The Arecibo Legacy Fast ALFA Survey

Arecibo Observatory

Preparation for UAT 2014 Workshop Observing Proposal Second Planning Telecon

Background Reading

Review Introduction to Gas Loss, Quenching of Star Formation, and Role of the Environment and answer the questions.
Review angular resolution, or beam size, of the telescope and how is it related to the diffraction limit at this link.
Review the L-Band Wide Receiver
Read about the ALFALFA L-Band Wide Followup Observing Modes (We will use high velocity mode)

Exercises

Check out this list of Galaxy Surveys/Databases and do the SDSS/NED exercise.

Use the tools you have learned to investigate example Observing Targets.

Questions

What is the frequency range covered by the L-Band Wide (LBW) detector? What wavelengths does this correspond to? Assuming that you were observing the 21-cm line, what range of velocities and redshifts does this correspond to?

What size bandpass will be using compared to the ALFALFA bandpass? Why is there a difference? How is the center of the bandpass determined for each observation?

What is meant by RFI?

What is meant by ON-OFF position switching? Why is this a useful technique?

What is the latitude of Arecibo Observatory? What is the declination of a source observed at the zenith?

Suppose we choose to observe a source with a declination of +09^o36'10" while it is on the meridian. We choose an azimuth angle of 360. What zenith angle would we use?

What will the (approximate) right ascension of the position of the OFF-source scan be when we observe a target at right ascension 11h48m28s?

What is meant by "quenching of star formation" and why might this happen in groups and clusters? What might the causes of quenching be different in groups vs clusters?

What kind of interaction(s) would you expect to be responsible for morphological change such as buildup of bulges or birth of giant ellipticals? Challenge question: what might cause the formation of a dwarf elliptical?

For the proposal:

Write a brief summary about each of the Observing Targets. Consider:

Star formation characteristics, e.g., what does the image look like? the spectrum?
What is the environment of the galaxy, e.g. is there any spectral information in the SDSS that would tell you whether the source is near another galaxy in space? How might diffraction limit our observation of galaxies near one another in space?

Prepare some figures showing information about the targets or a subset of the targets.

Answers will be discussed in the Second Observing Proposal Planning Telecon

Last modified: Thu Nov 21 09:46:17 EST 2013 by becky