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FOE 2017
Poster Contributions
Name: Katie Auchettl
Email: [email protected]
Presentation Type: Poster
Title: Studying the stellar populations of supernova remnants in the Small Magellanic Cloud
Abstract: Identification of the progenitor and the determination of the nature of supernova explosions (SNe), whether from
core-collapse of a massive star or from the thermonuclear detonation of a white dwarf, is a central problem of modern
astrophysics. For a handful of SNe, we have been able to identify the progenitor from pre-explosion images (e.g., Gerke et
al., 2015; Adams et al., 2016); however, for supernova remnants (SNRs), which are seen 1000s of years after the original
SN event, one has to rely on indirect methods to make the connection between the remnant and the properties of its
progenitor. One way to constrain progenitor characteristics is by studying the stellar populations directly surrounding the
location of these events. Towards this end, we build on the work of Badenes et al. (2009) and Lopez et al. (2014) to examine
the stellar populations in the vicinities of the 23 known SNRs in the Small Magellanic Cloud. Using the star formation
history maps of Harris & Zaritsky (2004), we characterise the nature of the SN progenitors of each remnant based on when
the star formation peaked. We compare these with the properties of the SNe derived from the remnants themselves and
discuss these results in the context of our understanding of the progenitors of SNe.
Name: Jordi Casanova
Email: [email protected]
Presentation Type: Poster
Title: The effect of turbulence in core-collapse supernovae
Abstract: While it is widely accepted that a neutrino-driven mechanism plays a major role in the onset of the explosion, the
nature of it is not fully understood. Recent multi-dimensional studies reveal that the growth of fluid instabilities, combined
with the development of convection, will contribute to the morphology of the explosion. We utilize the advanced
CHIMERA code, capable to model multi-dimensional simulations of core- collapse supernovae, to study the interplay
between turbulence and the dynamics of the explosion. The CHIMERA code is a parallel, multi-physics code, that includes
sophisticated nuclear physics and spectral neutrino transport. We have performed a set of wedge simulations (that is, a 90
degree shaped computational domain), for resolutions that vary from a quarter to two degrees. We will present a detailed
analysis of the development of turbulence in function of the resolution in two and three dimensions, and will discuss the
connection with the progress of the explosion.
Name: Emmanouil Chatzopoulos
Email: [email protected]
Presentation Type: Poster
Title: Hiding hydrogen lines in SN ejecta - circumstellar matter interaction models for superluminous supernovae
Abstract: Supernova ejecta - circumstellar matter (CSM) interaction has been proposed as a power-input mechanism for
hydrogen-rich (Type II) superluminous supernovae (SLSNe) and also supported by their spectroscopic observations that
exhibit intermediate-width Balmer emission lines due to hydrogen recombination following heating by a forward shock.
Nevertheless, the nature of hydrogen-poor (Type I) SLSNe remains debated. I present nLTE radiation transport models
spanning the revelant parameter space of CSM density, and SN ejecta and CSM velocity to investigate conditions that allow
for the obscuration of hydrogen emission lines in some SLSNe of Type I, and discuss work in progress to model CSM
interaction in the context of hydrogen-poor SN ejecta/CSM configurations.
Name: Teddy Cheung
Email: [email protected]
Presentation Type: Poster
Title: The MERger-event Gamma-Ray (MERGR) Telescope
Abstract: We describe the design and motivation to build the MERger-event Gamma-Ray (MERGR) Telescope for
deployment by ~2021. MERGR will cover the energy range from 20 keV to 2 MeV with a wide field of view (6 sr) using
nineteen gamma-ray detectors arranged on a section of a sphere. The telescope will work as a standalone system or as part
of a network of sensors, to increase by ~50% the current sky coverage to detect the putative short Gamma-Ray Burst
(SGRB) counterparts to neutron-star binary mergers within the ~200 Mpc horizon of gravitational wave detectors in the
early 2020's. Inflight software will provide realtime burst detections with mean localization uncertainties of 6 ̊ for a photon
fluence of 5 ph/cm^2 (the mean fluence of Fermi-GBM SGRBs) and <3 ̊ for the brightest ~5% of SGRBs, transmitted to the
Gamma-ray Coordinates Network. This will enable rapid multi-wavelength follow-up to identify a host galaxy and its
redshift. To minimize cost and time to first light, MERGR’s design and technology are directly derived from the Strontium
Iodide Radiation Instrumentation series (SIRI-1 and SIRI-2) demonstrators designed and built at the Naval Research
Laboratory (NRL) for the DoD Space Test Program (STP). This enables an aggressive schedule for final design and
assembly, for delivery to STP for launch and operations by 2021. We argue that the deployment of a network of such
instruments that provides all-sky coverage for SGRB detection are of immediate urgency to the multi-messenger
astrophysics community.
