Seminars of possible interest to people in the Berkeley Cosmology Group 2002-2003

Please contact Joanne Cohn to add to this list, thanks!

July 2003:

July 7-11 , 2-4:30 pm daily
Large Scale Structure Minicourse
Organized by B. Gerke and M. White

May 2003:

May 2 (Friday), 12 noon
Manoj Kaplinghat, UCD
Inpa Lounge, LBL, room 50-5026
""Fundamental Physics with Future CMB Experiments"

May 2 (Friday), 12 noon
Mike Blanton, NYU
544 Campbell Hall
"Cosmology and Galaxy Clustering in the SDSS"

May 8 (Thursday), 12 noon
Kenji Kadota, UCB
349 LeConte Hall
"Conversions and Correlations of Curvature/Entropy Perturbations"
Inflationary scenarios involving multiple degrees of freedom are generic consequences of particle theory and the detailed analysis for time-dependent dynamics for cosmic perturbations beyond horizon scales is crucial for the comparison with CMB data. In particular, conversions and correlations of curvature/entropy perturbations recently drew much attention, and I will discuss such issues inherent in cosmological models involving multiple scalar field dynamics. After a brief discussion of the advantages/disadvantages of using inflation to produce observed CMB spectrum, I will discuss the mechanisms of conversions and correlations of curvature/entropy perturbations and how they can affect CMB parameters such as spectral index at small scales and tensor to scalar ratio.

May 21(Wed), 2:15-3:15 pm (LBL Cosmology Teach-In
Martin White, UCB
INPA room, 50-5026, LBL
"Simulating the Universe"
Note this is the first talk in a series of Wednesday cosmology talks this summer.

Apr. 2003:

April 14 (Monday), 12 noon (Monday theory lunch)
Francisco Prada, IAC
501 Campbell Hall
"Observing the dark matter density profile of isolated galaxies "

April 16 (Wednesday), 12 noon (TAC seminar)
Andrey Kravtsov, Chicago
501 Campbell Hall
"Dwarf Tales: Formation & Evolution of Dwarf Satellite Galaxies and their Halos "

Apr. 23 (Wednesday), 12 noon (12:10 really) (TAC seminar)
Joanne Cohn, UCB
501 Campbell Hall
"Image multiplicites from strongly lensing galaxies: a puzzle and a resolution"

Apr. 28 (Monday), 12 noon (12:10 really) Monday Lunch
Alison Coil, UCB
501 Campbell Hall
"First Results from the DEEP2 Galaxy Redshift Survey"

Apr. 30 (Wed), 12:30 pm (particle theory seminar)
Kenji Kadota, UCB
50-5026, LBNL
"Modular Cosmology and the CMB"

Mar. 2003:

Mar. 12 (Wednesday), 12 noon (TAC seminar)
Andrew Benson, Caltech
501 Campbell Hall
"Heating of Galaxy Disks by Dark Satellites "

March 13 (Thursday), 12 noon
SZ reading group
468 Birge

Mar. 20 (Thursday), 4:10 pm (Astronomy Colloquium)
Jason Prochaska, UCSC
1 LeConte Hall
"Star Formation, Metal Enrichment, and a Mystery at z~3 "

Mar. 27 (Thursday), 12:30 pm
Cosmology Lunch
501 Campbell Hall
We'll discuss recent results from meetings, most notably the Davis inflation meeting.

Feb. 2003:

Feb. 13(Thursday), 4:10 pm (Astronomy Colloquium
Ned Wright, UCLA
1 LeConte Hall
"MAPping the origin of the universe"

Feb. 14 (Friday), 12 noon (Astro Journal Club time)
Guinevere Kauffmann, MPA
544 Campbell Hall
"SDSS galaxy and AGN properties"

Feb. 17 (Monday), 12 noon (Monday Theory Lunch)
Simon White, MPA
501 Campbell Hall
"Cluster and galaxy halo simulations"

Feb. 19 (Wednesday), 12 noon (TAC seminar)
Rupert Croft, CMU
501 Campbell Hall
"Ionizing radiation fluctuations and large scale structure in the Lyman-alpha forest"

Feb. 20 (Thursday), 3 pm
Hsin-Chia Cheng, Harvard
448 Birge
"Really Natural Inflation"

Feb. 21 (Friday), 12 noon (Astro Journal Club time)
John Bahcall, IAS
544 Campbell Hall
"Does the fine structure constant depend upon cosmological epoch?"

Feb. 21 (Friday), 1 pm
Sunil Golwala, CIT
544 Campbell Hall
"Cosmological Science with the Sunyaev-Zeldovich Effect and Bolocam"
The Sunyaev-Zeldovich effect -- the scattering of the cosmic microwave background by hot electrons in galaxy clusters and other large-scale structure -- is beginning to open a new window for cosmological observations. SZ effect measurements will have an impact on our understanding of the global energy density of the universe as well as on large scale structure. New instruments coming online now and in the near future will revolutionize this field. One such instrument is Bolocam, a millimeter-wave camera being commissioned for use at the Caltech Submillimeter Observatory. We describe the instrument and present the current status of analysis of an initial blank-field SZ survey at 2.1 mm wavelength, as well as commenting on other Bolocam science topics and the more distant future for SZ instrumentation and surveys.

