ANASAC Working Group Discussion on the User Support Survey
WG Members: C. Carilli, R. Crutcher, J. Glenn, L. Mundy, D. Sanders, J. Turner, P. Vanden Bout, C. Wilson, A. Wootten, M. Yun
- 11 Aug 2004
Large Project DRSP 1.1.2
From DRSP 1.1.2
Example 1: Large project, ~256 hours total time. "Unbiased survey of submm galaxies"
Total visibility data 1.6TB. Total image data 500 MB. One source, Four frequency images, 240pxx240pxx1024ch
An important way to study the history of galaxy formation is to
perform an unbiased redshift survey using CO. We propose a unbiased, high
sensitivity survey with 3" resolution over a 4x4' area
of the sky of a region already covered in the continuum with ALMA (see DRSP 1.1.1).
This is Part 2) Combined line and continuum survey at 3 mm, down to 7.5
microJy at the 5 sigma level.
In detected sources, owing to the compression of the spectrum the frequency interval between adjacent
CO lines decreases. Thus there will be at least one CO line for sources
with z>2, and two for sources with z>6. The are two blind redshift
regions: 0.4 -- 1, and 1.7 -- 2.0. The survey thus provides
a good coverage of the star formation history for redshifts above 1.
This survey should detect a few hundred sources; the integrated line flux sensitivity is 0.04 Jy.km/s
(at 5 sigma) which should be compared to present-day detection limits of 1-2 Jy.km/s reached by integrating on single fields for dozens of hours. This survey could not detect extragalactic line emission if done with present-day arrays within their normal scheduling constraints.
Small Project DRSP 3.5.5
From DRSP 3.5.5
Example 1: Small project, ~4 hours total time.
"Target of Opportunity Observing of Radio Supernovae"
Total visibility data 78GB. Total image data 0.2 MB. One source, Four frequency images, 1pxx1pxx1024ch
The radio emission from supernovae (SNe) is one of the best probes of
the final stages of evolution for the stellar progenitors. The
nonthermal synchrotron arises from the interaction of the SN shock
with the pre-supernova, wind-established, circumstellar medium (CSM).
Knowledge of the CSM provides strict constraints on the progenitor's
nature and evolution. However, the particle acceleration process is
still not known, and the absorption mechanism, which arises from the
CSM, is not completely obvious. Although progress has been made at
centimeter wavelengths over the last two decades, little has been
accomplished in the mm and submm due to the sensitivity constraints
and difficulty in scheduling target-of-opportunity projects. This project proposes to image a radio supernova
in the four frequency bands (3mm, 1mm, 870u, 450u). Data sizes above are for a single candidate.
Medium Project DRSP 2.4.3
Jean Turner contribution for medium project (13 Sept):
From DRSP 2.4.3
Example 2: Medium project, ~20-24 hours total time.
"Continuum survey for dust emission from protoplanetary disks
in Hydra from 80 to 900 GHz."
Total visibility data 3.8GB. Total image data 665 MB. Five sources, Four frequency images, 180pxx180pxx1024ch
Imaging of five sources in
Hydra at 0.1" resolution in the four frequency bands (3mm, 1mm,
870u, 450u) to study dust structure and emissivity on
10-15 AU sizescales. This is technically a spectroscopic project because line contamination is a serious issue at submm frequencies. Obtaining the evolution of the dust emissivity
as a function of radius is a key parameter in constraining the
dust coagulation process. (Based on DRSP 2.4.3, Guilloteau, Dutrey,
Discussion at 10 September telecon (excerpt):
Examples: Get these from the DRSP.
4, 10, 50 hour examples. A deep mosaic, a multiobject survey, a single object item.
. Dick, Al and Jean. An item for the wiki page.
ACTIONS: Talk to various people is in Paul's baliwick. Should make good progress by the
end of the month.
Making the form--Megan could do this. Should we worry about getting only one response per
person. Can we ask for email address. This would be anonymous--put in intro.
Min's 3 August note:
Diverse, enthusiastic voices were heard at the Maryland workshop
regarding the possibility of ALMA data reduction funding. Mixed
in were some cautionary voices, motivating the discussion in the
greater context of the NSF fuding in general. Last week, on my
way back from a GBT run, I stopped by CV and spoke with Fred Lo
and Paul Vanden Bout regarding this topic. This is obviously an
important ALMA user issue, and something NRAO itself has an
obvious difficulty taking the leading role in. ANASAC is the
best group to take the lead on the community discussion on this
topic, as we have done already at the Maryland workshop, and
carry out the necessary preparatory work.
As a first step in this effort, I would like to form a small
working group consisting of a subset of ANASAC members and a
few of the NRAO scientists. I would like to invite you to
participate in this working group, which has a short and
well defined list of tasks as outlined below. I hope you will be
able to contribute some of your time and thoughts to this effort.
The immediate task for the working group is to put together an
ALMA user survey that will help determing the level of enthusiasm
and funding requirements for such a program among the future
ALMA users. Convincing NSF to create such a funding program, if
the demand justifies, would require supporting documents and a
broad community support. This survey would be a first significant
step towards achieving this goal.
We should first discuss the goals of this survey as the outcomes
of such a survey can be strongly dictated by the way questions
are posed. We should then put together a survey that can be
broadly and quickly advertized to the potential future ALMA users.
There is some urgency in that this funding needs to be included
in Paul's formulation of the NA ASC budget to be discussed with
NSF, and this process has already started.
Let me first offer an example survey, which is something I cooked
up very quickly last night, without a great deal of thought given
to the goals of the survey. Paul had rattled off a short list
of questions we could include in such a survey, but he did not
send me his list before leaving town. It is intended purely as
a tool to get the discussion started, so have a look and start
thinking about what questions the survey should ask and what we
want to get out of such a survey. Find my example survey at
My proposed timeline for the working group is:
Aug. 20 -- WG telecon (to discuss the goals and details of the survey)
Sept. 10 -- ANASAC telecon (present the refined version of the survey
for broader comments by the entire ANASAC)
Sept. 15 -- Send out the survey to the astronomical community (via
the AAS bulletin? -- we should check with Kevin Marvel)
Oct. 1 -- Survey deadline
Let me know whether you can participate in this effort and whether
you can attend the proposed telecon on the 20th. This date is
extremely tentative at the moment. Send me your comments and additional
questions for the survey as soon as you can so that we can get as much of
this work done in advance via e-mail. I am looking forward to having
some good discussions and a great deal of input on the process by
everyone in this group.