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seminars:2015

2015-12-23

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<noinclude>== Seminars From 2015 - 2016 ==

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{{SeminarsHeaders|Date=09/20/2015|Title=Summer 2015}}

{{Seminars

|Note = Special Astro Seminar @ 4:00 - SERF 383 

|Date = 06/24/2015

|Speaker = <big><big>Douglas Finkbeiner</big></big>

|ShortName =

|Position = Professor of Astronomy and of Physics, Department of Physics

|Institution = Harvard University

|Url = https://www.physics.harvard.edu/people/facpages/finkbeiner

|Recorded =

|Host = Arnold

|Title = "Mapping the ISM in 3 dimensions with Pan-STARRS1 and 2MASS"

|Abstract = 2D emission-based maps have been used for decades to estimate the reddening and emission from interstellar dust, with applications from CMB foregrounds to surveys of large-scale structure. For studies within the Milky Way, however, the third dimension is required. I will present the status of our work on a 3D dust map based on Pan-STARRS1 and 2MASS over 3/4 of the sky, assess its significance compared to other dust maps, and say how we plan to approach the next step: R_V.

}}

{{SeminarsHeaders|Date=12/02/2015|Title=Fall 2015}}

{{Seminars

|Note =

|Date = 09/30/2015

|Speaker = <big><big>Yoel Rephaeli</big></big>

|ShortName =

|Position = Research Scientist -and- Professor, School of Physics & Astronomy

|Institution = UCSD-CASS -and- Tel Aviv University, respectively

|Url = http://casswww.ucsd.edu/index.php/faculty:Yrephaeli

|Url2 = https://english.tau.ac.il/profile/yoelr TAU

|Recorded =

|Host = Keating

|Title = "Energetic Particles & Their Radiative Yields in Clusters"

|Abstract = The galaxy population in a rich cluster includes many star-forming and radio galaxies. Energetic electrons and protons diffusing out of these galaxies traverse the magnetized intracluster (IC) gas and interact with ambient radiation fields, emitting in the wide range from radio to gamma ray. I will present results of detailed modeling of IC spectro-spatial distributions of galactic energetic electrons and protons and their radiative yields. Comparison of results of our calculations with radio 'halo' measurements, and upper

limits on X-ray and gamma ray emission, suggests that galactic energetic electrons and protons can account for the range of observed IC non-thermal phenomena, weakening the need to invoke efficient particle (re)acceleration outside galaxies.

}}

{{Seminars

|Note =

|Date = 10/07/2015

|Speaker = <big><big>Abigail Crites</big></big>

|ShortName =

|Position = Keck Postdoc Fellow

|Institution = Caltech

|Url = http://www.kiss.caltech.edu/people/postdocs/abigail-crites.html

|Recorded =

|Host = Keating

|Title = "Probing the Epoch of Reionization with the TIME-Pilot [CII] Intensity Mapping Experiment"

|Abstract = The epoch of reionization (EoR) is still a largely unknown period in the history of our universe and is an exciting frontier for scientific discovery. The Tomographic Ionized Carbon Intensity Mapping Experiment (TIME-Pilot) is a new millimeter-wavelength imaging spectrometer being designed to probe the EoR. This novel cryogenic instrument is a pathfinder for a new technique for studying the EoR through intensity mapping of the 157.7 um ionized carbon ([CII]) emission line. Specifically it is designed to detect [CII] clustering fluctuations and test the predicted [CII] amplitudes of faint emission from the earliest dwarf galaxies. The TIME-Pilot instrument will be sensitive to a wavelength range of ~200 - 300 GHz with R = 100, which will allow us to measure the redshifted 157.7 um [CII] line from z of 5 to 9, key redshifts for probing the EoR. It will also robustly detect CO clustering at low z (~1-3). [CII] intensity mapping offers a unique way to measure faint sources, which will be difficult to detect individually with JWST and ALMA. This method is also complimentary to other intensity mapping experiments such as 21-cm instruments that measure neutral matter rather than an ionized medium during the EoR. Measurements from TIME-Pilot will test the viability of the [CII] intensity mapping technique and a detection of the [CII] signal would set a strong foundation for building more sensitive line intensity mapping instruments for both ground- and space-based platforms.

