Events this week

Monday, September 29

Theoretical Astrophysics Seminars – no TAC seminar today

4D Seminars
Location: UCB – 402 Old Le Conte, 2:30 p.m.
Speaker: Mikhail Solon (UCB/LBNL)
Title: “Standard Model Anatomy of WIMP Observables”

Physics Department Colloquium
Location: UCB, 1 Le Conte Hall – 4:15 p.m.
Speaker: Bill Press (U. of Texas)
Title: “Eight Dimensions is Big Enough: Surprises in the Prisoner’s Dilemma Game”

Tuesday, September 30

String Seminar
Location: UCB – 402 Old Le Conte, 3:40 p.m.
Speaker: Aninda Dey (U. of Texas)
Title: “Field Theory on Gibbons-Hawking Spaces”

Physics Research Progress Meeting – no RPM today

Wednesday, October 1

BOSS Lunch
Location: LBNL – 50B-4205 – noon

Particle Theory Seminar
Location: LBNL – 50A-5132, 2:00 p.m.
Speaker:  Kiel Howe (Stanford)
Title: “Maximally Natural SUSY and its Natural New Signatures”

String Group Meeting
Location: UCB – 402 Old LeConte, 3:40 p.m.
Speaker: tba
Title: tba

CANDi
Location: LBNL, 50-5026, 3:30 p.m.
Speaker: tba

Thursday, October 2

Astronomy Lunch – tba

Astronomy Colloquium
Location: UCB, 2 LeConte Hall, 4:10 p.m.
Speaker: Hannah Jang-Condell (U. of Wyoming)
Title: “Using Young Disks as Laboratories for Studying Planet Formation”
Abstract: Exoplanets have been discovered in orbits as close as 0.05 AU, and as distant as hundreds of AU. Hence, exoplanets are a hot topic, but they are also pretty cool. How do such disparate planetary systems arise? The best way to learn is to directly study planets  while they are forming in young circumstellar disks. Gas-rich protoplanetary disks represent early stages of planet formation, when gas giants are still forming, while gas-free debris disks represent later stages of planet formation, when terrestrial planets could still be forming and dynamical interactions shape the system. In this talk, I will discuss some of the signatures of planets forming in disks, and show how the observations of these signatures informs our understanding of where, when, and how planets form.

Physics Research Progress Meeting
Location: LBNL – 50A-5132, 4:00 p.m.
Speaker:  Pat McDonald (LBNL)
Title: “The Dark Energy Spectroscopic Instrument”

Friday, October 3

Cosmology/BCCP seminar
Location: LBNL 50-5026 – 12 p.m.
Speaker: Yin Li, Chicago
Title: “The power spectrum super-sample effect”
Abstract: The impact of density fluctuations with wavelengths larger than a survey must be considered when extracting cosmological information from power spectrum measurements. These modes change the power spectrum in the same way as a change in the cosmological background does. Using a handful of separate universe simulations, we accurately capture this effect in terms of response of the matter power spectrum to a single mode — the mean density fluctuation in the survey volume. The unknown amplitude of this mean density mode contributes to a (typically dominant) error in the matter power spectrum estimators. Alternatively, it can also be simply included in parameter estimation and forecasts by treating the mean density fluctuation as an additional cosmological parameter. Parameter degeneracies arise since the response of the power spectrum to the mean density mode and cosmological parameters share similar properties in changing the growth of structure and dilating the scale of features.

SSL Colloquium
Location: SSL Addition Conference Room (#105) – 3:00 p.m.
Speaker: Claire Poppett, LBNL
Title: “Dark Energy Spectroscopic Instrument: Probing dark energy with optical fibers and 5000 robots”

BCCP Seminars

Friday, October 3
INPA/Cosmology/BCCP seminar
Location: LBNL 50-5026 – 12 p.m.
Speaker: Yin Li, Chicago
Title: “The power spectrum super-sample effect”
Abstract: The impact of density fluctuations with wavelengths larger than a survey must be considered when extracting cosmological information from power spectrum measurements. These modes change the power spectrum in the same way as a change in the cosmological background does. Using a handful of separate universe simulations, we accurately capture this effect in terms of response of the matter power spectrum to a single mode — the mean density fluctuation in the survey volume. The unknown amplitude of this mean density mode contributes to a (typically dominant) error in the matter power spectrum estimators. Alternatively, it can also be simply included in parameter estimation and forecasts by treating the mean density fluctuation as an additional cosmological parameter. Parameter degeneracies arise since the response of the power spectrum to the mean density mode and cosmological parameters share similar properties in changing the growth of structure and dilating the scale of features.

