ALFALFA data releases Rules of the scavenger hunts:
1. Some questions are labeled (F: first timer) and (R: returnee).
First time attendees should focus on the "F" questions; returnees on the "R" ones.
Everyone should answer the questions without designations.
In all cases,
return attendees shall not
reveal the answers to first timers until sufficient effort is
expended. (And, any bribes must be shared 50:50 will the Scavenger Hunt creators.)
2. You may consult any
source anywhere but please be sure to indicate where you got your information.
And watch out
for bad websites! Actually, if you find any mis-information, make a note
of it for the blog.
UAT12.01 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 next fall the ALFALFA drift at a Declination of
+33o05'36" (drift 136p2)?
1.1 We do not normally observe in the afternoon. Why not?
1.2 Why are we using L-band wide (LBW) instead of ALFA tonight?
1.3 What does J2000 refer to?
1.4 What declination will correspond to each of the six ALFA beams
when we observe next fall the ALFALFA drift 136p2 at a Declination of +33o05'36"?
Be sure to indicate numerically each beam according to ALFA convention. 1.5 At the current moment are the
ALFA amps on or off? Be sure to record the exact time/date when you provide this answer.
1.6 What is the LST time at 3:45 pm AST today
(January 17, 2011)?
1.7 (R) What is the declination of the
A2010 observation that was observed on March 21, 2010? Who conducted those observations?
1.8 (F) In what 1984 movie did the
unsympathetic government agent say:
"Do you seriously expect me to tell the President than an alien has landed, assumed the
identity of a dead housepainter from Madison Wisconsin and is presently out tooling around
the countryside in a hopped up orange and black 1977 Mustang?" 1.9 (R) In what 1942 movie did an observer report:
"Dark object floating off starboard bow, sir."?
1.10 (F) 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 1381.0 MHz?
To what velocity does a frequency of 1381.0 MHz correspond for the 21 cm HI line?
What RFI occurs at 1381 MHz?
1.11 (R) The ALFALFA followup LBW observing setup uses the
interim correlator which deliver spectra which cover 25 MHz total. The center frequency of the
spectrum is shifted according to the observing mode. Each spectrum has 2048 "channels" (or "pixels" in
frequency space, or "array elements", however you want to think of them).
To what velocity does a frequency of 1410.0 MHz correspond for the 21 cm HI line?
How does the spectral resolution of these observations compare to those obtained for the ALFALFA
legacy observations using the WAPPs?
What are the two observing modes adopted for the A2669 followup observations? What dictates
which of the two we use?
1.12 What is odd about the rotation of Venus, and how and when was
that determined?
1.13 What former Arecibo atmospheric scientist is the author
of the mystery novel "Murder at Arecibo"?
1.14 (R) How strong is the strongest radio continuum
source found within one degree of AGC 110977? (We may want to discuss how to go about answering this.)
1.15 How should you start up IDL for use here at the
workshop? Hint: follow this link 1.16 (F) Each team should investigate a galaxy detected by
ALFALFA. Try out the LOVEDATA procedures plotalfa and skyd.
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. These **are** interesting galaxies;
what is interesting about them?