}}

{{Seminars

|Note =

|Date = 10/14/2015

|Speaker = <big><big>Rachel Bezanson</big></big>

|ShortName =

|Position = Hubble Postdoc Fellow

|Institution = University of Arizona

|Url = https://lavinia.as.arizona.edu/~rbezanson/

|Recorded =

|Host = Sandstrom

|Title = "The Surprisingly Complex Lives of Massive Galaxies and the Stability of the Mass Fundamental Plane"

|Abstract = Once thought to be relics of a much earlier epoch, the most massive local galaxies are red and dead ellipticals, with little ongoing star formation or organized rotation. In the last decade, observations of their assumed progenitors have demonstrated that the evolutionary histories of massive galaxies have been far from static. Instead, billions of years ago, massive galaxies were more compact and morphologically different, possibly with more disk-like structures and many were still forming stars. The details of this observed evolution can place constraints on the physical processes that have driven massive galaxy evolution through cosmic time. I will discuss recent observational studies of the structural and dynamical properties of massive high-redshift galaxies. Specifically, I will demonstrate that in spite of their dramatic structural evolution, the mass fundamental plane, or the empirical relation between dynamics, sizes, stellar mass surface density of massive galaxies, has been in place since z~2. This relation appears to hold for massive galaxies of all types, not just red, dead ellipticals. Therefore, this scaling relation is an ideal tool to follow the evolution of galaxy populations through cosmic time. Finally, I will describe two ongoing spectroscopic surveys, CHOMP and LEGA-C, that will probe massive galaxy evolution since z~1.

}}

{{Seminars

|Note =

|Date = 10/21/2015

|Speaker = <big><big>Matthew Mewes</big></big>

|ShortName =

|Position = Assistant Professor, Physics Department

|Institution = Cal Poly, San Luis Obispo

|Url = http://www.physics.calpoly.edu/faculty/matthew-mewes

|Recorded =

|Host = Keating

|Title = "Breaking Relativity: The Why and How of Lorentz Violation"

|Abstract = Lorentz invariance lies at the foundations of all known physics. However, attempts to formulate an ultimate theory of everything suggest that Lorentz invariance may be slightly broken. This idea has led to numerous searches for Lorentz violation, ranging from modern versions of the classic Michelson-Morley experiment to tests involving the orbit of the Moon. The current best tests of Lorentz invariance are those that search for tiny defects in the propagation of light that has traveled cosmological distances. Astrophysical observations are probing nature at the very limits of our understanding and may help uncover some of the Universe's biggest secrets.

}}

{{Seminars

|Note =

|Date = 10/28/2015

|Speaker = <big><big>Courtney Dressing</big></big>

|ShortName =

|Position = Sagan Postdoc Fellow

|Institution = Caltech

|Url = https://www.gps.caltech.edu/content/courtney-d-dressing

|Recorded =

|Host = Konopacky

|Title = "The Frequency and Composition of Small Exoplanets"

|Abstract = Over the past twenty years, ground- and space-based investigations have revealed that our galaxy is teeming with planetary systems and that Earth-sized planets are common. I will focus on the results of the NASA Kepler mission and describe two investigations of the frequency and composition of small planets. First, we analyzed Kepler observations of small stars and measured a cumulative planet occurrence rate of 2.45 +/- 0.22 planets per small star with periods of 0.5-200 days and planet radii of 1-4 Earth radii. Within a conservative habitable zone based on the moist greenhouse inner limit and maximum greenhouse outer limit, we estimated an occurrence rate of 0.15 (+0.18/-0.06) Earth-size planets and 0.09 (+0.10/-0.04) super-Earths per small star habitable zone. Second, we explored the compositional diversity of small planets by using the HARPS-N spectrograph on the Telescopio Nazionale Galileo to measure the masses of transiting planets. Concentrating on the set of small planets with well-constrained masses and radii, we found that all dense exoplanets with masses of approximately 1-6 Earth masses are consistent with the same fixed ratio of iron to rock as the Earth and Venus. Future measurements of the masses and radii of a larger sample of planets receiving a wider range of stellar insolations will reveal whether the fixed compositional model found for these highly-irradiated dense exoplanets extends to the full population of low-mass planets.

