Astrophysics Seminar

"Special Astrophysics Seminar: Refusing to Go Quietly: Gamma-Ray Bursts and Their Progenitors"

Location: 
Kaplun building, Room No. 200
Sun, 02/11/2014 - 14:00 to 15:00

Lecturer: Prof. A. Fruchter Affiliation: STScI Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/astrophysics?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.4i45c201rse2b5jggtbp7f1364&hs=121

Astrophysics Seminar: "Unraveling GRB 060218"

Location: 
Kaplun building' Room No. 200
Tue, 16/02/2016 - 12:30 to 13:30

Lecturer: Dr. Christopher Irwin Affiliation: The University of Virginia Abstract: We consider a model for the long-duration, low- luminosity gamma-ray burst GRB 060218 that plausibly accounts for multiwavelength observations to day 20. The components of our model are: (1) a long-lived (t ~ 3000 s) central engine and accompanying low-luminosity (L ~ 1e47 erg/s), mildly relativistic jet; (2) a low- mass (~ 1e-2 Msun ) envelope surrounding the progenitor star; and (3) a modest amount of dust (A_V ~ 0.1) in the circumstellar or interstellar environment. Blackbody emission

"Astrophysics Seminar: Electromagnetic Counterparts to Gravitational Waves"

Location: 
Kaplun building, Room No. 200
Tue, 30/06/2015 - 12:30 to 13:30

Lecturer: Prof. K. Ioka Affiliation: The High Energy Accelerator Research Organization, KEK Abstract: Direct detection of gravitational waves (GWs) is on the horizon, with the most promising sources being the mergers of two neutron stars (NS-NS) or a black hole and a neutron star (BH-NS). Maximizing the scientific return of this new window into the universe requires identifying a coincident electromagnetic (EM) counterpart. One probable EM counterpart is a short gamma-ray burst (GRB) but the emission is highly collimated. Isotropic EM emissions are also suggested by the general

"Astrophysics Seminar: Pair-instability supernova progenitors with large mass loss"

Location: 
Kaplun building, Room No. 200
Thu, 22/01/2015 - 14:00 to 15:00

Lecturer: Dr. Takashi Moriya Affiliation: University of Bonn Abstract: Pair-instability supernovae (PISNe) are thermonuclear explosions of very massive stars. The stellar core needs to be heavier than about 60 Msun for stars to be PISNe. Mass loss prevents massive stars from making large enough cores to be PISNe, and PISNe are presumed to exist in metal-free or metal-poor environment where radiation-driven mass loss is small. Stellar evolution models show that such PISN progenitors evolve to red supergiants (RSGs) shortly before their explosions. However, RSGs are suggested to be

Astrophysics Seminar: "Dynamics and evolution of planetesimals in gaseous protoplanetary disks - the role of gas dynamical friction"

Location: 
Kaplun building, Room No. 200
Tue, 12/04/2016 - 12:30 to 13:30

Lecturer: Mr. Evgeni Grishin Affiliation: Technion - Israel Institute of Technology Abstract: The growth of small planetesimals into large planetary embryos occurs much before the dispersal of the gas from the protoplanetary disk. The planetesimal - disk interactions cause migration and orbital evolution of the planetesimals/planets. Small planetesimals are dominated by aerodynamic gas drag. Large protoplanets, >1000km in size, are dominated by type I migration torque. There is an additional size range, 200- 1000 km, of intermediate mass

"Astrophysics Seminar: Astrometric mock observations for determining the local dark matter density"

Location: 
Kaplun building, Room No. 200
Tue, 24/11/2015 - 12:30 to 13:30

Lecturer: Dr. Shigeki Inoue Affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem Abstract: It is a classical problem in astronomy to determine the local dark matter density (LDMD) of the solar system. The DM density at the solar radius can be estimated from the Galactic rotation curve using a spherical assumption for the dark matter halo. However, dark matter haloes are generally aspherical, therefore the DM density deduced from the rotation curve can differ from the LDMD around the solar system. In other words, the difference between

"Astrophysics Seminar: Investigating the links between galaxy structure and environment in the high redshift Universe"

Location: 
Kaplun building, Room No. 200
Tue, 14/04/2015 - 12:30 to 13:30

Lecturer: Dr. Caterina Lani Affiliation: Tel-Aviv University Abstract: It has been long known that, in the local Universe, galaxy morphology is strongly related to environment. Furthermore, massive passive galaxies were observed to be 2 - 4 times more compact at z ~ 2 compared to the present day. Environment, in the form of mergers, halo mass and interactions, could explain the observed size increase as well as morphological transitions. I will present compelling evidence for a strong correlation between galaxy size and environment to z ∼