ngVLA Tools & Materials
ngVLA Configuration Tools
A CASA guide that shows how to create simulated data for the ngVLA including a model repository is available at this link.
Configuration files for each ngVLA subarray can be downloaded below.
Configuration Files for CASA (updated Feb, 2022): The files below are for the reference configuration of the ngVLA developed by the ngVLA Imaging and Calibration work group as part of the Conceptual Design Review (CoDR) preparation (i.e., Rev.D -- ngVLA memo 92). These should be used for simulations and calculations that explore the science capabilities of the ngVLA. We expect that such investigations will lead to suggested modifications to these notional configurations for specific science cases, and hope the community will report on such findings via ngVLA memos and/or refereed publications.
We note that imaging with heterogenous arrays — i.e., arrays with different diameter antennas such as ngVLA + SBA — is not currently supported in the current CASA release (except for ALMA).
Numerous memos and science studies have been published that address the imaging parameters for optimal performance (sensitivity, PSF). We refer interested parties to the ngVLA memo series, in particular memos 16, 30, 35, 41, 55, 64, and 89.
- ngvla-revD.lba.cfg: The Long Baseline Array (LBA) consists of 10 continental-scale stations of 3 18 m antennas each. Long baseline stations are located in Hawaii, Washington, California, Iowa, West Virginia, New Hampshire, Puerto Rico, the US. Virgin Islands, and Canada.
- ngvla-revD.sba.cfg: The Short Baseline Array (SBA) has 19 close-packed antennas of 6 m diameter to complement the Core subarray for very low surface brightness imaging. The use of 4 18 m antennas in total power mode to fill in the uv-hole left by the SBA is being investigated. NOTE: In order to get the correct primary beam for the SBA (6 m antennas), a special procedure is required (see page 11 of ngVLA memo 43). Support for heterogeneous arrays other than ALMA (e.g., simultaneously using the ngVLA 18 m and 6 m antennas) is currently being commissioned.
- ngvla-revD.main.cfg: The ngVLA Main array component includes 214 antennas of 18 m diameter and has baselines up to ~1068 km. The Main subarray can be characterized by three sub-components or scales, composed by the Core, the Spiral and the Mid subarrays. Each of these three scales are broken out into separate subarrays in the following configuration files.
- ngvla-revD.core.cfg: This configuration consists of 114 18 m antennas in a semi-random distribution within a region of ~4 km diameter located on the Plains of San Agustin. This configuration is suitable for imaging lower surface brightness regions.
- ngvla-revD.spiral.cfg: This configuration is composed of 54 18 m antennas, extending from the edge of the Core in a five-armed spiral pattern out to ~39 km baselines located on the Plains of San Agustin. This configuration is suitable for imaging spatial scales similar to the existing VLA.
- ngvla-revD.mid.cfg: This configuration consists of 46 18 m antennas extending from the edge of the five-armed Spiral, mostly distributed in a roughly three-arm spiral pattern, expanding into parts of Texas, Arizona, and Northern Mexico.
- ngvla-revD.spiral_core.cfg: This subarray consists of 168 18 m antennas composed by the Spiral and the Core subcomponents.
- This zip file includes all above configurations and a README file.
ngVLA Receiver Configuration
The receiver configuration has progressed since the Reference Design, with an improved cascade analysis for the preferred 6-band concept.
This latest system noise estimate (Oct. 24, 2022) reflects updates to component selection and simulated performance, and also includes system linearity calculations.
ngVLA Sensitivity Calculator
Please refer to the Performance Table under the current Reference Design page to compute your sensitivity estimates for now. A web interface next generation Exposure Calculator Tool (ngECT) is currently being developed based on such investigations and will eventually supersede the values included in the performance metric table. In the meantime, this sensitivity calculator Python script can be used to estimate the performance sensitivity for many representative subarrays of the ngVLA (including point source and surface brightness sensitivities for lines and continuum).