}}

{{Seminars

|Note =

|Date = 11/04/2015

|Speaker = <big><big>Coral Wheeler</big></big>

|ShortName =

|Position = Graduate Student

|Institution = UC Irvine

|Url = http://localgroup.ps.uci.edu/coral/

|Recorded =

|Host = Keres

|Title = "Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites"

|Abstract = If LCDM is correct, then all dark matter halos hosting galaxies, from those hosting dwarfs to those hosting giant clusters, are filled with abundant substructure down to very low mass scales (<< 10^9 Msun). Specifically, even the dark matter halos of Local Group field dwarfs should be filled with subhalos, many of which should be fairly massive (~ 10^8 Msun), and thus are potential targets for hosting small (ultrafaint) galaxies. Here we make predictions for the existence of ultrafaint satellites of dwarf galaxies using the highest resolution cosmological dwarf simulations yet run (mgas~ 250 Msun). We simulate four halos — two each at the mass of classical dwarf galaxies (Mvir ~10^10 Msun) and ultrafaint galaxies (Mvir ~ 10^9 Msun) — down to z=0 using the GIZMO (Hopkins 2014) code. This code relies on state-of-the-art MFM hydrodynamics and implements the FIRE (Feedback in Realistic Environments) recipes (Hopkins et al. 2014) for converting gas into stars and capturing the energy fed back from those stars into the surrounding medium. We predict that ultrafaint galaxies (M* ~ 3,000 Msun) should exist as satellites around more massive dwarf galaxies (M* ~ 10^6 Msun) in the Local Group. These tiny satellites, as well as the two isolated ultrafaints, have uniformly ancient stellar population (> 10 Gyr) owing to reionization-related quenching. The more massive systems, in contrast, all have late-time star formation. Our results suggest that Mhalo ~ 5 x10^9 Msun is a probable dividing line between halos hosting reionization "fossils" and those hosting dwarfs that can continue to form stars in isolation after reionization. Importantly, we show that the extended ~50 kpc regions around Local Group “field” dwarfs may provide efficient search locations for discovering new ultrafaint dwarf galaxies, and discuss the prospects for their discovery in light of the new generation of large surveys and giant telescopes. If these tiny satellites are observed, this would provide evidence that dark matter substructure is truly hierarchical, as predicted in the standard paradigm.

}}

{{Seminars

|Note = No Seminar Today (UCSD closed for Veteran's Day holiday) 

|Date = 11/11/2015

|Speaker =

|ShortName =

|Position =

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}}

{{Seminars

|Note =

|Date = 11/18/15

|Speaker = <big><big>Kenneth Nollett</big></big>

|ShortName =

|Position = Assistant Professor, Department of Physics

|Institution = SDSU

|Url = http://www.physics.sdsu.edu/knollett/

|Recorded =

|Host = Fuller

|Title = "The new era of percent-level nuclear rates for astrophysics"

|Abstract = Astrophysical models of hot environments require nuclear rates as inputs, and these rates are a challenge for both theory and experiment to determine. Nuclear theory has traditionally not provided astrophysics with predictive tools of high precision, but rather with a set of approximate tools for fitting and interpolating the data emerging from nuclear laboratories. However, at least for the light nuclei important in the Sun, the big bang, and neutrino-driven winds, the situation is shifting. Experimental precision has improved in recent years, driven by improved techniques and by the need for higher precision in these astrophysical environments. Nuclear theory, too, is undergoing a revolution in methods. There are new opportunities to make its traditional task of data-fitting more systematic. However, the most important development is the arrival of first-principles models of nuclei as collections of realistically-interacting neutrons and protons. Theory is now providing predictions that are competitive in precision with laboratory data and arguably more useful for astrophysical calculations. I will provide examples of these developments and discuss prospects for the near future, emphasizing my own work on first-principles models and on applying methods from quantum field theory to make nuclear data fitting more systematic.

}}

{{Seminars

|Note = No Seminar Today (due to Thanksgiving holiday) 

|Date = 11/25/2015

|Speaker =

|ShortName =

|Position =

|Institution =

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{{Seminars

|Note =

|Date = 12/02/2015

|Speaker = <big><big>Mansi Kasliwal</big></big>

|ShortName =

|Position = Assistant Professor of Astronomy

|Institution = Caltech

|Url = https://www.pma.caltech.edu/content/mansi-m-kasliwal

|Recorded =

|Host = Wright

|Title = “See the Sound: In Search of the Electromagnetic Counterparts to Gravitational Waves”

|Abstract = The era of advanced gravitational wave (GW) interferometers has just begun. Hearing neutron star mergers may soon even be routine. Seeing the electromagnetic (EM) counterparts would enable measurement of basic astrophysical properties such as the luminosity, energetics, redshift and host galaxy environment of strong-field gravity events. Furthermore, it would serve as a litmus test for whether or not these mergers are indeed the long sought site of r-process nucleosynthesis (and produce half the elements heavier than iron). However, the challenge is unambiguously identifying the predicted faint, fast and possibly red counterpart in the coarse GW localizations. I present an ongoing Caltech EM-GW search motivated by end-to-end simulations. I also present the rapidly growing inventory of optical and infrared transients in the local universe that are fainter, faster and rarer than supernovae. New classes of transients have bridged the luminosity gap between novae and supernovae and represent missing pieces in our understanding of the fate of massive stars and the evolution of compact binaries. The next frontier in gap transients is the discovery of an EM-GW merger. The surge of EM-GW excitement may literally be dubbed the 21st century gold rush.