Authors: Lee J. Mitchell, B. F. Phlips, C. C. Cheung, J. E. Grove, M. Kerr, M. Rambert, R. S. Woolf (Naval Research
Laboratory), W. N. Johnson (Praxis, Inc.), M. Briggs (University of Alabama, Huntsville), J. Perkins (NASA/GSFC)
Name: David A Coulter
Email: [email protected]
Presentation Type: Poster
Title: The Swope Supernova Survey
Abstract: The discovery rate of supernovae (SNe) in the local Universe (z < 0.1) has increased exponentially over the last
two decades with ~1000 such SNe discovered in 2016 alone. To take advantage of this trove and address a variety of
physical questions ranging from explosions to cosmology, we have started a new follow-up transient survey, the Swope
Supernova Survey. Our program is using 200 nights/year on the Swope 1-m telescope at Las Campanas Observatory to
obtain high- cadence uBVgri of young SNe and other transients. This same well-calibrated photometric system was used to
conduct the Carnegie Supernova Survey, which observed 359 SNe. The Swope Supernova Survey will build on this legacy
of superb calibration. The survey started in June 2016, and thus far we have obtained ~6100 total photometric data points of
139 transients. We will present a detailed overview of this survey as well as initial results.
Name: John Cowan
Email: [email protected]
Presentation Type: Poster
Title: Clues to Core-Collapse Supernova Yields from Iron-Peak Elemental Abundances in Halo Stars
Abstract: Recent experimental atomic data has allowed for increasingly more precise stellar abundance determinations. We
have made new determinations of the iron-peak elements in several metal-poor halo stars. The new observational results
show a correlation among the four iron-peak elements Ti, Cr, V, and Sc. Theoretical models of core-collapse supernova
nucleosynthesis from the literature have been able to explain some, but not all of these abundance correlations. The new
observational results will also be compared to new core-collapse supernova yields (see abstract by S. Sinha). Our improved
observations provide strict new constraints on core-collapse supernova models. Iron-peak abundance derterminations also
provide direct cluses about early Galactic Chemical Evolution and the nature of nucleosynthesis at early times in the
Galaxy.
Name: Maria Dainotti
Email: [email protected]
Presentation Type: Poster
Title: GRBs as redshift estimators via a machine learning approach
Abstract: DeWe propose an alternative technique based on the semi-parametric generalized additive model, GAM (Hastie &
Tibshirani 1986). GAM allows to represent the relationship as the sum of smooth functions including very few predictors
and to identify these components of the model which can be reduced to the linear form.
According to our preliminary results, for the considered sample size of 116 GRBs the model produced by GAM has a
substantially larger predictive power than the model produced by random forest. It allows extraction of an unknown
variable, such as the redshift, from a set of known observables, such as the peak flux, Fpeak, the flux at time Ta, Fx(Ta),
Epeak, Tγ,Ta, etc. So far with this method we obtained a promising correlation coefficient, about 0.70, between the
observed redshift and the predicted one after N-1 cross validation method is applied (Dainotti, Bogdan & Hastie in
preparation) while the correlation is only 58% for random forest. This clearly shows that GAM is much less prone to
overfitting than the random forest. Another interesting observation is that while predictions made by the random forest on
the full data set have a small scatter they are also slightly biased: they systematically overestimate the true redshift when it
is smaller than 2, and underestimate when the redshift is larger than 4.
Finding an effective redshift estimator is a very important task, because many GRBs are needed to shed light on early faint
galaxies that provided the majority of the re-ionization photons, while the study of afterglows of high-z bursts in a multiwavelength domain are needed to cast light into their metal and dust content. When comparing our results to the ones
obtained by the random forest of Ukwatta et al. (2016), we can see a similar systematic bias: in Ukwatta et al. (2016)
redshifts are over-estimated if they are smaller than 2 and under-estimated if they are larger than 2. In addition, we can
observe that the predictive power of our relatively simple GAM model has an increase of 8.7% (62% vs 57%) even though
we use a smaller number of explanatory variables (7 vs 11) and a smaller training set (116 GRBs vs 284 GRBs). The
percentage quoted is obtained for both methods with the leave-one-out cross validation procedure. In these approaches three
predictors are the same (T90, the prompt photon index, alpha and the peak flux, Fpeak). We added in our computations
relevant predictors related to the fundamental plane and the Yonetoku relation.
