troscopy with a resolution of R ~ 4,000 , simultaneously covering the range between 0.37 – 2.35 microns .
The eight independent channels in OCTO- CAM allow the user to adjust exposure times in each bandpass for increased efficiency and the best match to observing conditions . By using state-of-the-art detectors — frame transfer in the optical and CMOS ( complementary metal-oxide semiconductor ) in the near-infrared ( NIR ) — OCTOCAM will have negligible readout times enabling high time-resolution observations . Table 1 provides a subset of the top-level requirements for OCTOCAM : centaurs in the Solar System ( Figure 2 ), exoplanets , neutron stars , X-ray binaries , active galactic nuclei , supernovae , tidal disruption events , and gamma-ray bursts .
OCTOCAM ’ s multi-wavelength spectroscopy ( and the possibility for simultaneous multiband imaging ) makes it the optimal machine for the efficient characterization of astronomical transients — similar to those expected to be discovered in the 2020s by LSST , which promises to play a leading role in advancing our understanding of these objects identified through their explosive variability . The availability of high time-resolution , coupled with Gemini ’ s rapid response capability , will
OCTOCAM Requirements
Parameter
Value
Spectrographic Wavelength Range 0.37 to 2.3 μm Simultaneous Coverage Yes Continuous Coverage Yes , excluding atmospheric bands
Resolving Power ( λ / Δλ ) ≥3500 (@ 455 nm ) and ≥4000 (@ 610 , 745 , 875 , 1035 , 1250 , 1630 , 2175 nm ) assuming a slit width of 0.54 ”
Spatial Sampling 0.18 ± 0.02 ” in all bands Imaging Natural Seeing FOV ≥ 170 ” x 170 ” Spatial Sampling 0.18 ± 0.02 ” in all bands Performance
Instrument Throughput Average > 20 % (@ 400 ) and > 35 % (@ 455 , 610 , 745 , 875 , 1035 , 1250 , 1630 ,
( ADC through detector ) 2175 nm ) in imaging Average > 20 % (@ 400 ) and > 30 % (@ 455 , 610 , 745 , 875 , 1035 , 1250 , 1630 , 2175 nm ) in spectroscopy
Photometric Time Resolution
≤ 50ms ( for a 30 x 30 pixel window @ 50 kHz ) in the g- , r- , i- , and z-band ≤ 50ms (@ 10 MHz ) in the Y- , J- , H- , and K S
-band Target Acquisition Time Integration time + 10s ( for automatic target acquisition and grism / slit setup )
OCTOCAM Science Cases
A capable instrument for extremely broadband observations ( both in imaging and long-slit spectroscopy ), OCTOCAM will deliver groundbreaking scientific output over a very broad range of topics that cover fields as diverse as trans-Neptunian objects and also allow researchers to use OCTOCAM to catch transient objects in their earliest phases and monitor their rapid evolution .
Spectral coverage from the optical to NIR , both in imaging and spectroscopy , is crucial for high-redshift sources in general , and high-redshift transients in particular . With
34 GeminiFocus January 2018 / 2017 Year in Review