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Control and Performance
The last part of defining a Science Goal is to specify variousperformance parameters that effect, predominantly, the telescopeconfigurations that will be used during the observations and theamount of time that the sources will be observed for. The latter isdisplayed if the
Time Estimate
button is clicked. The ALMASensitivity Calculator can also be selected for experimentation withthe requested parameters.
An example of the Control Parameters form is shown inFig.
6.3.5
with the following fields:
-
Representative Frequency
: It is used for various calculations within the OT including the field of view (primary beam size) of the various antenna sizes and the required observing time.
-
Antenna Beamsize
: Size of the primary beam. Currently only the value for a 12-m antenna is displayed as the ALMA Compact Array is not yet available.
-
Extended Config: Max Baseline and its Beamsize
: This gives the maximum angular resolution that can be obtained during Cycle 0 of Early Science in the extended (400-m baseline) configuration.
-
Compact Config: Max Baseline and its Beamsize
: This gives the maximum angular resolution that can be obtained during Cycle 0 of Early Science in the compact (125-m baseline) configuration.
-
Desired Angular Resolution
: This can be entered in either arcsec or fraction of the primary beam. It cannot be smaller than the (synthesised) beamsize displayed for the 400-m configuration. We recommend that you set this to one of the values given for the two Cycle 0 arrays above.
-
Largest Angular Scale of source
: This specifies the largest angular scale of the source emission that you wish to map. If your source will not be resolved at the requested angular resolution then click on
Point Source
. Otherwise, click on
Extended Source
and enter the expected value.
-
Desired Sensitivity per Pointing
: This can be entered in either in Jy or K - the equivalent value in the other unit will be displayed for information purposes. An equivalent value will not be displayed unless an angular resolution has been entered. Note that this parameter will be updated if it is changed in the Sensitivity Calculator.
-
Bandwidth used for Sensitivity
: This defines bandwidth that should be used for calculating the required time based on the sensitivity. There are a number of likely choices in a drop-down menu. Alternatively, a user-defined value can be entered. This should be chosen if you require less spectral resolution than what is provided by ALMA in your final spectrum.
-
Does your setup need more time?
: If you feel that you need more time than suggested by the
Time Estimate
button, then select
Yes
. See below for more information.
-
Is this observing time constrained?
: If
Yes
is selected, it is possible to enter a window within which the source should be observed - a calendar tool is available. A text box is available for entering information about your time constraints.
-
ACA Use
: This will eventually be used to test whether the ALMA Compact Array is required to meet your scientific goals.
Figure 6.10:
The Control Parameters form of the Science Goal.
|
Subsections
Next:
Sensitivity versus Time and
Up:
Adding Phase-1 Science Goals
Previous:
Calibration Setup
Contents
Index
The ALMA OT Team, 2011 May 20