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// ["Date","Name","Affiliation","Title","Abstract","Day","Time"]
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// Note: the format is as follows:
//September[0] =["20" ,"Name","Institution","Title","Abstract","",""];

September[0] =["6" ,"Hagai Perets","Technion","Strange supernovae, irregular moons and planets and chaotic stellar collisions","Many irregular astrophysical systems and phenomena are not so rare, and in fact constitute a large fraction of all astrophysical systems. I will discuss several such riregular systems, ranging from irregular moons in the Solar-system, re-captured runway planets, and planetary systems in evolved binaries, up to stellar collisions and strange supernovae. I wil likely not have the time to discuss all of the following, but I will try to focus on few of them, and briefly mention the rest. The observational discovery of new types of thermonuclear supernovae explosions and suggest novel explanations for their origin. Such supernovae potentially have major implications; some can produce unique type of iron-core white dwarfs (WDs), provide a mechanism for WD natal kicks, never explored before. Others may explain the origin of a large fraction of the calcium in the universe, and may be important for the productions of positrons and 511 kev emission. On the dynamical sides, I will suggest a novel origin for irregular moons formation, linking them to current understanding of extrasolar systems. I will also explore how mass loss in stellar and stellar cluster systems can produce unique planetary and stellar systems, and allow planetary and stellar exchanges between different systems, an may induce physical collisions between the systems components.","",""];
September[1] =["13" ,"Bob Penna","CfA","General Relativistic Magnetohydrodynamic Accretion Disks: Simulations and Theory","Standard accretion disk models fold the physics of magnetic fields and turbulence into a constant viscosity parameter, alpha.  Applications such as black hole spin measurements can be sensitive to the details of magnetic fields and turbulence, so more realistic disk models are needed. I will present simulations of three-dimensional, magnetohydrodynamic accretion disks in the Kerr metric for a range of black hole spins and disk thicknesses.  I will discuss models extending standard disk theory based on insights from the simulations.  I have found an analytical, relativistic thin disk solution with a more realistic inner boundary condition than the standard Novikov and Thorne solution.  I will emphasize recent results for the dependence of the alpha-viscosity parameter on radius and a one-dimensional model that captures the shape of alpha(r).  I will discuss the impact of these developments on black hole spin measurements.","",""];
September[2] =["20" ,"James Guillochon","UCSC","The Physics of Stellar Tidal Disruption","Approximately a dozen luminous flares located at the centers of their host galaxies have been associated with the tidal disruption of a star by a supermassive black hole. Analytical models of tides make one of two assumptions to make the problem tractable: Either the tidal force is weak compared to the star's gravity, or the star's gravity is weak compared to the tidal force. I will describe how hydrodynamical simulations have helped to improve our understanding of tides in the non-linear regime where these two forces are comparable, and how this new information can be utilized to characterize the luminous flares produced by tidal disruptions.","",""];
September[3] =["27" ,"Rouven Essig","Stony Brook","Direct Detection of sub-GeV Dark Matter","","",""];
October[0] =["4" ,"Douglas Finkbeiner","Harvard","The Galactic center 130 GeV line:  WIMP or artifact?","The recent claims of a gamma-ray line in the Galactic center at 130 GeV has generated excitement, not least because it could be a signal of dark matter annihilation.  I will summarize the current state of the observations of the Galactic center, clusters, and unassociated halo objects, and speculate about models of particle dark matter that could explain the data.","",""];
October[1] =["5 (Friday)" ,"David Kipping","CfA","The Hunt for Exomoons with Kepler","Extrasolar moons may be frequent, temperate abodes for life and their detection would not only have astrobiological significance but would also greatly further our understanding of planet/moon formation theories. For the first time, the detection of a transiting planet-moon system is moving from the realms of theory to observation due to the unprecedented photometric precision being achieved by Kepler. In this talk, I will discuss how we might find a transiting exomoon, exploring both the dynamical effects (such as transit timing variations) and the eclipse effects (such as mutual eclipses) which may be observable. It is shown that Kepler is capable of finding Earth-sized and -mass moons. I will then introduce a new systematic program to search these elusive objects, 'The Hunt for Exomoons with Kepler' (HEK). I will discuss the objectives, target selection methods, fitting techniques and vetting strategies for HEK along with the present status of the project.","",""];
