YCAA Logo
YCAA Logo
The Crab Nebula in Blue and White Credit & Copyright: Jay Gallagher (U. Wisc.),
The Crab Nebula in Blue and White Credit & Copyright: Jay Gallagher (U. Wisc.),
Interstellar Dust-Bunnies of NGC 891 Credit: C. Howk & B. Savage (Wisconsin);
Interstellar Dust-Bunnies of NGC 891 Credit: C. Howk & B. Savage (Wisconsin);
Hubble. Credit: R. Williams (STScI), the Hubble Deep Field-South Team, and NASA
Hubble. Credit: R. Williams (STScI), the Hubble Deep Field-South Team, and NASA
Dumbell. Credit & (c): Michael Pierce (Indiana U.) et al., WIYN, AURA, NOAO, NSF
Dumbell. Credit & (c): Michael Pierce (Indiana U.) et al., WIYN, AURA, NOAO, NSF
Abell 39.    (c): George Jacoby (WIYN Obs.) et al., WIYN, AURA, NOAO, NSF
Abell 39. (c): George Jacoby (WIYN Obs.) et al., WIYN, AURA, NOAO, NSF
Bubbling. Credit: Jeffrey Kenney (Yale) et al., WFPC2, HST NASA
Bubbling. Credit: Jeffrey Kenney (Yale) et al., WFPC2, HST NASA

Mailing Address

Yale Center for Astronomy and Astrophysics
Physics Department
P.O. Box 208120
New Haven, CT 06520-8120

Campus Address

260 Whitney Avenue
454 J.W. Gibbs Laboratory

Telephone: (203) 432-3392

Fax: 203) 432-3824

E-mail: ycaa@yale.edu

Upcoming YCAA Seminars

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Updated: 5 hours 18 min ago

NPA Seminar: Krishna Kumar, Stony Brook University, "Electrons are not Ambidextrous: New Insights from a Subatomic Matter of Fact" - Thu, March 5, 2015

5 hours 18 min ago
When: Thursday, March 5, 2015 3:30 PM - 4:30 PM
Where:
   EAL 108 Conference Room (EAL108)
   270 Whitney Avenue, New Haven 06520
   (Location is wheelchair accessible)
   Enter building through WNSL-West (268 Whitney). All other external doors are locked.
Tags: astrophysics, nuclear_physics, science, seminar, talk

Speaker/Performer: Krishna Kumar, Stony Brook University

Description: Fixed target experiments at accelerators have been used since the dawn of modern physics to study the structure of matter. The most precise and detailed information on fundamental forces and the size and shapes of atomic nuclei and their constituents have come from electron scattering experiments. Over the past forty years, significant new discoveries about subatomic matter have been made by employing longitudinally polarized electron beams. There is a tiny difference (of order parts per million) between the probabilities for scattering left- and right-handed electrons off subatomic matter (this constitutes a failure of parity symmetry), which can be used to gain unique new insights into neutron distributions in nuclei, the nature of constituent quarks and sea quarks in nucleons, and to search for new interactions that might have shaped the evolution of the early universe. I will describe the experimental technique to measure the tiny left-right parity-violating asymmetries in electron scattering, report on the nuclear and particle physics implications of recent measurements, and motivate the need for new and more precise experiments.

Open To: Yale Community Only
Contact Information:
   Megan Connors
   
   megan.connors@yale.edu
   

YCAA Seminar, Cora Dvorkin, CfA, Harvard Title: "Deciphering the Early Universe" - Tue, March 3, 2015

5 hours 18 min ago
When: Tuesday, March 3, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 Bass Auditorium
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm at the 3rd flr. hallway outside the auditorium
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Hubble Fellow Cora Dvorkin

Description: Abstract:Cosmological observations have provided us with answers to age-old questions, involving the age, geometry, and composition of the universe. However, there are profound questions that still remain unanswered.
The origin of the small anisotropies that later grew into the stars and galaxies that we see today is still unknown. However, the nature of the anisotropies in the Cosmic Microwave Background (CMB) provides strong evidence that they were generated long before the CMB radiation had its last interaction with ordinary matter.
In the first part of this talk, I will explain how we can use measurements of the CMB, which was last scattered when the universe was 380,000 years old, to reconstruct the detailed physics of much earlier epochs, when the universe was only a tiny fraction of a second old.
In the last part of this talk, I will present the results of a joint analysis from BICEP2/Keck Array and Planck measurements of CMB polarization at different frequencies, and I will discuss the potential of upcoming high-sensitivity experiments to further constrain the physics underlying inflation.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA Seminar:Daniel Huber, NASA/AMES Title: "The Space Photometry Revolution of Asteroseismology & Exoplanets" - Tue, February 24, 2015

