Events Archive

How Halo Concentration Impacts Subhalo Abundance and the Galaxy-halo Connection

Tue, Oct 13, 2015 at 1:00 pm

131A Campbell Hall

Yao-Yuan Mao (Stanford)

The existence of dark matter substructures is one of the most distinct predictions of the cold dark matter model, and the relation between dark matter substructures and satellite galaxies is one of the most critical questions about galaxy formation. We address some aspects of these theoretical questions with new suites of cosmological simulations and zoom-in …

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A CPU/GPU/FGPA telescope upgrade for Fast Radio Burst searching

Tue, Oct 13, 2015 at 12:00 pm

121 Campbell Hall

Matthew Bailes (Swinburne University)

Fast Radio Bursts (FRBs) are examples of dispersed radio pulses with such large sweeps in time that they appear to come from cosmological distances. Swinburne has provided a new custom 250 Tflop GPU cluster for the 18,000 m^2 Molonglo Observatory Synthesis Telescope to find more FRBs. This upgrade combines FGPAs, CPUs and GPUs to produce fan beams that can be searched in …

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Revealing X_CO and the CIB: globally modelling dust and gas in the Milky Way

Mon, Oct 12, 2015 at 3:00 pm

131A Campbell Hall

Daniel Lenz (Bonn)

The IRAS discovery of infrared cirrus clouds was the starting point of correlation studies of neutral atomic hydrogen and dust far-infrared emission. These yield important insights into the gas and dust physics, the accretion history of the Milky Way, the X_CO factor, and the distribution of the CO-dark molecular gas. So far, full-sky analyses were limited by the angular resolution of the HI …

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Planet Hunting with ALMA Observations of Molecular Emission

Mon, Oct 12, 2015 at 12:00 pm

131A Campbell Hall

Ilse Cleeves (CfA Harvard)

During the initial phases of planet-formation, young, self-luminous gas giants embedded in cold molecular disks can directly heat their local environment. The accretion luminosity from the planet can sublimate ices in the immediate vicinity that are otherwise fully frozen-out onto dust grains, creating a unique gas-phase signature. We have modeled the 3D chemical structure induced by the …

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Globular Clusters, Halo Stars and Galaxy Assembly

Thu, Oct 8, 2015 at 4:00 pm

1 LeConte

Jean Brodie (UCSC)

A variety of evidence suggests that metal rich globular clusters (GCs) trace the build-up of galaxy bulges, while metal poor GCs trace the build up of their halos. Wide field observations of galaxies are critically important for testing the currently favored two-phase paradigm for galaxy formation, because many signatures of galaxy assembly processes are only revealed at large radius.  …

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Department Lunch Talk 10-8

Thu, Oct 8, 2015 at 12:30 pm

131A Campbell Hall

Andrew Simieon (UCB)
David Jones (JHU)
Jean Brodie (UCSC)

The Department Lunch Talk series is a weekly event that features three 20 minute talks presented mainly by local scientists of any level to present their work to a broad spectrum of the department and usually includes one short talk by the astronomy colloquium speaker of the day. Subjects can include personal scientific research, reporting on other work appearing in journals, education and public outreach efforts, science policy, and professional development issues. Continue reading for this week's talk titles.

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CIPS Seminar 10-7

Wed, Oct 7, 2015 at 3:00 pm

131A Campbell Hall

Gérard Massacrier (CRAL, Lyon)
Shuai Zhang (UC Berkeley)

This weeks CIPS Seminar will feature two speakers (please continuing reading for complete abstracts and titles).

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Testing Gravity using Galaxy Redshift Surveys and CMB

Tue, Oct 6, 2015 at 1:00 pm

131A Campbell Hall

Shadab Alam, CMU

The Redshift Space Distortions (RSD) in galaxy redshift surveys can probe the local dynamics at a given epoch of galaxy. I will discuss how redshift can help us learn the local dynamics and hence measure the nature of gravity at the epoch of the galaxy. I will show results from our recent analysis of SDSS-III high redshift sample (CMASS). I will then talk about combining similar RSD …

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The Zen of Galaxies

Mon, Oct 5, 2015 at 12:00 pm

131A Campbell Hall

John Forbes (UCSC)

Over the past decade a quiet revolution has taken place in our picture of galaxy evolution. Rather than evolving through violent mergers, galaxies live quiet lives on narrow scaling relations. This is explained elegantly by the so-called "equilibrium model" of galaxy formation. I will present a simple extension to this model that can explain the finite scatter observed in …

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Reverberation Mapping as a Probe of Black hole Masses and AGN Structure: New Results from Intensive Monitoring Campaigns

Thu, Oct 1, 2015 at 4:00 pm

1 LeConte Hall

Aaron Barth (UC Irvine)

The method of reverberation mapping uses the time delay between continuum and emission-line variations in active galactic nuclei to probe the structure of the broad-line region and to derive estimates of black hole masses. Reverberation mapping results provide a fundamental low-redshift calibration for the methods used to trace the cosmological evolution of supermassive black holes. I will …

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Department Lunch Talk 10-1

Thu, Oct 1, 2015 at 12:30 pm

131A Campbell Hall

Francois Foucart (UCB)
Jeffrey Fung (UCB)
Aaron Barth (UCI)

Francois Foucart (UCB) - "Gravitational waves and electromagnetic signals from neutron star mergers" Jeffrey Fung (UCB) - "3D Disk-Planet Interaction using GPU Computing" Aaron Barth (UCI [colloq. spkr.],) - "ALMA observations of molecular gas disks in early-type galaxies".

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Giant Planet Formation and Snowlines in Protoplanetary Disks

Wed, Sep 30, 2015 at 3:00 pm

131A Campbell Hall

Ana-Maria Piso (Harvard)

The composition of planets is determined by and tightly linked to the composition of the protoplanetary disk in which they form. In the first part of my talk, I will discuss giant planet formation through core accretion. Specifically, I will show how the minimum core mass required to form a giant planet during the lifetime of the protoplanetary disk depends on the location in the disk, the …

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The Hydrodynamics of Common Envelope Episodes and the Formation of Close Neutron Star Binaries

Mon, Sep 28, 2015 at 12:00 pm

131A Campbell Hall

Morgan Macleod (UCSC)

A dynamic and crucial phase in the evolution of a binary star system comes when one star engulfs its companion in a shared gaseous envelope. The two stellar cores spiral tighter in response to drag forces. Eventually, they may deposit enough energy and momentum to expel the envelope, leaving behind a binary transformed by orbital tightening and mass accretion. This talk explores the …

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New Constraints on Cosmic Reionization from Planck and Hubble Space Telescope

Thu, Sep 24, 2015 at 4:00 pm

1 LeConte Hall

Brant Robertson (UCSC)

Understanding cosmic reionization requires the identification and characterization of early sources of hydrogen-ionizing photons. The 2012 Hubble Ultra Deep Field (UDF12) campaign acquired the deepest blank-field infrared images with the Wide Field Camera 3 aboard Hubble Space Telescope and, for the first time, systematically explored the galaxy population deep into the era when cosmic …

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Department Lunch Talk 9-24

Thu, Sep 24, 2015 at 12:30 pm

131A Campbell Hall

Dick McCray (UCB) - "Mapping the reverse shock in SN1987A" Vikram Ravi (Caltech) - "Pulsar timing limit on gravitational waves necessitates re-think of binary supermassive black hole evolution" Brant Robertson (UCSC [colloq. spkr.]) - “A New Model for Understanding Supersonic Turbulence”.

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