MUSTANG-2 Mapping Information#
MUSTANG-2’s primary scanning method is that of a Lissajous Daisy of varying radii. The mapping speed profiles have been scaled to a zenith opacity of 0.1 and elevation of 45 degrees.
This sensitivity assumes an effective smoothing of 10.0” FWHM. If heavier smoothing is acceptable the sensitivity is better by a factor of (FWHM/10.0 arcsec).
Historically, we have reported mapping speeds based on the RMS within a circle of radius 2 arcminutes. These values have now been extended to a range of scan sizes seen below.
Scan size (radius, arcminutes) |
Mapping speed in central 2’ (\(\mu\) K hr \(^{1/2}\)) |
Sensitivity (\(\mu\) Jy/beam) |
Sensitivity (compton y) |
---|---|---|---|
2.5 |
73 |
56.2 |
2.0E-5 |
3.0 |
74 |
57 |
2.0E-5 |
3.5 |
77 |
59.3 |
2.1E-5 |
4.0 |
85 |
65.5 |
2.3E-5 |
4.5 |
98 |
75.5 |
2.7E-5 |
5.0 |
117 |
90.1 |
3.2E-5 |
- Notes on the above table:
The mapping speeds above are calculated based on the RMS in the central 2 arcminutes. For small scans, this region has roughly uniform noise.
The conversion from \(\mu\) K to \(\mu\) Jy/beam is roughly 0.77; i.e. multiple the \(\mu\) K noise by 0.77 to get a noise estimate in \(\mu\) Jy/beam.
The conversion from \(\mu\) K to Compton y is roughly 2.74E-7; i.e. multiple the \(\mu\) K noise by 2.74E-7 to get a noise estimate in Compton y.
Extended signal on scales up to 5’ should be imaged with reasonable fidelity, but faint signal more extended than this may be difficult to detect. Bright emission (20 mJy/beam or more) can be reconstructed over scales of many arcminutes. The angular resolution of MUSTANG on the GBT is typcally 9” (FWHM) and the instantaneous field of view is a 4’ diameter circle. Recovery of signal depends on data processing.
Mapping Memo#
Here is a MUSTANG-2 mapping speeds memo
.