Name: Maria Dainotti
Email: [email protected]
Presentation Type: Oral
Title: A fundamental Plane for GRB afterglows
Abstract: A class of long gamma-ray bursts (GRBs) with a plateau phase in their Xray afterglows obeys a three dimensional
(3D) correlation (Dainotti et al. 2016), between the rest-frame end-time of the plateau, Ta, and its corresponding X-ray
luminosity, La, and the peak luminosity in the prompt emission, Lpeak, an extension of the two dimensional Dainotti
correlation. This 3D correlation identifies a GRB fundamental plane. In the present study we test the independence of this
plane from other relevant physical GRB parameters by extending the analysis of the fundamental plane with X-ray data
from July 2014 to July 2016 ending up with a total sample of 183 Swift GRBs with afterglow plateaus and known redshifts.
We confirmed that this correlation exists. We used both a sample of only long GRBs (132), selected from the total sample
by excluding GRBs with associated supernovae (SNe), X-ray flashes and short GRBs with extended emission and the gold
sample, composed only by GRBs with light curves with good data coverage and almost flat plateaus. We extend the
previous ‘gold sample’ to 45 GRBs obtaining an intrinsic scatter compatible within one σ with the previous result. We
evaluated that other correlation planes which rely on the mentioned GRB categories are not statistically different from plane
derived from the gold sample and that the fundamental plane derived from the gold sample has an intrinsic scatter smaller
than any other planes derived from the other sample categories. In the further analysis we found that the fundamental plane
is independent from several prompt and afterglow parameters, such as the jet opening angle, θj , the prompt emission
duration, T90, the peak energy, Epeak, and the temporal decay index after the plateau emission, α..
Name: Paolo D'Avanzo
Email: [email protected]
Presentation Type: Poster
Title: Characterising explosive transients in the next decade: the new SOXS spectrograph at the ESO-NTT
Abstract: In the near future, we will enter the golden age of time-domain astronomy having in place deep ground- based
optical surveys (such as ZTF, PanSTARRS, DES, LSST), space-based optical surveys (Gaia and Euclid), high-energy
instruments (Swift, Fermi, MAXI and SVOM), radio surveys (LOFAR, SKA), Gravitational Wave (GW) experiments
(aLIGO/Virgo), neutrino experiments (KM3Net), all calling for a rapid follow-up and characterisation (and distance
determination) of the detected transients. SOXS (Son Of X-Shooter) will be a unique spectroscopic facility for the ESONTT 3.5-m telescope in La Silla (Chile), able to cover the optical/NIR band. The design foresees a high-efficiency
spectrograph capable of simultaneously observing the complete spectral range 350 - 1750 nm at a resolution R~5000 with a
good sensitivity and with imaging capabilities in the visible band. SOXS will be operative starting from 2021. A fraction of
open ToO time will also be offered to the community and data will be immediately public. We will outline the stauts of the
project, the instrument capabilities and the perspectives of scientific exploitation in the forthcoming time-domain astronomy
era.
Name: Paolo D'Avanzo
Email: [email protected]
Presentation Type: Poster
Title: Insights on short GRB progenitors: a comparison between the intrinsic NH and the host galaxy masses
Abstract: When compared in the same redshift bin, the distribution of the instrinsic X-ray absorbing column densities
obtained from X-ray afterglow spectroscopy (NH) of long and short GRBs are found to be fully consistent. Such result,
confirmed by independent studies reported in the literature, can be considered as an evidence for a common environment for
long and short GRBs. However, such a conclusion struggles with the commonly accepted scenario for long and short GRB
(different) progenitors. A complementary approach to the problem can be to compare NHs and the GRB host galaxy
masses. Such a study has been recently carried out for long GRBs. The result is that long GRB NHs are found to correlate
with the host galaxy masses, providing a clear indication that long GRBs are primarily obscured by galaxy-scale gas.
Following this approach, we carried out a systematic analysis of short GRB NH in the X-ray band. When compared with
their HG mass, no apparent correlation is found, at variance with long GRB. On average, for a given host galaxy mass, the
NH is found to be lower for short GRBs. These results clearly favor an association with an older stellar population and/or
significant migration (kicks) of short GRBs from their birthplaces, in agreement with the compact object merger progenitors
scenario.
Name: Parviz Ghavamian
Email: [email protected]
Presentation Type: Poster
Title: Is N103B the Remnant of a Single Degenerate Type Ia SN?
