Events this week

Monday, April 21

Theoretical Astrophysics Center Seminar
Location: UCB – B5 Hearst Field Annex, 12:10 p.m.
Speaker: Melissa Graham & Josiah Schwab (UCB)
Title:
“Physical Explanations for the Observed Diversity in Type IA Supernovae”

4D Seminars
Location: UCB – 402 Old Le Conte, 2:30 p.m.
Speaker: Satoshi Shirai (UCB)
Title: “Flavor and Minimal SUSY GUT”

Physics Department Colloquium
Location: UCB – 1 Le Conte Hall, 4:15 p.m.
Speaker: James Sethna (Cornell)
Title: “Sloppy Models, Differential Geometry, and How Science Works”

Tuesday, April 22

Berkeley Cosmology Seminars
Location: UCB – Hearst Field Annex B1, 1:10 p.m. (also videoconferenced to LBNL 50-5026)
Speaker: Leonardo Senatore (Stanford)
Title:
“The Effective Field Theory of Large Scale Structures”
Abstract: After discussing briefly some implications for Inflation after BICEP2, I will focus on Large Scale Structures surveys, as they promise to be the next leading probe of cosmological information. It is therefore crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbation theory for the weakly non-linear regime of dark matter, where correlation functions are computed in an expansion of the wavenumber k of a mode over the wavenumber associated with the non-linear scale k_nl. Since most of the information is contained at high wavenumbers, it is necessary to compute higher order corrections to correlation functions. I will present the predictions of the EFTofLSS up to 2-loops. We find that it matches to percent accuracy the non-linear matter power spectrum up to k~0.6 h/Mpc, requiring just one unknown coupling constant that needs to be fit to observations. Given that Standard Perturbation Theory stops converging at k~0.1 h/Mpc, our results demonstrate the possibility of accessing a factor of order 200 more dark matter quasi-linear modes than naively expected. If the remaining observational challenges to accessing these modes can be addressed with similar success, our results show that there is tremendous potential for large scale structure surveys to explore the primordial universe.

String Seminar
Location: UCB – 402 Old Le Conte, 3:40 p.m.
Speaker: Jaime Varela (UCB)
Title: “Semi-Classical Field Theory as Decoherence Free Spaces”

Physics Research Progress Meeting- no RPM today

Wednesday, April 23

Weekly BOSS lunch
Location: LBNL -  outside
Speakers: tba

Particle Theory Seminar – no seminar today

String Group Meeting – no meeting today

CANDi
Location: LBNL, INPA Room 50-5026, 3:30 p.m.
Speakers:  tba

Thursday, April 24

Weekly Astronomy Lunch
Location: UCB, 210 Wheeler, 12:30 p.m.
Speakers:  • Omar Bromberg: Direct Observation Evidence for the Collapsar Model in Gamma-ray Bursts and How to Really Tell a Long Burst From a Short One
• James McBride: Bent Jets Reveal a Stripped Interstellar Medium in NGC 1272
• Lucio Mayer: Orbital Decåy of Massive Black Hole Binaries in a Clumpy Interstellar Medium

Astronomy Colloquium
Location: UCB, 2 LeConte Hall, 4:00 p.m.
Speaker: Lucio Mayer (ETH Zurich)
Title:  “Formation Pathways for Massive BH Seeds and their Subsequent Evolution as Massive Black Holes Binaries in Gas-Rich Galaxy Mergers”
Abstract: The emergence of bright Quasars as early as z > ~ 7 strongly suggests the existence of a rapid pathway to form supermassive black holes. Conventional models based on the growth of light BH seeds from primordial Population III stars have difficulties in explaining such a rapid assembly. As a result, models in which massive BH seeds form by direct gas collapse in protogalaxies have received significant attention in the last few years. In the most common variants such models rely on fairly idealized thermodynamical conditions of gas flows in protogalaxies, such as suppression of cooling via dissociation of molecular hydrogen and metal-free gas in order to suppress fragmentation. We have recently developed a novel formation scenario that does not rely on any of such restrictive conditions (Mayer et al. 2010, Nature, 466, 1082). It is based on mergers between the most massive, already metal enriched protogalaxies at z < ~ 10, in which gas inflows in excess of 10^4 Mo/yr can arise in less than 10^5 yr following the merger. The latter give rise to supermassive, gravitationally unstable nuclear clouds with masses  in excesse of 10^8 Mo. These are likely precursors of massive BH seeds that could form after a short supermassive star and/or a quasi-star phase. I will show new simulations which confirm this scenario further using more sophisticated radiative cooling , highligthing the role of gravitoturbulence in achieving prominent inflows while minimizing the effect of fragmentation and star formation in the nuclear gas. Using the Millenium simulations combined with the latest semi-analytical galaxy formation models with black hole growth we compare our scenario with a Pop III-based scenario. We find specific signatures of massive BH seeds formed by our direct collapse in the clustering and morphology of the host galaxies  at both high and low redshift. Our model is so far the only one consistent with very recent determinations of the accreting SMBH population in dropout galaxies at z~6-8.

