FOE 2017 Invited Review Talks

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1 FOE 2017 Invited Review Talks Name: Rino Bandiera Title: Some theoretical issues on Supernova Remnants Abstract: Supernova Remnants are a very broad subject, and can be seen under a variety of different perspectives, focusing for instance on the endpoints of stellar evolution, on the properties of the circumstellar and interstellar ambient medium, on the thermal and non-thermal properties of the blast wave, on blast waves themselves as unique plasma laboratories, on particle acceleration and the origin of cosmic rays, on some statistical properties of the supernova events, as well as of global properties of the interstellar medium structure. After a short general introduction, I will focus on some physical aspects related to diffusive shock acceleration, like magnetic obliquity dependence of the acceleration efficiency, turbulent field amplification, feedback of the accelerated particles on the shock structure itself, role of neutral atoms in influencing the shock structure and the acceleration processes as well. On these and similar topics the interplay between theory and observations is fundamental, in order to devise powerful and reliable diagnostic tools. Observational input to discuss such topics mainly comes from intensity and polarisation maps of the radio synchrotron emission, and from maps and spectra of the non-thermal X-ray emission. Useful diagnostics can also be extracted from Balmer-line maps and spectral structure. A caveat for all these approaches is that physical and geometrical effects must be clearly separated, before safely drawing conclusions and estimating physical parameters. Due to its very neat structure and to the extended observations available, SN1006 can be used as an very good case to discuss some of the above issues. Name: Ryan Chornock chornock@ohio.edu Title: Transient Surveys (TBC) Name: Maria Drout mdrout@carnegiescience.edu Title: Peculiar Transients: Observed Populations, Nature, and Intrinsic Rates

2 Name: Rodrigo Fernandez Title: Progress and open questions in kilonova modeling Abstract: Neutron star mergers are expected to be detected in gravitational waves within the next few years. These sources are also expected to generate electromagnetic counterparts that cover a wide range of timescales and wavelengths. The detection of some of these counterparts would not only improve the sky localization obtained from gravitational waves, but also contribute with independent information. In this talk I'll review the processes that generate electromagnetic emission in NS mergers, and focus on a supernova-like optical/infrared transient powered by the radioactive decay of r-process elements: a kilonova/macronova. I'll discuss recent progress in the generation of kilonova predictions and outline areas of current research, including the long-term evolution of merger remnants, r-process nucleosynthesis, and opacities from r- process elements. Name: Wen-fai Fong wfong@ .arizona.edu Title: Observations of Short Gamma-ray Bursts: Lessons Learned, Open Questions, and Constraints for the GW Era Abstract: Short-duration gamma-ray bursts (SGRBs) are among the most luminous transients in the universe with prompt emission durations of <2 sec. A decade of observations probing their environments from sub-parsec to kiloparsec scales has provided a wealth of circumstantial evidence linking them to NS-NS/NS-BH merger progenitors. Furthermore, their connection to r-process kilonovae has provided the first direct evidence of their origin. SGRBs thus serve as important probes of gravitational wave sources and potential sites of heavy element nucleosynthesis. In this talk, I will discuss lessons learned from observations of SGRBs, and what outstanding questions still remain. With the detection of NS-NS/NS-BH mergers by gravitational wave facilities on the horizon, I will also present constraints from SGRBs on more isotropic EM counterparts to gravitational wave sources. Name: François Foucart francois.foucart@gmail.com Title: Simulating Electromagnetic and Gravitational Wave Signals from Compact Binary Mergers Abstract: Following the first detections of merging black holes by gravitational wave observatories, we expect merging black holes and neutron stars to be observed at a steadily increasing rate over the next few years. These mergers will provide us with new information about the properties of compact objects, and allow for further testing of general relativity. In the presence of at least one neutron star, the gravitational wave signal from the merger may be followed by a range of bright electromagnetic transients, including short gamma-ray bursts and radioactively powered optical/infrared ``kilonovae. The ejection of neutron rich matter may also play a dominant role in the synthesis of many heavy elements (e.g. gold, platinum). Finally, using merging binaries to measure the size of neutron stars can provide us with important constraints on nuclear physics and on the properties of dense matter. In this talk, I will review the crucial role played by numerical simulations in modeling observable signals from merging compact objects. I will in particular focus on recent improvements to the physical realism of simulations of black hole-neutron star and neutron star-neutron star binaries, and on the crucial role played by magnetic fields and neutrino-matter interactions when building models of the electromagnetic signals powered by these mergers.

