Macalester
Past Events
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4/20/2018
Build Your Own Rocket!
Ever been curious about rocket science, but didn't know where to start? Ever wanted to build and fly your own rocket? Well, now's your chance! Join the Mac Rocketry Team in the Idea Lab on Tuesday 4/17 and Friday 4/20 from 4:30-6:30. You'll have an opportunity to learn about what we do (including last semesters successful launch and our preparation for NASA’s Space Grant Midwest High-Power Rocketry Competition in May), and to construct and fly your own model rocket! Absolutely no experience necessary!!! Just grab some friends, come on over, and get ready to have a blast!
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4/20/2018
Physics & Astronomy Senior Capstone Presentations
Paul Chery will give his capstone presentation, "Modeling Recombination in Solar Cells."
Solar cells are a competitive alternative to nonrenewable energy sources such as fossil fuels. However, the efficiency of these devices is limited by photogenerated carrier recombination. I use a numerical model to study recombination phenomena in the absorber layer of solar cells including alternate recombination models and the effects of spatial distribution of recombination centers.
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4/18/2018
Physics & Astronomy Senior Capstone Presentations
Catie Ball will present her honors thesis, "Star Formation Diagnostics in the Cosmic Eye."
Studying the properties of lensed galaxies circumvents distance-related limitations in spatial resolution and sensitivity and offers unique insights out to the high-redshift universe. We present analysis of Atacama Large sub-Millimeter Array (ALMA) and Hubble Space Telescope (HST) observations of the Cosmic Eye, a gravitationally lensed Lyman Break Galaxy at z=3.074. These observations trace the harness of stellar radiation and the nature of dust attenuation in a distant galaxy, allowing us to resolve variations in the nature of star-formation on sub-galactic scales.
Snacks at 3 p.m.
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4/17/2018
Build Your Own Rocket!
Ever been curious about rocket science, but didn't know where to start? Ever wanted to build and fly your own rocket? Well, now's your chance! Join the Mac Rocketry Team in the Idea Lab on Tuesday 4/17 and Friday 4/20 from 4:30-6:30. You'll have an opportunity to learn about what we do (including last semesters successful launch and our preparation for NASA’s Space Grant Midwest High-Power Rocketry Competition in May), and to construct and fly your own model rocket! Absolutely no experience necessary!!! Just grab some friends, come on over, and get ready to have a blast!
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4/13/2018
Physics & Astronomy Senior Honors Thesis Presentation
Elizabeth Ruvolo is presenting her honors thesis, "SHIELD: The HI Mass-Diameter Relation."
The Survey of HI in Extremely Low-mass Dwarfs (SHIELD) is a multi-wavelength galaxy survey which seeks to explore the properties of sources with extremely low-mass HI reservoirs in order to refine our understanding of galaxies and to populate understudied regions of parameter space. In this work, I use the SHIELD sample to help populate the low-mass regime of the HI mass-diameter relation.
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4/11/2018
Physics & Astronomy Senior Honors Thesis Presentation
Brian Eisner is presenting his honors thesis, "Surveying Radio Line Spectra of Nearby Galaxies."
Complex molecules have more degrees of freedom than smaller molecules, increasing the potential information yield, but simultaneously weakening the transitions. We sample the centimeter spectrum of nine nearby star-forming galaxies using the Australia Telescope Compact Array, and detect transitions from six species: recombination lines, H2CO, H2O, OH, NH3, and c-C3H2. The Next-Generation Very Large Array will be able to prove a ~150 times larger number of galaxies to sample to the same S/N ratio, and thus complex molecules should be observable in the closest galaxies with this instrument.
Snacks at 3 PM.
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4/9/2018
Physics & Astronomy Seminar--From Galaxies to Fridge Magnets: Searching for the origin of magnetic fields
The Physics & Astronomy Department presents a seminar featuring Dr. Anna Williams, a candidate for the visiting professor of physics position. Williams is a lecturer at the Univ. of Wisconsin. Please attend, then help the department evaluate the candidate with your feedback.
Magnetic fields play important roles in our everyday lives. They make our headphones work, keep reminders posted on the refrigerator, and help us get from point A to point B. Magnetic fields are also important beyond our planet where most ordinary matter is ionized and in the form of plasma. In stars, magnetic fields cause huge surface eruptions and can slow rotation. In galaxies, magnetic fields provide pressure support against gravity and affect the energy balance by accelerating and confining charged particles. Despite their prevalence, we still do not know how or when magnetic fields came about in the universe. In my talk, I will explain how astronomers observe astrophysical magnetic fields, and show how my research to detect and measure magnetic fields in galaxies helps us understand the origin of magnetic fields and their co-evolution with galaxies.
