An Update from the World’s Largest Telescope
In January 2012, two Hartwick physics majors accompanied me to the National Astronomy and Ionosphere Center (NAIC) in Arecibo, Puerto Rico in order to participate in the 2012 Undergraduate ALFALFA Workshop.
The NAIC is one of the world's premier scientific facilities and host to a wide range of cutting-edge research in radio astronomy and beyond. The main reflecting dish is more than 1,000 feet in diameter and contains the surface area of more than 26 football fields, making it the world's largest telescope of any kind. It is used to observe everything from distant galaxies and pulsars hundreds of millions of light years away to phenomena in our own ionosphere that can help with studies of the Earth's climate. The NAIC is also one of only a handful of facilities capable of tracking near Earth asteroids, and is used to determine if any of these pose a serious threat to us.
The 2012 Undergraduate ALFALFA Workshop was funded by the National Science Foundation and brought together researchers involved in the ALFALFA extragalactic survey from colleges and universities coast to coast. It provided faculty and students with lectures by leaders in extragalactic astronomy, atmospheric science, radio astronomy engineering and planetary science.
More importantly, it provided hands-on training with specific data analysis techniques, opportunities to share recent research progress with ALFALFA and some highly valuable experience at the controls of the telescope itself using a new detector.
Catherine Weigel '12 and Nathan Nichols '14 each presented results of work they completed last summer at Hartwick in collaboration with Jaclyn Patterson '13 and me. This research is part of a continuing effort by several ALFALFA institutions to study groups and clusters of galaxies. These particular systems had between 48 and 166 galaxies each.
Catherine presented work quantifying the amount of star forming gas in individual galaxies. This allows one to characterize the cluster environment, determine each galaxy's ability to create new stars, and can help assess how often galaxy collisions have taken place. She was also one of two student leaders for an observing proposal providing the scientific justification for attaining valuable telescope time.
Nathan presented work focused on determining the amount of overall mass each cluster has using four dynamical methods. These calculations rely on measurements of the speed and location of galaxies within the cluster. His mass estimates are designed to include the effects of mysterious stuff called "dark matter", which emits no light and can be inferred only by its gravitational effects. Nathan also wrote two computer codes that will provide other researchers involved in ALFALFA some important tools to use for their studies. In addition to the workshop presentations at Arecibo, Hartwick students Weigel, Nichols, Patterson and Michelle Brault '11 have each presented their research work at one of the national meetings of the American Astronomical Society in Seattle, Boston or Austin, TX over the past year.
Since last March, I have been also using the giant radio telescope from confines of the Johnstone Science Building on campus. So far, seven undergraduate students have participated in this "remote observing" team and observations have been carried out from Hartwick over seven different nights. It makes use of a secure link between the NAIC in Arecibo and computers in the Physics Department.
When the ALFALFA observations are completed next fall, they will cover more than 7,000 square degrees of the sky and detect more than 30,000 galaxies. This is an enormous portion of the sky in can be used to make statistical arguments about the universe as a whole (for reference, four moons fit into one square degree).
At the workshop this January, the ALFALFA team began the second phase of the research, which will include performing follow-up observations of many of the most interesting candidates found in the massive survey. The targeted follow up is called "Harvesting ALFALFA" - an appropriate nickname. It will involve a different sort of observing procedure demonstrated for the first time at the workshop by Dr. Martha Haynes from Cornell University. This will involve using longer exposure times and a more sensitive receiver called "L-Band Wide" (LBW).
Already, in the very first nights of LBW observing, the ALFALFA team has detected some galaxies appearing to have interesting properties never seen before. Needless to say, the whole collaboration is very excited! I will once again to travel to Arecibo in the coming months with Hartwick students Jaclyn Patterson '13 and Kyle Murray '15 in order to perform more of these LBW follow up observations, so... stay tuned!
This work was funded by National Science Foundation grants AST - 724918, AST - 0725267, AST - 0725380 and a Hartwick College Freedman Research Prize.
ALFALFA stands for Arecibo Legacy Fast Arecibo L-Band Feed Array.