3 Name: Christa Gall Title: Observations of Dust in Supernovae Abstract: The origin of dust in the Universe is unknown, but supernovae, notably SN 1987A, are known to produce dust. This is consistent with the large amounts of dust detected in galaxies and quasars at high redshift which require a rapid production mechanism. I will review the latest findings on supernova dust production and address the challenge of determining dust masses observationally. I will highlight the importance of the survivability of newly formed dust grains. Name: Jose Groh jose.groh@tcd.ie Title: Massive Stellar Evolution Abstract: Name: Terese Hansen thansen@carnegiescience.edu Title: Exploring nucleosynthesis in the early Universe with extremely metal-poor stars Abstract: The abundance patterns of extremely metal-poor (EMP) stars directly record the nucleosynthesis of their progenitors, as the gas from which these stars formed was polluted by at most a few enrichment events --- perhaps even a single explosion. The chemical abundances of these stars therefore provide valuable information about the evolution and nucleosynthesis of the first (Population III) stars, and Galactic chemical evolution. Recent years homogeneous abundance analysis of large samples of EMP stars have revealed two main abundance peculiarities seen in some EMP stars: carbonenhancement and enhancement of Eu and other elements associated with the rapid neutron-capture (r-) process. I will present a review of the recent observational results for metal-poor stars, including abundance analysis of carbon enhanced metal-poor (CEMP) stars, showing evidence for neutron-capture element production at the earliest times in our Galaxy, and the discovery of r-process enhanced stars in two ultra faint dwarf galaxies, along with first results from from a new survey effort aimed at quadrupling the numbers of known halo r-process enhanced stars, based on ``snapshot'' high-resolution spectroscopy of bright very metal-poor stars.

4 Name: Shunsaku Horiuchi Title: Observations of Neutrino Emission in CCSNe Abstract: Neutrinos and gravitational waves play key roles in probing the heart of the core-collapse supernova phenomenon: from the stellar core density, explosion mechanism, to compact remnant. I will review the critical role played by neutrinos in unraveling these and other core-collapse physics. In particular, recent simulation and observational efforts are starting to shed light on the question of which stars core collapse to neutron stars vs black holes. I will discuss how future neutrino observations can unravel these channels. Name: Satoru Katsuda katsuda@phys.chuo-u.ac.jp Title: Probing Supernova Explosion Mechanisms through Observations of Supernova Remnants Abstract: Supernova remnants in our galaxy and nearby galaxies provide us with unique opportunities to study detailed supernova explosion physics, especially because they are located close enough for us to resolve fine structures with current observatories. I will present recent progresses derived from mainly X-ray observations of supernova remnants. The topics will include detailed 3D explosion geometries revealed by high-resolution spectroscopy with gratings onboard XMM- Newton and Chandra, line diagnostics of Fe-peak elements by sensitive spectroscopy with Suzaku and other X-ray satellites, and close-up views of Cas A and Kepler, focusing on detailed Ti distribution in Cas A and the properties of the circumstellar medium in Kepler. I will also briefly talk about future prospects with the next Japan-US X-ray astronomy satellite to be launched in 2021, which is a recovery mission of the Hitomi satellite. Name: Andrew J Levan A.J.Levan@warwick.ac.uk Title: Observations of kilonovae: isotropic signals from compact object mergers Abstract: I will present observational constraints on the presence of kilonovae/macronovae, both in the afterglows of short duration GRBs and in other searches, in particular of gravitational wave error boxes and generic wide-field surveys. I will outline the range of expected properties and colours of these events, which may provide an isotropically visible signature of compact object mergers. Model uncertainties, and relatively meagre observational constraints to date mean that a wide range of possibilities must be considered in ongoing searches, and I will discuss ways in which surveys may be optimised for kilonova/macronova identification.

5 Name: Marco Limongi Title: Hydrostatic and Explosive Nucleosynthesis of Core Collapse Supernovae Abstract: I will review the current status of the research on the presupernova evolution, explosion and nucleosynthesis of massive stars in a wide range of initial masses, metallicities and rotation velocities Name: Keiichi Maeda keiichi.maeda@kusastro.kyoto-u.ac.jp Title: Observational Constraints on Progenitors and Explosions of Type Ia Supernovae Abstract: I will provide a review on the current status of observational constraints on the progenitor systems and explosion mechanisms of type Ia Supernovae (SNe Ia). Recent development in the field is highlighted by accumulating observational discoveries of diversities of SNe Ia. An idea is emerging that SNe Ia are not at all a uniform system as previously believed for many years, and thermonuclear explosions may lead to various outcomes which could correspond to various types of transients. In this talk, I will summarize different observational constraints placed for different sub-types of SNe Ia and related phenomena, and connect these findings to different types of progenitors and modes of explosions which have been theoretically predicted. Name: Dick McCray mccrayr@me.com Title: Supernova 1987A Abstract: Supernova 1987A in the Large Magellanic Cloud is the brightest supernova to be observed since SN1604 (Kepler). Observations taken with almost every type of telescope, on the ground and in space, have yielded a rich story of the evolution of the explosion debris and its interaction with its circumstellar environment. It is a unique laboratory of almost all kinds of physics, at temperatures ranging from 10 9 K to 20 K and densities ranging from to g cm -3. After a brief review of the physics of SN1987A, I ll describe what we are learning from our recent observations with the Hubble Space Telescope and the Atacama Large Millimeter Array (ALMA). I ll conclude with a summary of the outstanding mysteries of SN1987A and the prospects for unraveling them.