October[2] = ["8 (Monday at 3pm)" , "Sun Kwok","University of Hong Kong","Synthesis of Complex Organics in the Late Stages of Stellar Evolution","Infrared spectroscopic observations of the stretching and bending modes of aliphatic and aromatic compounds are now seen throughout the Universe, from the diffuse interstellar medium of the Milky Way Galaxy to distant galaxies. Observations of evolved stars have revealed a rapid (~10^3 year time scale) and continuous synthesis of organic materials from the end of the asymptotic giant branch (AGB), to proto-planetary nebulae, to planetary nebulae. These synthesized products are ejected into the interstellar medium through stellar winds and as a result enriching the Galaxy with complex organics. Over 70 gas-phase molecules, including rings, radicals, and molecular ions, as well as fullerene (C60) have been identified by millimeter-wave and infrared spectroscopic observations through their rotational and vibrational transitions. Possible chemical pathways leading to the formation of complex organics will be discussed. Analysis of the infrared spectra suggests that the chemical structure of the carrier is consistent with that of mixed aromatic and aliphatic nanoparticles (MAON). These structures are very similar to those of the insoluble organic matter found in meteorites, suggesting that the early solar system may have been enriched by stellar ejecta.","",""];
October[3] =["11" ,"Mike McCourt","Berkeley","Sculpting Cosmic Gas into Galaxy Clusters","Galaxy clusters are filled with a hot, tenuous plasma known as the intracluster medium, or ICM.  I will discuss recent work aimed at understanding how the plasma can cool to form multi-phase gas, and what implications this cooling has for the structure of the ICM.  I apply this result to the observed non-self-similarity (analogous to the missing baryon problem) in clusters.  I will also discuss a project to understand the temperature profiles in the ICM and what implications this has for convection and turbulent pressure support in clusters.","",""];
October[4] =["18" ,"Tobias Baldauf","Zurich","Halo Clustering beyond the Local Bias Model","The clustering of galaxies in ongoing and upcoming galaxy surveys contains a wealth of cosmological information. Extracting this information is a non-trivial task since galaxies and their host haloes are stochastic tracers of the non-linear matter density field. The relation between matter and halo distribution is commonly expressed in terms of a local bias model. Recent studies have revealed inconsistencies between the simple local Eulerian bias model and simulations. I will explain two effects that can explain and partially cure these inconsistencies. Firstly, non-local bias terms proportional to the tidal tensor are generated by gravitational evolution and their presence can be detected in the halo bispectrum. Secondly, I will explain how discreteness of haloes and their small scale exclusion alters the large scale halo power spectrum.","",""];
October[5] =["24 (Wednesday at 11am)" ,"Andreas Kuepper","University of Bonn","Weighing the Milky Way using Tidal Tails of Globular Clusters","The distribution of mass within the Milky Way halo is an important but largely unknown quantity. Stellar streams of Galactic satellites, such as the Sagittarius stream, offer a possibility to infer the Galactic mass distribution. Such streams trace their progenitor’s orbits about the Galaxy. From numerical modeling of stellar streams we can gain orbital information of the progenitor satellite and, finally, deduce the underlying Galactic mass distribution. I will demonstrate that the most powerful streams for measuring the Galactic mass distribution are tidal tails originating from globular clusters. These tidal tails are kinematically much colder and thinner than, e.g., the Sagittarius stream. Hence, they yield tighter orbital constraints. In addition, globular cluster tidal tails exhibit dynamical substructures, which contain unique orbital information. Using the example of the outer-halo globular cluster Palomar 5, I will show how this information can be extracted and used to weigh the Milky Way.","","",""];
October[6] =["25" ,"Christopher Tully","Princeton","Plans for Relic Neutrino Detection at PTOLEMY: Princeton Tritium Observatory for Light, Early-Universe, Massive-Neutrino Yield","The direct detection of relic neutrinos from the Big Bang is one of the greatest challenges in experimental particle physics.  The basic concepts were laid out in a paper by Steven Weinberg in 1962.  At that time the tritium endpoint spectrum could be measured with an energy resolution of 120eV.  Since the development of cryogenic TES calorimetry, the potential for sub-eV energy resolution is now a possibility.  A small-scale prototype using two superconducting magnets, a MAC-E filter, and a 100 microgram tritium source is near completion at PPPL.  The design concepts will be validated with this setup in the coming year.  The outcome will be a proposal based on proven technologies for a large-scale 100 gram tritium experiment at PPPL with the capability to detect the relic neutrino background or to rule out one of the most widely accepted predictions in cosmology.","",""];
November[0] =["1" ,"Peter Goldreich","Caltech","The Physics Of Stochastic Excitation Of Stellar Modes","A stellar mode achieves approximate energy equipartition with the kinetic energy of convective eddies whose correlation times are comparable to its period. The energies of the most visible modes are similar to those of individual granules, or equivalently to the stellar flux that passes through a granule during its lifetime. Interactions that excite and damp an acoustic mode take place above the mode’s acoustic cavity; they merely tickle the mode’s evanescent tail. As a consequence, the mode’s linewidth is much smaller than its frequency and the modal peak rises above the level of the convective noise in velocity and intensity power spectra. Scaling observational properties of stochastically excited modes from helio-seismology to asteroseismology implicity assumes that the maximum convective Mach number, M, is the same in all stars with convective envelopes. For some properties, such as the frequency of maximum visibility, this works pretty well; M is expected to be of order a few tenths and only enters to the first power. Other observational quantities depend more sensitively on M. Peaks of low degree modes rise by of order M−4 above the convective noise in velocity and intensity power spectra formed from observations of an unresolved star. The ratio of linewidth to mode frequency depends even more sensitively on M. Scaling of velocity amplitudes is more direct than those of intensity since the latter are sensitive to variations in the opacity. The κ-mechanism operating just below the photosphere mutes flux variations associated with excited modes thereby decreasing signal to noise in intensity power spectra relative to those in velocity.","",""];