Refreshments at 4 p.m.
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4/6/2018
Physics & Astronomy Senior Honors Thesis Presentation
Theo Jacobson will present his honors thesis, "Gravitational Leptogenesis and One-Loop Effective Actions."
Inflation, the leading paradigm in modern cosmology, provides a theoretical framework for understanding the physics of the early Universe. To demonstrate its robust phenomenology, we show how one particular inflationary model provides a natural mechanism for generating the matter-antimatter asymmetry in our visible Universe. At a more formal level, we investigate how such a model can arise from more general quantum field theories.
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4/4/2018
Physics & Astronomy Senior Capstone Presentations
The Physics and Astronomy Department presents its Senior Capstone talks with:
- Masao Miazzo, "Imaging the Natural Gas of Extremely Low-mass Dwarfs"
- A. Cotter, "Actinometry of Hydrogen Plasmas"
Refreshments at 3 PM.
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4/2/2018
Physics & Astronomy Seminar
Observing & Interpreting Very High Energy Gamma Rays from Blazars
The Physics & Astronomy Department is presenting a seminar featuring Caitlin Johnson, a candidate for the visiting professor of physics position. Caitlin Johnson is a Ph.D. candidate at UC Santa Cruz. Please attend, then take this opportunity to help the department evaluate the candidate with your feedback.
Blazars, a subclass of active galactic nuclei, host powerful relativistic jets that are pointed along our line of sight. These jets produce some of the most energetic radiation observed in the universe: gamma rays. To date, questions remain about the particle physics processes responsible for creating gamma-ray emission and how they relate to overall evolution and classification of active galaxies. VERITAS, a gamma-ray telescope located in Arizona, uses a unique technique to observe gamma rays from the ground, that is if the gamma rays can actually make it to Earth.
Refreshments at 4 PM.
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3/28/2018
Physics & Astronomy Senior Honors Thesis Presentation
Alex Gordon will present his honors thesis, "A Narrowband Emission-Line Survey of the Large Magellanic Cloud."
The Large and Small Magellanic Clouds provide sites to study the interstellar medium (ISM) and its components at all scales, from small to global. The UM / CTIO Magellanic Cloud Emission-Line Survey (MCELS) is as a deep imaging survey of both of these nearby galaxies in the emission of Hα, [S ii], and [O iii]. These emission-line images are being used in detailed optical and multi-wavelength studies of planetary nebulae (PNe), H ii regions, supernova remnants (SNRs), su- perbubbles, and supergiant shells. Here we present a deep and wide view of the ∼ 104 K ionized gas in the interstellar medium of the Large Magellanic Cloud (LMC) using the MCELS data. We present large-scale flux-calibrated continuum- subtracted optical emission-line mosaics of the 8 × 8 square degree central region of the Large Magellanic Cloud created from the combination of thousands of ob- servations taken over hundreds of nights, providing a detailed view of most of the gaseous extent of the galaxy. With these mosaics in hand we conduct a systematic analysis of the [S ii] to Hα ratio of 59 known X-ray supernova remnants in the Large Magellanic Cloud. For 44 of these supernova remnants, Hα and [S ii] flux values along with [S ii] / Hα emission-line ratios have been derived. All derived [S ii] / Hα emission-line ratios ≥ 0.4, strengthening their identification as true rem- nants. We compare our values to spectroscopic values in the literature. This work has uncovered at least one previously unidentified candidate supernova remnant, triggering an ongoing spectroscopic followup campaign.
Refreshments at 3:00 PM
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3/7/2018
Physics & Astronomy Seminar--The Sunburst Arc: A Unique, Lensed Galaxy at Redshift ~2.4 with a Perforated ISM
Thøger (Emil) Rivera-Thorsen, Postdoctoral Fellow, Institute for Theoretical Astrophysics, University of Oslo is presenting.
The radiative transport and escape of Lyman alpha and UV continuum photons from distant galaxies is a critical process that bears directly on galaxy evolution and on the cosmic reionization. To explore these inter-related issues, I will present an extremely bright and extremely strongly lensed star forming galaxy at redshift 2.37 known as the "Sunburst Arc."
Snacks at 3 PM.
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2/23/2018
Physics & Astronomy Seminar: Graduate School--The Final Frontier
Wondering what the next step in your scientific career might be like? Come hear Macalester Alumni Yillikal Ayino ’12, (UMN Physics Ph.D. candidate), Minh Nguyen '14 (UMN Physics Ph.D. candidate), and Dr. Hallie Boyer ’08 (Dreyfus Postdoctoral Fellow, Carnegie Mellon and 2017 UMN Mechanical Engineering Ph.D.) talk about their research, their experiences and making the transition from Macalester to graduate school.