Feb. 24 (Monday), 4:30 pm Physics Colloquium
Bill Holzapfel, UCB
1 Le Conte Hall
"Imaging the Early Universe with ACBAR"
Primary anisotropies of the Cosmic Microwave Background (CMB) encode a wealth information about the early Universe. Recent degree-scale experiments have begun to exploit the potential of the CMB as a precision probe of cosmology with encouraging results. High-resolution images of the CMB can be used to provide improved constraints on cosmological parameters and study the growth of structure in the Universe. The Arcminute Cosmology Bolometer Array Receiver (ACBAR) is a powerful new instrument designed to image the CMB with resolution of 5 arcminutes. ACBAR was deployed to the South Pole in December 2000, and has recently produced the most sensitive images of the CMB of any experiment to date. I will discuss the construction and operation of the receiver, and present the key results from the first two years of observations.

Feb. 26 (Wednesday), 12 noon (TAC seminar)
Doug Finkbeiner, Princeton
501 Campbell Hall
"WMAP Observations of spinning dust in the Galaxy"

Feb. 27 (Thursday), 12 noon
SZ reading group
lounge next to 349 LeConte

December 2002:

Dec. 9 (Monday), 12 noon (Monday theory lunch)
Lev Pogosian (Imperial) and Phil Marshall(Cambridge)
501 Campbell Hall
"Signatures of primordial helical magnetic fields in the CMB/Joint Analysis of Cluster datasets"

Dec. 10 (Tuesday), 3 pm
Alice Shapley
544 Campbell Hall
"Detailed Astrophysical Properties of Lyman Break Galaxies and Their Impact on the Intergalactic Medium at z~3"
We present new results about z~3 Lyman Break Galaxies (LBGs) and their impact on the intergalactic medium (IGM). We place particular emphasis on what can be learned from LBG rest-frame UV spectra. Previously, the spectra of LBGs have been used primarily as redshift indicators for the purpose of describing large-scale properties such as clustering and luminosity functions. However, our knowledge of LBG UV spectral properties is now advancing along two complementary fronts. First, by using very high-quality spectra of a small sample of exceptionally bright objects, we derive detailed information about their interstellar abundance patterns, outflow kinematics and geometry. Second, by drawing from our database of $\sim 1000$ spectra, and constructing higher S/N composite spectra from galaxies grouped according to properties such as Lyman-alpha profile, kinematics, luminosity, and extinction, we show how the rest-frame UV spectroscopic properties systematically depend on other galaxy parameters. One of the basic properties indicated by LBG UV spectra is the large-scale outflow of interstellar material accelerated by the mechanical energy input from supernovae explosions. By comparing the large-scale distributions of LBGs, and intergalactic HI and metals, we show how these outflows may have a profound influence on the state of the IGM at z~3.

Dec. 11 (Wed), 12 noon (TAC seminar)
Lloyd Knox
UC Davis
501 Campbell Hall
"Applications of Secondary CMB Anisotropies"

November 2002:

Nov. 7 (Thursday), 4 pm (Astro Colloquium)
Matthew Colless
2 LeConte Hall
"The 2dF and 6dF Galaxy Redshift Surveys"
The 2dF Galaxy Redshift Survey was completed in April 2002 after measuring 221,000 galaxy redshifts. I will describe the survey observations and database, and present the main cosmological results that have emerged from the survey so far. Highlights include measurements of the mean mass density of the universe both from the galaxy power spectrum and from redshift-space distortions, an estimate of the baryon fraction from acoustic oscilllations in the power spectrum, an improved upper limit on the neutrino mass, and the first measurements of the galaxy bias parameter. By combining the 2dFGRS and CMB power spectra, strong new constraints have also been placed on the Hubble constant, the cosmological constant and equation of state of the dark energy.
The 6dF Galaxy Survey is currently observing all the objects with 2MASS magnitudes brighter than K=12.75 over the whole southern hemisphere with |b|10. As well as measuring redshifts for ~120,000 nearby galaxies, the survey is also measuring peculiar velocities for ~15,000 early-type galaxies within 15,000 km/s, and surveying a range of additional target samples with sources from surveys of QSOs and AGN, and all-sky surveys at X-ray, infrared and radio wavelengths. I will review the science goals of the survey and report on its status.

Nov 8 (Friday), 12 noon (Astro Journal Club time)
Joe Hennawi
544 Campbell Hall
"Mapping the Dark Matter: Mass Selected Galaxy Clusters from Weak Lensing"
The distortion of images of faint high-redshift background galaxies can be used to probe the intervening mass distribution. This weak gravitational lensing effect can be used to detect dark matter in clusters of galaxies, allowing one to effectively "image" and "weigh" these dark objects. In addition, if photometric redshifts of background source galaxies are available, mass tomography enables one to ascertain the cluster redshift. This opens up the possibility of mapping the 3-d locations of a mass selected sample of galaxy clusters from weak gravitational lensing alone. The efficacy and reliability of these techniques is investigated using a large ensemble of fast cosmological N-body simulations specifically tailored to investigate the statistics of lensing by clusters. Recent purported detections of baryon poor "dark clusters" are reviewed and interpreted. An Adaptive Matched Filtering scheme which combines tomography and matched filtering is introduced and proves superior to filtering techniques used in previous studies. The possibility of using mass selected cluster samples to probe cosmological parameters is discussed. Specifically, the redshift distribution of clusters is a sensitive probe of the equation of state parameter of the dark energy w, and is robust against the uncertain state of baryons in clusters.