Special Seminar
Location: LBNL, INPA Common Room, 50-5026, 4:00 p.m.
Speaker:  Laura Gladstone (U. of Wisconsin-Madison)
Title: “Neutrino Oscillations with IceCube”
Abstract: The IceCube Neutrino Observatory at the South Pole can detect particles in a wide energy range, extending down as low as 10 GeV. This makes IceCube sensitive to studies of the neutrino mixing angle theta23 by observing atmospheric neutrinos from the opposite hemisphere. We use likelihood event reconstructions to find the energy and direction of the observed particles, and several oscillation search methods are already showing promising results.

Physics Research Progress Meetingno RPM today

Friday, April 25

INPA Seminar
Location: LBNL – INPA Common Room (50-5026), 12:00 p.m.
Speaker: Igor Ostrovskiy (Stanford)
Title:  “Gean4: “Search for Majorana Neutrinos with the First Two Years of EXO-200 Data”
Abstract: tba

Upcoming Events

April  29 -  1:10 p.m. (Cosmology-BCCP)
Speaker:  Charlie Conroy, UCSC
Location:  UCB, Hearst Field Annex, B1 (also videoconferenced to 50-5026)
Title: “Extragalactic Archeology”
Abstract: One of the primary avenues for understanding the formation and evolution of galaxies is through studying their stellar populations. A new generation of population synthesis tools that we have been developing are now capable of measuring an unprecedented amount of information from high quality spectra of galaxies. In this talk, I will present results from an ongoing program aimed at measuring the stellar initial mass function, ages, and detailed elemental abundance patterns of early-type galaxies over the interval 0 < z < 1. Constraints on the abundances of the alpha, iron peak, and neutron capture elements offer the promise of reconstructing the detailed star formation histories of these now dormant galaxies. By measuring the evolution of these quantities through cosmic time, we are gaining fresh insights into the assembly histories of galaxies. The techniques we are developing will enable `extragalactic chemical tagging’ and, more generally, will open up the low resolution universe for detailed study.

BCCP Seminars

Tuesday, April 29
Location: UCB, Hearst Field Annex B-1, 1:10 pm
Speaker: Charlie Conroy, UCSC
Title: “Extragalactic Archeology”
Abstract: One of the primary avenues for understanding the formation and evolution of galaxies is through studying their stellar populations. A new generation of population synthesis tools that we have been developing are now capable of measuring an unprecedented amount of information from high quality spectra of galaxies. In this talk, I will present results from an ongoing program aimed at measuring the stellar initial mass function, ages, and detailed elemental abundance patterns of early-type galaxies over the interval 0 < z < 1. Constraints on the abundances of the alpha, iron peak, and neutron capture elements offer the promise of reconstructing the detailed star formation histories of these now dormant galaxies. By measuring the evolution of these quantities through cosmic time, we are gaining fresh insights into the assembly histories of galaxies. The techniques we are developing will enable `extragalactic chemical tagging’ and, more generally, will open up the low resolution universe for detailed study.

 

BCCP Lunches

BCCP Lunch Events

BCCP Lunch Events usually take place in Hearst Field Annex  (HFA) B-1 at noon. The venue and dates may be subject to change. To keep you notified, please contact Melissa Barclay (mbarclay@berkeley.edu) to be added to the lunch mailing list.

April 15

Joint BCCP-BCTP luncheon
Location: UCB, 4th floor Le Conte interaction area, noon
Speaker: Eva Silverstein (Stanford) and a conversation about BICEP2 results, inflation, and string theory
Pizza will be served

Visitors

 

Visitors Program

We maintain an active program for visiting scholars. BCCP hosts visitors at all levels, from senior scientists to postdocs, graduate students, and undergraduates. If you would like to visit BCCP, please fill out the form here.