Abstract: A small number of young SNRs now attributed via X-ray observations to Type Ia events show evidence for dense
circumstellar media that may have arisen from the relic wind of a single-degenerate progenitor system. One such object is
SN1604 (Kepler's SNR) in our Galaxy, and a similar but somewhat older example is N103B in the LMC. Like Kepler’s
SNR, N103B exhibits both Balmer-dominated shocks and strong interaction with dense, clumpy material. Recent HST
imagery (Li et al. 2017) have revealed a possible surviving companion. Here we present preliminary results from a multiwavelength observing program to understand whether the abundance and kinematics of this clumpy material are consistent
with stellar wind material from the secondary.
Our data include optical and IR imagery of the entire SNR with
HST/WFC3, complementary to the existing data. Our spectroscopic observations include optical spectra acquired with the
WiFeS integral field spectrograph, which we use for kinematic analysis of Balmer-dominated shocks along the periphery of
N103B, as well as HST/COS spectra in the ultraviolet, which we use for abundance analysis of the radiatively shocked
clumps. Broad Balmer lines indicate shock speeds ~ 2000 km/s and a kinematic age ~ 660 years for N103B, while
emission line ratios in the COS spectra indicate densities ~ 50,000 cm^-3 in the densest radiative knots, with shock speeds ~
150-200 km/s. Combined with a more detailed abundance analysis of our spectra and our recently acquired Cycle 16
Chandra observation (400 ks) of N103B, we will be able to discuss plausible scenarios for the progenitor evolution and the
SN explosion.
Name: Ryosuke Hirai
Email: [email protected]
Presentation Type: Poster
Title: Formation Scenario of the Progenitor of iPTF13bvn
Abstract: iPTF13bvn is famous for being the only type Ib supernova with a corresponding pre-supernova image. This and
the light curve properties have greatly helped us in speculating the nature of the progenitor star. It is almost certain that the
progenitor was in a binary system, and various binary evolution scenarios have been proposed that satisfy the observational
constraints. Most binary scenarios predicted that a bright companion star will show up in the remnant in the near future.
However the later observations revealed that such bright companion does not exist, meaning that the formation scenario
should be reconsidered. In this work I re-assess the observational constraints and discuss the relevance of existing formation
scenarios. Unfortunately all the scenarios have difficulties in satisfying all constraints consistently. I propose an alternative
scenario that involves a relatively large black hole companion, which seems to reproduce all observational features
according to binary evolution calculations by MESA. I also discuss the origin of this possible black hole companion.
Name: Wolfgang Kerzendorf
Email: [email protected]
Presentation Type: Poster
Title: Dalek - Automatic supernova spectral fitting within a Bayesian framework
Abstract: Comparing physical models with observations is one of the main challenges in supernova research. One
particularly complex task is the analysis of the evolving spectral sequences. These complex sequences also contain a wealth
of information about the object and are thus invaluable to the understanding of these objects. With the profusion of data in
the “big data” era, it is essential to have tools that allow automated extraction of physical quantities from the abundance of
spectra.
We have created a code (TARDIS - Kerzendorf & Sim 2014) that can quickly synthesize supernova spectra with some
physical accuracy (using well tested methods). The code is designed to accommodate new physics in a modular form that
will allow us to test the systematic uncertainty of several approximations. In addition to the spectral synthesis code we have
created a framework (nicknamed Dalek) that uses sophisticated algorithms to find the maximum likelihood of parameters
for a given observed spectrum as well as exploring the uncertainties.
In this talk, I will introduce the code, then will give an overview of some of the preliminary results and will close with an
overview of our future research.
Name: Jim P Kneller
Email: [email protected]
Presentation Type: Poster
Title: Neutrinos from Type Ia supernovae
Abstract: Despite their use as cosmological distance indicators and their importance in the chemical evolution of Galaxies,
the unequivocal identification of the progenitor systems and explosion mechanism of normal Type Ia supernova (SN Ia)
remains elusive. The leading hypothesis is that such a supernova is a thermonuclear explosion of a carbon-oxygen white
dwarf but the exact explosion mechanism is still a matter of debate. Observation of a Galactic SN Ia would be of immense
value in answering the many open questions related to these events. One potentially useful source of information about the
explosion mechanism and progenitor is the neutrino signal. We compute the expected neutrino signal from both
Deflagration-to-Detonation Transition (DDT) and Gravitationally Confined Detonation (GCD) explosion scenarios for a
SN~Ia and show how the flux at Earth contains features in time and energy that are unique to each. We then calculate the
expected event rates in the Super-K, Hyper-K, JUNO, DUNE, and IceCube detectors. From the comparison of the GCD and
DDT signals we find the overall event rate is the most discriminating feature between the two scenarios followed by the
event rate time structure. Using the event rate in the Hyper-K detector alone, the DDT can be distinguished from the GCD at
2-sigma if the distance to the supernova is less than 2.3 kpc for a normal mass ordering and 3.6 kpc for an inverted ordering.
