Doc. 9.10, Ver. 1.0 | March 2022

ALMA Observing Tool Quickstart Guide

ALMA, an international astronomy facility, is a partnership of ESO (representing its member states), NSF (USA)and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in
cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

For further information or to comment on this document, please contact your regional Helpdesk through the ALMA User
Portal at www.almascience.org. Helpdesk tickets will be directed to the appropriate ALMA Regional Centre at ESO,NAOJ or NRAO.

Version1 (IT3)1 (OT release Cycle 0)
1 (OT release Cycle 1)
1 (OT release Cycle 2)
1 (OT release Cycle 3)
1 (OT release Cycle 4)
1 (OT release Cycle 5)
1 (OT release Cycle 6)
1 (OT release Cycle 7)
1 (OT release Cycle 8)
1 (OT release Cycle 8 2021)
1 (OT release Cycle 8 2021)
1 (OT release Cycle 9)

Date

Editors

15.03.2011
30.03.2011
31.05.2012
07.10.2013
12.03.2015
17.03.2016
15.03.2017
14.03.201804.03.201904.03.2020
01.03.2021
13.04.2021
08.03.2022

S. Randall, D. Espada
S. Randall, D. Espada, E. Humphreys
E. Hatziminaoglou, S. Randall
S. Randall
S. Randall
S. Randall
S. Randall
A. Biggs
A. Biggs
A. Biggs
A. Biggs
A. Biggs
A. Miotello

The ALMA OT Team, and the many Testers.

In publications, please refer to this document as:
ALMA Observing Tool Quickstart Guide, ALMA Doc. 9.10, Version 1.0

Contents
1 Scope32 Getting Started

3

3 General Proposal Information

44 Science Goals

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5 Source Information

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6 The Spectral Setup
6.1 Spectral Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Single Continuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3 Spectral Scans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4 The Representative Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5 Entering Rest Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.6 The spectral visualiser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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7 Finalising the Spatial Setup
7.1 Individual Pointing(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2 1 Rectangular Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3 The spatial visualiser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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16
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8 Calibration Strategy

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9 Control and Performance18

10 Technical Justification23

11 Validating and Submitting

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1

Scope

This document is intended as a concise guide to Phase-1 proposal preparation in Cycle 9 for novice and experienced ALMA users alike. While novice users should carefully follow the step-by-step instructions, experienced
users may want to concentrate on the boxed texts. These highlight new features, useful tips and tricks, andissues to be aware of, and can be identified by the corresponding icons.
A more comprehensive description of the OT and the different aspects of proposal preparation can be foundin the ALMA OT User Manual. The ALMA OT Reference Manual provides a more concise explanation for all
the fields and menu items in the OT, and can be accessed interactively from within the OT by clicking on the‘ ?’ icons. The User Manual and Reference Manual can also be accessed and interactively searched
via the Help menu in the OT. The OT also contains helpful tooltips that appear when you mouse-over text
boxes or radio buttons.
Unfortunately, the screenshots have not been updated since Cycle 5, but the OT’s appearance has not greatlychanged since then.

2

Getting Started

In order to access the ALMA Archive and submit an observing proposal, you must have previously registeredwith the ALMA Science Portal. You can then download the OT from the OT page in the ALMA Science
Portal. Please follow the detailed installation instructions there; in case of any problems you can consult the
Troubleshooting page. Depending on your installation option, you start the OT either by double-clicking on
an ALMA OT icon (installer) or from the command line by executing a script (e.g. ./ALMA-OT.sh on Linux)
in the installation directory (tarball). An initial dialogue box with different options will appear. To follow the
step-by-step guide for creating a new proposal please select the first option, Create a new proposal.
The option to install the OT using Web Start is no longer available since Cycle 8 2021. To replace Web
Start, a new installer has been created which will lead the user through the steps required to install the OT
and allow the memory to be changed from its default of 4 GB. More memory might be necessary for complicatedproposals requiring many Science Goals or containing many sources. The tarball installation method remains
available. Detailed instructions can be found in the Science Portal.
It is possible to re-use a proposal from a previous cycle as a template for your new proposal using the File >Open Project as New Proposal feature. Regardless of its status (e.g. it might have been accepted and had SBs
generated) it will be retrieved from the ALMA archive and open in the OT as a new Phase 1 proposal without
a project code. Any Phase-2 materials (e.g. SBs) will have been removed. Note that time estimates, allowed
configurations etc. may have changed from previous cycles. This feature also allows conversion between normal
and DDT proposals.
Alternatively, once the OT has opened you can select the green New Proposal (Phase 1) button from the toolbar
in the OT. You will be presented with the window shown in Fig. 1, which illustrates the main Graphical User
Interface (GUI) components:
Menu: Allows access to all functions available in the OT via pop-up submenus.
Toolbar: A selection of icons for some of the most frequently used functions in the Menu.
Project Structure Pane: Visualisation and navigation of the Project Tree. Each part of the tree isknown as a “node” and many of these can be expanded or collapsed by clicking (“turning”) the handle icons.
A convenient shortcut for expansion of all nodes below a given node is to click there and then type Ctrlor Cmd-Z.
Editor Pane: The technical specifications of the project are filled and edited in this pane. The content
of the editor pane changes depending on the branch of the Project Tree selected. For spatial and spectral
setup, the editor pane is composed of several panels.

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Figure 1: OT Graphical User Interface.
Feedback Pane: Provides feedback on the validation process and allows you to identify problems withyour proposal.
Overview Pane: Informative summary of the proposal creation process and contextual help.

You can customize the GUI according to your needs. The size of the different panes can be
modified by clicking and dragging their borders, or maximised/minimised by clicking on thetriangular arrow symbols. You can toggle the Overview and Feedback panes by clicking on View
> Feedback/Overview in the Menu, e.g. in order to maximise the Editor pane. The Feedback
pane will normally not be visible upon starting the OT, but it will pop up when the project isvalidated (see Section 11). You can customise the OT further by selecting File > Preferences.
In particular, you may want to change the font size or colour scheme, or preferentially show
certain editors.

