Current Status: Commissioning/Shared risk science
ʻAlaʻihi is an insert that can be installed within the Nāmakanui instrument. It is a dual-polarization, single-sideband (SSB) receiver, operating in upper sideband (USB) only, with a LO frequency range 80.0 to 88.5 GHz. This corresponds to a sky frequency of approximately 86.0 to 94.5 GHz given an IF of 6 GHz. The instrument’s performance for different IF values (e.g., 7 GHz) is under ongoing characterization. Supported observing modes include Stare, Jiggle, and Raster observing modes.
Current Status for proposals
Although the instrument is still being commissioned, EAO already has a preliminary sensitivity calculator (integrated into the Hedwig proposal system). Measurements of the main beam and aperture efficiency will be taken throughout the commissioning process, and will be made available to users.
Data Reduction
All ‘Ala‘ihi data are reducible by the Starlink software suite and the output provides a spectra. For details on running ‘Ala‘ihi reductions, visit the Heterodyne Data Reduction pages. It is recommended that initially users reduce data from both polarizations separately to check for issues.
Notable Molecular Transitions
| Molecule | Transition | Rest Frequency |
|---|---|---|
| CH3OH | (5-1 − 40E) | 84.5 GHz |
| SiO | (2 – 1) | 86.2 GHz |
| HCN | (1 -0) | 88.6 GHz |
| HCO+ | (1 – 0) | 89.2 GHz |
References
Mizuno et al. (2020), Commissioning of Nāmakanui on the JCMT,
Proceedings of the SPIE, Volume 11453, id. 114533T 19 pp. 10.1117/12.2561742