Name: Denis Leahy
Email: [email protected]
Presentation Type: Poster
Title: Supernova Remnants in the Large Magellanic Cloud: Environments, Energetics and Birth Rates
Abstract: The supernova remnants in the Large Magellanic Cloud arguably form one of the best samples, in terms of
completeness, for studies of properties of supernova remnant populations. Here a spherically symmetric supernova remnant
evolution model is applied to observed X-ray emissions from the forward shock. The initial explosion energy, age, and
circum-stellar medium density is deduced for each supernova remnant. The distribution of energies and densities is well fit
by log-normal distributions. The ages are well fit by a constant birthrate of 1 per 500 yr.
Name: Shing Chi Leung
Email: [email protected]
Presentation Type: Poster
Title: Nucleosynthesis of Type Ia supernovae
Abstract: Type Ia supernovae (SNe Ia) are important building blocks of the universe owing to its contribution to the ironpeak elements. Its explosion mechanism as the thermonuclear runaway of a carbon-oxygen white dwarf has been well
known for decades. But many theoretical uncertainties persist, for example, the tension between single degenerate vs.
double degenerate progenitor and the exact physical conditions of the deflagration-detonation transition. To constrain the
theoretical uncertainties, comparing chemical composition between observations and theoretical models is one of the viable
ways. In this presentation we explore the effects of model parameters on SNe Ia. We carry out two-dimensional
hydrodynamics simulations of SNe Ia in the explosion phase for both Chandrasekhar mass and sub-Chandrasekhar mass
white dwarfs using the turbulent deflagration model with delayed detonation transition and the helium- detonation-induced
double detonation model respectively. We also calculate the corresponding nucleosynthesis. How the ignition density,
metallicity, ignition kernels and the progenitor accretion history affect the nucleosynthesis is studied. Applications of our
models to the galactic chemical evolution, and constraints on some observed SNe Ia remnants, such as SN2012cg,
SN2011fe, are discussed.
Name: Quintin A Mabanta
Email: [email protected]
Presentation Type: Poster
Title: Effects of Turbulent on the Critical Conditions of Explosion
Abstract: We investigate how neutrino-driven convection helps to improve the explosion condition for core-collapse
supernovae (CCSNe). Multi-dimensional simulations suggest that turbulence eases the condition for explosion, but how has
not yet been clearly defined. Contrary to prior tentative suggestions, we find that turbulent ram pressure is not the dominant
factor in reducing the condition for explosion. Instead, we find that there are many contributing factors, ram pressure being
only one of them, but the dominant factor is turbulent dissipation (TD). Primarily, TD provides extra heating, adding
significant thermal pressure and altering the postshock profile. The source of this TD in our model is neutrino-driven
convection, which ultimately derives its source of energy from the higher potential created by the convectively unstable
entropy profile. By incorporating the turbulence models of Murphy et al. (2013) in conjunction with the integral condition
for explosion of Murphy & Dolence (2017), we can easily examine the relevant physics involved. The former allows us to
explore the intricacies of turbulence in detail, while the latter presents us with a clear diagnostics tool for explodability. We
find that, when including all turbulent terms, the critical curve is reduced by ~30%, in rough agreement with simulations.
Though we find that turbulent dissipation is a significant contributor to successful supernova explosions, it is important to
note that this work is to some extent qualitative and requires further investigation by multi-dimensional simulations.
Name: Jessica T Maldonado
Email: [email protected]
Presentation Type: Poster
Title: Next Generation VLA: An Imperative Tool for Next Generation Supernova Remnant Studies
Abstract: Determining the Type-Ia supernova progenitors remains an important unsolved problem, and measuring the
supernova rate as a function of stellar age (the Delay Time Distribution) has revealed hints to the solution. We have
established a new way to measure the Delay Time Distribution using surveys of supernova remnants in high-quality radio
continuum images of Local Group galaxies like M31. We present our deep Jansky VLA survey of M31, and discuss the
promise of NGVLA to provide the long-needed sensitivity and resolution for next- generation supernova remnant studies.
Name: Héctor Martínez Rodríguez
Email: [email protected]
Presentation Type: Poster
Title: Observational evidence for high neutronization in SNRs
Abstract: The physical process whereby a carbon-oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains
highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process because it depends on the mass
and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new
method to determine ejecta neutronization using Ca and S lines in the X-ray spectra of Type Ia supernova remnants (SNRs).
