A Quickstart Guide for Proposing to Use ALMA During Early Science

A Few Introductory Comments on this Draft Document

It is not clear that this document will be incorporated into the official ALMA User documentation. It is largely replaced by the "CfP Manual".

As currently written, this document is aimed toward helping those from North America prepare ES proposals. It could certainly be modified to have a larger scope (ES Proposal Quick Start Guide) or a smaller scope (NAASC Users Guide).

Some of what is written here is only a place holder meant to impart information that needs to be included in the final document.

[Items in red I have made up. They need to be addressed later.]

Real Content Begins Here

ALMA At A Glance

Important Dates
Early Science Call for Proposals March 31, 2011
Early Science Proposal Deadline June 1, 2011
Early Science Observing Period Sept 1, 2011 - May 31, 2012

ALMA Early Science Frequency Coverage
Band 3 6 7 9
Frequencies (GHz) 84-116 211 - 275 275 - 373 602 - 720
Wavelength (mm) 3.57 - 2.59 1.42 - 1.09 1.09 - 0.80 0.50 - 0.42
Approx Resolution (arcsec) 2.4 1.0 0.8 0.4

ALMA Location
Latitude 23 01 22 South
Longitude 67 45 18 West
Altitude 5060 m

Important Links
ALMA User Portal (and Helpdesk)
Observing with ALMA Primer
NRAO/CASA Helpdesk
ALMA Sensitivity Calculator


The Atacama Large Millimeter/Submillimeter Array (ALMA) is a telescope that will enable transformational research into the physics of the cold universe, where the sky is dark in the visible part of the spectrum but shines brightly at millimeter wavelengths. ALMA is an interferometric telescope that, when completed, will have at least 66 high-precision antennas located on the Chajnantor plain in Chile. At least 50 of these antennas will be 12-meter dishes used for sensitive, high-resolution imaging. Four additional 12-meter antennas will comprise the ALMA Total Power Array, which will be used for total power observations. Another twelve 7-meter antennas comprise the ALMA Compact Array, to enhance wide-field imaging. At full operation, the telescope will be capable of imaging and spectroscopy in atmospheric windows between 31 - 950 GHz.

ALMA is funded and managed as a partnership between Europe, North America, East Asia, and Chile. Astronomers using the telescope will interact with ALMA through one of the ALMA Regional Centers (ARCs). The North American ARC is embodied in the North American ALMA Science Center (NAASC) located at NRAO headquarters in Charlottesville, VA.

This document provides a starting point for North American astronomers who wish to propose to use ALMA during the Early Science period (mid-2011 thorugh mid-2012). Astronomers should also read the document Observing with ALMA: A Primer for Early Science for additional information on the telescope and its capabilities during Early Science.

Early Science with ALMA

ALMA is expected to reach full operation in 2013. Prior to that time, the telescope will be made available for science observations with reduced, but still substantial, capability. About 500 hours of telescope time between late 2011 and mid 2012 will be used for "Early Science" (ES) projects, with the remaining time going to commissioning and science verification activities. Because many ALMA support scientists will be engaged in commissioning activities, there will be somewhat less support for science observations during the ES period than there will be during full operations. The telescope capabilities will be ever growing through the ES period, and will include at least 16 antennas with maximum baselines reaching at least 250 m, corresponding to an angular resolution up to ~ 0.4" at 700 GHz. The number of antennas and the array configurations will change throughout the ES period. Observers cannot be guaranteed a particular sensitivity or resolution. Observations for early science should be planned around 16 antennas with 250 m maximum baselines.

Following the first round of ES observations that will be completed in late 2012, there will be a second round running approximately from late 2012 through late 2013. ALMA full operations are expected to begin in late 2013.

Types of ES proposals

Early Science proposals can fall into one of two categories: Standard Proposals and Target of Opportunity Proposals.

Most early science ALMA projects will be be submitted as "standard proposals." A typical project accepted during early science will be completed in a few hours observing, or less. "Large proposals", defined here as those that require more than 100 hours, will not be accepted by the proposal system during early science. Most standard proposals will have targets that can be observed whenever the target is up, the weather conditions are appropriate, and telescope status permits the observation. The category "standard proposal" will also encompass monitoring observations or other projects in which the targets must be observed with a specific cadence, and projects in which the target must be observed at a specific date and time, when that date and time are known at the time the proposal is submitted (e.g. a comet reaching its point of closest approach).