6 Name: Jess McIver Title: Gravitational wave observations Abstract: I will review the observed gravitational wave signals reported by the LIGO-Virgo Collaboration to date and discuss the prospects for observing gravitational waves produced by supernovae with current and next generation interferometer technology. Name: Takashi Moriya takashi.moriya@nao.ac.jp Title: Theories of superluminous supernovae Abstract: I will review theories of superluminous supernovae to explain their huge luminosities. Name: Bernhard Mueller bernhard.mueller@monash.edu Title: Understanding the Explosions of Massive Stars Abstract: Core-collapse supernovae, the violent deaths of massive stars, are among the most spectacular phenomena in astrophysics: Supernovae can only outshine their host galaxy for weeks; they are laboratories for the behavior of matter at extreme densities; and they also play a central role for the chemical evolution of galaxies, e.g. as the dominant producers of oxygen and many other elements. Yet the mechanism by which massive stars explode has eluded us for decades. As I shall explain in this talk, this is about to change: Recent first-principle 3D simulations of these events have finally been able to demonstrate that the most popular explosion scenario, the so-called neutrino-driven mechanism, is viable. Including the initial seed asymmetries in the progenitors from convective shell burning could further help to produce even more robust supernova explosion models. Distilling the physical essence of modern 3D supernova simulations into semi-analytic models also allows us to predict the properties of supernova explosions and compact remnants across the whole range of stellar initial masses in reasonable agreement with observations.

7 Name: John Nousek Title: Neil Gehrel's contributions to the astrophysics of transients Name: Takaya Nozawa Title: Dust formation theory in astronomical environments Abstract: There are increasing pieces of observational evidence that core-collapse supernovae produce a significant amount of dust grains in the expanding ejecta. On the other hand, our understanding of dust formation process has been entangled by diverse theoretical studies during the past decade. In this talk, I review two theoretical approaches that are based on nucleation theory and chemical reaction networks, by introducing the virtues and shortcomings of those approaches. I will also compare the results from these different approaches and discuss their implications for the formation of dust under astronomical environments such as supernova ejecta and stellar winds. Name: Kelly M Patton kmpatton@uw.edu Title: Presupernova neutrinos: Realistic emissivities from stellar evolution Abstract: Neutrino emission from core collapse supernovae has been a rich field of study since their first detection during SN1987A. The neutrinos produced during collapse have important roles in both the dynamics of the explosion and the nucleosynthesis that occurs. Thousands of potential events are expected in neutrino detectors around the world from the next galactic supernova. While the neutrino emission from supernovae has been examined from many angles, studies of the emission leading up to the death of large stars have been relatively few. However, several recent papers have shown that these presupernova neutrinos could be observed in current and future detectors, providing information about late time stellar evolution. Contributions from beta processes and pair annihilation in particular have been shown to dominate the neutrino emissivity above realistic detector thresholds. In this talk, I will summarize recent efforts to calculate the detector signal of presupernova neutrinos and what such a signal can teach us. In addition, our efforts to calculate detailed neutrino spectra in the hours leading up to core collapse using state of the art stellar evolution code MESA will be discussed.

8 Name: Enrico Ramirez-Ruiz Title: Triggering Short Gamma-Ray Bursts Abstract: There is now general agreement that short gamma-ray bursts (sgrbs) are capable of producing directed beams of relativistic matter with a kinetic luminosity exceeding by many millions that of active galactic nuclei. Given the twin requirements of energy and compactness, it is widely believed that GRB activity is ultimately ascribable to a modest fraction of a solar mass of gas accreting onto a stellar mass black hole or to a precursor stage whose inevitable end point is a stellar mass black hole. Astrophysical scenarios involving compact mergers are reviewed, along with other possible alternatives. If a black hole lies at the center of this activity, then the fundamental pathways through which mass, angular momentum and energy can flow around and away from it play a key role in understanding how these prime movers can form collimated, relativistic outflows. On the other hand, statistical investigations of sgrb niches also furnish valuable information on their nature and evolutionary behavior. The formation of particular kinds of progenitor sources appears to be correlated with environmental effects and cosmic epoch. Some important unresolved questions are identified, along with the types of observation that would discriminate among the various progenitor models. Name: Ken Shen kenshen@astro.berkeley.edu Title: The Turbulent Landscape of Type Ia Supernova Theory Abstract: The theory of Type Ia supernova progenitors and explosion modeling has undergone a remarkable upheaval in the past decade. Evidence has mounted against the standard "single degenerate" scenario, and a variety of scenarios have sprung up as alternatives. In this talk, I will give an overview of the various progenitor scenarios and highlight what I see as the most promising model: the "dynamically-driven double degenerate double detonation" scenario. Name: Stephen J Smartt s.smartt@qub.ac.uk Title: Superluminous supernovae - cosmic origins and evolution Abstract: A rare type of supernovae have been found in recent wide field surveys that are times brighter than normal thermonuclear and core-collapse supernovae. The origin of this remarkable luminosity is not yet firmly established and there are currently three competing theories, all involving massive stars. The explosions appear to exclusive occur in dwarf galaxies which implies that their progenitor stars are of low metallicity. I will discuss recent results from Pan-STARRS, PESSTO and other surverys and show how these supernovae are being used as novel probes of the high redshift universe.