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

-- AlWootten - 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 (at 5 sigma) which should be compared to present-day detection limits of 1-2 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, & Saito)

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. NAASC. 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.

Min Yun
Topic revision: r8 - 2004-09-23, AlWootten
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding NRAO Public Wiki? Send feedback