Applying this method to Suzaku data of Tycho, Kepler, 3C 397, G337.2-0.7 in the Milky Way, and N103B in the Large
Magellanic Cloud, we find that the neutronization of the ejecta in N103B is comparable to that of Tycho and Kepler, which
suggests that progenitor metallicity is not the only source of neutronization in SNe Ia. We then use a grid of SN Ia explosion
models to infer the metallicities of the stellar progenitors of our SNRs. The implied metallicities of 3C 397, G337.2-0.7, and
N103B are major outliers compared to the local stellar metallicity distribution functions, indicating that progenitor
metallicity can be ruled out as the origin of neutronization for these SNRs.
Name: Christopher M Mauney
Email: [email protected]
Presentation Type: Poster
Title: Atomistic Nucleation Theory and the Formation of Refractory Dust Grains in CCSNe
Abstract: The formation of molecular cores of astrophysical dust grains has proven difficult to study in detail. I present new
results for the structure, binding energies, and nucleation rates of carbon and silicate (forsterite) refractory grains. Global
minima search algorithms, basin-hopping and minima-hopping, are used to determine candidates for the ground state
structures. The density functional theory code Quantum Espresso is used to calculate the quantum-mechanical structure and
binding energy of these candidates. Binding energies of carbon clusters n=2 to n=99, and of forsterite clusters n=2 to n=14
are presented. These results are used to determine the critical cluster size of nucleation, and nucleation rates are calculated
using the atomistic formulation of nucleation theory. I also present preliminary results of my dust growth model, where
nucleation is coupled with gas-phase chemistry to produce new dust yields in CCSNe.
Name: Broxton J Miles
Email: [email protected]
Presentation Type: Poster
Title: The Importance of Curvature and Density Gradients for Nucleosynthesis by Detonations in Type Ia
Supernovae
Abstract: Accurately reproducing the physics behind the detonations of Type Ia supernovae and the resultant
nucleosynthetic yields is important for interpreting observations of photospheric spectra and remnants. The scales of the
processes involved span orders of magnitudes, making the problem computationally impossible to ever fully resolve in full
star simulations. Consequently, studies have resorted to using sub-grid models to capture the energetics of the explosion and
post-processing the results with large nuclear networks to calculate nucleosynthetic results. These sub-grid models should
have accurate treatments of detonation physics such as curvature or shock strengthening. In the lower density regions of the
star, the curvature of the detonation front will slow the detonation, affecting the production of intermediate mass elements.
In this same region of the progenitor, the density sharply decreases outward and this may strengthen the detonation causing
more complete burning than would be expected at these densities. In order to verify the results of calculations using subgrid models, it is imperative there be a set of benchmark calculations with which to compare. We aim to produce such
results by completing one dimensional, high resolution calculations with large reaction networks and comparing to the
results of fully resolved calculations of steady-state detonations. We utilize the open source hydrodynamics software
instrument FLASH in conjunction with the reaction network from Modules for Experiments in Stellar Astrophysics
(MESA). The MESA reaction network is used in both the explosion simulations as well as the post-processing for
consistency. Improving the accuracy of models will allow for better prediction, comparison, and interpretation of
nucleosynthetic results.
Name: Takashi Nagao
Email: [email protected]
Presentation Type: Poster
Title: Effects of circumstellar dust on polarization of Type IIP SNe
Abstract: Type IIP supernovae (SNe IIP) are known as the most common class of core-collapse SNe. Supernovae in this
class often show rapid increase of polarization degree just after entering the nebula phase following the luminosity drop. It
is generally believed that this time evolution originates from the appearance of the inner aspherical core, while an effect of
polarized-scattered echoes by circumstellar (CS) dust around the SNe may also substantially contribute to this polarization
feature. In this study, we examine the effects of the scattered echoes on the SN polarization through radiation transfer
simulation, including various kinds of geometry and various amounts of CS dust. We have found that asymmetrically
distributed CS dust, which is generally inferred for red supergiants, could indeed reproduce the observed polarization
features. We applied our results to SN 2004dj and SN 2006ov, deriving the geometry and amount of CS dust to explain their
observed polarization features.