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12/6/2017
Physics & Astronomy Seminar--A Matter of Life and Death
Professor John Bischof, University of Minnesota Institute for Engineering in Medicine, will speak.
Gold and iron oxide nanoparticles have unique and tunable properties that allow transduction of optical (light), or radiofrequency (RF) electromagnetic fields to affect heating of biomaterials at multiple scales. This talk will explore the underlying physics and relative advantages of each form of nanoparticle heating for therapeutic treatment of cancer or other disease by heating (i.e. magnetic hyperthermia or photothermal cancer therapy). In addition, this same heating helps improve regenerative medicine by “nanowarming” vitrified (i.e. cryopreserved) biomaterials back to a transplantable state through rapid and uniform warming that avoids crystallization and cracking. This nanoparticle warming addresses an important technology bottleneck for both large systems (i.e. tissues and organs) and smaller systems (i.e. embryos and oocytes). In summary, this talk demonstrates the growing opportunities for nanoparticle heating in biomedical applications.
Snacks at 3 PM
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11/29/2017
Physics & Astronomy Seminar--Preliminary Investigations of Passive Acoustics in Lake Superior
Prof. Jay Austin, Large Lakes Observatory, Dept. of Physics & Astronomy, U of M, Duluth presents.
While a great deal of effort has been put into characterizing propagation properties and the passive (natural) acoustic soundscape of the world oceans, little if any effort has been put into the same topics with regards to freshwater systems around the world. In this talk, I will discuss the history of these sorts of observations, and present results from two deployments in Lake Superior in 2016-2017. The majority of the background signal is due to either wind/wave processes or passing vessels. These signals are used to characterize the propagation properties of the lake under different stratification conditions. Previously unobserved resonant structures and clicks of potential biological origin are discussed, as well as the possibility that they may reveal a behavioral reaction to the presence of surface vessels.
Snacks at 3 PM.
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11/27/2017
Public Observing Tonight
What's the difference between an open cluster and a globular cluster? A protoplanetary disk and a planetary nebula? Come find out at public observing night! We love the cosmos and we know you do, too! All are welcome! If the sky is cloudy, we'll still be around to chat but we won't open the 'scope.
Note: there will be no regular observing nights next semester, so we have only a few more opportunities this academic year!
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11/20/2017
Public Observing Night
Planets! Stars! Clusters! Nebulae! Galaxies! We <3 the cosmos and we know you do to! All are welcome for public observing night. If the sky is cloudy, we'll still be around to chat but we won't open the 'scope.
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11/15/2017
Physics & Astronomy Seminar--Searching for new Physics with the CMS Experiment
Julie Hogan, Assistant Professor, Bethel University, Physics & Engineering Department will present.
The Large Hadron Collider is one of the most powerful machines in the world, accelerating protons to nearly the speed of light to provide 40 million collisions per second at particle detectors such as the Compact Muon Solenoid. The CMS detector is highly versatile, featuring the largest superconducting solenoid ever built and over 100 million detection elements. CMS physicists were instrumental in the discovery of the Higgs boson in 2012 and are now searching for evidence of new physics, including heavy vector-like quarks. I'll present a recent search for vector-like quarks using W and Higgs boson jet reconstruction algorithms, and introduce a new effort to use computer vision techniques to classify jets at the high luminosity LHC.
Snacks at 3 PM.
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11/9/2017
Philosophy/Physics Colloquium
Join the Philosophy and Physics Departments for a talk by Robert DiSalle, Professor of History and Philosophy of Science Space-Time Theories at the University of Western Ontario titled “Laws & Necessities: On the Ineffective Reasonableness of Mathematics” All are welcome.
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11/9/2017
Physics & Astronomy Summer Research Information Session
Studying the Mysteries of the Universe: Summer Research Opportunities for Students.
Interested in doing physics and astronomy research in summer 2018? Join us for pizza and learn about both on-campus and off-campus summer research opportunities. We will discuss whatoptions are available and the application procedures. Find your ideal research project!
Pizza lunch provided.
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11/8/2017
Physics & Astronomy Seminar--Signatures of Particle Physics from Cosmological Inflation
Professor Marco Peloso, Minnesota Institute for Astrophysics, University of Minnesota, Physics & Astronomy Department. is presenting.
There are strong motivations to believe that the so-called "big-bang" cosmology was in reality preceded by a stage of fast and accelerated expansion, known as cosmological inflation. Inflation solves several problems of big-bang cosmology (explaining for example why the primordial universe was so homogeneous), and it provides a natural mechanism for the generation of the primordial perturbations, which seeded the present large structures in the universe (galaxies, and clusters of galaxies). Particle physics processes during inflation can leave an imprint in the primordial density perturbations (leading to characteristic patterns in the temperature anisotropies, and, possibly, to primordial black holes) and in the primordial stochastic background of gravitational waves, both at extra-galactic (thus affecting the Cosmic Microwave Background observations) and at interferometer scales (such as those probed by LIGO, and future related experiments).
