Astrophysics Seminar

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

Astrophysics Seminar: "Evolution of Supernova Remnants near the Galactic Center"

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

Lecturer: Mr. Almog Yalin Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: Supernovae near the galactic center evolve differently from regular galactic supernovae. This is mainly due to the environment into which the supernova remnants propagate. Instead of a static, uniform density medium, SNRs near the galactic center propagate into a wind- swept environment with a velocity away from the galactic center, and a graded density profile. This causes these SNRs to be non - spherical, and to evolve faster than their galactic counterparts.

Astrophysics Seminar: "On the abundance of biotic exoplanets and life on planets of Red Dwarfs"

Location: 
Kaplun building, Room No. 200
Tue, 10/05/2016 - 12:30 to 13:30

Lecturer: Dr. Amri Wandel Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: The Kepler mission has shown that Earthlike planets within the Habitable Zone of their host stars are common. I derive an expression for the abundance of life boring (biotic) extra-solar-system planets (exoplanets) in terms of the of the (yet unknown) probability for the evolution of biotic life. This "biotic probability" may be estimated by future missions and observations, e.g. spectral analyses of the atmospheres of exoplanets, looking for

Astrophysics Seminar: "Quasar outflows are situated thousands of times further from the Super-massive black-hole than previously thought"

Location: 
Kaplun building, Room No. 200
Tue, 07/03/2017 - 12:30 to 13:30

Lecturer: Prof. Nahum Arav Affiliation: Department of Physics, Virginia Tech Abstract: Theoretical modeling tends to place quasar outflows at distances of ~0.01 pc. from the central source. Here we report the results of two unbiased surveys targeting outflows that show troughs from S iv. We find that at least 50% of quasar outflows are at distances larger than 100 parsecs from the central source, and at least 12% are at distances larger than 1000 parsecs. These results have profound implications to the study of the origin and acceleration mechanism of

Astrophysics Seminar: "The Dark Energy Survey: more than Dark Energy"

Location: 
Kaplun building, Room No. 200
Tue, 19/07/2016 - 12:30 to 13:30

Lecturer: Prof. Ofer Lahav Affiliation: University College London 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.mt58gjejn1i7iu2havg77nhlq8&hs=121

Special Astrophysics Seminar: "The CARMENES search for exoplanets around M dwarfs Activity-induced radial-velocity variations of RV-loud stars"

Location: 
Kaplun building, Room No. 200
Sun, 05/11/2017 - 14:30 to 15:30

Lecturer: Dr Lev Tal-Or (IAG), Institut fur Astrophysik, Georg-August-Universitat, Goettingen, Germany Abstract: Thousands of planetary systems were discovered around Sun-like stars in the past 30 years. However, the fraction of planets detected around M dwarfs is still way below their representation in the Galaxy. M stars bring both great promise and great challenge for planet detection---their lower mass and luminosity make their low-mass habitable-zone planets detectable by nowadays radial-velocity (RV) instruments, but their faintness and activity make such measurements challenging.

Astrophysics Seminar: "The New Way of Doing Time-Domain Astronomy: From Supernovae to TDEs to Gravitational Waves"

Location: 
Kaplun building, Room No. 200
Tue, 29/11/2016 - 12:30 to 13:30

Lecturer: Dr. Iair Arcavi Affiliation: Department of Physics, University of California Santa Barbara Abstract: Time-domain astronomy is undergoing a revolution. New technologies and techniques for studying time-varying astronomical phenomena are providing a stream of discoveries and insights into the most energetic events in the Universe. I will show how robotic telescopes operating as a network allow us to (1) monitor supernovae both in their rapidly-evolving early stages, and in their long-lasting late stages, (2) study the rare phenomena of tidal disruption events

Special Astrophysics Seminar: "Science with orbital phase curves in the space age"

Location: 
Kaplun building, Room No. 200
Sun, 08/01/2017 - 14:00 to 15:00

Lecturer: Dr. Avi Shporer Affiliation: California Institute of Technology (CALTECH) Abstract: We are living in the golden age of time series photometry, when high-quality data is delivered by space-based surveys for a large number of stars in visible light. This enables a detailed study of the minute variability following the orbital motion of stellar binaries and star-planet systems, at a precision which is beyond reach from the ground. These orbital modulations are induced by a combination of gravitational and atmospheric processes, hence the

Astrophysics Seminar: "Towards Infinity and Beyond in Babylonian Mathematics and Astronomy"

Location: 
Kaplun building, Room No. 200
Tue, 21/06/2016 - 12:30 to 13:30

Lecturer: Prof. Wayne Horowitz Affiliation: The Institute of Archaeology, The Hebrew University of Jerusalem Abstract: Ancient Mesopotamian mathematics and astronomy are represented by thousands of cuneiform tablets ranging in date from the mid-third millennium BCE to the end of cuneiform writing in the first century CE. This paper examines the notion of infinity in time, space, and mathematical notation through a selection of cuneiform mathematical, astronomical, and mythological works bringing us time and place from the beginnings of the universe to the scribal academy,