Tue, 02/24/2015 - 5:09am
When: Tuesday, February 24, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm at the 3rd floor BASS hallway outside the auditorium
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Dr. Daniel Huber

Description: Abstract:Asteroseismology - the study of stellar oscillations - is a powerful tool to probe the structure and evolution of stars. In addition to the large number of newly discovered exoplanets, space-based telescopes such as Kepler have revolutionized asteroseismology by detecting oscillations in thousands of stars from the main sequence to the red-giant branch. In this talk I will highlight the most recent asteroseismic discoveries by Kepler, focusing in particular on exoplanet host stars. I will furthermore discuss current efforts to improve fundamental properties of the Kepler parent sample and their importance for deriving accurate planet occurrence rates. Finally I will present first asteroseismic results by Kepler's ecliptic plane follow-up mission, K2, and discuss its role for probing the chemo-dynamical history of stellar populations in our Galaxy (galactic archeology).

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA Seminar, Johanna Teske, Carnegie Institution, Title:"Constraining Exoplanet Compositions via Host Star Abundances" - Tue, February 17, 2015

Tue, 02/17/2015 - 5:28am
When: Tuesday, February 17, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm at the 3rd floor BASS hallway outside the auditorium 305
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Dr. Johanna Teske

Description: Abstract:It is an open and actively researched question how/to what extent the presence and chemical compositions of planets correlate with those of their host stars, beyond the well-known giant planet-metallicity correlation. Particularly interesting is the relative importance of elements like C, O, Mg, or Si in the formation and heavy element enrichment of giant planets. The C/O ratio can be indicative of planetary formation history and location, and these are currently the most promising elements for measurement in both star and exoplanet atmospheres. Giant planet formation may be (more strongly) regulated by the presence of more refractory elements, like Si and/or Mg, if cores are dominated by rocky rather than icy material. The formation of small planets does not seem to show the same overall dependence on host star metallicity, but studies of solar twins and analogs suggest the formation of small planets may still imprint a signature on their host star abundances. I will present results of ongoing high resolution, high S/N spectroscopic studies of host star abundances to investigate how/to what extent planet composition, atmospheric and interior, is dependent on host star composition. I will also highlight why binary host stars are a valuable opportunity for disentangling how an individual star’s atmosphere may be affected by the formation of planets and its broader position in/motion through the Galaxy.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA Seminar, Mar Mezcua, Harvard, CfA, Title: Growing Black Holes: From the First Seeds to Active Galactic Nuclei - Tue, February 10, 2015

Tue, 02/10/2015 - 4:27am
When: Tuesday, February 10, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS auditorium
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at the 3rd floor BASS hallway outside the auditorium
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Mar Mezcua

Description: Abstract:Supermassive black holes of up to 10^9 solar masses already existed when the Universe was less than ~1 Gyr old. To reach this mass in such a short time, they should have started as seed intermediate-mass black holes (IMBHs) of 100-10^6 solar masses and grow very fast via accretion and mergers. Such IMBHs are the missing link between stellar and supermassive black holes and they should be present in the nucleus of low-mass galaxies and in the halos of large galaxies, e.g. in the form of ultraluminous X-ray sources (ULXs). Nevertheless, observational evidence of their existence is still scarce.
To probe the existence of the initial seed IMBHs from which supermassive black holes grow, we studied jet radio emission in ULXs. The observations reveal two potential IMBH candidates, one of them in the nucleus of a dwarf galaxy, as well as the detection of the largest non-nuclear extragalactic jet ever discovered. Its location in the arm of a spiral galaxy likely undergoing a minor merger indicates that the nuclei of minor mergers remain amongst the best candidates for IMBHs. We thus carried out a photometric study of double-nucleus disk galaxies candidates to minor mergers. We find that active galactic nuclei (AGN) activity can be triggered by mergers, as expected from simulations, and define one of the largest samples of binary AGN candidates with physical separations below 1 kpc.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA Seminar, Karoline Gilbert, STScI, Title:Stellar Halo Formation in a Hierarchical Universe: Lesson from Andromeda - Tue, February 3, 2015

Tue, 02/03/2015 - 5:13am
When: Tuesday, February 3, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 Bass Auditorium
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm at the 3rd floor BASS hallway outside the auditorium
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Karoline Gilbert

