Events Archive

Turbulent Heating from Central AGN in Galaxy Clusters Brightest in X-rays

Mon, Nov 30, 2015 at 12:00 pm

131A Campbell Hall

Irina Zhuravleva (Stanford)

Cores of relaxed galaxy clusters are often disturbed by AGN activity as revealed by deep Chandra observations. Such perturbations reflect density and temperature fluctuations in the hot X-ray gas induced by shocks, subsonic gas motions, bubbles of relativistic plasma, etc. In my talk I will address the questions on the nature and energetics of the AGN-driven perturbations in the brightest …

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Characterizing Infrared Excess Sources in the Galactic Center with Adaptive Optics

Mon, Nov 23, 2015 at 12:00 pm

131A Campbell Hall

Breann Sitarski (UCLA)

The nature of G2, the cold emission-line object at the Galactic Center that survived its 2014 closest approach to the supermassive black hole at the center of our Galaxy, has been heatedly debated for the last several years. Its survival means that it most likely has a stellar core. Its large inferred size and cold temperature implies that it may be a black-hole driven binary merger. Using …

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The Multiwavelength Perspective on Gas, Dust and Star Formation in Nearby Galaxies

Thu, Nov 19, 2015 at 4:00 pm

131A Campbell Hall

Karin Sandstrom (UCSD)

The efficiency at which interstellar gas is converted into stars is one of the major factors governing the evolution and observable properties of galaxies at all redshifts.  In the Milky Way we can study the star formation process in great detail, but only over a limited range of environmental conditions.   We must move to nearby galaxies to expand this range.  Over the …

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Department Lunch Talk 11-19

Thu, Nov 19, 2015 at 12:30 pm

131A Campbell Hall

Kazumi Kashiyama, UCB
Mike Belyaev, UCB
Karin Sandstrom, UCSD [colloq. spkr.]

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.

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Towards an age for every star: calibrating the age-rotation relations

Wed, Nov 18, 2015 at 3:00 pm

131A Campbell Hall

Ruth Angus (Oxford)

In order to explore the evolution of planetary systems, we first need to improve the existing methods for inferring stellar ages. The age-rotation, or 'gyrochronology' relations have the potential to be an extremely powerful stellar dating method since only measurements of rotation period and mass (or mass proxy) are required to infer a star's age. However, data from the Kepler …

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Connecting CO Intensity Mapping to Molecular Gas and Star Formation in z > 2 Galaxies

Mon, Nov 16, 2015 at 3:00 pm

131A Campbell Hall

Tony Li (Stanford)

Intensity mapping, which images a single spectral line from unresolved galaxies across cosmological volumes, is a promising technique for probing the early universe. I will present predictions for the intensity map and power spectrum of the CO(1-0) line from z~2.4-2.8 galaxies, based on a parameterized model for the galaxy-halo connection, and then demonstrate the extent to which properties of …

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The Story of Strongly Lensed Jets and Cosmology

Mon, Nov 16, 2015 at 12:00 pm

131A Campbell Hall

Anna Barnacka (Harvard)

The most straightforward method of estimating the Hubble constant relies on time delays between mirage images of strongly lensed sources. It is a puzzle, then, that the values of H0 obtained with this method span a range from 50 to 100 km/s/Mpc. We investigate the complex structure of the sources as the underlying physical explanation of the wide spread in values of the Hubble constant based …

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21cm Cosmology: The End of the Beginning

Thu, Nov 12, 2015 at 4:00 pm

1 LeConte Hall

Aaron Parsons (UCB)

Since it was first proposed nearly two decades ago, measuring 21cm emission from neutral hydrogen in our early universe has tantalized us as a powerful probe of both cosmology and astrophysics.  While the science case for 21cm cosmology, particularly during the Epoch of Reionization, is well established, the technical path toward measuring this signal has been more problematic.  …

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Department Lunch 11-12

Thu, Nov 12, 2015 at 12:30 pm

131A Campbell Hall

Sedona Price (UCB)
Zaki Ali (UCB)
Aaron Parsons (UCB, [colloq. spkr.])

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.

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Beyond the CMB: The Effective Field Theory of Large Scale Structure

Tue, Nov 10, 2015 at 1:00 pm

131A Campbell Hall

Ashley Perko (Stanford)

The next hope to constrain cosmological parameters observationally is in surveys of the large scale structure (LSS) of the universe. LSS has the potential to rival the CMB in cosmological constraints because the number of modes scales like the volume, but the nonlinear clustering due to gravity makes it more difficult to extract primordial parameters. In order to take full advantage of the …

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Characterizing the polarization response of the ALMA primary beam

Mon, Nov 9, 2015 at 3:00 pm

131A Campbell Hall

Chat Hull (CfA Harvard)

Most observations of linear polarization with the SMA and CARMA include only on-axis polarization calibration. This has not posed much of a problem in the past, considering the sensitivity limits and the relatively large fields of view of the two arrays. However, the era of ALMA is upon us, and with it come both extremely sensitive observations and smaller fields of view. Consequently, we set …

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Core-Collapse Supernova Neutrinos and Explosions!

Mon, Nov 9, 2015 at 12:00 pm

131A Campbell Hall

Evan O'Connor (NCSU)

Core-collapse supernovae are some of the optically-brightest astrophysical phenomena in the modern universe. This is impressive, especially given that most of the energy released is not photons, but in neutrinos. The ultimate source of energy for core-collapse supernovae is gravity. It is released when the iron core of a massive stars becomes gravitationally unstable …

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Stellar Forensics with Explosions: Supernovae, Gamma-Ray Bursts, and their Environments

Thu, Nov 5, 2015 at 4:00 pm

1 LeConte Hall

Maryam Modjaz (NYU)

Nature's two magnificent explosions, long-duration gamma-ray bursts (GRBs) and stripped-envelope supernovae (SNe), are both products of collapsing massive stars. Yet, over the last 15 years, we have not determined the detailed make-up of the stellar progenitors of each kind of explosion, nor the conditions that lead to each kind of explosion in massive stripped …

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Department Lunch 11-5

Thu, Nov 5, 2015 at 12:30 pm

131A Campbell Hall

Ilian Roth (SSL)
Jing Luan (UCB)
Maryam Modjaz (NYU)

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.

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Using Protoplanetary Disks to Weigh the Youngest Stars and Constrain The Earliest Stages of Stellar Evolution

Wed, Nov 4, 2015 at 3:00 pm

131A Campbell Hall

Ian Czekala (CfA)

Mass is the fundamental property that determines the evolutionary path of a star. In particular, the masses of young stars are of great relevance to many astrophysical problems, including star and planet formation. We have developed a novel approach that combines spatially resolved sub-millimeter spectral line imaging and optical/near-infrared high resolution spectroscopy to derive the …

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