ASTRONOMY 3303   HW#5     due Wed Oct 18, 2017


Print a copy of this page and enter it in your portfolio.


Part I: FAST
The new FAST radio telescope is now nearing completion. Prepare a one-page handout of relevant information about FAST directed to an audience of your peers (Cornell undergrad phys/astro/engr/similar majors). Include at least one diagram, table or image; choose it to make a scientific or technical point, not just for flash. Also, include a direct comparison (not only in size) to other large single-dish radio telescopes in the US, such as the Green Bank Telescope (GBT) and Arecibo.


Part II: The ALFALFA galaxy population
ALFALFA, the Arecibo Legacy Fast Arecibo L-band Feed Array survey, is a survey of HI 21cm emission in nearby and low-redshift galaxies, led by Cornell professors Martha Haynes and Riccardo Giovanelli. Find here a CSV file containing useful information extracted from the population of galaxies included in both the 2011 public ALFALFA survey catalog (α.40 Haynes et al. 2011) and the SDSS DR7 database. Let's use this file to explore some interesting characteristics of the population of galaxies detected by ALFALFA. Examine the contents of the file before you start working with it and be sure that you understand what all the columns mean (remember the SDSS help page); if you don't understand any of them, ask. This information on the radio spectrum may be useful in the context of understanding and interpreting radio observations. In general, remember to use wikipedia with care - it is a useful source of information, but not a scholarly source like the textbook or refereed scientific publications.


Part III: Group discussion: G2
In class, we had a detailed discussion about the Galactic center. A few years ago, the exciting object G2 was discovered near the supermassive black hole, as discussed, e.g., here:

http://www.eso.org/public/news/eso1332/ : 2013 ESO press release on G2


What did people think at the time the nature of this object is, and its fate? Discuss with your group the relevance of these observations, and how they were made. For possible paths of inquiry, look at your previous discussions. After you have studied the press release in detail, research on the web (including the astronomy query tools you have encountered so far) what has happened to this discovery since, and what other ideas have been proposed for the nature of the object. Use at least one recent scientific publication in your discussion. Also, as a group, be prepared to give a 3 minute summary of your discussion during the lecture on October 18th, as a lead-in to discussing your findings with the other groups. It may be useful to assign a discussion leader and a note taker within your group. If you require any form of media, please prepare handouts or anything equivalent that is suitable for sharing at the table. Also, as usual, please provide a brief (1-2 page) write-up of your discussion.
NOTE: Self-organize in groups of up to 3-4 students for this discussion. Clearly indicate and give credit to all members of the discussion group, and clearly reference all source materials you consider in your discussion (e.g., specific parts of the press release, newspaper articles based on this release, the textbook, class notes, etc.). You may hand in only one copy of the report for your group if preferred, but make sure that all names are provided!