Description: Abstract:Diffuse, extended stellar populations encode information about the earliest stages of a galaxy’s formation. The growth of the outer stellar halos of large disk galaxies like the Milky Way and Andromeda are thought to be dominated by the hierarchical merging of smaller stellar systems, while the inner halos are thought to be built through a combination of mergers and in situ star formation. Stellar halos thus provide a window into the growth of structure as well as an archaeological record of the population of dwarf galaxies that did not survive until the present day.
Large scale surveys of Andromeda's resolved stellar populations have revolutionized our view of this galaxy over the past decade. The combination of large-scale, contiguous photometric surveys and pointed spectroscopic surveys has been particularly powerful for discovering and following up new substructures and disentangling the structural components of Andromeda. I will review what we have learned about Andromeda's stellar halo, dwarf galaxy population, and disk from these surveys, with a focus on recent results from the SPLASH survey, which has now amassed spectra of nearly ten thousand red giant branch stars in Andromeda.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

Joint NPA/WIDG seminar: Antonin Vacheret, University of Oxford, "SoLid Search for Oscillations with a Lithium-6 Detector at the SCK•CEN BR2 Reactor," - Tue, February 3, 2015

Tue, 02/03/2015 - 5:13am
When: Tuesday, February 3, 2015 12:00 PM - 1:00 PM
Where:
   EAL 108 Conference Room (EAL108)
   270 Whitney Avenue, New Haven 06520
   (Location is wheelchair accessible)
   Enter building through WNSL-West (268 Whitney). All other external doors are locked.
Tags: astrophysics, interactions, nuclear_physics, science, seminar, talk

Speaker/Performer: Antonin Vacheret, University of Oxford

Description: The disappearance of reactor antineutrino into a new neutral state (called sterile neutrino) has been proposed as a possible explanation for the recent reactor and Gallium anomalies arising from the re-analysis of reactor flux and calibration data of previous neutrino experiments. A way to test this hypothesis is to look for distortions of the anti-neutrino energy caused by oscillation from active to sterile neutrino at close stand-off (~ 6-8m) of a compact reactor core. Due to the small anti-neutrino cross-section, the main challenge in achieving a precise measurement is to control the high level of gamma rays and neutron background that are present at close stand off. The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillation at very short baseline of the SCK•CEN BR2 research reactor. It utilises a novel approach to anti-neutrino detection based on a highly segmented detector design. High experimental sensitivity can be achieved compared to other state-of-the-art technology with the combination of high granularity, high neutron-gamma discrimination using 6LiF:ZnS(Ag) and precise localisation of the Inverse Beta Decay products. This compact system requires limited passive shielding and rely on spatial topology to determine the different class of backgrounds. l will introduce the BR2 reactor and the SoLid experimental set up. The principle of detection and detector design with expected performance will be described and the expected sensitivity to new oscillations will be presented.

Open To: Yale Community Only
Contact Information:
   Karsten Heeger
   
   karsten.heeger@yale.edu
   

YCAA Seminar, Michelle Collins, Title:"The Faintest Galaxies as Probes of Dark Matter and Galactic Evolution" - Tue, January 27, 2015

Tue, 01/27/2015 - 5:40am
When: Tuesday, January 27, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS auditorium
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm on the 3rd floor hallway outside the auditorium
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Michelle Collins

Description: Abstract:The masses measured for the faintest galaxies in the Universe — the dwarf spheroidals — appear to be at odds with those expected from cosmological simulations. The tension is that the systems we observe around the Milky Way have lower masses than predicted by dark matter only models. This leads to what has been termed the ‘Too Big to Fail’ (TBTF) problem. In this talk, I will present spectroscopic observations of the dwarf spheroidal galaxies orbiting our nearest spiral neighbor, Andromeda, in order to test some of the proposed solutions to the TBTF problem. I will examine whether this tension can be resolved by assuming the Milky Way has a fairly low mass, and whether the tidal forces exerted on dwarf galaxies as they orbit their hosts are much stronger than assumed in dark matter only simulations. I will also show new results for several surprisingly low mass dwarf spheroidal galaxies in the Local Group, whose properties challenge our expectations, and discuss various processes that may have led them to their present state.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA Seminar: David Hogg, New York University Title: "Data-driven Models of Stars" - Tue, January 20, 2015

Tue, 01/20/2015 - 5:36am
When: Tuesday, January 20, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS Auditorium
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm in the 3rd flr. hallway BASS outside the auditorium
Tags: astrophysics, science, seminar, talk

Speaker/Performer: David Hogg

Description: Abstract:Despite incredible maturity, physical stellar models do not match all the detailed properties of stellar spectra, and different models compared to different sections of stellar spectra return different stellar parameter and abundance estimates. At the same time, we have enormous data sets containing high-resolution, high signal-to-noise spectra of tens of thousands of stars. I discuss ways to build partially or fully data-driven stellar models, potentially permitting stellar parameter estimation and chemical tagging experiments without good physical models. I will show successes with the SDSS-III APOGEE data. I will also talk about data-driven approaches to stellar variability using data from the Kepler satellite.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