Snacks at 3 PM.
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11/1/2017
Physics & Astronomy Seminar--A Materials Informatics Approach to the Study of van der Waals Materials
Postdoctoral Fellow Trevor Rhone, Harvard University, Physics Department will present.
The explosion in the recent number of proposed van der Waals (vdW) materials has increased the promise of uncovering novel physics and developing new applications for 2D atomic crystals. Though this large number of newly identified vdW materials brings the potential for discovery, immense challenges also emerge. Traditional experimental and theoretical methods for studying a large database of materials are slow and expensive. A novel approach to materials investigation is desirable. With the advent of materials informatics (the combination of statistical tools, computational methods, and materials science), one is able to efficiently screen a large database of materials and make predictions of desirable properties. I will discuss how materials informatics can be used to study 2D atomic crystals and present some initial results.
Snacks at 3 PM
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10/23/2017
Public Observing Night
Planets! Stars! Clusters! Nebulae! Galaxies! Hop on the shuttle as we explore the cosmos and ponder the infinite. All are welcome for public observing night! If the sky is cloudy we'll still be around to chat but we won't open the 'scope.
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10/18/2017
Physics & Astronomy Seminar--Magnetism & Crystal Defects: Joined at the Slip
Anna Lindquist, Visiting Assistant Professor, Geology Department, Macalester College will present.
Magnetite (Fe3O4) is the primary mineral responsible for our understanding of how Earth's magnetic field has changed over time. When sufficiently heated, it can act like a compass needle, aligning with Earth's magnetic field. Once cooled, it locks in a record of Earth's magnetic field that can last hundreds of millions of years or longer. However, like any mineral, magnetite grains vary in size and can be full of defects. These defects can affect the magnetic alignment and remagnetization of magnetite. By collecting nanometer-scale videos and images, we will be able to quantify the interactions between defects and magnetism and discuss the implications of these interactions.
Snacks at 3 PM
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10/18/2017
Skype with computational astrophysicist Dr. Jennifer Barnes '09
Dr. Jennifer Barnes will skype with Physics/Astronomy students to talk about the big news in the universe: the first observation of a neutron star merger event!
Dr. Barnes is a computational astrophysicist and an expert in compact object mergers. She will join the Macalester faculty after finishing her postdoctoral position at Columbia University. Jenni graduated from Macalester in 2009 with majors in physics and sociology, and she received her PhD degree in physics earlier this year from UC Berkeley.
Jenni is looking forward to engage with current Macalester students! Please join in an informal discussion about her research and how it relates to yesterday's exciting announcement of the first-ever observation of a neutron star merger. She will also be happy to answer any of your questions! -
10/16/2017
Public Observing Night
Crystal clear skies are expected for public observing night! Take advantage of a perfectly crisp fall evening and peep the stars. Hop on the shuttle as we explore the cosmos and ponder the infinite. All are welcome!
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10/11/2017
Physics/Astronomy & Chemistry Joint Seminar--Asteroids: Friends or Foes?
Distinguished Macalester alum, Richard Binzel '80, now Professor of Planetary Sciences and Margaret MacVicar Faculty Fellow, MIT, will present.
Asteroids make for popular disaster movies, but is there any real threat? We will look at the facts and focus on the science results delivered by physical and chemical studies of asteroids and meteorites. Richard Binzel began his forefront scientific studies of asteroids as a student at Macalester College, enabled by the dedicated teaching and the diligent telescope making of Professor Sherman W. Schultz. This work was recognized by the 1980 Apker Award from the American Physical Society.
Snacks at 3 PM
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10/9/2017
Public Observing Night
Did you know that Macalester has its very own 16 inch reflecting rooftop telescope? You're invited to come check it out at public observing night! Hop on the shuttle as we explore the cosmos and ponder the infinite. All are welcome; bring your friends, bring a date, or come alone! If the sky is cloudy we'll still be around to chat but we won't open the 'scope.
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10/2/2017
Public Observing Night
Join us for public observing night! Hop on the shuttle as we explore the cosmos and ponder the infinite. All are welcome; bring your friends, bring a date, or come alone! If the sky is cloudy we'll still be around to chat but we won't open the 'scope.
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9/20/2017
Physics & Astronomy Seminar--Career Development Center Resources
Michele Moylan, head, Employer Relations team, & Amanda Duffy, career counselor, The STEM, Career Development Center, Macalester College are presenting.