Target of Opportunity (ToO) Proposals will also be accepted. ToO proposals should be used to observe targets that can be anticipated but not specified in detail, such as new supernovae or gamma ray bursts. Like standard proposals, these proposals must be submitted by the ES proposal deadline. While the target list may be left unspecified, observing modes and sensitivity requests must be specified in detail for ToO observations. ToO observations will be assigned an upper limit time allocation.

In addition to these categories, a small fraction of time will be set aside to be used at the Director's discretion. Observers can apply to use this time after the proposal deadline. It can be used, for example, to observe transient targets that require rapid response observations. Applications for Director's discretionary time will be emailed to the Director's Office.

Note that the ALMA proposal process (specifically, the Observing Tool) does not allow the user to specify a set number of observing hours required to complete the project. The observer will specify, instead, the rms required to reach the science goals. Nevertheless, the observer can estimate the number of hours required for the project using the ALMA Sensitivity Calculator.

Allocation of ALMA Observing Time

Any astronomer worldwide can propose to use ALMA during the Early Science period. Each of the ALMA partners has a fixed percentage of science time on the telescope, and each science project will be charged against the allocations of one or more of the ALMA partners' allocations. For standard proposals, time will be charged to one of the ALMA partners based on the affiliation of the PI. For large proposals the project team can define a set of Co-PI's, and the charged time will be divided among the ALMA partners' allocations based on the affiliations of the Co-PI's.

During the first year of Early Science it is anticipated that about 500 hours of observing time will be used for ES. Of this time, 35% is allocated to observers working through the North American ALMA Regional Center. The proposal selection process and time allocation is handled by the Joint ALMA Observatory.

The ALMA User Portal

Before you can propose to use ALMA, you must be registered with the ALMA User Portal. The User Portal is the primary access point for several ALMA-related services, including:

  • User registration, required for all ALMA investigators
  • the Observing Tool (OT), which is required for preparing proposals
  • the ALMA Science Archive, where a user can download ALMA data
  • the ALMA Helpdesk
  • the project tracker, which gives the status of observations in the ALMA observing queue

Register with the User Portal here.

During registration, users must specify their primary home institution. Eventually users will be able to register with multiple affiliations, but for Early Science users will register a single affiliation. Time scheduled on ALMA is "charged" to a specific executive member based on the affiliation of the project's PI. Also, each ALMA user will be supported primarily through a single ALMA Regional Center (ARC), and the affiliation determines which ARC will provide support to that user. Users in certain geographic areas may be offered a choice of ARCs to use for support. This paragraph needs to be cleaned up. Some of this may be unnecessary here.

The ALMA Helpdesk

The ALMA helpdesk is available through the User Portal. The helpdesk can be used for all question relating to ALMA, including ALMA capabilities, proposal preparation, the Observing Tool, Splatalogue, CASA, workshops and tutorials, and requests to visit an ARC for assistance with data reduction and analysis. To submit a question to the Helpdesk, users must be authenticated (i.e. must log in to the UP with their username and password). Users can expect a response to their question within two working days. During the week prior to the proposal deadline, the helpdesk staff will make every attempt to answer tickets even more promptly.

The helpdesk includes an intelligent search feature that will detect keywords in the question, as it is typed. Based on these keywords, the helpdesk will refer the user to a short list of relevant articles stored in a "knowledgebase". If the user's answer is not available in one of the knowledgebase articles, the question can then be submitted directly to the helpdesk. It is also possible to browse and search articles in the knowledgebase through the User Portal directly, without starting a helpdesk ticket. Browse and search features do not require authentication.

ALMA Capabilities During Early Science

The official description of ALMA capabilities during the ES period will available from a document provided by the JAO. Provide link here, when available. Meanwhile, here is a summary of those capabilities.

Frequency range:

ALMA observations will be limited to the following frequencies during ES.