Yale Center for Astronomy & Astrophysics seminar: Braninir Sesar,"The Nature and Orbit of the Ophiuchus Stream" - Tue, January 13, 2015

Tue, 01/13/2015 - 5:04am
When: Tuesday, January 13, 2015 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS auditorium
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm in the hallway outside the auditorium third floor BASS
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Branimir Sesar

Description: Abstract:"The Ophiuchus Stream is the most recently discovered stellar tidal stream in the Milky Way (Bernard et al. 2014). Due to its location (~5 kpc from the Galactic center) and its puzzling morphology (a thin and short stream, and yet with no visible progenitor), this stream may represent an important piece in our efforts to understand the Galactic potential and the dynamical evolution of accreted structures. In this talk, I will present a follow-up study of the stream during which we obtained high-quality spectroscopic data on 14 stream member stars using Keck and MMT telescopes. I will show how a probabilistic approach and a rich data set can be used to tightly constrain i) the distance, ii) the 3D kinematics, iii) the chemical abundance, iv) and the orbit of the stream.
I will describe the nature of its progenitor and will finish by discussing prospects for characterization of stellar streams using Pan-STARRS1, Palomar Transient Factory, and GAIA data."

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

Time change: Nuclear Particle Astrophysics Seminars: Alessandro Bettini, Laboratorio Subterraneo de Canfranc, Spain, "The Canfranc Underground Laboratory (LSC), Physics and more" - Thu, December 11, 2014

Thu, 12/11/2014 - 5:33am
When: Thursday, December 11, 2014 11:00 AM - 12:00 PM
Where:
   EAL 108 Conference Room (EAL108)
   270 Whitney Avenue, New Haven 06520
   (Location is wheelchair accessible)
Tags: astrophysics, nuclear_physics, particle_theory, science, seminar, talk

Speaker/Performer: Alessandro Bettini

Description: The LSC is a small underground laboratory excavated under the Spanish Pyrenees between a road and unused train tunnels, with 850 m rock overburden. I shall summarise the scientific program we are developing. It includes dark matter search, both searching for annual modulation with NaI detectors (ANAIS) and not with a liquid Ar TPC (ArDM), neutrino-less double beta decay with a high pressure enriched 136Xe TPC (NEXT), deep underground microbiology and under-surface geodynamics and hydrology.

Open To: General Public
Contact Information:
   Karsten Heeger
   
   karsten.heeger@yale.edu
   

YCAA Seminar: Gerard van Belle, Lowell University,Directly Determined Linear Radii, Effective Temperatures, and Shapes of Stars from Long-Baseline Optical Interferometry - Tue, December 9, 2014

Tue, 12/09/2014 - 5:34am
When: Tuesday, December 9, 2014 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm in the hallway outside BASS 305
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Staff Astronomer Gerard van Belle

Description: Abstract:A brief introduction to the concepts of long-baseline optical interferometry (LBI) will be presented, followed by a review of fundamental stellar parameters as directly determined using LBI. Special attention will be paid to the progression of precision over the years of the observables of linear radius and effective temperature, with the current state-of-the-art measures approaching sub-percent levels for hundreds of stars (and being limited primarily by the ancillary data products of distance and bolometric flux, not measured angular size). Discussion will also be presented on the diminishing meaning of these gross parameterizations of stellar atmospheres, as higher-order surface details such as shapes, limb darkening, gravity darkening, and spotting are beginning to be imaged with LBI.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

Nuclear Particle Astrophysics Seminars: Mark Caprio, Notre Dame, "Emergence of nuclear rotation in ab initio calculations" - Thu, December 4, 2014

Thu, 12/04/2014 - 5:21am
When: Thursday, December 4, 2014 11:00 AM - 12:00 PM
Where:
   EAL 108 Conference Room (EAL108)
   270 Whitney Avenue, New Haven 06520
   (Location is wheelchair accessible)
Tags: astrophysics, nuclear_physics, particle_theory, science, seminar, talk

Speaker/Performer: Mark Caprio

Description: A fundamental goal in nuclear theory is to obtain an ab initio description of the nucleus--that is, to understand the strongly correlated motion of nucleons within the nucleus directly from the underlying interactions of these constituents. Particularly intriguing is the question of how simple excitation patterns, indicating the presence of collective modes, arise out of the complex interactions within the nuclear many-body system. The emergence of rotational bands has recently been observed in ab initio no-core configuration interaction calculations of light nuclei. The results demonstrate the possibility of well-developed rotational structure in such calculations, using realistic nucleon-nucleon interactions, and within finite, computationally-accessible configuration spaces. This talk will focus on results for rotation in both the even-mass and odd-mass Be isotopes, as well as on the challenges of obtaining converged results for observables relevant to rotation.

