2013 Dunlap Research Projects
Stars around the supermassive black hole at the centre of the Milky Way Galaxy
The centre of the Milky Way Galaxy represents one of the most extreme astrophysical environments in the nearby Universe, with a supermassive black hole of 4 million solar masses and stellar density greater than 1 million stars per pc3. Given its proximity, we can study the effects of such extreme environments on star formation and the long term interaction between stars and a supermassive black hole in detail.
The advent of adaptive optics in the past decade and the recent addition of instruments on the Hubble Space Telescope has provided us with the means to obtain imaging and spectroscopy of individual stars even in this crowded region. The interested student will use data from the Keck telescopes, Gemini and the Hubble Space Telescope to study the stellar population and star formation history of the galactic centre, or to construct a dynamical model of stars around the supermassive black hole.
An extremely young star-formation system in a nearby cluster
In our galaxy, most stars form in clustered environments. The Serpens South Cluster is a nearby cluster of embedded young stellar objects identified in the Serpens molecular cloud through mid-infrared imaging as part of the Spitzer Gould Belt Legacy Survey. Star formation in the cluster has likely only very recently begun, as many of the detected sources are extremely young. The cluster star formation rate is also very high, suggesting that many more stars will be able to form before the surrounding dense gas is removed through radiation and stellar winds.
This cluster thus offers an unusual chance to study an extremely young system before gas dispersal and stellar dynamics have dramatically altered the landscape. The student will work on analysis of a large (~ 0.5 square degree) map of ammonia (NH3) emission towards the Serpens South Cluster taken with the Green Bank Telescope. NH3 observations selectively probe the dense gas associated with the cluster, revealing the regions where stars may yet be forming. The student will gain familiarity with data cubes, spectral-line analysis, and dark cloud chemistry, and will analyse the kinematics of the gas on small- and large-scales with the goal of comparing the results to theoretical models of star cluster formation.
Exploring the Sagittarius Stellar Stream: Multi-body interactions in the galactic halo
The Sagittarius (Sgr) dwarf spheroidal galaxy is one of the most well-studied companions to the Milky Way Galaxy. Currently just 16 kpc from the galactic center, gravitational tides are shredding Sgr into streams of stars that have been observed to wrap entirely around the Milky Way Galaxy. The path of these stellar streams is dictated by the gravitational potential of our galaxy, and thus tells us about the underlying size and shape of the galactic dark-matter halo.
The student will study N-body simulations of the path of the Sgr dwarf, and will help to develop models that incorporate multi-body interactions. A background in astronomy is preferred, as is a familiarity with scientific programming languages (C++ and Fortran particularly).
Polarized Microwave Calibrator
The Cosmic Microwave Background (CMB) has proved an invaluable source of cosmological information, providing us with an image of the Universe when it was only a few hundred thousand years old. Current experiments have moved on from measuring the intensity of the CMB to mapping the faint polarization patterns imprinted by various cosmological processes.
This project is to help develop a general-purpose polarized microwave calibration source, to be lofted into the far field of microwave telescopes on a weather balloon. In the long run, we aim to fly a balloon to ~15km altitude to calibrate the polarization sensitivity axes of the South Pole Telescope, an aptly-named 10m telescope located at the geographic south pole.
To correctly perform this calibration, we must be able to reconstruct the attitude (orientation) of the source during flight to very high accuracy. The student will work on various systems to help with this calibration, including a high-accuracy Sun sensor and a star camera. This work will involve at least one test flight of a high-altitude balloon and payload, and likely also a nighttime flight using the star camera to verify other methods of attitude reconstruction.
CHIME Pathfinder Commissioning
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is an ambitious project to map the large-scale structure of the Universe over half the sky and a broad swath cosmic history, using 21cm emission from neutral hydrogen. It is a planned 100m x 100m “digital” radio telescope—a fixed structure which, rather than physically steering to survey different regions, simultaneously observes much of the overhead sky, at high resolution, using digital interferometry.
Since CHIME will be among the first in this new class of digital telescopes, a reduced-scale pathfinder instrument is under construction to test many of the technologies and techniques which will be required by full CHIME. The pathfinder will be commissioned throughout 2013, and there are several projects where students could become involved:
- Pulsars drift overhead regularly, and form near-ideal calibration sources for mapping beams and monitoring gains. The student will analyze data from the dozens of known pulsars passing through our beams and develop an automated system so this analysis runs continuously and in real-time.