ALMA Observing Frequencies for ES
Band 3 6 7 9
Frequencies (GHz) 84-116 211 - 275 275 - 373 602 - 720
Wavelength (mm) 3.57 - 2.59 1.42 - 1.09 1.09 - 0.80 0.50 - 0.42
Approx Resolution (arcsec) 2.4 1.0 0.8 0.4
Primary Beam (arcsec) 56 27 18 9
Continuum Sensitivity (mJy) 0.05 0.1 0.2 0.7

Continuum sensitivity is quoted for a xx minute observation.

Correlator Modes:

A limited number of ALMA correlator modes will be available during ES. The available modes are listed in the following table. UPDATE THIS

ALMA Correlator Modes for ES
Mode Available Bandwidth Number of Spectral Channels Spectral Resolution Polarization
(MHz) (kHz)
7 1875 3840 488 Dual
9 469 3840 122 Dual
12 58.6 3840 15 Dual
18 58.6 1920 30 Full
70 2000 64 31.25 Full

ALMA will be able to observe between declinations +XX and -90. Because the ES array will be in a compact configuration, observers should be aware that shadowing could significantly reduce telescope performance for observations at very high declinations. Flesh this out. Here we need more information about ALMA observing limitations during ES. e.g. What will happen as new antennas are added to the array? Will projects be able to take advantage of the increases sensitivity and uv-coverage? Will science observations be primarily at night, with daytime reserved for commissioning?

Designing an ALMA Observation and Proposal

To the extent possible, ALMA proposals will need to characterize the observations completely, in the proposal itself. This means all target positions must be given to the required precision, any targets used for test observations must be specified directly in the proposal, nonstandard calibration observations must be outlined in detail, and all frequencies and correlator configurations must be specified exactly as they will be used in the observations. Changes to the observing program as described in the proposal will require approval and coordination through the NAASC, for Northa American observers. The ALMA OT will generate a preliminary set of scheduling blocks, which are the instructions that will be used by the ALMA control software to make the observations. The OT will allow observers to choose a "standard" calibration strategy in which the tool chooses calibrators. If the observer wishes to observe more than one calibrator, or observe a specific calibrator as part of the the project, these requirements must be specified explicitly in the proposal.

To submit an ALMA proposal, each user should prepare the following:

  • A science justification, in PDF format, that describes the scientific background and goals of the observations. If appropriate, a technical justification should be iincluded as part of this document. The document, including tables and figures, must be four pages or fewer.
  • Target positions and recession velocities, or
  • If the source list is long, an ascii file with target positions and velocities
  • A list of all line frequencies to be observed
  • Required rms sensitivities for each line to be observed

Standard Observing Modes

Need to flesh this section out.

ALMA will be able to observe in several "standard observing modes," including:

  • Single-pointing spectroscopy
  • Single-pointing Continuum
  • Small mosaic spectroscopy or continuum
  • Polarization?
  • What else?

There are other modes that will be available later, but not during ES:

  • Large mosaics
  • On-the-fly continuum mapping (?)
  • "Single-dish" on-the-fly spectral line mapping (?)

Science Goals

ALMA observations are built around the concept of science goals. A science goal is defined as the application of one receiver, correlator configuration, and rms requirement to a set of targets. In other words, if a user would like to observe CO(1-0) toward five nearby galaxies, all with the same absolute rms, this task could be described by a single science goal. If the user wished to observe a band scan toward a single target across all four available receivers, this task would require one sceince goal for each frequency range to be observed.

Specifying an ALMA Observation

Observations in ALMA are described by a set of target positions, observing frequencies, and sensitivities. Observing times are not specified directly in a standard ALMA proposal. Times associated with calibration, slewing, and other overheads do not need to be specified explicitly for typical proposals. These overheads will be calculated and accounted for by the proposal submission software. Observers can run the ALMA Sensitivity Calculator to see how sensitivities relate to observing time, and vice-versa.

In addition to requiring that an observation achieve a specified rms noise level, some observers will be concerned with issues such as image fidelity and dynamic range, and these are determined in part by u-v coverage. To assist with predicting image fidelity, observers should use the SIMdata program, which is available as an application in CASA. CASA is available here. Help with CASA is available through the CASA Guides pages, and there is a guide specific to SIMdata here.