Longer term visits involving collaborative activities with BCCP members are especially encouraged. BCCP can provide financial support for longer term visitors working with BCCP members on BCCP related projects. The applications are reviewed by a committee several times a year. All decisions are based on the availability of space and funding.

Spring 2014

  • Evan Scannapieco (ASU) – January 3-May 31
  • Irshad Mohammed (University of Zurich) – January 9-June 30
  • Miguel Zumalacárregui (University of Heidelberg) – January 22-February 10
  • Paul Shellard (University of Cambridge) – February 6-7
  • Arka Banerjee (University of Illinois, Urbana-Champaign) – February 9-22
  • Tong-Jie Zhang (Beijing Normal University) – February 27-May 27
  • Zvonimir Vlah (Univ of Zurich, ITP) – March 3-April 2
  • Louis Garrigue (ENS-Ecole Normale Supérieure, Paris) – March 17-July 11
  • Neal Dalal (Univ of Illinois) – March 26-28

Fall 2013

  • Elizabeth Krause (U Penn) – September 10-11
  • Zvonimir Vlah (Univ of Zurich, ITP) – September 17-December 20
  • Michael Kopp (LMU) – October 28-November 2
  • Juliana Kwan (Argonne National Lab) – November 13-22
  • Amol Upadhye (Argonne National Lab) – November 13-December 20
  • Teppei Okumura (IEU Korea) – November 13-30
  • Jonathan Blazek (OSU) – December 5-13

Summer 2013

  • Azadeh M. Dizgah (SUNY-Buffalo) – May 16-July 16
  • Jeremy Tinker (NYU) – May 30-August 20
  • Sudeep Das (Argonne National Lab) – July 9-27
  • Daniel Holz (Chicago) – August 27-28
  • Neal Dalal (Illinois) – August 30,
  • Wayne Hu (Chicago) – August 29-30
  • Joel Johansson (Stockholm) – August 29-30

Spring 2013

  • Alireza Hojjati (IEU Korea) – January 14-February 5
  • Chris Blake (Swinburne) – January 14-February 5
  • Tamara Davis (Queensland) – January 14-18
  • Morag Scrimgeour (Western Australia) – January 14 -
  • Sudeep Das (Argonne National Lab) – January 28-31
  • Chiaki Hikage (Nagoya University) – February 10-16
  • Miguel Zumalacarregui (Universidad Autonoma de Madrid) – February 15-22
  • Jaiyul Yoo (Univ. of Zurich) – February 23 – April 27
  • Laura Baudis (Univ. of Zurich) – April 26-May 4

Fall 2012

  • Stephen Appleby (IEU Korea) – October 7-26, 2012
  • Roland de Putter (Caltech/JPL) – October 19-25, 2012
  • David Pietrobon (JPL) – October 19-26, 2012
  • Tobias Baldauf (ITP, University of Zurich) – September 12-December 9, 2012
  • Johan Samsing (DARK Cosmology Centre, Copenhagen) – February-December 2012
  • Masanori Sato (Nagoya University, Japan) – October 5 – November 22, 2012
  • Andreu Font (University of Zurich) – November-December 2012
  • Teppei Okumura (Institute for the Early Universe, Seoul, Korea) – November 5-December 21, 2012

 

Oliver Zahn

oliver

Zahn originally came to Berkeley as inaugural BCCP Fellow after undergraduate work at Max-Planck-Insitute for Astrophysics and NYU, as well as doctoral work at Harvard and Heidelberg.

He recently became the executive director of BCCP and as such oversees the centers’ cosmology program as well as its new interdisciplinary data science initiative. Zahn is a multipurpose cosmologist, advancing the understanding of the origin and evolution of structure in the Universe by applying a variety of statistical methods to complementary astrophysical observables. He connects data to theory through cutting edge numerical simulations of cosmological structure formation.

 Zahn frequently analyses terabyte surveys of the Cosmic Microwave Background, Galaxies, and Galaxy clusters for to generate insights into the workings of the cosmos. He has also been involved in studies exploring the redshifted 21 cm line as a new cosmological probe, and his research has acted as a driver for pushing a new generation of radio telescopes that might revolutionize studies of reionization, inflation, and dark energy/gravity theory.  By maintaining a data driven  approach,  Zahn has achieved several “firsts” and other important findings together with his working groups.