- The instrument performance will ultimately decide how precise the final maps and measurements of cosmic expansion are, and it is important to get a sense of that early on so we can correct for unexpected problems. This primarily constitutes a study of the noise in and crosstalk between each of the 128 feeds channels.
- Operating over the 400-800MHz band, CHIME encounters a host of terrestrial Radio Frequency Interference (RFI), ranging from digital television stations to cell phone towers, and a system is needed to identify, flag and ultimately remove contaminated data.
Looking at MaNGA: Data visualization and software development for SDSS
Over the past 10 years, the Sloan Digital Sky Survey has systematically mapped the sky, cataloguing galaxies from our nearest neighbors to the most distant reaches of the Universe. In 2014, the SDSS will take us in a radical new direction: INSIDE nearby galaxies. MaNGA (Mapping Nearby Galaxies at APO) is a next-generation component of SDSS-IV that will obtain integral-field spectra for 10,000 nearby galaxies, mapping the velocities of their stars and gas, and measuring their chemical composition. MaNGA will consist of 15 integral-field units assembled from 20-100 fibers, with additional fibers dedicated to sampling the background sky. The survey will run for six years and will yield millions of individual spectra.
We have two openings for students to work with us in preparation for MaNGA:
(1) We are looking for a student to help us work on the development of visualization and analysis software to display and interact with the large quantities of data that will be delivered by MaNGA. The student will gain expertise in working with integral-field kinematic data, as well as analysis software to extract kinematical and chemical information of the observed galaxies out of the spectra. A background in computer science is preferred, as is a familiarity with scientific programming languages (in particular IDL), but students from other disciplines who have a strong interest in extragalactic astronomy and background in scientific computing will also be considered.
(2) We are looking for a student to work with us on calibration software for MaNGA. This summer we will have test data available from MaNGA prototypes, which can be used to optimize the calibration of our MaNGA data, and to make sure that we get the maximal quality out of our data set. The student will gain expertise in working with integral-field data, as well as analysis software to extract kinematical and chemical information of the observed galaxies out of the spectra. A background in astronomy or computer science is preferred, as is a familiarity with astronomy data reduction and scientific programming languages (in particular IDL), but students from other disciplines who have a strong interest in extragalactic astronomy and background in scientific computing will also be considered.
Science Studies and Simulations of IRIS, a First-light Instrument for TMT
IRIS will be a revolutionary instrument for the future Thirty Meter Telescope (TMT) that will study celestial objects at all distant scales, ranging from the nearby asteroids to the most distant galaxies in the Universe. IRIS is being designed to exploit the adaptive optics system being designed for TMT, which will yield unprecedented spatial resolutions and detail of sources that will be better than any other current optical ground-based and future space-based telescopes.
Students will participate in the development and investigation of science cases for IRIS and TMT. They will learn about near-infrared astronomical imaging, unique spectroscopic techniques like integral-field spectroscopy, and adaptive optics. Students will develop programming skills and data reduction and analysis techniques. Students will work with a data simulator and investigate in detail science cases for IRIS on potential topics like first-light galaxies, gravitational-lensed galaxies, nearby galaxies, microlensing, and Solar System objects. Depending on the timing of the project and instrumental progress, there may also be an opportunity to work on instrumentation testing and research for IRIS in the laboratory.
150 MHz Feed Design and Construction for the 46m Algonquin Radio Telescope
The 46m radio dish at the Algonquin Radio Observatory (ARO) is being re-commissioned for use—along with the Giant Meterwave Radio Telescope in India—in imaging pulsars via Very Long Baseline Interferometry (VLBI). As part of this work, a new 150 MHz radio feed needs to be built and installed at the ARO. VLBI is a technique pioneered in Canada in the late 1960s that combines signals from observatories around the world to synthesize a planet-sized telescope and achieve micro-arcsecond resolution. We aim to use interstellar lenses to boost this resolving power even further; and to maximize the signal, observations will be done at 150 MHz.
The interested student should have some basic skill in electrical engineering and, more importantly, a willingness to explore the complexities of antenna design. This project will involve at least one site trip to the ARO, located in Algonquin Provincial Park, north of Toronto, for installing and testing of the feed. The project will be supervised by Dunlap Professor Keith Vanderlinde. For more information, contact Prof. Vanderlinde.