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Search for Student Research Assistant I’m looking for a student research assistant or two for Fall 2015 semester. It is possible that further research work could go on the student’s transcript. The research may lead to publication in a journal or presentation at a conference. Prerequisites: Currently in 2nd semester of Intro Astronomy, or on a calculus-based physics track. Ability to program computers is a plus. Skills to pick up on the project: Use of Unix or Linux computer operating system. Programming in Mathematica or IDL languages. Projects Available: 1) Designing a “Citizen Science” site. We use citizen science sites in Astronomy Lab. For a taste, go to http://www.zooniverse.org The idea is that regular people can be very useful to astronomers by categorizing data over the internet. Computers are still not very good at recognizing patterns. That is why when a website needs you to prove that you are a human being and not a program using the site, you will be given a “Capcha” image and have to read the distorted letters. For example, within the “Zooniverse” was something called the “Galaxy Zoo” that showed images of galaxies seen with the Hubble Space Telescope to users over the internet. What I imagine us doing is creating a site where users can help us understand the flickering of X-rays around black holes by helping to recognize where each oscillation starts and stops. I’m particularly interested in the data of the black hole system GRS 1915+105. 2) Entering a “Big Data” contest on Kaggle.com. One contest in particular involves computer methods to make discoveries about the basic particles of nature. The contest is called “Flavours of Physics: Finding , and you can have a look at the site here: https://www.kaggle.com/c/flavours-of-physics There is a total of $15,000 awarded for those who do very well on this contest. Basic summary: we will use data from the Large Hadron Collider, humanity’s most advanced particle experiment. Just as there are electrons in atoms, there is a possibility of a heavier, similar particle called a muon, or There is a still heavier particle called or tau. We will develop some advanced computer programs to find evidence for a particular reaction in nature where a tau particle breaks apart into three muons. 3) Flickering radiation from a dead star may reveal details of the gas flowing around it. Scorpius X-1 (Sco X-1 for short) is a double star system. It’s actually the brightest spot in the sky in X-rays (other than the Sun). Of the two stars, one is a normal star, slightly less massive than our own Sun, but the other is a neutron star (a collapsed star only about 10 km across). Sco X-1 was the first discovered star system of its type. It is particularly interesting because although it has a neutron star, no pulsations have been seen. It is the brightest of a class of neutron star systems called ``Z sources”. What is the project and what would the student do? In August, ultraviolet observations from the Hubble Space Telescope of this star system became public. The main investigator told me he is looking to study the gas in front of the star, and not the star itself, so that we are not duplicating his effort. I have a plan to study how the ultraviolet spectrum of the star itself is changing. There is a very small chance we could discover pulsations from this star system, never seen before, but there is also very interesting flickering “noise” that we could measure and compare at different times and wavelengths. This project would involve learning and using the IDL programming language and learning “time series analysis” and “Fourier transforms and power spectra” which are useful in many fields of science, mathematics, and economics. More information: technical paper my team wrote on Hubble data 10 years ago, http://iopscience.iop.org/0004637X/502/1/441/pdf/36461.pdf. Paper on Fourier techniques of time-series analysis: http://dl.dropbox.com/u/8721683/Fourier_techniques.pdf. PowerPoint summary of Fourier techniques in time series analysis: http://pulsar.sternwarte.uni-erlangen.de/blackhole/2ndschool/talks/amsterdam_ITNschool_2010.pdf. 4) A method to figure out which X-ray stars are black holes and which are neutron stars. A collaborator of mine at Harvard has an idea for a way to find out, from the varying spectrum of a star in X-rays, whether it is a neutron star or a black hole. The method is a little similar to the “HR diagram” taught in Astronomy 1020. Two kinds of colors are plotted for each star at each time along with the apparent brightness, for a 3D plot. We are using the Mathematica software to make 3D plots we can see from different angles. We have already applied the method to X-ray stars in the Milky Way and nearby galaxies, but now we want to use it on galaxies further away. The student who works on this project will have to pay close attention to computer files that record the brightness of X-ray stars in different X-ray colors. We will have to put together data from different forms to make these 3-dimensional plots. More information: http://heawww.harvard.edu/~saku/SED.html This project does NOT require ability in advanced math techniques, only finding ways to organize and present data. A student could also go a little further and work with me on making a theory of why the method seems to work. 5) Cygnus X-1 is a star system that very probably contains a black hole feeding off a normal massive star. I have been working with a student to understand dips in X-rays coming from the star system periodically along with the orbit of the two stars. The dips tell us about gas flowing in the system. The black hole can be in different “states” of brightness and the gas flows can be affected based on what state of X-ray brightness the black hole is in. Let’s try to compute theoretically how the gas might flow and compare with the observed dips. Starting with some publically available programs (probably in FORTRAN) we can modify the program to study how the gas flows in a binary star system, influenced by gravity, by heating, and by ionization from an X-ray star. This is a potentially challenging project both for the student and for me. There would be an advantage if we could hook up several computers to work on the problem at the same time. This would be a very challenging project (for both student and myself). The student would learn computational hydrodynamics. 6) Helping to make some preliminary studies and writing a proposal to observe the star system Centaurus X-4. This is a binary star system with a normal star and a neutron star. What’s unusual here is that the gas flow is very weak. Only every once in a while does it turn up to strong steady gas flow and the X-rays become bright. We’re trying to understand what happens at low gas flow, because it’s harder to see when it doesn’t light up as much. Does the heat get carried along with the gas, instead of being released in radiation? What could we see with the Hubble Space Telescope pointed to observe Cen X-4? There are already some crude observations with Hubble, but new instruments allow us to see things better. 7) Developing new techniques of “Doppler Tomography”. Doppler Tomography lets one reconstruct how a binary star system looks from changing spectral lines. This project would involve programming in Mathematica and could involve either Fourier methods or a data technique called “Maximum Entropy Reconstruction” or a method borrowed from radio astronomy called “CLEAN”. We would apply this method to different star systems. Goals are to test experimental methods to get a 3-dimensional view of the star system (most methods only get a 2-dimensional view) and to use separate spectral lines to see through the gas. 8) A more “out-there” project is to work on models of quantum physics in which space and time are not infinitely divisible, but in which there is a discrete smallest possible size or time interval. I’m offering this project for students who can handle quantum and math concepts and want to work on something more unusual. There are some physicists who speculate the Planck length may be a lower bound for size in the universe, and we could work on improving models related to “the Feynman checkerboard” or the material graphene which explain quantum behavior, but that are limited in some ways.