Come spend time talking with the new STEM-specific career counselor and the head of the Career Development Center's Employer Relations team to learn more about what the CDC can offer to Physics majors. We will cover basic 4-year timelines for thinking about graduate school and jobs; we will talk about some of the major employers in the Physics space; we will talk about how to build a community of alumni to support your path; and we will talk about some of the new initiatives that the CDC is launching this year that can benefit physics majors, including local and national visits to labs and employers! Bring your questions!
Snacks at 3 PM.
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9/13/2017
Chemistry & Physics/Astronomy Seminar: Growing 2D Heterostructures and Probing Exciton Dynamics
James Johns, Asst. Prof., Dept. of Chemistry, U of MN, will present.
Two Dimensional Materials is a new exciting area of research in chemistry and physics. From a chemical perspective, how can we make materials that are only a couple of atoms thick but macroscopically large? Which materials are stable, how can we control the thickness and, how can we interface different 2D materials together are some of the relevant chemical questions. Physically, the behavior of electrons depends on their dimensionality. The ability to make truly 2D systems allows us to explore novel electronic and optical behavior in these materials that are relevant for electronic and optical applications. I discuss my lab’s efforts to grow monolayer transition metal dichalcogenides and to interface different TMDCs together, and the role spin-orbit coupling in the optical properties of these materials explored by ultrafast spectroscopy.
Snacks at 3 PM.
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9/11/2017
Public Observing Night
The Macalester College observatory hosts regular public observing nights on our very own 16-inch rooftop telescope! Hop on the shuttle as we explore the cosmos and ponder the infinite. Weather permitting, potential targets include the Moon, planets, globular clusters, open clusters, galaxies, planetary nebulae, and binary star systems. In the case of bad weather, we can’t open the dome for observing; however, we’ll still be present to show the facility and answer questions.
All are welcome! We’re obsessed with the cosmos and we could talk about it forever (roughly a Hubble time). Bring your friends, bring a date, or come alone!Hope to see you there!
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9/6/2017
High-power Rocketry, Stratospheric Ballooning, & other MnSGC Build Projects at the U of MN
James Flaten, Ph.D., Associate Director of NASA’s MN Space Grant Consortium, Aerospace Engineering and Mechanics Department, U of MN, Twin Cities will present at this joint Physics/Astronomy & Geology Seminar.
In this talk, Dr. Flaten will discuss NASA’s Minnesota Space Grant Consortium (MnSGC), a NASA/aerospace promotion higher education program of which Macalester is a member. In particular, he will discuss MnSGC-sponsored build projects at the U of MN which engage students from many different majors, not just Aerospace Engineering (though that is where the MnSGC is housed on the Minneapolis campus). Dr. Flaten will also talk about two new training initiatives to help people at other schools, possibly Macalester, learn to build and fly high-power rockets and “near-space” craft for stratospheric balloon missions.
Don't forget to join us beforehand for the first departmental TEA of the semester at 3 PM in the OLRI Atrium.
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4/19/2017
Physics & Astronomy Senior Honors Thesis Presentation
Tayeb Zaidi will present his Physics and Astronomy Senior Honors Thesis on "The Wavelet Methods for Photometric Supernova Classification."
Refreshments at 3 p.m. in Olin-Rice atrium.
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4/12/2017
Physics & Astronomy Senior Capstone Presentations
Physics and Astronomy Senior Capstone presentations continue with Gunnar Footh speaking on "Transient Photoconductivity of a Thermoelectric Nanomaterial."
Refreshments at 3 p.m. in Olin-Rice atrium.
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4/5/2017
Physics & Astronomy Senior Capstone Presentations
Physics and Astronomy Senior Capstone presentations continue with:
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Michaela Koller, "Conductivity Measurements of a Thermoelectric Nanomaterial through THz Spectroscopy"
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Sophia Wiedmann, "Physical Principles Governing the Accumulation of Microbes during the Formation of a Biofilm"
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3/29/2017
Physics & Astronomy Seminar--Development of Multifunctional Graphene-Based Nanocomposites for Energy Conversion and Storage
Dr. Lifeng Dong, Assoc. Prof., Hamline Univ., Physics Dept., will present "Development of Multifunctional Graphene-Based Nanocomposites for Energy Conversion and Storage."
Due to their unique structure, chemical, electrical, mechanical, optical, and thermal properties as well as relatively ease of synthesis and functionalization, graphene and graphene-based nanocomposites have been extensively investigated for broad applications, such as in biosensors, catalysis, electronics, energy conversion and storage, and medicine. This talk presents recent progress and general aspects of graphene and graphene-based nanocomposites in renewable energy production and storage, especially dye-sensitized solar cells, organic solar cells, proton exchange membrane fuel cells, supercapacitors, lithium-ion batteries, and lithium-air batteries. In addition, challenges and future perspective in these fields are also discussed.