}}

{{Seminars

|Note = NOTE: Today's seminar will be held in SERF 329 

|Date = 12/09/2015

|Speaker = <big><big>James Guillochon</big></big>

|ShortName =

|Position = Einstein Postdoc Fellow

|Institution = Harvard-Smithsonian CfA

|Url = http://astrocrash.net/

|Recorded =

|Host = Fuller/Wright

|Title = "Tidal disruptions of stars by supermassive black holes: dynamics, light, and relics"

|Abstract = Most supermassive black holes in the local universe lie dormant, with only one in a hundred accreting at their Eddington limits. Aside from this active minority, and the black holes in nearby galaxies that we can observe to influence the dynamics of stars and gas, most remain difficult to study. Tidal disruptions of stars by supermassive black holes give these dormant black holes a chance to be seen once every ~10,000 years, and each tidal disruption brings along with it a host of observable signatures that can be studied from gigaparsecs away, from the moment of the disruption to millennia after a disruption has occurred. In my talk I will present work I have done on tidal disruptions of stars, and describe their dynamics, observational signatures from real-time monitoring, and relics of disruption that may exist in plain sight.

}}

{{SeminarsHeaders|Date=03/09/2016|Title=Winter 2016}}

{{Seminars

|Note =

|Date = 01/06/2016

|Speaker = <big><big>Norm Murray</big></big>

|ShortName =

|Position = Professor

|Institution = University of Toronto

|Url = http://www.cita.utoronto.ca/~murray/

|Recorded =

|Host = Keres

|Title = "Collapse and Star Formation in Self-gravitating Turbulent Fluids"

|Abstract = 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, including research done in Heidelberg, suggests that stars form in converging flows in this turbulence. I will describe recent analytic and numerical work that has resulted in a detailed description of the evolution of such converging flows. I will show that the flows set up density structures that do not vary with time; the converging gas flows through fixed run of density onto a central star or star cluster. The collapse drives turbulent motions, resulting in deviations from Larson's Law (the size-linewidth relation), and slowing the inflow velocity below the free-fall rate. However, the infall velocity is proportional to the square root of stellar mass, resulting in a mass accretion rate that grows linearly with time.

}}

{{Seminars

|Note = Special Astro-Plasma-CER Seminar Today @ Noon in SERF 383 (Pizza provided)

|Date = 01/8/2016

|Speaker = <big><big>Alexander Tchekhovskoy</big></big>

|ShortName =

|Position = Einstein Postdoc Fellow, Department of Astronomy

|Institution = UC Berkeley

|Url = http://astro.berkeley.edu/researcher-profile/2358131-alexander-tchekhovskoy

|Recorded =

|Host = Diamond

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 01/13/2016

|Speaker = <big><big>Elisa Quintana</big></big>

|ShortName =

|Position = Research Scientist

|Institution = SETI Institute

|Url = http://www.seti.org/users/elisa-quintana

|Recorded =

|Host = Burgasser

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note = Special Astro Seminar Today @ 2:00 in SERF 383

|Date = 01/20/2016

|Speaker = <big><big> Yacine Ali-Haimoud</big></big>

|ShortName =

|Position = Postdoc Fellow, Department of Physics & Astronomy

|Institution = Johns Hopkins University

|Url = http://physics-astronomy.jhu.edu/directory/yacine-ali-haimoud/

|Recorded =

|Host = Keating

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 01/20/2016

|Speaker = <big><big>Felix Fuerst</big></big>

|ShortName =

|Position = Postdoc in Physics

|Institution = Caltech

|Url = https://pma.caltech.edu/content/felix-s-fuerst

|Recorded =

|Host = Rothschild

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note = Special Astro Seminar Today @ Noon in SERF 383 (Pizza provided)

|Date = 01/22/2016

|Speaker = <big><big>Kate Rubin</big></big>

|ShortName =

|Position = Clay Postdoc Fellow

|Institution = Harvard-Smithsonian CfA

|Url = http://www.mpia.de/~rubin/Homepage/Welcome.html

|Recorded =

|Host = Keating?

