Speaker（発表者）

Johan Samsing (Princeton University)

Date/Place（日程/場所）

15:00-, 15(Tue), Oct. @ES606

10月15日(火)15:00-＠ES606

Title（題名）

Formation of Black Hole Mergers in Dense Stellar Systems.

Abstract（概要）

I will present recent results on how binary black holes (BBHs) merge in dense stellar systems through chaotic few-body interactions. By taking into account GR effects in the equation-of-motion, I will show that dense stellar systems are likely to produce non-circular (eccentric) mergers in both LISA and LIGO with rates that are 10-100 times larger than what have been computed over the last decades using Newtonian N-body codes. In particular, I will demonstrate using simple analytical arguments that 5-10% of all BBH mergers from classical globular clusters will be eccentric in LIGO. This makes eccentricity a promising parameter for distinguishing BBH merger channels from each other. I will further discuss new ideas related to how the BBH merger distribution indirectly can be mapped using interrupted stellar tidal disruptions.

Speaker（発表者）

Takao Endo（遠藤隆夫）

Date/Place（日程/場所）

13:00-, 16(Wed), Oct. @ES606

10月16日(水)13:00-＠ES606

Title（題名）

The Alcock Paczynski test in HI intensity mapping survey

Abstract（概要）

The Alcock Paczynski test is the one of the way to probe expansion history (or geometry) of the universe by observing the size of objects along the line of sight and angular directions. Previous studies have shown that stacked voids, the under dense region of the large scale structure, can be one of the candidate for the test, but there are some drawbacks coming from the number of voids in galaxy surveys. In order to overcome the difficulty, we propose a new way to detect voids in the HI intensity mapping survey which will observe a neutral hydrogen distribution along the large scale structure (or galaxy and dark matter distribution) so that we will obtain a sufficient number of voids. In this talk, we will present results of our analysis using hydrodynamical simulation data such that the shape of stacked HI voids are spherical in real space but contaminated in the redshift space due to the peculiar velocity around voids.

Speaker（発表者）

Yuka Matsui（松井由佳）

Date/Place（日程/場所）

10:00-, 23(Wed), Oct. @ES606

10月23日(水)10:00-＠ES606

Title（題名）

Abstract（概要）