Refreshments at 3 p.m.
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3/22/2017
Physics & Astronomy Senior Capstone Presentations
Physics & Astronomy Senior Capstone presentations continue with:
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Kathleen Fitzgibbon speaking on "A Direct Comparison of Lyman-Alpha and Neutral Hydrogen Morphologies;"
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Quinton Singer speaking on "Almost Dark Galaxies: The Search For Stellar Counterparts."
Refreshments at 3 p.m.in Olin-Rice atrium.
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3/8/2017
Physics & Astronomy Senior Capstone Presentations
Join Physics & Astronomy for more Senior Capstone presentations.
Kelsey Harmatta will speak on "Controlling Resistivity: Charge Carrier Density Modulation in Barium Stannate via Ion Gel Gating." Elliot Weiss will speak on "Carrier Lifetime versus Temperature in an Intermediate Band Semiconductor."
Refreshments at 3 p.m. in Olin-Rice atrium.
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3/1/2017
Physics & Astronomy Seminar -- Nanoscience Research at the University of Minnesota
James Marti, Ph.D., Senior Scientist & Outreach Coordinator, University of Minnesota Nano Center
Nanoscience and applied nanotechnology have attracted interest from scientists, engineers, and the general public for decades. But what is nanotechnology, and why would someone want to do research in the field of nanoscience? This presentation will offer an introduction to nanoscience and nanotechnology, present a summary of some of the current nanoscience research focus areas at Minnesota, and describe opportunities for faculty and students from other institutions to collaborate with the Nano Center.
Refreshments at 3:00 PM
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2/23/2017
Physics & Astronomy Seminar -- Extreme Science! Submillimeter Instrumentation and the Study of Galaxies in the Early Universe
Dr. Carl Ferkinhoff, Asst. Prof., Physics Dept., Winona State is presenting.
Our galaxy, the Milky Way, is a pretty typical galaxy. There are many galaxies, both in the early universe and nearby, that are not so typical and are quite extreme in their properties. These galaxies, called ultra-luminous infrared galaxies (ULIRGs) can be hundreds to thousands of times brighter than the Milky Way, emit most of their light at infrared wavelengths, and produce many thousands of stars per year. One of the best ways to study these galaxies is by observing spectral lines that are emitted in or redshifted into the submillimeter regime (wavelengths of light between 0.2 to 1 mm). My research involves studying the submillimeter radiation from these extreme galaxies in the early universe by using extreme instruments and telescopes like the Atacama Millimeter/Submillimeter Array (ALMA) or our instrument ZEUS-2. This talk will explore the extreme locations and extreme technologies that are required by submillimeter astronomy. It will provide an overview of what we have learned so far and of new extreme science projects providing key insights into extreme galaxies and their evolution over cosmic time.
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2/22/2017
Physics & Astronomy Senior Capstone Presentations
Physics & Astronomy Senior Capstone Presentations kick off with Joshua Rollag speaking on "Intervalley Scattering in Tellurium" and Eli Lilleskov on "The Chiral Magnetic Effect."
Refreshments at 3 p.m. in Olin-Rice atrium.
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2/1/2017
Physics & Astronomy Seminar--Laboratory Astrophysics: Looking Up by Looking Down
Assistant Professor Michael Wood, University of St. Thomas, Physics Department, will present "Laboratory Astrophysics: Looking Up by Looking Down."
Astronomical research often includes a combination of observations, theoretical models, and computer simulations. Laboratory measurements, which help astronomers understand and interpret their data, are a fourth and often forgotten piece of astronomy. Small-scale laboratory experiments have far-reaching implications in the search for exoplanets, discovering the nature of dark matter, and understanding the origins of life. In this talk I will discuss the role of laboratory astrophysics by focusing on one particular aspect: atomic spectroscopy. Modern astronomical observations demand higher quality and quantity atomic data to, for example, understand the evolution of the chemical elements throughout the history of the Galaxy.
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12/7/2016
Physics & Astronomy Seminar--High Precision, Not High Energy: Looking for Exotic Physics Using Atoms and Molecules
Dr. Chad Orzel, Assoc. Prof., Union College is presenting.
The Standard Model of particle physics is one of the most successful theories in the history of science, but we know from phenomena like matter-antimatter asymmetry, dark matter and dark energy, and neutrino masses that the Standard Model is not complete. While the best-known searches for physics beyond the Standard Model involve particle accelerators and huge detectors, there are smaller experiments in labs around the world looking for signs of new physics with atoms, molecules, and lasers. While the effects of exotic particles are tiny at the atomic scale, the unparalleled precision of modern spectroscopic techniques makes it possible to detect even such minuscule effects. These measurements provide some of the tightest constraints we know of on physics beyond the Standard Model.