The OT GUI can be made more modern by selecting a ’flat’ look and feel. You can customise
the look and feel by selecting File > Preferences > Appearance > Look and Feel. This also
appears to speed up the GUI’s response times.

3

General Proposal Information

Start by filling the fields in the Proposal editor labelled Proposal Title and Abstract, select the Proposal
Type and Scientific Category using the radio buttons and choose up to two Keywords from a list (to select4multiple keywords hold the Ctrl button or the Cmd button on Macs).
Special Proposal Types
Target of Opportunity (ToO) proposals are designed for observations that can be anticipated, but
for which the source coordinates and the timing are not known at proposal submission time. Examplesof typical ToO targets are supernovae, gamma ray bursts or transients. A proposal that simply has time
constraints is not a ToO but should instead be submitted as a Regular proposal, with the requested time
constraints specified in the Control And Performance editor (see Section 9).
VLBI proposals use ALMA in conjunction with VLBI telescopes around the world. They have a special
VLBI proposal interface at the Science Goal level and the spectral setup is limited to pre-defined continuum
setups in Bands 3, 6, and 7, and spectral-line observing (SiO) in Band 3. Users should normally selectthe system-defined calibration option as all necessary calibrations will be carried out by the observatory.
Unlike standard proposals, VLBI observations require a time estimate (including overheads, which makeup ∼50 per cent of the expected time on source) rather than a sensitivity to be entered. Note that ALMAVLBI programs must also have been submitted to the appropriate VLBI network by their independent
deadline. Passive phasing can be used to enable the detection of weaker (<0.5 Jy) science targets.
Phased Array proposals request that the 12-m Array be used as a single dish i.e. using the same phasing
hardware that produces the signal used for VLBI, but without correlating this with the signals from othertelescopes – it is an ALMA-only mode. This mode is currently only available for the observation of pulsars.
Large Programs are proposals that require more than 50 hours of 12-m Array time, or more than 150
hours of 7-m array time requested as part of stand-alone Atacama Compact Array (ACA, also known as
the Morita Array) Science Goals. For these programs, co-PIs may be specified and the observing timerequired will be split between the PI and co-PIs’ Executives (Europe, North America, East Asia or Chile).

Observations using Band 8 can be proposed with all configurations. Observations in Band 9
are now also allowed in configurations C-8 and C-9 and Band 10 observations in configuration
C-8.

It is now possible to select a predefined continuum setup in Band 7 – in addition to Band 3
and Band 6, that were already available – for VLBI proposals. VLBI spectral-line observing
is now also allowed only in Band 3, even though this is significantly different to the standard
ALMA case. The VLBI data are only taken in a single spectral window at a fixed sky frequencyof 86.268 GHz, this being used to observe the SiO v = 1(2 − 1) line with a rest frequency of
86.243370 GHz. None of the parameters of this spectral window can be edited by the user. It
is also necessary to enter a date for the observation in the time-constraint interface (Control
and Performance) in order for the OT to check that the line will be observable.
In order for you to be able to submit the proposal, you will have to select yourself as PI by scrolling down,pressing the Select PI button and searching by name, email or ALMA ID in the pop-up window (see Fig. 2).
The ALMA ID is your Science Portal login.
You can select an unlimited number of Co-Is in a similar way, provided that they have previously
registered with the ALMA Science Portal. Please make sure they do so at least 24 hours prior to thesubmission deadline. If you have a long list of Co-Is you may prefer to add them from a proposal previously
saved on disk using the Add from proposal button.

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Figure 2: Selecting the PI and Co-Is in the Proposal editor using the User Registry search interface.

Proposal review for proposals that are neither Larg Programs ot ToOs, will now be done using
distributed peer review i.e. the reviewing will be done by the PIs submitting such proposals.
Unless Large Program is selected, the OT will require that one of the investigators be selected
as a proposal reviewer. If this person is the PI and does not have a PhD, a mentor can be
named who would assist the PI with the reviewing.
You are not required to indicate if your proposal constitutes a re-submission. This will be determined by
the observatory (please refer to the Proposer’s Guide for details). However, you should justify any duplicate
observations of archival data or previously accepted programs.
The Science Case used for the the scientific assessment of your proposal needs to be attached as a PDF
file not exceeding 4 pages in total (6 pages for Large Programs), including any figures and tables. The
science case should put the proposed observations in a broad scientific context, highlight their impact on the fieldof research and present the immediate goal you expect to achieve. With the move to dual anonymous proposal
review, all PDFs should be written in a neutral style such that it is not possible for the reader to determine theidentity of the author. More information can be found in the Proposer’s Guide. Large Programs must include aManagement Plan as a separate PDF, with a maximum of one page and a maximum size of 1 MB.
While the text of the technical justification is entered directly into the OT (see Section 10), any associatedfigures must still be included in the PDF. For more details please refer to the Proposer’s Guide.
The fonts used in the PDFs must have a minimum size of 12 points. The OT will issue anerror if >15 per cent of the text is smaller than 12 points. Be aware that an image cropped
from another PDF may contain text that lay outside of the cropped area, even though this is
not displayed.

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Figure 3: Adding the source information in the Field Setup editor.

