple interpolation methodology for spectroscopic time series based on conventional interpolation techniques (random forests) implemented in widely available libraries. We demonstrate that our existing library …
View article: Abundances and Transients from Neutron Star–White Dwarf Mergers
Abundances and Transients from Neutron Star–White Dwarf Mergers Open
We systematically investigate the mergers of neutron star–white dwarf binaries from beginning to end, with a focus on the properties of the inflows and outflows in accretion disks and their electromagnetic emissions. Using population synth…
View article: Multimessenger Diagnostics of the Engine behind Core-collapse Supernovae
Multimessenger Diagnostics of the Engine behind Core-collapse Supernovae Open
Core-collapse supernova explosions play a wide role in astrophysics by producing compact remnants (neutron stars or black holes) and the synthesis and injection of many heavy elements into their host galaxy. Because they are produced in so…
View article: Constraining Inputs to Realistic Kilonova Simulations through Comparison to Observed r-process Abundances
Constraining Inputs to Realistic Kilonova Simulations through Comparison to Observed r-process Abundances Open
Kilonovae, one source of electromagnetic emission associated with neutron star mergers, are powered by the decay of radioactive isotopes in the neutron-rich merger ejecta. Models for kilonova emission consistent with the electromagnetic co…
View article: The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers*
The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers* Open
The LIGO HET Response (LIGHETR) project is an enterprise to follow up optical transients (OTs) discovered as gravitational-wave merger sources by the LIGO/Virgo collaboration (LVC). Early spectroscopy has the potential to constrain crucial…
View article: Adaptive Angular Quadrature Scheme for a backwards-in-time Method of Characteristics Solution to the Radiative Transfer Equation [Slides]
Adaptive Angular Quadrature Scheme for a backwards-in-time Method of Characteristics Solution to the Radiative Transfer Equation [Slides] Open
Radiative transfer/radiation transport are important problems to solve in astrophysics and high energy density physics. Various methods exist to solve radiation transport, such as Monte Carlo (MC), Discrete Ordinates (SN), Method of Charac…
View article: Anomalous Behavior of Newtonian Hydrodynamics Coupled with Radiation Transport
Anomalous Behavior of Newtonian Hydrodynamics Coupled with Radiation Transport Open
This study shows that Newtonian hydrodynamics coupled with radiation transport, using a wide range of methods for treating the material-motion corrections, results in anomalous behavior. In particular, the flow of infinite-medium equilibra…
View article: Monte Carlo Radiation Transport for Astrophysical Transients Powered by Circumstellar Interaction
Monte Carlo Radiation Transport for Astrophysical Transients Powered by Circumstellar Interaction Open
In this paper, we introduce SuperLite , an open-source Monte Carlo radiation transport code designed to produce synthetic spectra for astrophysical transient phenomena affected by circumstellar interaction. SuperLite utilizes Monte Carlo m…
View article: The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers
The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers Open
The LIGO HET Response (LIGHETR) project is an enterprise to follow up optical transients (OT) discovered as gravitational wave merger sources by the LIGO/Virgo collaboration (LVC). Early spectroscopy has the potential to constrain crucial …
View article: Monte Carlo Radiation Transport for Astrophysical Transients Powered by Circumstellar Interaction
Monte Carlo Radiation Transport for Astrophysical Transients Powered by Circumstellar Interaction Open
In this paper, we introduce \texttt{SuperLite}, an open-source Monte Carlo radiation transport code designed to produce synthetic spectra for astrophysical transient phenomena affected by circumstellar interaction. \texttt{SuperLite} utili…
View article: Multi-Messenger Diagnostics of the Engine behind Core-Collapse Supernovae
Multi-Messenger Diagnostics of the Engine behind Core-Collapse Supernovae Open
Core-collapse supernova explosions play a wide role in astrophysics by producing compact remnants (neutron stars, black holes) and the synthesis and injection of many heavy elements into their host Galaxy. Because they are produced in some…
View article: Interpolated kilonova spectra models: necessity for a phenomenological, blue component in the fitting of AT2017gfo spectra
Interpolated kilonova spectra models: necessity for a phenomenological, blue component in the fitting of AT2017gfo spectra Open
In this work, we present a simple interpolation methodology for spectroscopic time series, based on conventional interpolation techniques (random forests) implemented in widely-available libraries. We demonstrate that our existing library …
View article: Surrogate light curve models for kilonovae with comprehensive wind ejecta outflows and parameter estimation for AT2017gfo
Surrogate light curve models for kilonovae with comprehensive wind ejecta outflows and parameter estimation for AT2017gfo Open
The electromagnetic emission resulting from neutron star mergers have been shown to encode properties of the ejected material in their light curves. The ejecta properties inferred from the kilonova emission has been in tension with those c…
View article: Surrogate light curve models for kilonovae with comprehensive wind ejecta outflows and parameter estimation for AT2017gfo
Surrogate light curve models for kilonovae with comprehensive wind ejecta outflows and parameter estimation for AT2017gfo Open
The electromagnetic emission resulting from neutron star mergers have been shown to encode properties of the ejected material in their light curves. The ejecta properties inferred from the kilonova emission has been in tension with those c…
View article: StaNdaRT: a repository of standardised test models and outputs for supernova radiative transfer
StaNdaRT: a repository of standardised test models and outputs for supernova radiative transfer Open
We present the first results of a comprehensive supernova (SN) radiative-transfer (RT) code-comparison initiative (StaNdaRT), where the emission from the same set of standardised test models is simulated by currently used RT codes. We ran …