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 01/27/2016

|Speaker = <big><big>Andrew Wetzel</big></big>

|ShortName =

|Position = Researcher

|Institution = Caltech

|Url = http://www.tapir.caltech.edu/~awetzel/homepage/About_Me.html

|Recorded =

|Host = Keres

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 02/03/2016

|Speaker = <big><big>Tuan Do</big></big>

|ShortName =

|Position = Researcher

|Institution = UCLA

|Url = http://www.astro.ucla.edu/~tdo/

|Recorded =

|Host = Konopacky

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 02/10/2016

|Speaker = <big><big>Geoffrey Lovelace</big></big>

|ShortName =

|Position = Professor

|Institution = Cal State Fullerton

|Url = http://physics.fullerton.edu/gwpac/people/faculty-staff/item/geoffrey-lovelace

|Recorded =

|Host = Keating

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 02/17/2016

|Speaker = <big><big>Brian O'Shea</big></big>

|ShortName =

|Position = Professor

|Institution = Michigan State University

|Url = http://www.pa.msu.edu/~oshea/

|Recorded =

|Host = Norman

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 02/24/2016

|Speaker = <big><big>Vivian U</big></big>

|ShortName =

|Position = UC Chancellor's Postdoctoral Fellow

|Institution = UC Riverside

|Url = http://astro.ucr.edu/members/postdocs/vivianu/

|Recorded =

|Host = Sandstrom

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 03/02/2016

|Speaker = <big><big>Aaron Barth</big></big>

|ShortName =

|Position = Professor

|Institution = UC Irvine

|Url = http://sites.uci.edu/barth/

|Recorded =

|Host = Wright

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 03/09/2016

|Speaker = <big><big>Alan Weinstein</big></big>

|ShortName =

|Position = Professor

|Institution = Caltech

|Url = https://pma.caltech.edu/content/alan-j-weinstein

|Recorded =

|Host = Fuller

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note = No Seminar Today (Kyoto Prize Lecture @ 3:30 PM - Price Center) 

|Date = 03/16/2016

|Speaker = <big><big>Michel Mayor,</big></big> speaker/recipient

|ShortName =

|Position = Professor of Astronomy

|Institution = University of Geneva

|Url = https://www.kyoceradocumentsolutions.eu/index/about/kyocera_press_area/press_details.L3ByaW50ZXJfbXVsdGlmdW5jdGlvbmFscy9uZXdzLzIwMTUva3lvdG9fcHJpemVfMjAxNV8~.html

|Recorded =

|Host = Wright?

|Title =

|Abstract =

}}

{{SeminarsHeaders|Date=06/10/2016|Title=Spring 2016}}

{{Seminars

|Note =

|Date = 03/30/2016

|Speaker = <big><big>Brooke Simmons</big></big>

|ShortName =

|Position = Einstein Postdoc Fellow

|Institution = UCSD-CASS

|Url = https://cass.ucsd.edu/index.php/postdocs:Bsimmons

|Recorded =

|Host = Coil

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 04/06/2016

|Speaker = <big><big>Jerry Sellwood</big></big>

|ShortName =

|Position = Professor

|Institution = Rutgers

|Url = http://www.physics.rutgers.edu/~sellwood/

|Recorded =

|Host = Keres

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note =

|Date = 05/18/2016

|Speaker = <big><big>Aomawa Shields</big></big>

|ShortName =

|Position = NSF/TED Postdoc Fellow

|Institution = UCLA

|Url = http://www.astro.ucla.edu/~ashields/

|Recorded =

|Host = Burgasser/Konopacky

|Title = Title TBA

|Abstract = Abstract TBA

}}

{{Seminars

|Note = Hans E. Suess Memorial Lecture @ 4:00 

in lieu of today's Astro Seminar 

|Date = 05/25/2016

|Speaker = <big><big>Karin Oberg</big></big>

|ShortName =

|Position = Professor

|Institution = Harvard

|Url = https://www.cfa.harvard.edu/~koberg/Home.html

|Recorded =

|Host = Thiemens/Wright

|Title =

|Abstract =

}}

{{Seminars

|Note =

|Date = 06/01/2016

|Speaker = <big><big>Ryan Cooke</big></big>

|ShortName =

|Position = Hubble Postdoc

|Institution = UC Santa Cruz

|Url = http://www.ucolick.org/~rcooke/Ryan/Home.html

|Recorded =

|Host = Fuller

|Title = Title TBA

|Abstract = Abstract TBA

}}