ALFALFA data releases Rules of the scavenger hunts: You may consult any
source anywhere but please be sure to indicate where you got your information.
And watch out
for bad websites!
UAT09.01 Scavenger Hunt #1: Using Arecibo and using ALFA for ALFALFA
This scavenger hunt will explore some details of how we use ALFA and how we use it for ALFALFA.
1.0 Which of the ALFA
beams are "uphill" when we observe a source at a Declination of
+03o24'24"?
1.1 We do not normally observe in the afternoon. Why not?
1.2 What does J2000 refer to?
1.3 What is the LST time at 3:45 pm AST?
1.4 What declination will correspond to each of the six ALFA beams
when we observe ALFALFA drift 14p2 at a Declination of +03o24'24".
Be sure to indicate numerically each beam according to ALFA convention.
1.5 In a famous movie,
where was Roger Thornhill when he
said "I don't like the way Teddy Roosevelt is looking at me"?
1.6 The ALFALFA observing setup uses the
WAPP spectrometers which deliver spectra which cover 100 MHz total,
centered on 1385 MHz. Each spectrum has 4096 "channels" (or "pixels" in
frequency space, or "array elements", however you want to think of them).
What channel corresponds to 1385.0 MHz?
To what velocity does a frequency of 1385.0 MHz correspond for the 21 cm HI line?
1.7 Each team should investigate a galaxy detected by
ALFALFA. Make a note of links where you were able to find information about the
galaxy. Distinguish between observed properties and derived ones. Also develop a
"wish list" of what more you'd like to know/do. There is nothing particularly
special about these objects but of course, all galaxies are interesting!