Nov 18 (Monday), 12 noon (Monday theory lunch)
Bhuvnesh Jain
501 Campbell Hall

Nov 20 (Wed), 12 noon (TAC seminar)
Andy Taylor
501 Campbell Hall
"Mapping the Dark Matter in 2 and 3-D with Gravitational Lensing"
In the last few years considerable attention has been focused on the direct mapping of the Cosmological Dark Matter via Weak Gravitational Lensing and its implications for cosmology. I present the latest results from this analysis using the new COMBO17 dataset. These results are compared and combined with the latest results from the CMB and the 2dF. Finally I show how the lensing method can be extended to 3-D mapping of the Dark Matter distribution and the cosmological growth of structure.

Nov 25 (Monday), 4:30 pm (Physics Colloquium)
Chung-Pei Ma
1 LeConte Hall
"From the CMB to Dark Matter: A Boltzmann Approach to Modern Cosmology"

October, 2002:

Oct 10 (Thursday), 4 pm (Astro Colloquium)
Andrew Baker
2 LeConte Hall
"Dust and Gas in Galaxies at z > 2.5"

Oct 17 (Thursday), 4 pm (Astro Colloquium)
John Carlstrom
Chicago, CfCP
2 LeConte Hall
"Detection of Cosmic Microwave Background Polarization with DASI"

Oct 22 (Tuesday), 12 noon (TAC Seminar)
Steve Furlanetto
501 Campbell Hall
"Probing the State and Composition of the Intergalactic Medium"
Radiative and mechanical feedback from galaxies and quasars play a crucial role in determining the characteristics of the intergalactic medium (IGM), including its temperature, ionization state, and heavy element content. However, the extent and power of feedback remain uncertain, and observational probes of the IGM at a variety of redshifts are needed. I will describe several techniques to constrain feedback scenarios in the coming years. For example, observations of the 21 cm hyperfine transition of hydrogen in the neutral IGM at high redshifts allow us to probe its thermal state and the early radiation background. Studies of metal absorption lines at high redshift can also constrain the extent of heavy element pollution in the IGM. Finally, I will describe how observations of the environments of radio jets can probe the physics of relativistic outflows.

Oct 23 (Wednesday), 12:30 pm (INPA Seminar)
Patrick Greene
INPA Conference Room - Bldg. 50-5026 - LBNL
"Everpresent Lambda"
A variety of observations indicate that the universe is dominated by dark energy with negative pressure, one possibility for which is a cosmological constant. If the dark energy is a cosmological constant, a fundamental question is: Why has it become relevant at so late an epoch, making today the only time in the history of the universe at which the cosmological constant is of order the ambient density. We explore an answer to this question drawing on ideas from unimodular gravity, which predicts fluctuations in the cosmological constant, and causal set theory, which predicts the magnitude of these fluctuations. The resulting ansatz yields a fluctuating cosmological ``constant'' which is always of order the ambient density.

Oct 24 (Thursday), 4 pm (Astro Colloquium)
Dick Bond
2 LeConte Hall
"The Microwave Background and the Cosmic Web"

Oct 28 (Monday), 12 noon
Sidney Bludman
DESY and Penn
LBL 50-5026
"Bad News For Tracking Quintessence"
We review the phase dynamics of a flat universe now dominated by dark energy, parametrized by a slow-rolling scalar field (quintessence). The original motivation for quintessence had been to find a dark energy dynamics that makes the present Universe insensitive to initial conditions ("tracking quintessence"). Unfortunately, recent supernova and CMB observations show that the effective equation of state w_eff = P/rho < -0.85 consistent with 0. For an inverse power scalar field potential, this makes quintessence practically indistinguishable from a cosmological constant and tracking only for a narrow range of initial conditions. This rules out tracking quintessence and requires that any quintessence potential depart appreciably from scaling in the background dominated era, going back to the cosmological sound horizon.

Oct. 30 (Wednesday), 12 noon (TAC seminar)
Siang-Peng Oh
501 Campbell
"A History of Gas Cooling from the Dark Ages to the Present"

Oct. 31 (Thursday), 1pm
SZ reading group
501 campbell hall note place!

September 2002:

Sep. 23 (Monday), 12 noon (Monday theory lunch)
Risa Weschler
U. Michigan
501 Campbell Hall
"Halo mergers and semianalytic galaxy formation"

August, 2002:

Aug 13, Noon
SZ reading group
349 LeConte

Aug. 27, 12 noon (TAC Seminar)
Saleem Zaroubi
501 Campbell Hall
"The Thermal History of the IGM and the Epoch of Reionization"

Past Cosmology Seminars in 2001-2002 Academic Year

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