Poster: http://www.physics.uwo.ca/colloquia/Colloquia%20Notices/2011_2012/DESERT%20Research%20Talk.pdf

The University of Western Ontario
DEPARTMENT OF PHYSICS AND ASTRONOMY

PHYSICS & ASTRONOMY COLLOQUIUM

Date:           Monday, 30^th April 2012
Time:          1:30 p.m.
Location:    Physics & Astronomy Seminar Room 22

Dr. Jean-Michel Désert
Harvard College Observatory
Harvard-Smithsonian Center for Astrophysics (CfA)

“From statistics to individual characterization of exoplanets”

ABSTRACT

The field of exoplanetary science has changed gear from the investigation of individual objects to statistical studies. In this talk, I discuss both the statistical approach and individual atmospheric characterization.

The Kepler mission has revealed an extraordinary and unprecedented number of small exoplanet candidates. However, a fundamental question remains about the overwhelmingly large sample of Kepler candidates: are these objects bona-fide planets? Importantly, we would like to know the false positive rate of this sample. I present a large program, obtained with the Spitzer Space Telescope, whose goals are to validate the planetary status of candidates and to estimate the Kepler false positive rate. Our results suggest that the Kepler false positive rate in this subset of candidates is low.

Answers to key questions about exoplanet science come not only from statistics, but also from individual characterization. Observations of their atmospheres are the only effective way at present to address the composition of exoplanets quantitatively and, by necessity, remotely. I present an ongoing comparative exoplanetology program to characterize planetary systems transiting nearby stars through the observation of their atmospheres. This project provides a powerful insight into the formation and evolution of planetary systems in general and enhances our understanding of our own solar system’s formation, one of the central questions in astrophysics. I also discuss the prospect of probing rocky exoplanet atmospheres orbiting in the habitable zone of their parent stars with future facilities.

TODAY @ 1:30

The University of Western Ontario
DEPARTMENT OF PHYSICS AND ASTRONOMY

PHYSICS & ASTRONOMY COLLOQUIUM

Date:          Monday, 23^rd April 2012
Time:          1:30 p.m.
Location:    Physics & Astronomy Seminar Room 22

Dr. Stanimir Metchev
Department of Physics and Astronomy

Stony Brook University, New York

“Exoplanetary Worlds: Atmospheres, Architectures, and Evolution”

ABSTRACT

The detection of global weather phenomena in irradiated extrasolar hot Jupiter planets has provided tremendous insights into their atmospheric structure. Non-irradiated substellar atmospheres probe weather in an entirely different regime, where global atmospheric flows result primarily from a combination of rapid rotation and internal convection—e.g., as in the atmosphere of Jupiter—rather than from external forcing. Isolated brown dwarfs are ideal targets for such investigations because they possess planet-like atmospheric dynamics, yet have greater intrinsic brightnesses and lack nearby bright stars to contaminate observations. I will overview recent results on non-irradiated brown dwarf and planetary atmospheres, and will present the prospects for the direct characterization of extrasolar planets with the coming generation of extreme-contrast imaging telescopes.

Here is a nice piece calling the scientific community to put more effort in spreading their research through social media.

See also the link to “Science Sushi”for an interesting point of view.

So maybe tweeting our research resultswas not a bad idea after all!

These high energy particles, usually protons, are for most astronomer the annoying little critters whose signature must be subtracted from all of our data before we can work with it.  But for some they are an observable all of their own and an enigmatic one at that.  Their origins remain a mystery…

This post is one in the category “I know that dude”.

Fomalhaut is one of the brightest stars in the night sky, and a young star known to have a circumstellar disk around it. Hubble images have shown a fairly sharp inner edge to that disk, suggesting that a planet is keeping the dust belt in check. There’s been claims about direct imaging of a planet with Hubble, but that claim has been somewhat controversial.

Dust absorbs light of all sorts of wavelengths, and emits itself at infrared wavelengths. The dust disk of Fomalhaut is thus an ideal target for the Herschel space observatory. Bram Acke analyzed those observations. Bram is one of those fine, young Belgian astronomers that is also involved in oureach, and that likes playing music.

As is often the case, the dust properties inferred from those new observations at far-IR wavelengths were at first sight not compatible with those inferred from the Hubble Space Telescope. Fortunately, Bram is a smart guy and he figured it out: the dust must be fluffy, like dust particles ejected from comets. It also implies that comets must be colliding there all the time!

Another example of cool science at long wavelengths!

You can find the ESA press release here:

http://www.esa.int/export/esaSC/SEM1XBHWP0H_index_1.html

I’m not an expert on dark matter, but I’ve always liked the idea of a Dark Entity that we can’t see, but whose influence is quite clear nonetheless. Here’s a paper now where the authors claim that in our galactic neck of the woods, there is no dark matter. I’m not sure what to think of it (please leave comments if you do!), but if this turns out to be correct, it adds another awesome twist. You just gotta love science when something strange becomes totally weird.

You can read the press release here, and there’s a link to the preprint on that page as well if you’re more hardcore.

TODAY – @ 1:30 and 4 p.m.

TWO talks by Dr. John Berlinsky:

Poster:  http://www.physics.uwo.ca/colloquia/Colloquia%20Notices/2011_2012/BERLINSKY%20Colloquium.pdf

Western University
DEPARTMENT OF PHYSICS AND ASTRONOMY

PHYSICS & ASTRONOMY COLLOQUIUM

Date:          Thursday, 19^th April 2012
Time:          1:30 p.m.
Location:    Physics & Astronomy Seminar Room 22

Dr. John Berlinsky
Perimeter Institute for Theoretical Physics

“Quantum Oscillations in High Temperature Superconductors”

ABSTRACT

High temperature superconductivity occupies one region of the phase diagram of the rare earth cuprates, which also includes regions of antiferromagnetism at low doping and pseudogap, stripe, and strange metal behaviour for intermediate doping, as well as a normal Fermi liquid at high doping. These are clearly strongly correlated systems and, since the beginning, much of this strange behaviour has been interpreted in terms of Mott-Hubbard physics. And so the discovery of quantum oscillations, which are usually a clear signature of normal Fermi liquid-like behaviour, came as something of a surprise which deepened the mystery of high T_c, rather than clarifying it. Furthermore it was difficult to understand the observed frequencies of the quantum oscillations without invoking some kind of translational symmetry breaking and superlattice model. In this talk we will describe the general situation of the phase diagram and the observations of quantum oscillations and then present some recent results for a simple model of quantum oscillations arising from superconducting stripes.

Coffee & cookies will be available, courtesy of PASA.

In addition, Dr. Berlinsky will make a second presentation later in the day:

Date:          Thursday, 19^th April 2012
Time:          4:00 p.m.
Location:    Physics & Astronomy Classroom 117

Dr. John Berlinsky
Perimeter Institute for Theoretical Physics

“Perimeter Scholars International (PSI) Information Session”

Perimeter Scholars International is a one-year Masters level course in Theoretical Physics designed to bring highly qualified, highly motivated graduate students to the cutting edge of theoretical physics in an intense, interactive learning environment.

http://www.perimeterscholars.org/

For those of you dealing with exam anxiety, here’s a site with some great advice and tips. Give it a read and it just might help. Just follow the link here