Snacks at 3 PM in the first floor atrium.
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11/22/2016
Physics & Astronomy Seminar--Observational Tests of Stellar Physics
Dr. Philip Rosenfield, National Science Foundation Postdoctoral Fellow, Harvard-Smithsonian Institute for Astrophysics
Stellar evolution models are fundamental to nearly all studies in astrophysics. They are used to interpret the light from distant galaxies, to derive the star formation histories of nearby galaxies, and to understand fundamental parameters of exoplanets. Despite the success in using stellar evolution models, some important aspects of stellar physics remain poorly constrained and their uncertainties rarely addressed. In this talk, I will discuss how I use Hubble Space Telescope observations of star clusters and nearby galaxies to better understand the physics of stars.
Lunch will be served.
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11/16/2016
Physics & Astronomy Seminar--Tracking the maturation of organelles and signaling cluster with quantitative super-resolution microscopy
Dr. Elias Puchner, Assistant Professor, Physics & Nanotechnology, University of Minnesota-Twin Cities, is presenting.
Quantitative Super-Resolution Microscopy is evolving into a powerful biophysical technique to study biological processes below the optical diffraction limit. However, a deeper understanding of the biological structures under investigation is often limited by the inability to quantify their molecular composition while resolving their size and shape. I will present our solution to this challenge, an intracellular calibrated Photoactivated Localization Microscopy (PALM) approach, that can measure the size of individual organelles with 20nm resolution as well as count the absolute numbers of molecules they contain.
Using this technique, we simultaneously characterized the size of individual vesicles in the yeast endocytic pathway and the number of accessible PI3P binding sites they contain. The analysis of many steady-state super-resolution snapshots revealed a characteristic vesicle maturation trajectory of composition and size as well as mechanistic information indicating that PI3P production precedes fusion into larger endosomes. Colocalization analysis with known markers of vesicle maturation showed that these regulatory proteins (clathrin, Vps21, Ypt7) associate with different regions of the observed endosome maturation trajectory. I will conclude by presenting ongoing technical developments from my new lab to correct for movement of organelles during PALM imaging in live cells.
In addition I will present the application of single molecule tracking to study the spatial clustering and change in diffusion of signaling complexes, which presents an additional regulatory layer that actively tunes pathway gain. We demonstrate that clustering of the signaling complex itself activates the pathway bypassing receptor activation and that the degree of clustering correlates with the adaptive output.
Snacks at 3 PM, OLRI atrium.
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11/10/2016
Stand Back--I'm going to try Science
Physics and astronomy majors, You are cordially invited to the annual physics and astronomy summer research information session on Thursday, November 10, from 12 to 1 pm, in Olin-Rice room 350 (please note the unusual location).
Learn all about interesting, paid summer research opportunities both here at Macalester and at other institutions. Participation in a research project is a transforming experience that is an essential part of your training to become a professional physicist. It is also a graduation requirement.
So come to the meeting and have some pizza as well!
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11/9/2016
Physics & Astronomy Seminar: First Direct Detections of Gravitational Waves
Dr. Vuk Mandic, Associate Professor, School of Physics & Astronomy, University of Minnesota will present.
During their first observation run the Advanced LIGO gravitational-wave detectors recorded signatures of mergers of binary black hole systems. These events mark the beginning of gravitational-wave astrophysics, enabling a new approach to studying various astrophysical phenomena. I will describe the LIGO detectors and the events they recorded, and I will discuss the implications of these observations as well as our expectations for future observations.
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11/3/2016
Physics & Astronomy Seminar: Little Big Bangs at the Relativistic Heavy Ion Collider
Prof. Marzia Rosati, Iowa State University, Physics Dept. will speak on 3 November, 4:30 PM, 100 OLRI (Please note: different day, time, place from usual Physics/Astronomy seminars).
The Relativistic Heavy Ion Collider facility at Brookhaven National Laboratory on Long Island, NY collides gold (Au) nuclei at an energy of 200 GeV per colliding nucleon pair with the goal of creating and studying the `quark-gluon plasma' (QGP) in the laboratory. The QGP is a unique state of strongly interacting matter that is predicted to exist at temperatures in excess of 1011 ºK when the protons and neutrons in nuclear matter dissolve, releasing the normally confined quarks and gluons. This deconfined phase of matter is similar to conditions in the early universe when it was only a few microseconds old. In this talk I will review the remarkable and unexpected results from RHIC and what they may tell us about the properties of hot, strongly interacting nuclear matter.