Tuesday, October 7

Location: UCB, Hearst Field Annex B-1 – 1:10 pm
Speaker: Benedikt Diemer, Chicago  
Title: “The (non-)universality of halo density profiles”
Abstract: The density profiles of dark matter halos are an essential input for models of galaxy formation, as well as for the interpretation of numerous observations such as weak and strong lensing signals. The profiles are commonly thought to follow a simple, universal shape, and only depend on two parameters, mass and concentration. Using a large suite of cosmological simulations, I will show that the outer halo density profiles depend on an additional parameter, the mass accretion rate, and present an accurate new fitting formula that takes this dependence into account. I will further discuss the question of universality, and show that the definition of the halo boundary plays a crucial role. Similarly, halo concentrations are usually described as a universal function of mass and redshift. Instead, I will present a model in which concentration depends on an additional parameter: the local slope of the matter power spectrum. I will demonstrate that this model accurately (to better than 10-15%) describes simulated concentrations over a large range of redshifts, halo masses and cosmological parameters, and is in excellent agreement with the recent observations of the CLASH cluster survey.

BCCP events this week

Friday, October 3
INPA/Cosmology/BCCP seminar
Location: LBNL 50-5026 – 12 p.m.
Speaker: Yin Li, Chicago
Title: “The power spectrum super-sample effect”
Abstract: The impact of density fluctuations with wavelengths larger than a survey must be considered when extracting cosmological information from power spectrum measurements. These modes change the power spectrum in the same way as a change in the cosmological background does. Using a handful of separate universe simulations, we accurately capture this effect in terms of response of the matter power spectrum to a single mode — the mean density fluctuation in the survey volume. The unknown amplitude of this mean density mode contributes to a (typically dominant) error in the matter power spectrum estimators. Alternatively, it can also be simply included in parameter estimation and forecasts by treating the mean density fluctuation as an additional cosmological parameter. Parameter degeneracies arise since the response of the power spectrum to the mean density mode and cosmological parameters share similar properties in changing the growth of structure and dilating the scale of features.

Upcoming Events

Tuesday, October 7

Location: UCB, Hearst Field Annex B-1 – 1:10 pm
Speaker: Benedikt Diemer, Chicago  
Title: “The (non-)universality of halo density profiles”
Abstract: The density profiles of dark matter halos are an essential input for models of galaxy formation, as well as for the interpretation of numerous observations such as weak and strong lensing signals. The profiles are commonly thought to follow a simple, universal shape, and only depend on two parameters, mass and concentration. Using a large suite of cosmological simulations, I will show that the outer halo density profiles depend on an additional parameter, the mass accretion rate, and present an accurate new fitting formula that takes this dependence into account. I will further discuss the question of universality, and show that the definition of the halo boundary plays a crucial role. Similarly, halo concentrations are usually described as a universal function of mass and redshift. Instead, I will present a model in which concentration depends on an additional parameter: the local slope of the matter power spectrum. I will demonstrate that this model accurately (to better than 10-15%) describes simulated concentrations over a large range of redshifts, halo masses and cosmological parameters, and is in excellent agreement with the recent observations of the CLASH cluster survey.

 

Aspen conference winter 2015

Program and application information coming soon!

Workshops

Aspen Conference  

Website: Cosmology On The Slopes, March 8-14, 2015, Aspen, Colorado  

 

BCCP Workshop: 5th Essential Cosmology for the Next Generation Meeting

BCCP and the Instituto Avanzado de Cosmologia Mexico held the 5th Essential Cosmology for the Next Generation meeting on January 13-17, 2014, popularly known as Cosmology on the Beach. The conference blends a winter school of lecture courses by world-leading scholars with plenary talks on hot research topics. This year, topics included CMB polarization, gravitational wave cosmology, particle physics, tests of gravity, and statistical and experimental methods. To see slides from the BCCP/IAC meeting Essential Cosmology for the Next Generation 2014 workshop, please click here.  They are also available on the Presentations Page. ****************************************************************************************************************************************** Link to April 17-19, 2013 Cosmology Beyond the Power Spectrum Workshop