Contact Information:
   
   
   francesco.iachello@yale.edu
   

YCAA Seminar: Francesca Civano, Yale University Title:"Learning about the High-z Universe with COSMOS X-ray Surveys" - Tue, December 2, 2014

Tue, 12/02/2014 - 5:30am
When: Tuesday, December 2, 2014 2:25 PM - 3:25 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm in the hallway outside BASS 305
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Research Associate Francesca Civano

Description: Abstract:The equatorial 2 deg2 COSMOS area is the only large field for which a complete, deep, pan-chromatic data set exists, from an outstanding survey effort, and that all large telescopes can observe. During 2013, this pioneering and ambitious COSMOS survey had a major extension, pushing its frontiers via the newly approved Chandra COSMOS Legacy Survey, the second largest Chandra proposal ever approved, plus new deep Spitzer, JVLA and NuSTAR surveys all aimed to study the formation of the structures in the high redshift Universe and the role of active super massive black holes. The Chandra COSMOS-Legacy survey uniformly covers the 1.7 deg2 COSMOS/HST field with 2.8 Ms of Chandra ACIS-I imaging at ~150 ksec depth.
At Chandra energies, we are able to detect unobscured and obscured sources, up to columns of NH=10^23. Therefore, to have a complete selection with no obscuration bias, we employed 3 Megaseconds of NuSTAR time to cover the same Chandra area and have the best unbiased view of the X-ray sky. In this talk, I will present the first results from both surveys focusing on the high-z sample. With the ~4000 sources detected in the X-ray band, we can finally have enough statistic to study Active Galactic Nuclei at high redshift and faint luminosity, using multiple approaches, and learn about their evolution and the Dark Matter halos in which these sources reside.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA seminar Sarah Gallagher, University of Western Ontario Title: "Winds, Winds Every Where: Radiatively Driven Outflows from Supermassive Black Holes" - Tue, November 18, 2014

Tue, 11/18/2014 - 5:32am
When: Tuesday, November 18, 2014 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served 2:00pm on 3rd floor BASS outside the auditorium hallway
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Professor Sarah Gallagher

Description: Abstract:Supermassive black holes reside in the centers of every massive galaxy. In relatively brief spurts, black holes grow as luminous quasars through the infall of material through an accretion disk. Remarkably, the light from the accretion disk can outshine all of the stars in the host galaxy by a factor of a thousand, and this radiation can also drive energetic mass outflows. Mass ejection in the form of winds or jets appears to be as fundamental to quasar activity as accretion, and can be directly observed in many objects with broadened and blue-shifted UV emission and absorption features. A convincing argument for radiation pressure driving this ionized outflow can be made within the dust sublimation radius. Beyond, radiation pressure is still important, but high energy photons from the central engine can now push on dust grains. This physics underlies the dusty wind picture for the putative obscuring torus. I'll describe our model of the dusty wind and evaluate its success in accounting for observed properties of quasars such their mid-infrared spectral energy distributions, fractions of hidden objects, and column densities of important ions.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu
   

YCAA Seminar: Kaitlin Kratter, University of Arizona Title:"What we can learn from Planets in Binary Systems" - Tue, November 11, 2014

Tue, 11/11/2014 - 5:29am
When: Tuesday, November 11, 2014 2:30 PM - 3:30 PM
Where:
   Bass Center for Molecular and Structural Biology (BASS), 305 BASS
   266 Whitney Ave., New Haven, CT 06511
   (Location is wheelchair accessible)
   Tea will be served at 2:00pm in the hallway outside BASS 305
Tags: astrophysics, science, seminar, talk

Speaker/Performer: Assistant Professor Kaitlin Kratter

Description: Abstract:Exoplanet surveys have revealed a surprising array of planetary systems hosted by binary stars. The diversity and architecture of these systems provides insight into the fundamentals of planet formation relevant for a wide range of systems. Moreover, these planets provide an important final boundary condition for our models of star formation, and especially binary formation. I will review the statistics of these surprisingly un-exotic systems, describe the theoretical implications, and discuss the prospects for progress with observational facilities of the future.

Open To: General Public
Contact Information:
   Laurelyn Celone
   
   laurelyn.celone@yale.edu