4

Science Goals

All the technical specifications for your project are contained in one or more Science Goals, each of whichcontains six nodes covering different aspects of the observations. Each Science Goal may contain one or more
sources of the same Target Type (individual pointing(s) or 1 rectangular mosaic) and is limited to one correlator
setup with up to five frequency tunings, one calibration strategy and one set of Control and Performance parameters (see Section 9). You create a new Science Goal by clicking on the New Phase 1 Science Goal iconin the toolbar or selecting Edit > New Phase 1 Science Goal from the menu bar.
Right-clicking on the Science Goal node in the Project Tree will allow you to select a number of actions tobe performed, such as renaming, copying or deleting the Science Goal. Some of the actions (e.g. copying)
are also available for nodes within a Science Goal, e.g. the Spectral Setup. It is important to understand that
Science Goals can only be pasted at the Proposal or Planned Observing node level, and parts of a Science Goal
can only be pasted at the Science Goal node level (i.e. a higher-level node must be selected and right-clicked
after copying in order to bring up the paste action). You cannot paste a Science Goal into another Science Goal.
Copy and paste of a Science Goal or parts of a Science Goal can also be achieved with the usual Ctrl-C andCtrl-V keyboard shortcuts or by dragging and dropping.

5

Source Information

A source can contain either one or more (overlapping) individual pointings or 1 rectangular mosaic. All pointings
defined in a given source share the velocity information and Expected Source Properties. Setting up the actual
pointings within a source is covered in Section 7. For the moment, it is sufficient to enter the source information,
especially the velocity, as this will be used for the spectral setup.

7

The algorithm for tiling a rectangular area with mosaic pointings has been updated such that
it is now possible to have an even number of pointings along a single row. In general, it is likelythat there will be small differences in the number pointings compared to previous versions of
the OT.
By default, the Field Setup editor contains one source tab. The first thing to select is the Target Type:
Individual Pointing(s) or 1 Rectangular field. The Target Type must be the same for all sources in a Science
Goal, and it is not possible to switch to 1 Rectangular field once additional sources have been added. You canthen use the Add source button at the very bottom to open additional source tabs. You will need to specify
the source information for each source individually. If your source has an entry in SIMBAD, you cansimply type its name in the Source Name field and hit Resolve to import the field centre coordinate and velocity
information from there (see Fig. 3). Otherwise, this information must be entered by hand. Solar System targets,
including the Sun, can be selected from a pull-down list if the Choose a Solar System Object box is checked.
Within a Science Goal, the OT uses a clustering algorithm to group sources within 10◦ into
separate SBs (1◦ for long-baseline SGs) to allow good phase calibration of all sources. Information on the different source clusters can be found in the Planning and Time Estimate pop-up
available from the Control and Performance node. A source cluster can contain a maximum of
150 pointings.
Galactic coordinates are supported. The spatial visualiser will display externally loaded images in Galactic
coordinates correctly and will also convert between different coordinate systems. For example, if the source
information is defined in Galactic coordinates and the displayed image uses ICRS/J2000 (as is always the casefor the OT’s default image servers) the rectangle will be rotated to show the correct orientation in the ICRS
frame. Source coordinates read in via a text file will be interpreted as Galactic if they are given in decimaldegrees.
For each source, you are required to provide an estimate of the expected source properties. The peak flux
density entered should be an estimate of the weakest component driving the sensitivity requirement of your
Science Goal. For continuum observations only the Peak Continuum Flux Density per Beam is required, while
for spectral line and spectral scan observations the Peak Line Flux Density per Beam and the (FWHM) Line
Width must be specified. In the latter case it may also be appropriate to enter the Peak Continuum Flux Density
per Beam if you want to observe both lines and continuum. The Line/Continuum Polarization Percentages are
required only if full-polarization observations are requested. The expected source parameters entered are used to
calculate a number of quantities in the Technical Justification editor (see Section 10) and the proposal/Science
Goal Summary Sheets. They should be used for guidance when choosing the correlator setup and sensitivity
requirements for your Science Goal.
It is your responsibility to ensure that the source information is correct. The source
coordinates and the velocity are used by the OT to calculate the pointing(s) and the sky
frequencies respectively, and can normally not be changed after a proposal has been accepted.
The expected source properties are used for the technical feasibility assessment of your proposal,
and incorrect or incomplete information may lead to the rejection of your proposal on technicalgrounds. For more information on how to convert existing flux measurements for your source
to the peak flux density per synthesised beam required by the OT please see this and thisKnowledgebase article, or consult video number 2 available here.
If you have a large number of sources, you may prefer to read in the complete source information from an
ASCII file using the Load from File... button at the bottom of the Field Setup editor. As with adding sources
manually you should make sure that the correct Target Type is set before you load the source list. For therequired file format, please see the Field Setup section of the ALMA OT Reference Manual.
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For solar observing you should specify the solar activity level and potentially enter a dummy ephemeris filecreated using the ALMA Solar Ephemeris Generator. The ephemeris will be updated in coordination with theobservatory before any observations take place. Solar observing is currently restricted to continuum setups only.
Unlike most ALMA proposals, you do not request a sensitivity and instead enter the on-source time requiredon the interferometric array.
It was previously the case that solar observing with the Total Power (TP) array would only
produce maps of the full solar disc. It is now, however, possible to also obtain TP imaging of
the area of interest on the Sun’s surface, i.e., that imaged by the interferometric array. The TP
regional mapping area will be centred on the interferometric mapping position.
The only source property required for VLBI observing is whether the source is so faint (<0.5 Jy) that passive
phasing will be required. In this mode, the phasing up of the antennas in the 12-m Array is performed on a
nearby calibrator and these then retained when observing the science target. This mode is enforced if the Phased
Array is requested. If selected, it will be necessary to define a fixed phase calibrator in the Calibration Setup.

