Physics Commons^™

Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2 M_⊙-1.0 M_⊙ using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2 M_⊙, 0.2 M_⊙) ultracompact binaries to be less than 1.0 x 10⁶ Gpc^-3 yr^-1 and the coalescence rate of a similar distribution of (1.0 M_⊙, 1.0 M_⊙) ultracompact binaries to be less …

Understanding Higher-Order Nonlocal Halo Bias At Large Scales By Combining The Power Spectrum With The Bispectrum, Shun Saito, Tobias Baldauf, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Understanding the relation between underlying matter distribution and biased tracers such as galaxies or dark matter halos is essential to extract cosmological information from ongoing or future galaxy redshift surveys. At sufficiently large scales such as the baryon acoustic oscillation (BAO) scale, a standard approach for the bias problem on the basis of the perturbation theory (PT) is to assume the "local bias" model in which the density field of biased tracers is deterministically expanded in terms of matter density field at the same position. The higher-order bias parameters are then determined by combining the power spectrum with higher-order statistics …

Implementation And Testing Of The First Prompt Search For Gravitational Wave Transients With Electromagnetic Counterparts, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations.

Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify …

Forecasting The Cosmological Constraints With Anisotropic Baryon Acoustic Oscillations From Multipole Expansion, Atsushi Taruya, Shun Saito, Takahiro Nishimichi

Physics Faculty Research & Creative Works

Baryon acoustic oscillations imprinted in the galaxy power spectrum can be used as a standard ruler to determine the angular diameter distance and Hubble parameter from high-redshift galaxies. Combining redshift distortion effect which apparently distorts the galaxy clustering pattern, we can also constrain the growth rate of large-scale structure formation. Usually, future forecasts for constraining these parameters from galaxy redshift surveys are made with the full 2D power spectrum characterized as a function of wave number k and directional cosine µ between line-of-sight direction and wave vector, i.e., P(k,µ). Here, we apply the multipole expansion to the full 2D power …

Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito

Physics Faculty Research & Creative Works

We present an improved prescription for the matter power spectrum in redshift space taking proper account of both nonlinear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the nonlinear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with the monopole …

Nonlinear Evolution Of Baryon Acoustic Oscillations From Improved Perturbation Theory In Real And Redshift Spaces, Atsushi Taruya, Takahiro Nishimichi, Shun Saito, Takashi Hiramatsu

Physics Faculty Research & Creative Works

We study the nonlinear evolution of baryon acoustic oscillations in the matter power spectrum and correlation function from the improved perturbation theory (PT). Based on the framework of renormalized PT, which provides a nonperturbative way to treat the gravitational clustering of large-scale structure, we apply the closure approximation that truncates the infinite series of loop contributions at one-loop order, and obtain a closed set of integral equations for power spectrum and nonlinear propagator. The resultant integral expressions are basically equivalent to those previously derived in the form of evolution equations, and they keep important nonperturbative properties which can dramatically improve …