November[1] =["8" ,"Wyn Evans","Cambridge","A Ghost Story: The Stellar Halo of the Milky Way Galaxy","The history of the Galaxy is imprinted in the kinematics and chemical properties of the stars in the stellar halo. Their study allows us partially to reconstruct the Galactic past because the time required for stars in the halo to exchange their energies and momenta is very long compared with the age of the Galaxy. This field has been revolutionised in recent years by data from the Sloan Digital Sky Survey Data, which has revealed a super-abundance of substructure. There are ghostly streams from disrupting dwarf galaxies and globular clusters, analogues of meteor streams along old cometary paths in the Solar. There are ultrafaint phantom galaxies composed of old and faint stars, so puny that the entire galaxy is outshone by a single red giant star. There are smooth, flattened, halo populations, such as the blue horizontal branch stars.  Dominating the Galactic halo, there is the magnificent double arch of the Sagittarius stream criss-crossing the whole sky.  These tracers enable the study of the assembly of the Galaxy, as well as its present-day mass and gravitational field. The quality of the data permit confrontation -- and conflict -- with modern-day cosmological simulations of galaxy formation.","",""];
November[2] =["15" ,"Rennan Barkana","Tel Aviv","Detecting the First Stars at Redshift 20","Understanding the formation and evolution of the first stars and galaxies is one of the exciting frontiers in astronomy. Since the universe was filled with neutral hydrogen at early times, the most promising method for observing the epoch of the first stars is using the prominent 21-cm spectral line of hydrogen. Current observational efforts are focused on the reionization era (around redshift 10), with earlier times considered much more challenging. We show that stars at redshift 20 may be observable as a result of a recently noticed effect of relative velocity between the dark matter and gas. We produce simulated maps of the first stars and show that the relative velocity effect significantly enhances large-scale clustering and produces a prominent cosmic web on 100 comoving Mpc scales in the 21-cm intensity distribution. The particular signature of this clustering should make it easier to confirm the existence of million solar-mass halos at early times.","",""];
November[3] =["16 (Friday)" ,"Ondrej Pejcha","Ohio State","The Explosion Mechanism of Core-Collapse Supernovae and its Observational Signatures","Many massive stars explode as core-collapse supernovae. Supernova simulations show that the shock wave accompanying formation of the proto-neutron star evolves into a quasi-static accretion shock and it proves difficult to revive its outward propagation. The stalled accretion shock turns into explosion when the neutrino luminosity from the collapsed core exceeds a critical value L_crit (the 'neutrino mechanism'). I will show the connection between the steady-state isothermal accretion flows with bounding shocks and the neutrino mechanism: there is a maximum, critical sound speed above which it is impossible to maintain accretion with a standoff shock. I will derive the 'antesonic' condition, which characterizes the transition to explosion over a broad range in accretion rate, PNS properties and microphysics. Additionally, I will characterize the effects of accretion luminosity and collective neutrino oscillations on L_crit. The physics of the explosion mechanism and the progenitor structure are imprinted in the observed distribution of neutron star masses. I will use Bayesian analysis to model the double neutron star mass distribution to infer the properties of the progenitor binary population, fallback during the explosion, and constrain the mass coordinate where the explosion develops.","",""];
November[4] =["22" ,"Thanksgiving","No Seminar","","","",""];
November[5] =["29" ,"Jonathan Fortney","UCSC","Examining the Interior Structure of Transiting Planets:  From Exo-Jupiters to Kepler's Super-Earths","We have now reached the point in studying transiting planets that we can begin to examine the Jupiter-class planets as a class of astrophysical objects.  At the same time, thanks to Kepler, the number of transiting planets below 10 Earth masses is now moving beyond just a handful.  For the Jovians, we point out that there is an emerging population of planets that are relatively cool (Teff<1000 K) that appear to be unaffected by whatever is inflating the radii of the hottest members of this class.  We have searched this cool group for correlations, and we find several interesting properties regarding the amount of heavy elements within these planets.  For the lowest-mass planets, such as the 6-planet Kepler-11 system, signs point to an unexpectedly large populations of mini-Neptunes---low-mass, low-density planets with hydrogen-dominated envelopes.  The Kepler-11 system may tell us much about the evaporation of the envelopes of these kinds of planets.","",""];
December[0] =["6" ,"Maryam Modjaz","NYU","Stellar Forensics with Explosions: Supernovae, Gamma-Ray Bursts, and their Habitats","","",""];
December[1] =["13" ,"Greg Novak","IAP","Radiative Transfer, Black Hole Growth, AGN Feedback in Galaxies","","",""];