6

The Spectral Setup

In the Spectral Setup editor, start by selecting the Spectral Type and the Polarization Products Desired as thesewill influence the choices you have for defining your spectral setup. In particular, selecting Full polarization will
limit you to measurements in Bands 3, 4, 5, 6 and 7. If you are not interested in polarization information you
should generally leave the radio button set to the default of Dual. XX polarization is appropriate only if you
need extremely fine spectral resolution (<30 kHz).
90-degree Walsh switching is available in Bands 9 and 10. This allows the user to access the information
not only from the spectral windows specified, but also from the resulting “image” spectral windows which lie in
the other sideband and which were being suppressed in previous cycles. Note that only the actual spectral
windows can actively be defined in the spectral line table, and that the image spectral windows willautomatically shift anytime LO1 is recomputed (e.g. if additional spectral windows are added, or the bandwidth
is changed). Walsh switching is activated by ticking the Produce image sidebands option in the Spectral Typesection. If you select this option you will be given the option to view the frequencies of the image spectral
windows with the Show image spectral windows tick-box (see Fig. 6). Walsh switching is available only when
all spectral windows in the setup use the widest (1875 MHz bandwidth) correlator mode. Note thatstoring (and delivery to the PI) of the image spectral window data can be switched on or off for each spectral
window individually using the Store Image tickbox. For the Single Continuum (see Fig. 8) and Spectral Scan
spectral types with 1875-MHz-wide spectral windows, Walsh switching is automatically enabled by the OT – theuser has no choice in the matter.
The decision as to whether band-to-band (B2B)observing is required is now based on a search of
the calibrator catalogue. This requires internet connectivity and time estimates made in the absence of an internet connection will assume B2B for Bands 7 to 10 where nominal configurations
C-8 and larger are required.

6.1

Spectral Line

Selecting Spectral Line will present you with a spectral window table for each of four available basebands. Unless
your Science Goal requires more than 4 spectral windows, you will normally define one spectral window
per baseband. It is good practice to fill any basebands not needed for spectral line observations with continuum
spectral windows as this aids calibration, especially in the case of narrow spectral windows.

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Figure 4: The Spectral Line Selector tool.

For Bands 3 to 8, for technical reasons it is not possible to place three basebands in one of the
sidebands and one in the other. This restriction does not apply to Bands 9 and 10.

You define spectral windows individually for each baseband using either the Add Spectral Window Centred
on a Spectral Line or the Add Spectral Window Manually buttons. The first option brings up the Spectral Line Selector tool (see Fig. 4) which allows you to search an extensive database (The Splatalogue –https://splatalogue.online) for popular transitions based on species, ALMA Band, sky frequency, maximum
upper-state energy or molecules detected in a variety of astronomical sources. Simply select the transition you
want, press Add to spectral window list and a spectral window centred on the transition will be created uponclosing the tool. The second option Add Spectral Window Manually allows you to manually enter a spectral
window central frequency. Conversion between rest and sky frequencies is automatically performed based on thesource velocities defined in Section 5.

If you cannot find the transition you want in the Spectral Line Selector tool, try the Search
Online button: you will then be able to search online from a more extensive database. Bydefault, the Spectral Line Selector shows only transitions that are simultaneously observablewith any other transitions already defined in the spectral setup; untick the Hide unobservablelines option to display all transitions corresponding to the search criteria.

10Figure 5: Visualisation of spectral line observations in the Spectral Setup editor.

Figure 6: Spectral line observations with Walsh switching turned on, and the mirror image saved for one of thespectral windows.

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Spectral windows must be associated with a correlator mode which can be selected independently for eachbaseband. Double-click on the entry in the Bandwidth, Resolution column to bring up the list of available
options. The entry in bold text corresponds to the lowest spectral resolution (single-continuum) mode – TDM.
All other modes have much higher spectral resolution and are referred to as FDM. Please make sure that the
bandwidth and resolution selected for each spectral window are appropriate for the expected spectral propertiesof your source(s) as entered in Section 5.
The spectral averaging factor is by default set to 2 in order to lower data rates. Note that an averaging
factor of 2 degrades the spectral resolution only marginally (by ∼15 per cent) but halves the data rate for thatspectral window. You can modify the spectral averaging factor by double-clicking on the default ‘2’ entry in theSpec Avg. column of the spectral window table. This will bring up a list of possible spectral averaging factors.
Selecting one of the values will immediately change the spectral resolution in the table. No spectral averaging ispossible for TDM spectral windows.
The OT enforces a strict upper limit of 70 MB s−1 for the data rate of the 64-input correlator (used for 12-m
configurations). In addition, this is calculated using 50 antennas, the maximum that might be used during anobservation. Although the sensitivity calculations are all made using 43 antennas, 50 is assumed for the data rate
as the SB will not run if 70 MB s−1 is exceeded. This figure refers to the ‘peak’ data rate i.e. the instantaneous
value written out by the correlator. If the limit of 70 MB s−1 is exceeded, spectral averaging should be used (orspectral windows removed) until the validation error disappears.
The data rate of the ACA correlator is also checked. Exceeding the maximum data rate willthough be quite difficult and is most likely to affect large TP mapping areas with four FDM
spectral windows.
Based on the spectral windows defined, the OT will try to configure a spectral setup and display it in
the spectral visualiser (see Fig. 5). In order for your proposal to pass validation, all spectral windows forall source velocities must fit within a valid sideband configuration and the same ALMA Band.
If several sources with different velocities were specified in Section 5, the OT will generate up to 5 separate
frequency tunings based on the velocities, the width of the spectral windows and spectral line width entered in
the Expected Source Properties. The number of tunings may affect the time estimate for a Science Goal andcan be checked in the Time Estimate dialogue (see Section 9).
A warning will be given if a velocity has not been entered for all sources. This is to encourage
users to give source velocity information, mainly for use in the ALMA Science Archive. Solarsystem objects are exempt.
It is possible to define up to 4 spectral windows per baseband, yielding a maximum total of 16 spectral windows
in a single spectral setup containing 4 basebands. Simply press Add Spectral Window Centred on a Spectral Lineor Add Spectral Window Manually to place extra spectral windows in the baseband tables. Because only a fixed
number of channels are available for each baseband they must be divided between the spectral windows defined,
implying that at a given resolution the bandwidth available for each of two spectral windows will be half thatavailable for a single spectral window. Therefore, the fraction of the baseband assigned to each spectral window
must be changed in such a way that the sum of all fractions does not exceed 1. The available choices for thecorrelator modes in the Bandwidth, Resolution field will then be automatically updated to reflect the lower
number of channels available. Note that within a baseband all spectral windows must have the same spectral
resolution (before spectral averaging).