Name: Jacek A Niemiec
Email: [email protected]
Presentation Type: Poster
Title: Electron injection at nonrelativistic perpendicular shocks of young supernova remnants
Abstract: Particle pre-acceleration constitutes a central unresolved problem for diffusive shock acceleration processes. Here
we report on recent studies of high Mach-number nonrelativistic perpendicular shocks with fully kinetic two-dimensional
particle-in-cell simulations in application to forward shocks of young supernova remnants. We analyse conditions leading to
efficient electron heating and pre-acceleration. We confirm the electron injection through shock-surfing acceleration in the
foot of high Mach-number shocks. We show that the injection efficiency is not stationary and varies with the phase of the
cyclic shock reformation. It also nonlinearly depends on the upstream plasma temperature. We also discuss further electron
energization processes in the turbulent shock ramp that contains magnetic filaments. We demonstrate that electron
acceleration can occur there due to spontaneous magnetic reconnection. The magnetic reconnection formation rate depends
on plasma beta and also on numerical parameters assumed in 2D simulations, such as the ion-to-electron mass ratio and the
configuration of the average magnetic field with respect to the simulation plane. We discuss resulting injected electron
spectra and relevance of our results to the physics of fully three-dimensional systems.
Name: Ilka Petermann
Email: [email protected]
Presentation Type: Poster
Title: On the impact of spatial and temporal resolution on pre-supernova structure
Abstract: Massive stars are essential to the evolution of galaxies due to their intense radiation and strong winds as well as
their powerful deaths as supernovae. In this study, we aim at understanding the non-monotonic behavior of crucial
properties like the final iron-core masses of massive stars in analyzing stellar models with respect to the influence of
underlying numerics and study the implications on their final fates in terms of their structural and nucleosynthesis patterns
and the possible connections of their initial masses and final fates.
Name: Paul P Plucinsky
Email: [email protected]
Presentation Type: Poster
Title: An Archival X-ray Study of the Large Magellanic Cloud Supernova Remnant N132D
Abstract: We present the results of an analysis of the archival XMM-Newton EPIC data and the Chandra X-ray Observatory
ACIS data of the brightest X-ray supernova remnant (SNR) in the Large Magellanic Cloud (LMC) N132D. N132D has been
routinely observed by XMM-Newton over its 17 year mission as a calibration target. We have combined the data from all
calibration observations suitable for scientific analysis to create the deepest X-ray images of N132D. N132D has been
classified as an ``O-rich'' remnant based on the UV and optical spectra which show emission from C, O, Ne, Mg, and Si.
These spectra of the central optical knots do not show any emission from elements with Z higher than Si, yet the
nucleosynthesis models predict significant quantities of these higher Z elements. Our spectral analysis of the deep XMM
data clearly shows emission lines from S, Ar, Ca, and Fe, with indications of other possible features between Ca and
Fe. We discuss the interpretation of the emission from the high Z elements as a "hot ejecta" component or a high
temperature shell component and the implications for the progenitor.
Name: Matthew R Siebert
Email: [email protected]
Presentation Type: Poster
Title: A Relational Database for Type Ia Supernova Observations
Abstract: Type Ia supernovae (SNe Ia) are excellent cosmological probes and the primary tool for understanding dark
energy. After making light-curve shape corrections, there remains an intrinsic distance scatter that belies so-far unaccounted
SN physics. Spectra provide an opportunity to examine subtle differences between SNe Ia with similar light-curve
properties, and careful examination of SN Ia spectra may result in additional physical understanding of the progenitor
systems/explosions or improved cosmological utility. We have compiled a sample of 4818 spectra of 751 SNe Ia and their
relevant metadata (light-curve parameters, host-galaxy properties, etc) in a public, open-source relational database. This
database will be an invaluable tool for the supernova community. As an example of its utility, we use the database to
produce composite spectra of SNe Ia with various properties and examine the subtle spectral differences for various
subpopulations. Our composite spectra (and corresponding variance spectra) will also be useful for improved SEDmodels of
SNe Ia and improved subclassification.
Name: Mads Sørensen
Email: [email protected]
Presentation Type: Poster
Title: A 35-Myr-long history of solar neighbourhood supernovae
Abstract: Except for the most recent, < 3 Myr, and very close, < 100 pc, Supernovae (SNe) being able to leave a still
detectable imprint of their existence in Earths geology, the close SNe, within 1 kpc of the Sun, remain illusive and leave
little trace of them having ever occurred. Yet, they form the emergent interstellar medium we observe today and may even
have had effects on Earths evolution. A way of probing most likely positions and times of some past SN events is to
reconstruct the motion and the stellar evolution of open clusters (OC), which can be rich reservoirs of SN progenitors. We
have combined observationally inferred open cluster data, with single- and binary population synthesis models and a
Galactic potential to reconstruct the SN activity of these OCs in time and space for the past 35 Myr.
The result is a 2d probability density map of the most likely positions and times of past SNe from OCs around the Sun. We
also derive the SN rate as a function of time within 1 kpc of the Sun for the past 35 Myr.
