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Abstract: What is the dynamics of the universe? While it is true that one needs General Relativity for a full description of the dynamics of the universe, most of the key elements can be understood using a usual Newtonian intuition. For this talk I will briefly review the dynamics of the cosmological expansion and the development of large-scale structure due to gravitational instability, as well as hydrodynamics of cosmic fluids. I will then talk about the roles they have played for a recent, remarkable progress in our understanding of the universe and the mysteries they have provided.
Abstract: Can we use the Fermi satellite like WMAP? In 2006, S. Ando and I proposed to use anisotropies in the gamma-ray background (not CMB!) as a smoking-gun signature of annihilation of dark matter particles in the universe. The idea is simple: since dark matter traces the large-scale structure of the universe, the emission from dark matter must be anisotropic, and its spatial pattern is predictable. The use of anisotropy (especially the power spectrum) was new to the gamma-ray community, so I teamed up with the Fermi-LAT team to look for this signature. Here, we report on the first detection of anisotropy in the diffuse gamma-ray background measured by Fermi-LAT. We find that the detected signal is very likely due to unresolved blazers. Subtracting this signal, we can place a fairly stringent upper limit on the residual anisotropy signal, which would then put constraints on dark matter properties.
Abstract: Near-infrared bands offer a window into a high-redshift universe (z>6). Detecting individual galaxies at z>6 is one thing, but we can also detect the diffuse infrared background from unresolved galaxies as well. This gives us a unique opportunity to probe the early star formation history and structure formation at z>6. In this talk, we present the latest theoretical calculations of the cosmic near infrared background, including both the mean intensity and the fluctuations. Then we discuss implications for the ongoing experiments targeting the near infrared background such as CIBER.
Abstract:宇宙マイクロ波背景輻射を始めとする様々な宇宙論観測より、宇宙の標準理論の枠組みはほぼ固まった。しかし、暗黒物質や暗黒エネルギーの正体は未知のままであるし、インフレーション宇宙の物理も未知のままだ。ニュートリノには質量がある事はわかっているが、質量の絶対値はわかっていない。"Astro2010"と呼ばれる、米国ナショナルアカデミーがまとめた天文・天体物理のDecadal Surveyによれば、これらのトピックが向こう10年間の宇宙論分野の最重要課題であると言う。それでは、どのような観測をすればこれらの課題の理解を深められるのだろうか？そして理論的課題は何だろうか？本講演では、宇宙の大規模構造を軸にしてこれらの課題に立ち向かう方法論を紹介する。具体的には、この分野の基礎となる物質揺らぎの線形および非線形成長理論、2点関数と3点関数、赤方偏移の歪み（redshift space distortion）、アルコック・パチンスキー（AP）テスト、非ガウス統計などを概観した後、現在および将来の銀河の大規模サーベイの有り様と、これから必要となる理論的枠組みを議論してゆきたい。
Canceled due to Hurricane Irene... What a pity. Here is what happened:
- Aug 27: told that IAD-MAD has been canceled, so we booked IAD-MUC-MAD on Aug 28.
- Aug 28: AUS-IAD was delayed, and it was clear that we would miss IAD-MUC. Told that the next available flight to MUC or MAD would be SEPTEMBER 4. What?! That's after the end of the conference! Decided to cancel a whole trip to Spain. Sob, sob...
How fragile is the aviation system in the east coast?! This is just a stupid cat-1 hurricane, which is now just a tropical storm! Come on America, you can do better than this.
And this is what I was supposed to do in Spain...
Abstract: American National Academy of Science's Astronomy and Astrophysics Decadal Survey (Astro2010) ranks (1) physics of cosmic inflation; (2) nature of dark energy; (3) nature of dark matter; and (4) properties of neutrinos, as the key science topics in the area of cosmology over the next decade. How would one approach these questions? I will discuss possible strategies such as the B-mode polarization of the cosmic microwave background and non-Gaussian correlations of primordial fluctuations for probing the physics of inflation, and large-scale structure observations for probing the nature of dark energy and dark matter, as well as for measuring the absolute mass of neutrinos.
Abstract: In the WMAP 7-year data release, we have presented the studies of clusters detected by WMAP via the Sunyaev-Zel'dovich effect. In this talk I will present some of the results we have obtained and compare them to the new, more sensitive results from Planck. They include: (1) the SZ measurement of Coma and importance of separating CMB fluctuation; (2) consistency of the X-ray and WMAP data on individual clusters; (3) effects of dynamical states of clusters on the SZ-Xray comparison; and (4) issues regarding the stacking analysis of many clusters.
Abstract: 宇宙マイクロ波背景輻射を始めとする様々な宇宙論観測より、宇宙の標準理論の枠組みはほぼ固まった。しかし、暗黒物質や暗黒エネルギーの正体は未知のままであるし、インフレーション宇宙の物理も未知のままだ。ニュートリノには質量がある事はわかっているが、質量の絶対値はわかっていない。"Astro2010"と呼ばれる、米国ナショナルアカデミーがまとめた天文・天体物理のDecadal Surveyによれば、これらのトピックが向こう10年間の宇宙論分野の最重要課題であると言う。それでは、どのような観測をすればこれらの課題の理解を深められるのだろうか？そして理論的課題は何だろうか？本講演では、宇宙論の基本的な物理とこれまでの到達点を概観した後、私個人がどのようにこれらの課題に立ち向かおうとしているのか紹介したい。
Abstract: Can we falsify inflation, or at least falsify single-field models? The squeezed-limit bispectrum has been recognized as a powerful tool for ruling out all single-field models. We have been working on scrutinizing this method. In particular, we find that a departure from a non-Bunch-Davies vacuum yields an interesting phenomenology which sheds a new light on the squeezed-limit bispectrum method. We apply this to the scale-dependent bispectrum of dark matter halos, which is sensitive to the squeezed-limit bispectrum. Finally, we comment on a possible way to rule out all inflation models (including multi-field models) using the relation between the local-form bispectrum and one of the local-form trispectra.
Abstract: The Cosmic Microwave Background (CMB), the fossil light of the Big Bang, is the oldest light that one can ever hope to observe in our Universe. The CMB provides us with a direct image of the Universe when it was still an "infant" - 380,000 years old - and has enabled us to obtain a wealth of cosmological information, such as the composition, age, geometry, and history of the Universe. Yet, can we go further and learn about the primordial universe, when it was much younger than 380,000 years old, perhaps as young as a tiny fraction of a second? If so, this gives us a hope to test competing theories about the origin of the Universe at ultra high energies. In this talk I review the present status and future prospects on our quest to probe the physical condition of the very early Universe.