6.2

Single Continuum

Selecting the Single Continuum option is basically a shortcut to defining 4 continuum (TDM) spectral windows maximising the available bandwidth (see Fig. 8). You are presented with a drop-down list of standard
continuum frequency setups for each of the available ALMA Bands, chosen so as to optimise atmospheric12transparency. The sky frequency of the setup can be changed to anything that still yields a valid spectral setup,
but any deviation from the standard frequencies must be fully justified in Section 10. An alternative option isto enable the use of the FDM correlator mode. in the Single Continuum setup. This provides much higher spectral resolution than TDM and can be useful, for example, if a continuum spectra is contaminated with narrowspectral lines.
Single Continuum and Spectral Scan observations are specified in the “sky” (observed) reference
frame. Unlike Spectral Line mode, the velocity information entered in Section 5 is ignored inthis case and all sources are observed with the same frequency tuning.
The spectral windows set up by the OT based on the input continuum frequency for each baseband are listed
in the spectral window tables and displayed graphically in the spectral visualiser. Note that the sky frequency
specified corresponds to the LO frequency and is not itself observed for Bands 3–8.
For Bands 9 and 10, the sky frequency corresponds to the frequency at the centre of the 8 GHz wide upper
sideband. Note that Walsh switching is always used for Single Continuum observations, yielding a
combined bandwidth of 15 GHz in Bands 9 and 10.

6.3

Spectral Scans

The Spectral Scan interface is a convenient way of setting up several correlator tunings to cover a wide, uninterrupted frequency range within a single ALMA Band. You need to specify the start and end frequency as wellas the desired Bandwidth, Resolution of each spectral window making up the scan. A maximum of 5 tunings
can be observed within one Science Goal, which means there is a trade-off between achieving a high spectral
resolution and covering a wide frequency range (if you want to cover a wider frequency range than possible with
5 tunings you will have to split the spectral scan across multiple Science Goals). Spectral averaging is possible
in the same way as it is for Spectral Line observations. Spectral scans are available for use with the 7-m Array,in either stand-alone mode or in conjunction with 12-m-Array observations. Spectral scans with the TP Array
have not yet been commissioned.

Despite the recent increases in observing efficiency, spectral scans can still have very high time
estimates. This will happen mostly for observations with relatively long on-source times andmany frequency tunings. It may be more efficient to set up such spectral scans using separate
Science Goals for each frequency tuning.
If the requested spectral scan can be set up successfully, the frequency tunings calculated by the OT aredisplayed in the spectral visualiser (see Fig. 7) and also listed in the spectral-scan table. If not, a red error message
will appear, indicating the origin of the problem. Spectral-scan observations are offered only for Individual
Pointing(s) field setups with one pointing per source and a maximum limit of 150 pointings over all tunings (i.e.
for 5 tunings the maximum number of pointings is 30). Note that for Band-9 and -10 observations Walshswitching is automatically turned on if the widest (1875 MHz) spectral windows are selected,
otherwise it is turned off.

6.4

The Representative Frequency

Every spectral setup is characterised by a representative frequency, which is used to compute the spatial parameters of the Science Goal (primary beam, synthesised beamsize, maximum recoverable scale) and controls
the atmospheric transmission used in the time estimate (see Section 9). It defaults to the centre of one of thespectral windows defined, but can be changed by the user to lie anywhere within the spectral windows of the13

Figure 7: Visualisation of spectral-scan observations in the Spectral Setup editor.
setup using the representative window radio button and/or typing in the relevant field below the baseband tables.
For spectral line observations, the representative frequency is a rest frequency that will be transformed to a sky
frequency using the velocity information for each source. Please check it carefully for each source, andmodify it if necessary.
The exact choice of representative frequency can severely impact the time estimate,especially in Band 5 and the higher frequency bands 7, 8, 9 and 10. If it falls in aregion of poor atmospheric transmission the time estimate will sky-rocket compared to a setup
with a representative frequency in an area of good atmospheric transmission. It is importantthat the representative frequency is set to the line of interest that falls into the region of thepoorest atmospheric transmission, otherwise the requested sensitivity will not be reached forthis line.

A warning will be given if the Representative Window lies in a part of the frequency spectrum
where the atmospheric transmission is less than 5%. A validation error will result if the spectral
window is not representative.

6.5

Entering Rest Frequencies

You should enter the rest frequencies of any spectral lines observed with your spectral setup in the
Rest Frequencies section below the spectral line tables. These will be stored and used for data reduction andquality assurance purposes (e.g. to provide the proper velocity scale for different image cubes, check that lines
near the edges of spectral windows are fully observed). They do not affect the spectral setup. Clicking Definerest frequencies brings up an incarnation of the spectral line picker. Any transitions used to define spectral
windows in the spectral setup are automatically stored, but we encourage users to additionally enter
any other transitions they expect to detect with the proposed observations. Only transitions falling within the
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Figure 8: The Spectral Setup editor. Here, continuum observations have been defined.
spectral setup as defined are permitted.