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10/27/2016
Extra Public Observing Night
This week there will be an extra Public Observing Night due to the Fall Sampler! Same time, same place: 8:30 to 10:30 pm in Olin-Rice 404 (use southwest staircase). Bring a pf, bring friends, bring yourself.
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10/14/2016
Physics & Astronomy Seminar--Non-Equilibrium Quantum Phenomena: Rydberg Bosons, Dirac Fermions and Beyond
Dr. Jigang Wang, Assoc. Professor, Dept. of Physics & Astronomy, Ames Lab, Iowa State U. will speak.
The challenge to push the gigahertz switching speed-limit of today’s electronic devices into the terahertz regime underlies the entire field of information processing, storage, communication as well as integrated multi-functional systems. One key fundamental issue is how photoexcitations evolve in time into Coulomb-bound, collective excitations and unbound charge carrier transport. Up to now, the initial quantum dynamics following photoexcitation remains inaccessible in many newly–discovered, exotic materials despite of their significant potential for photovoltaic, quantum and optoelectronic technologies. In this talk, I will discuss to implement an emerging theme: use ultrashort and low-energy laser pulses to both probe and control non-equilibrium quantum dynamics under salient conditions of femtosecond in time and milli-electron volts (terahertz) in energy. I will elaborate two recent examples in our program, from the quantum formation pathways in the birth of Rydberg bosons in the hybrid perovskites to control coherent Dirac fermion transport in topological insulators. Finally I will briefly discuss long-term vision and far-reaching consequence of this cross-cutting theme in future science and technology.
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10/13/2016
Extra Public Observing Night
This week there will be an extra Public Observing Night - OLRI 404 (use southwest staircase). Bring a pf, bring friends, bring yourself!
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10/10/2016
Public Observing Night
Love to look at the stars? Come to Public Observing Night! Check out Macalester's very own 16 inch telescope and gaze at such varied objects as Neptune, the Owl Cluster, the Albireo binary system, and more (weather permitting). (Take the southwest stairs).
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10/7/2016
Distinguished Alumni Lecture: Biniyam Taddese
Biniyam Taddese, PhD, '06 majored in Physics, Math and Computer Science and will be speaking in Libby Shoops' Computer Systems Organization class
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10/7/2016
Distinguished Alumni Lecture: Biniyam Taddese
Biniyam Taddese, PhD, '06 majored in Physics, Math and Computer Science and will be speaking in James Heyman's Modern Physics class
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10/5/2016
Joint Physics & Chemistry Seminar--Quantum Dot Photocatalysis
Dr. Emily Weiss, Chemical Physicist, Department of Chemistry, Northwestern University will speak.
This talk, based on the research by Stephen C. Jensen, Stephanie Bettis Homan, and Emily Weiss, will describe the use of cadmium sulfide quantum dots (CdS QDs) – single crystals of CdS with diameters of ~3 nm – as visible-light photocatalysts for the reduction of nitrobenzene to aniline through six sequential photoinduced, proton-coupled electron transfers in water. Transient absorption spectroscopy and nuclear magnetic resonance (NMR) are used to analyze the mechanisms of molecular adsorption to the QD, and to show us how the environment at the surface of the QD promotes chemical transformations.
Snacks at 3:00 PM.
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9/19/2016
Physics & Astronomy Seminar--The Visible-to-Shortwave-Infrared Spectrum of Atmospheric Polarization: Modeling, Applications, and Future Growth
Laura M. Dahl & Wataru Nakagawa, Electrical & Computer Engineering, Montana State
Environmental remote sensing and military sensing use optical polarization imaging to retrieve atmospheric properties for climate studies and to identify man-made objects in space, in the air, or on the ground. Knowledge of the polarization state of natural skylight is important to growing applications using polarimetric sensing. Polarization adds an additional dimension beyond basic image intensity and color for enhanced target detection. Skylight becomes partially polarized when sunlight is scattered in the atmosphere and our research focuses on how skylight polarization changes from the visible-to-shortwave-infrared. We have studied how skylight polarization can be used to detect poorly resolved airplanes in flight during daytime partly cloudy and smoky conditions and in other conditions.
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9/12/2016
Public Observing Nights
Did you know that Macalester has an observatory? And that we open it to the public? Come check out the night sky with Physics and Astronomy! We hold Public Observing Nights on alternate Mondays and Wednesdays from 8:30 pm until 10:30 pm. So come up tonight to Olin-Rice 404 (use the southwest stairwell) and admire the stars!
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9/1/2016
Physics & Astronomy Informational Session
The force is strong with us. And weak. And gravitational. And electromagnetic.
Join the Department of Physics & Astronomy for an informational session about the physics major. Faculty members, students, and the Physics and Astronomy Club will provide a wealth of information about the power of physics. Pizza and pop provided.