Events Archive

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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Subhalos in the real Universe: satellite galaxy-galaxy lensing

Tue, Nov 3, 2015 at 1:00 pm

131A Campbell Hall

Cristobal Sifon (Leiden)

I present galaxy-galaxy lensing measurements of the total masses of satellite galaxies in galaxy groups and clusters, obtained by combining high-quality imaging data with large spectroscopic galaxy catalogs. I focus on the overlap between the Kilo-Degree Survey (KiDS) and the Galaxy And Mass Assembly (GAMA) survey and present preliminary results on massive clusters from the Canadian Cluster …

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Collapse and Star Formation in Self-gravitating Turbulent Fluids

Mon, Nov 2, 2015 at 3:00 pm

131A Campbell Hall

Norm Murray (Toronto)

Observations of star forming regions in the Milky Way have established that stars form in large molecular clouds or GMCs. The spectral lines of these GMCs are usually interpreted as the signature of turbulent motion. The kinetic energy in the turbulence is similar to the gravitational binding energy of the GMC. Work over the last decade suggests that stars form in converging flows in this …

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Rotation and angular momentum transport in stars - hydrodynamic processes

Mon, Nov 2, 2015 at 12:00 pm

131A Campbell Hall

Andrea Caleo (Oxford)

The recent wealth of information on the internal rotation of the Sun (and other stars) has made the problem of understanding rotation profiles and angular momentum transport inside these structures prominent in stellar physics. I will review the observational data and explain which challenges are presented to the theorist. Among these is the problem of the spreading of the tachocline, the …

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Astrophysics of Molten Salt Breeder Reactors: Building a Nuclear Reactor Better than the Sun

Thu, Oct 29, 2015 at 4:00 pm

1 LeConte Hall

Frank Shu (UCSD)

Climate change is real, here, and potentially catastrophic in its effect. We argue that the scale of the transformation needed to mitigate climate change requires breakthroughs in current technologies, most importantly, in new forms of fission reactors that are:   (1) safe in their inherent design, (2) sustainable in terms of meeting future energy demand for several centuries as …

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Department Lunch Talk 10-29

Thu, Oct 29, 2015 at 12:30 pm

131A Campbell Hall

Jonathan Seising (UCSC)
Pete Williams (CfA)
Frank Shu (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. Continue reading for this week's talk titles.

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