6.6

The spectral visualiser

The spectral visualiser is shown by default in the Spectral Setup editor. It shows the ALMA Bands offered in
the current cycle (Bands 3 to 10) as well as the atmospheric transmission curve of the Chajnantor site. The OT
automatically chooses the water vapour column density appropriate for the observing frequency and bases thesensitivity calculation on this. The Manual Choice is for visualisation purposes only and has no effecton the estimated time. Once you specify at least one spectral window, a tuning is calculated and (yellow)
sidebands appear in the visualiser. The sidebands show where basebands may be placed and do not indicate thefrequency range that will be sampled by the observations. Up to four 2-GHz-wide basebands (not displayed in
the spectral visualiser) are available within each of which one or more spectral windows may be placed. Spectral
windows are defined directly by the user from within the spectral-window table and are shown in the visualiser inblue. The LO1 frequency, sidebands and basebands are automatically calculated by the OT basedon the spectral windows defined and cannot be controlled by the user directly. If the OT cannot
compute a valid spectral setup for your spectral windows, the sidebands will turn grey and an error message willappear.

You can zoom in/out of the spectral visualiser by left/right-clicking on the magnifying glass
symbol cursor, or by using the Zoom to Band and Reset buttons. You can move along thefrequency axis by moving the cursor near the axis and dragging the green sliding bars or using
Pan to Line. For a practical demonstration of the spectral editor please watch the spectral
setup video tutorial.

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7

Finalising the Spatial Setup

Having specified the spectral setup and in particular the representative frequency, you are now ready to finalise
the spatial setup based on the sources you defined in Section 5. The maximum total number of pointings in thelargest array (12-m or 7-m for Standalone ACA) is 150, regardless of whether these are treated as mosaics, offset
pointings or separate sources.

7.1

Individual Pointing(s)You can visualise and configure the spatial setup for each source individually by selecting the relevant sourcetab. By default, there will be just one pointing at the source coordinates specified earlier. Offset pointings canbe added, edited and deleted directly in the Field Center Coordinates panel or interactively in the Spatial Visual
Editor (see boxed text). The Import button will read offset pointings for a given source from an ASCII file insimple RA, DEC format. You can also Export pointings, e.g. to be used for simulations, in different coordinate
formats.
When importing, the ASCII table of source details is now treated as being case-insensitive.

Non-overlapping offset pointings are no longer allowed within one field source. Instead, all pointings within
one field source must overlap and will be processed as one image.
If ACA 7-m observations are requested (Section 9) these will have the same pointing centres as the 12-m
pointings defined; any custom-defined mosaic will not be adjusted for the larger primary beam size of the 7-m
antennas. Also, the sensitivity specified in Section 9 is assumed to be per pointing and the estimate enteredshould take into account any overlap.

7.2

1 Rectangular Field
By default, the spatial editor shows only the rectangular area defined for the mosaic. To see theindividual pointings set up by the OT, you need to press the Show pointing positions button in
the toolbar above the spatial editor.

The Rectangular Field option is a convenient way to easily set up evenly sampled rectangular mosaics on a
per-source basis. You simply specify the size of the field as p length times q length, the Position Angle and theSpacing of individual pointings. By default, the spacing is set to Nyquist sampling (Spacing = 0.51 times fractionof antenna beamsize). If you change this, you must carefully justify your choice in the Technical Justification(Section 10). For rectangular fields, the 7-m Array pointings are automatically set up to optimally sample thearea specified, therefore the number of pointings will be smaller than for the 12-m Array. You may wish toexport the coordinates of the individual pointings; this is done using the Export button next to the displayed
number of pointings.
Mosaics are allowed also in full-polarization mode. These can be defined in the usual way as either a collectionof individual pointings or as a rectangular box that is automatically tiled by the OT. Nyquist sampling is highly
recommended and for rectangular boxes the OT will warn if the pointings are sampled at less than the Nyquist
frequency. If a polarization mosaic is requested, the spectral setup will be forced to a Single Continuum setup at
the standard continuum frequencies for the selected band. In case high spectral resolution is required in orderto remove spectral lines, the Single Continuum mode now contains the option to select FDM.

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Figure 9: Visualisation of individual pointings in the spatial tab of the Field Setup editor.

7.3

The spatial visualiser

The spatial visualiser (see Figs 9 and 10) is found under the Spatial tab of the Field Setup editor. It can beused to view and edit pointings on a per-source basis and will work properly only if you load an image.
Either Query one of the image servers selected from the drop-down menu to display a catalogue image of thearea surrounding your source, or load and display your own FITS image by clicking the folder icon in the spatial
editor toolbar. The primary beams of the pointings defined are represented by red circles, and can be moved,
added and deleted interactively. They can be displayed for either the 12- or 7-m antennas if ACA observations
have been requested. If Total Power observations are requested, the area scanned is shown by a turquoisebox. For individual pointings, this box dynamically adapts to cover the pointings defined. You can use thebuttons in the toolbar above and below the spatial visualiser to perform simple visualisation operations such as
adjusting the cut levels, zooming, and saving the image. Please see the spatial setup video tutorial for a practicaldemonstration of all functionalities.

The sensitivity in a single pointing is not uniform, but gradually falls off away from the pointing
centre. For rectangular mosaics, the fall-off in sensitivity is automatically taken into accountby the fact that the individual pointings are set up so as to overlap. The HPBW of the antenna
beam is represented by a red circle in the spatial visualiser and a smaller green circle (1/3 ofthe HPBW) is shown to emphasize the inner area where the sensetivity is highest.

17Figure 10: Visualisation of a rectangular mosaic.

