Astrophysics Seminar

Astrophysics Seminar: "Efficiency of Planetesimal Ablation in Jovian Envelopes"

Location: 
Kaplun building, Room No. 200
Tue, 03/01/2017 - 12:30 to 13:30

Lecturer: Dr. Arazi Pinhas Affiliation: Institute of Astronomy, University of Cambridge Abstract: Observations of exoplanetary spectra are leading to unprecedented constraints on their atmospheric elemental abundances, particularly O/H, C/H, and C/O ratios. Recent studies suggest that elemental ratios could provide important constraints on formation and migration mechanisms of giant exoplanets. A fundamental assumption in such studies is that the chemical composition of the planetary envelope represents the sum-total of compositions of the accreted gas and

Special High Energy Astrophysics Seminar: Accretion in relativistic binary black hole systems

Location: 
Kaplun building, Room No. 200
Sun, 28/05/2017 - 12:30 to 13:30

Lecturer: Prof. Julian Krolik Affiliation: Johns Hopkins University Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://plus.google.com/hangouts/_/mail.huji.ac.il/high-energy?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.rd31g26l8om1re9sv0n0570h2o&hs=121

Astrophysics Seminar: "Determining the acceleration mechanism of quasar-driven outflows and the thermal properties of circumgalactic gas"

Location: 
Kaplun building, Room No. 200
Tue, 27/12/2016 - 12:30 to 13:30

Lecturer: Dr. Jonathan Stern Affiliation: Galaxies and Cosmology Department Max-Planck-Institute for Astronomy [MPIA] Abstract: I will present two novel observational tests of astrophysical theories that are central to our understanding of galaxy evolution. The first test concerns quasar- driven galactic-scale outflows, which are often invoked by cosmological simulations to regulate star formation in massive galaxies. Several physical mechanisms have been proposed for the acceleration of these outflows, such as the ram pressure of shock-heated

Astrophysics Seminar: "Cosmic Ray Diffusion in a Dynamic Milky Way: Implications to Composition, Positron/electron Ratio and the Gama Ray Sky"

Location: 
Kaplun building, Room No. 200
Tue, 14/06/2016 - 12:30 to 13:30

Lecturer: Mr. David Benyamin Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: Over the years, significant effort has been devoted to the understanding of cosmic ray propagation in the galaxy, based on the energy dependence of the secondary to primary ratios in galactic cosmic rays. We developed a fully three dimensional numerical code describing the diffusion of cosmic rays in the Milky Way. This code enables us to explore a model in which a large fraction of the cosmic ray acceleration takes place in the vicinity of galactic spiral arms and

Astrophysics Seminar: "TBA" (Dr. Elinor Medezinski, Department of Astrophysical Sciences, Princeton University)

Location: 
Kaplun building, Room No. 200
Tue, 21/11/2017 - 12:30 to 13:30

Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://plus.google.com/hangouts/_/mail.huji.ac.il/astrophysics?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.2rj2e02855c6e7jvu7o0v693l9&hs=121

Astrophysics Seminar: "Angular correlation of cosmic neutrinos with astrophysical cosmic-ray and γ-ray sources"

Location: 
Kaplun building, Room No. 200
Tue, 15/11/2016 - 12:30 to 13:30

Lecturer: Dr. Reetanjali Moharana Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: IceCube is the world’s largest detector for cosmic neutrinos, built in South Pole. Recently reported 54 high-energy starting events (HESE) by IceCube is one of the main attractions for astrophysics as well as particle physics. This sample collected within 1347 days of operation, have deposited energy ranging from 20 TeV to 2 PeV. These events correspond to a 6.5σ detection of cosmic neutrinos above an estimated ~9.0 atmospheric neutrino

Astrophysics Seminar: "The tidal disruption of G2"

Location: 
Kaplun building, Room No. 200
Tue, 09/05/2017 - 12:30 to 13:30

Lecturer: Mr. Elad Steinberg Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: Recently a gas cloud, called G2, has been observed in the midst of being tidally disrupted in the center of our galaxy. I'll talk about recent advances in the understanding of the disruption process, obtained with analytic arguments coupled with simulations done with the RICH code. Additional details of the upcoming Astrophysics'

Astrophysics Seminar: "Childhood Obesity Among Black Holes - on The Early Growth of Supermassive Black Holes and Their Host Galaxies"

Location: 
Kaplun building, Room No. 200
Tue, 20/12/2016 - 12:30 to 13:30

Lecturer: Dr. Benny Trakhtenbrot Affiliation: Institute of Astronomy, ETH Zurich Abstract: Supermassive black holes (SMBHs), with masses reaching ten billions solar masses, are found in the centers of most galaxies, and their growth and energy release mechanisms appear to be closely linked to the galaxies that host them, making them central to our understanding of galaxy evolution. However, the existence of these extreme systems less than 1 Gyr after the Big Bang poses major challenges to our understanding of black hole formation and early growth. I will

Astrophysics Seminar: "Galaxy Evolution at the Peak Epoch of Cosmic Star Formation: Witnessing In-situ the Growth and Transformations of Young Galaxies"

Location: 
Kaplun building, Room No. 200
Tue, 24/05/2016 - 12:30 to 13:30

Lecturer: Dr. Natascha M. Forster Schreiber Affiliation: MPE Abstract: Eight to eleven billion years ago, galaxies were undergoing their most rapid mass assembly phase, forming stars at prodigious rates 10 to 20 times faster than observed today in the Milky Way and other nearby galaxies. While the statistical census of surveys measuring the global properties of faint distant galaxy populations and the fossil record from stars in present-day galaxies have enabled us to pin down when galaxies formed, detailed and resolved in-situ observations of individual

Astrophysics Seminar: "Hot Jupiters from alternative secular high-eccentricity migration scenarios"

Location: 
Kaplun building, Room No. 200
Sun, 29/01/2017 - 12:30 to 13:30

Lecturer: Dr. Adrian Hamers Affiliation: Princeton University Abstract: One of the proposed formation origins of hot Jupiters (HJs) is high-eccentricity (high-e) migration. In this case, the eccentricity of the orbit of a planet initially beyond the ice line is dynamically excited by a secular process, which leads to small periapse distances and strong tidal dissipation. An extensively-studied scenario of high-e migration involves an inclined and/or highly eccentric binary companion (star or massive planet). A major problem is that the predicted formation rates are too low

Astrophysics Seminar: "Probing unexplored exoplanet demographics with new microlensing campaigns"

Location: 
Kaplun building, Room No. 200
Tue, 01/11/2016 - 12:30 to 13:30

Lecturer: Dr. Yossi Shvartzvald Affiliation: NASA-JPL Abstract: Gravitational microlensing is unique in its ability to probe several relatively untapped reservoirs of exoplanet demographics, including planets near the "snowline," the Galactic distribution of exoplanets, and the population of free-floating planets. However, converting from the standard microlensing observables to the fundamental physical properties of the lensing system requires additional information beyond the basic microlensing light curve. In the past few years we have achieved significant