Institute for Nuclear and Particle Astrophysics (INPA) at LBNL

The INPA Seminar weekly talks are on Fridays, starting at 12:00 pm, unless informed otherwise. The seminar talk starts with a brief presentation of the weekly scientific news. Typically, the talks conclude by 1:00 pm. The seminars are held in the Sessler Conference Room,  located in Bldg. 50A- 5132.

The committee members are:

The seminar schedule for the Institute for Nuclear and Particle Astrophysics (INPA) is tentative and becomes final a few days before the Friday talk.

Please send all suggestions for future INPA talks and speakers to the INPA Committee.

To be added to the INPA News Mailing List, please contact Erica Hall.

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Hillary Child – Nonlinear Structure Formation at Two Scales: from Bispectrum Baryon Acoustic Oscillations to Evolution of Halo Profiles

February 1, 2019 @ 12:00 pm - 1:00 pm

The “cosmic web” of dark matter halos forms via the collapse of post-inflation density fluctuations. While linear perturbation theory describes this process well at large scales and low densities, it fails at small scales and high densities. I explore two facets of nonlinear structure formation that constrain cosmology: at mildly nonlinear scales, measuring the baryon acoustic oscillation (BAO) distance scale in the bispectrum, and at deeply nonlinear scales, tracking the evolution of simulated dark matter halo profiles.
At mildly nonlinear scales, the BAO distance scale constrains the expansion history of the universe and dark energy. The BAO feature has been detected in both the three-point correlation function and the bispectrum, but challenges remain in fully exploiting three-point data. I present a strategy to select triangle configurations that maximize the amplitude of the BAO signal in the bispectrum. A relatively small set of bispectrum measurements can improve constraints on the BAO length scale over power spectrum measurements alone.
I next turn to the internal structure of dark matter halos, whose formation is highly nonlinear. The spherically-averaged density of a halo is well described by the Navarro-Frenk-White (NFW) profile, a function of two parameters: concentration, which describes the density of the central region of the halo, and halo mass. These two parameters are correlated, and the resulting concentration-mass (c-M) relation is sensitive to cosmological parameters. I present a robust measurement of the c-M relation from the largest ever sample of simulated halos (~30 million) and track the evolution of individual halos to connect halo formation time and concentration.

Details

Date:
February 1, 2019
Time:
12:00 pm - 1:00 pm

Venue

50A-5132- Sessler
50A-5132 Sessler Conference Room CA

INPA guests from campus can now come to the lab early on Fridays. The INPA Common Room (50-5026) is reserved for our guests from 10:00 a.m. to 12:00 noon and from 1 p.m. to 5 p.m. Note that the seminars are now held in 50A-5132 to accommodate a more significant number of attendees.

CPTea Series (also known as INPA Tea Series)

The Physics Division CPTea Series invites you to an In-Person Tea Series 1st Friday of every month at 3:30 pm INPA Conference Room 50-5026.

Everyone is welcome to attend the open forum. Tea and light refreshments will be served.

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INPA Common Room (50-5026)
Fridays
3:30 pm

Access to the Lab

For a shuttle pass, please email Erica Hall. The pass is only valid for the day of the seminar.

Erica Hall