8

Calibration Strategy

You should normally use the default System-defined calibration option in the Calibration Setup editor. The
system-defined calibration is designed to fully calibrate your science observations using the most appropriate
sources available at execution time, and will at least include pointing, bandpass/flux and phase calibration.
Science Goals requiring full polarization will receive an appropriate calibration strategy. Only experts whose
projects have special calibration requirements should specify User-defined calibration.
An extra option is available for the system-defined calibration strategy: force separate amplitude calibration
using solar system object. By default, the OT assumes that it is acceptable to use the same quasar from a
regularly monitored sample for both amplitude and bandpass calibration. However, if you have any special
amplitude calibration requirements you can force an extra observation of a Solar System object to betaken for amplitude calibration. This will add a few minutes to your time estimate (see Section 9).
If passive phasing has been selected, you will need to define a fixed (specific) phase calibrator instead ofa query. The user-defined calibration interface should have been selected automatically and the existing phase
query should be deleted. Then choose Add Fixed Calibrator and select a specific source from the ALMA calibrator
catalogue. Calibrators need to have a flux in the band of interest ≥0.5 Jy and ideally be within 5◦ of the sciencetarget. The choice of calibrator should be described in the Technical Justification.

9

Control and Performance

The final technical specifications of your Science Goal are entered in the Control and Performance editor (seeFig. 11). The Configuration Information section at the top of the page displays information on the array
configurations available in the current cycle, and uses the representative frequency defined in the spectral setup
to calculate the Synthesized beamsize and the Maximum Recoverable Scale of the observations.
The Desired Angular Resolution (AR) and the Largest Angular Structure (LAS) are used together to deter18

Figure 11: Control and Performance editor and the Time Estimate box. Here, a range of acceptable angularresolutions has been specified.
mine the array configuration(s) the observations can be executed in. PIs cannot explicitly request specificconfigurations, but should instead make sure that the AR and LAS parameters entered are correct. The array
configurations selected for your observations will together have baselines long enough to match the AR requested,
and be compact enough to resolve the LAS. Often this will mean that a number of configurations are acceptable
for a given Science Goal or that up to two 12-m configurations as well as ACA 7-m and TP observations areincluded (for limitations and possible array combinations see Section A.4 of the Proposer’s Guide). Details on
the configuration setup devised by the OT can be found in the Planning and Time Estimate pop-up.
Users do not directly select whether ACA 7-m and/or Total Power observations should be added
to their 12-m observations or not. Instead, the ACA is imposed by the OT if required to achieve
the LAS requested. Whether or not ACA observations will be scheduled can be easily seen in
the Planning and Time Estimate pop-up (see Fig. 11) or the Proposal Time Summary dialogue(“clock” icon on the menu bar).

Users of the 12-m array have the option of entering a single value (as in previous cycles), a range of acceptable
AR values, or asking for observations with any AR. If a range of AR values is entered, the OT will assign one
or more configurations that match the AR anywhere in the specified range. This gives more flexibility forscheduling observations where the AR requirement is only loosely constrained. Note that if an
AR range is given and the sensitivity requirement is entered as a brightness temperature, the OT assumes themost extended configuration when computing the time estimate as this requires the most time. The equivalentbrightness temperature achieved for the more compact end of the AR range is indicated for information only.
The Any button (see Fig. 12) in practice limits the AR to the values given in the Configuration Information forthe most compact and most extended 12-m configuration, excluding long-baseline configurations (since these areless efficient to calibrate). For this option users must enter the requested sensitivity in Jy.
19

Figure 12: The user has specified that Any angular resolution is acceptable.
It is not the case that every configuration will be visited during a cycle. For example, the two largest
configurations (C-9 and C-10) have not been visited in Cycle 8 2021. The OT will be configured to know which
configurations are available and will adjust the achievable angular resolutions accordingly.
ACA stand-alone observations are requested explicitly by selecting Standalone ACA as the option for the
Desired Angular Resolution. If necessary to achieve the LAS requested, Total Power observations will be added
only for spectral line observations in Bands 3–8. Note that for stand-alone observations the ACA 7-m time
estimate is specifically computed for the sensitivity requested, rather than being a multiple of the 12-m Array
time. Given the greatly reduced total collecting area of the 10 7-m antennas compared to the 12-m array, astand-alone ACA proposal will require significantly more ACA time for the same sensitivity request.
You can define and check technical details of the observations using the following fields (fields displayed in
red must be filled):• Desired Angular Resolution: your choice is guided by the synthesized beamsizes corresponding to
the most compact and most extended configurations available in the current cycle as displayed in the
Configuration Information. The value(s) entered cannot be smaller than the synthesized beam size of themost extended configuration and cannot be larger than the synthesized beam size of the most compact
configuration.
• Largest Angular Structure in source: here you should enter the largest angular structure that you
wish to image in your source(s), which may be different from the actual size of the source. The value
entered determines whether you need multiple 12-m configurations and/or the ACA, and therefore has adirect influence on the time estimate (see the Maximum recoverable scale for the 12-m configurations in the
Configuration Information table for guidance). The input units are the same as for the angular resolution.
It is not used if an angular resolution of Any is selected.
• Desired Sensitivity per Pointing: you should enter the 1-σ rms sensitivity required for the mostrestrictive line/continuum observation to achieve the scientific aims of the Science Goal, and if relevant
mention the S/N achieved for the remaining lines/continuum in the Technical Justification. In the case of arectangular field mosaic you should specify the sensitivity required over the mosaic, not that for individual20overlapping pointings. We recommend that the sensitivity requested is good enough to give a 3 σ detection
at the very least, ideally 5 σ.
• Bandwidth used for Sensitivity: for continuum observations, this field is automatically set to AggregateBandwidth. For spectral line or spectral scan observations you can pick one of six choices given in the
dropdown menu:- RepresentativeWindowBandWidth: the bandwidth of the spectral window chosen as the representative
spectral window (and containing the Representative Frequency) in Section 6.
- RepresentativeWindowResolution: the (Hanning-smoothed) spectral resolution of the representative
spectral window, taking into account spectral averaging. This is the default for spectral-line setups.
- AggregrateBandwidth: the summed, non-overlapping bandwidth of all your selected spectral windows.
This is the default for single continuum.
- LargestWindowBandwidth: the bandwidth of your widest spectral window defined.
- FinestResolution: the finest (Hanning-smoothed) resolution of any spectral window, taking into account spectral averaging.
- User : a bandwidth of your choice (useful if you are intending to smooth your data after observationto achieve a certain S/N).
Observations requesting very small angular resolutions (i.e. those making use of long baselines)
are inefficient because they need to be frequently calibrated to correct for atmospheric phasefluctuations. Since the array configuration is determined based on the AR defined in the OT,
it is possible to inadvertently trigger long baseline observations by entering an AR just slightly
smaller than that actually required. You can see if the observations defined make use of long
baselines in the Planning and Time Estimate pop-up – the first 12-m configuration will belabelled C-7 to C-10 and the number of phase calibrator observations per SB execution will
be larger than usual. Long baselines should be avoided if they are not necessary to achieve a
Science Goal.