What to Put in Your Technical Justification

Many straightforward ALMA observations will use standard calibration strategies and the ALMA Observing Tool provides the option to select appropriate calibrators and design the calibration steps automatically. These projects can have a minimal technical justification, in which the proposer outlines the sensitivity request, line widths expected, correlator modes specified, and so on.

Some science goals will not be accomodated by the standard ALMA calibration strategy. In these cases, a more detailed technical justification must be included to describe the technical needs of the project. Examples here would be projects that:
  • require more than one phase calibrator
  • require more uv coverage than would be granted based on the target rms noise requirement
  • must be scheduled at a particular time
  • require certain ALMA capabilities (e.g. resolution) that may not be available in all array configurations during ES

Creating and Submitting an ALMA Proposal with the OT

Anyone preparing an ALMA proposal must first be registered with the ALMA User Portal.

The preparation and submission of ALMA observing proposals is accomplished with the Observing Tool (OT). Here we give the requirements needed to run the tool, and list the resources that observers should prepare for their proposals. The best way to get started with the OT is to follow the OT Walkthrough. The OT also has a User's Guide and a Reference Manual.

ALMA users can either download the ALMA Observing Tool to be run locally, or can use a "webstart" version of the tool [provide link]. The OT runs on Mac OS X 10.6, Windows XP/Vista, several Linux variations including RedHat, and Sun/Solaris. The OT is a java application that requires the Java Runtime Environment version 6.0, which contains Java Virtual Machine 1.6.

The following section is NAASC specific. We need either to break this off into a separate document, or include similar information on the other ARCs.

The NAASC: Supporting North American ALMA Users

The North American ALMA Science Center (NAASC) is the primary point of contact for ALMA science support for North American astronomers. The NAASC provides a number of services. These include:

  • Organizing and delivering ALMA training to the North American community
  • Organizing ALMA-related meetings and workshops
  • Operating the ALMA helpdesk
  • Helping observers design ALMA observations and prepare proposals
  • Maintaining ALMA web sites and user documentation
  • Hosting visits by ALMA scientists to help with data reduction and analysis

Visiting the NAASC

ALMA users can visit the NAASC in Charlottesville, VA to get support for their ALMA projects after their projects have observed. These visits would be about one week in duration. For each approved project, observers may request funding support to help pay for travel costs of one visitor. Only visitors from U.S. institutions are eligible for NAASC support of travel expenses, but others may visit under their own funding. Students visiting the NAASC for the first time must be accompanied by an advisor. When both a student and advisor visit the NAASC for the same project, both may apply for financial support to cover travel expenses. The policies and procedures for visiting the NAASC are described fully here. Will need to update this link.

The NAASC also supports short-term visits prior to the actual observations, for particularly complicated projects or other cases where the user needs help in preparing the scheduling blocks.

Longer visits to the NAASC are also available to scientists and engineers interested in working on hardware or software upgrades.

Visits to the NAASC can be arranged by sending a ticket to the ALMA Helpdesk, available through the User Portal.

Page Charge Support

NRAO will support page charges for ALMA publications, in accordance with the policies that apply to users of all NRAO facilities. When requested, NRAO will pay page charges for authors at U.S. scientific or educational institutions, when the publication uses an NRAO telescope, including ALMA. The full policy for NRAO support of page charges is here.

Student Support

Does this apply to ALMA?

NRAO operates the Student Observing Support program to fund qualified students who are working on approved NRAO observing projects. Both graduate and undergraduate students at U.S. institutions are eligible to receive support, and the level of funding can range up to a full year's stipend. Details on the program can be found here.

NRAO also runs other student support programs of interest to the ALMA community, including a Graduate Student Internship Program to support extended student visits to NRAO sites. This program allows students to work directly under the supervision of an NRAO staff member for periods ranging from a few weeks to a few months, Details on other student support programs are available here.

-- JimBraatz - 2010-11-05
Topic revision: r19 - 2011-02-10, JimBraatz
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