Name: Tyler K Takaro
Email: [email protected]
Presentation Type: Poster
Title: Constraining the Delay Time for Type Iax Supernovae
Abstract: Type Iax supernovae (SNe Iax) are the most common class of peculiar SNe, thought to be thermonuclear whitedwarf (WD) SNe that are observationally similar to, but distinct from SNe Ia. Unlike SNe Ia, where roughly 30% occur in
early-type galaxies, SNe Iax occur almost exclusively in late-type galaxies, suggesting a relatively short delay time and a
distinct progenitor system. Furthermore, one SN Iax progenitor system has been detected in pre- explosion images with its
properties consistent with a short-lived (~100 Myr) progenitor system consisting of a WD primary and a He-star
companion. Using deep Hubble Space Telescope images of six nearby (closer than 35 Mpc) SN Iax host galaxies, we
measure the properties of stars near the SN position. The ages of local stars, some of which will have a similar starformation epoch as the SN progenitor system, can constrain the delay time. We compare the local stellar properties to
synthetic photometry of single-stellar populations, fitting to a range of possible delay times for each SN. With this sample,
we produce a unique constraint on the delay-time distribution for SNe Iax, which, in turn, constrains the progenitor systems
for the class.
Name: Tomoya Takiwaki
Email: [email protected]
Presentation Type: Poster
Title: Three dimensional simulation of core-collapse supernovae: effect of stellar rotation
Abstract: I'll show our three dimensional supernova models with the stellar rotation, if possible I'll also want to introduce
our recent elaboration on neutrino transport.
Name: Alexey Tolstov
Email: [email protected]
Presentation Type: Poster
Title: Ultraviolet emission of superluminous supernovae: radiation hydrodynamics simulations
Abstract: At the present time there is no universally accepted model for superluminous supernovae. Several most popular
scenarios are widely discussed: interaction with circumstellar medium, magnetar and pair-instability SN. Observations of
Gaia16apd revealed extremely luminous UV emission among superluminous supernovae (SLSNe). We performed a
comparison of UV light curves and spectral characteristics among the most popular SLSN models and in combinations of
energy sources using radiation hydrodynamics simulations. Particularly, for Gaia16apd we found that interaction model is
the easiest way to explain extreme UV luminosity. Observations at UV wavelengths can be used to clarify the nature of
SNSNe and they need to be paid more attention in the future follow-up observations.
Name: Brad E Tucker
Email: [email protected]
Presentation Type: Poster
Title: GLUV - A High-Altitude Balloon-Borne UV Survey
Abstract: GLUV is a balloon-borne system, with a plan to simultaneous fly 50 telescope systems in multi-month
campaigns. GLUV will perform the first UV time-domain survey using small, wide-field telescopes in the near-UV (250 350nm). The main focus of GLUV will be supernova, gravitational wave follow-up, and exoplanet atmospheres. However,
with a large, community-driven component and open-data policies, we expect GLUV to benefit the entire astronomical
community.
Name: Tyrone E Woods
Email: [email protected]
Presentation Type: poster
Title: Type Ia Supernova Archaeology: Searching for the relics of progenitors past
Abstract: Despite the critical role that Type Ia supernovae (SNe Ia) play in the chemical enrichment of the Universe and
their great importance in measuring cosmological distances, we still do not know for certain how they arise. Most models
can be broadly grouped into either ``accretion'' or ``merger'' scenarios, with the former typically implying a hot, luminous
phase (0.1 -- 1 million K, 10^38 erg/s) at some point prior to explosion. Past efforts to directly detect the progenitors of very
recent, nearby SNe Ia in archival soft X-ray images have produced only upper limits, and are only constraining assuming
progenitors with very high temperatures immediately preceding the explosion. In this talk, I will outline our new approach:
given that such objects should be strong sources of ionizing radiation, one may instead search the environment surrounding
nearby SN Ia remnants for interstellar matter ionized by the progenitor. Such ``relic'' nebulae should extend out to tens of
parsecs and linger for roughly the recombination timescale in the ISM, of order 10,000 -- 100,000 years. With this in mind,
I will introduce our new narrow-band survey for relic nebulae surrounding young Magellanic SN Ia remnants and accreting
white dwarfs, already underway using the Magellan Baade telescope. In a similar manner, we have also placed deep upper
limits on the temperatures and luminosities of the progenitors of Tycho (SN 1572) and other Galactic SNe Ia from the study
of their Balmer-dominated shocks. This promises to begin a new era of "SN Ia archaeology," which may unveil at last the
progenitors of SNe Ia.