Please pay close attention that the Bandwidth used for sensitivity is appropriate for your scientific aims. For spectral line observations we recommend that it is at most 1/3 of the expected
spectral line width. Selecting too wide a bandwidth will lower the time estimate but yield too
low a sensitivity.

The Planning and Time Estimate button will estimate the total time required to achieve the desired sensitivity
goal on the largest array, either the 12- or 7-m, including calibration (pointing, bandpass and phase, as well
as flux calibration if requested and reference positions for TP observations) and overheads (telescope slewing,
computational latencies). The time for the smaller configurations is estimated using multiples of the time required
for the largest array. The multipliers are based on simulations – see the Technical Handbook for more details.
Additional options that affect the time required are:• Override OT’s Sensitivity-Based Time Estimate: If your Science Goal is not sensitivity driven, butinstead requires a certain time (e.g. for a monitoring experiment) you can choose to override the OT’s time
estimate. The time entered should be the total time (including calibrations and overheads) for the more
extended 12-m configuration needed; time estimates for the ACA are the automatically calculated by the
OT.
• Are the Observations Time-Constrained?: The OT has the ability to capture the following time
constraints:
21

Figure 13: The time constraints interface and Time Estimate box for the example of Multiple Visits and Simultaneous 12-m and 7-m observations.
- Single Visit: specify fixed time intervals during which your observations should be executed. The
observations will be carried out only once in total, within any of the time windows specified. You
can manually Add time windows individually or Import a list of time slots from an ASCII file. See
the Control & Performance section of the ALMA OT Reference Manual for the format required.
- Multiple Visits: define multiple visits for your Science Goal. The timing constraints of the individual
visits are specified in terms of arbitrary, fixed or relative time intervals. Here, the observations will be
carried out once for each visit specified. The time estimate computed by the OT will be multipliedby the number of visits (see Fig. 13).
• Simultaneous 12-m and ACA observations: If this is selected, it is assumed that the observations
will be observed at the same time. The total time required for the largest array configuration will also
be assigned to the smaller arrays. note that configurations C-7, C-8, C-9, and C-10 are however excluded
from simultaneous observing, as they cannot be paired with ACA.

Selecting Tool in the OT menu gives you access to a number of useful tools to help you better
plan your observations. You can use the Sensitivity Calculator to bring up a pop-up windowthat allows you to experiment with project execution times and sensitivities, the Project Time
Summary (“clock” icon) to give a time and data-rate summary, and generate printable and
PDF summaries of individual Science Goals as well as the whole proposal (including a coversheet).

22

Figure 14: The technical justification editor.

10

Technical Justification

For the majority of proposals, the technical justification is entered in three sections: Sensitivity, Imaging, andCorrelator configuration. Relevant parameters are taken or computed from the Science Goal setup and the
Expected Source Properties are displayed for each section. If the OT detects values it thinks should be doublechecked, an informative message is displayed in blue. You should pay special attention to these issues in yourjustification text. Note that any supporting figures (e.g. simulations) should be included in the science case PDF.
You must enter a short justification text in the free-format text boxes of each section. In addition, text
boxes will appear for any choices that need to be justified. These include using single polarization, non-standard
continuum frequencies, non-Nyquist spatial sampling, a user-defined calibration strategy, overriding of the OT’s
suggestion of the ACA or time estimate, low maximum elevation of a source and time-constrained observations.
For detailed guidelines on filling the Technical Justification please see the Proposer’s Guide and the technicaljustification video tutorial.

11

Validating and Submitting

A proposal must pass validation before it can be submitted. This is most easily checked by clicking on the “tick”
icon in the toolbar which will cause any errors or warnings to be shown in the Feedback pane (see Fig. 15).
Warnings are for your attention and should be double-checked, but they do not prevent you from submitting atechnically sound proposal. Double-clicking on an error/warning message will take you to the relevant Science
Goal so that you can easily identify and correct the problem. With all errors corrected, your project is now readyto be submitted.
To submit your project to the ALMA archive select File > Submit Project in the menu bar. You and all23

Figure 15: An example of failed validation.
of your Co-Is should receive a confirmation email after each proposal submission. Once you have submitted,
the Unsubmitted Proposal label in the blue proposal status bar will be replaced by a red Submitted label. This
indicates that the proposal has been stored in the ALMA archive and assigned the Project Code listed in thetitlebar of the OT GUI. You are encouraged to save your project to disk after submission in order to ensure thatany updates are made on the submitted version.
It is now possible to submit your proposal using a button on the toolbar (cloud-shaped iconwith an up-facing arrow).

You can make changes and re-submit your Submitted proposal until the deadline; any re-submission will
overwrite the previous version of the proposal stored in the archive. For more detailed information on the
ALMA OT and the technical capabilities in the current cycle you are invited to consult the documentation
available on the Science Portal. If you have any questions or comments please feel free to submit a ticket to the
ALMA Helpdesk.

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