Astrophysics Seminar

Astrophysics Seminar: "The LIGO Discovery and Primordial Black Hole Dark Matter"

Location: 
Kaplun buildilng, Room No. 200
Sun, 18/12/2016 - 12:30 to 13:30

Lecturer: Dr. Ely Kovetz Affiliation: Johns Hopkins University Abstract: The LIGO observatory has recently reported several detections of gravitational waves from the coalescence of binary black holes. We consider the extraordinary possibility that the detected events involving heavier masses are mergers of primordial black holes making up the dark matter in the Universe. We will describe various ways of testing this proposition once more gravitational wave data is gathered, survey some of the existing constraints and present a novel probe of

Astrophysics Seminar: "The Galactic distribution of X-ray binaries and its implications for compact object formation and natal kicks"

Location: 
Kaplun building, Room No. 200
Tue, 17/05/2016 - 12:30 to 13:30

Lecturer: Dr. Serena Repetto Affiliation: Technion - Israel Institute of Technology Abstract: The aim of this work is to study the imprints that different models for black hole (BH) and neutron star (NS) formation have on the Galactic distribution of X-ray binaries (XRBs) which contain these objects. We find that the root mean square of the height above the Galactic plane of BH- and NS-XRBs is a powerful proxy to discriminate among different formation scenarios, and that binary evolution following the BH/NS formation does not significantly affect the Galactic

Astrophysics Seminar: "A Martian Origin to the Mars Trojan Asteroids"

Location: 
Kaplun building, Room No. 200
Tue, 24/01/2017 - 12:30 to 13:30

Lecturer: Dr. David Polishook Affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology (MIT) Abstract: Seven out of nine Mars Trojan asteroids belong to an orbital grouping and likely a single progenitor (Christou 2014, Cuk et al. 2015). Here we report new near-infrared observations of two of them (311999 and 385250) and we find that both present an identical olivine-rich reflectance spectrum, that is similar to the reflectance spectrum of 5261 Eureka, the largest of these seven Trojans (Rivkin et al. 2007). These

Astrophysics Seminar: "Inhomogeneities as a bias and as a probe"

Location: 
Kaplun building, Room No. 200
Tue, 08/11/2016 - 12:30 to 13:30

Lecturer: Dr. Ido Ben-Dayan Affiliation: DESY, Theory Group, Universität Hamburg Abstract: Precision Cosmology requires us to take into account the small scale inhomogeneities in the Universe when discussing cosmology. After a general introduction, I will discuss the effect of small scale inhomogeneities on the luminosity distance - redshift relation within LCDM: 1) How inhomogeneities bias the Hubble parameter due to peculiar velocities. This bias ameliorates the tension between CMB and and Supernovae measurements of the Hubble parameter. 2) How inhomogeneities serve

Astrophysics Seminar: "The NIHAO project: simulating galaxy formation in a dark universe"

Location: 
Kaplun building, Room No. 200
Tue, 17/01/2017 - 12:30 to 13:30

Lecturer: Prof. Andrea Macciò Affiliation: NYU Abu Dhabi Abstract: In a Universe dominate by Dark Matter and Dark Energy, galaxy formation is a complex mixture of hierarchical halo assembly, dissipational processes and secular evolution. I will then review the past years efforts of my research group at NYUAD in creating realistic (disk) galaxies in a cosmological context, with particular emphasis on the role of stellar feedback. I will then introduce the NIHAO project, a new, unmatched, suite of high resolution cosmological simulations. I will highlight

Astrophysics Seminar: "The Galactic distribution of X-ray binaries and its implications for compact object formation and natal kicks"

Location: 
Kaplun building, Room No. 200
Tue, 03/05/2016 - 12:30 to 13:30

Lecturer: Dr. Serena Repetto Affiliation: Technion - Israel Institute of Technology Abstract: The aim of this work is to study the imprints that different models for black hole (BH) and neutron star (NS) formation have on the Galactic distribution of X-ray binaries (XRBs) which contain these objects. We find that the root mean square of the height above the Galactic plane of BH- and NS-XRBs is a powerful proxy to discriminate among different formation scenarios, and that binary evolution following the BH/NS formation does not significantly affect the Galactic

Astrophysics Seminar: "Observational Studies of Exoplanets – Transits and More"

Location: 
Kaplun building, Room No. 200
Tue, 10/01/2017 - 12:30 to 13:30

Lecturer: Dr. Aviv Ofir Affiliation: Weizmann Institute of Science Abstract: How can one study objects one cannot even see? This is the challenge that observational exoplanets researchers are facing. In this talk I will start by shortly reviewing the different observational techniques used for studying exoplanets: radial velocity, transits, microlensing, direct imaging and astrometry. I will then focus on transits - the passage of an exoplanet in from of its host star. These are usually thought of as the passage of a circular black disk in front of a luminous

Astrophysics Seminar: "The space road to UHECRs studies in the large exposure era: JEM-EUSO and its pathfinders"

Location: 
Kaplun building, Room No. 200
Tue, 28/06/2016 - 12:30 to 13:30

Lecturer: Dr. Etienne Parizot Affiliation: APC Paris Abstract: Ultra-high-energy cosmic rays (UHECRs) stand as one of the pillars of the rapidly developing multi- messenger strategy for high-energy astrophysics and astroparticle physics. JEM-EUSO is currently the most advanced international project aiming at a significant increase in exposure for the study of UHECRs. As a space- based instrument, it will allow for the first time a full-sky coverage with identical exposure and experimental performances, which appears essential to investigate individual

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