GeminiFocus April 2017 | Page 18

with a resolution of R ~ 4,000, simultane- ously 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 (comple- mentary metal-oxide semiconductor) in the near-infrared (NIR) — OCTOCAM will have negligible readout times enabling high time-resolution observations. Table 1 pro- vides a subset of the top-level requirements for OCTOCAM: centaurs in the Solar System (Figure 2), exo- planets, 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 multi- band imaging) makes it the optimal machine for the efficient characterization of astronom- ical 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 identi- fied through their explosive variability. The availability of high time-resolution, coupled with Gemini’s rapid response capability, will OCTOCAM Requirements Parameter Spectrographic Value Wavelength Range Simultaneous Coverage Continuous Coverage Resolving Power (λ/Δλ) Spatial Sampling 0.37 to 2.3 μm Yes Yes, excluding atmospheric bands ≥3500 (@455 nm) and ≥4000 (@610, 745, 875, 1035, 1250, 1630, 2175 nm) assuming a slit width of 0.54” 0.18 ±0.02” in all bands Natural Seeing FOV Spatial Sampling ≥ 170” x 170” 0.18 ± 0.02” in all bands Instrument Throughput (ADC through detector) Average > 20% (@400) and >35% (@455, 610, 745, 875, 1035, 1250, 1630, 2175 nm) in imaging Average > 20% (@400) and >30% (@455, 610, 745, 875, 1035, 1250, 1630, 2175 nm) in spectroscopy ≤ 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 Integration time + 10s (for automatic target acquisition and grism/slit setup) Imaging Performance Photometric Time Resolution Target Acquisition Time OCTOCAM Science Cases A capable instrument for extremely broad- band observations (both in imaging and long-slit spectroscopy), OCTOCAM will de- liver groundbreaking scientific output over a very broad range of topics that cover fields as diverse as trans-Neptunian objects and 16 GeminiFocus also allow researchers to use OCTOCAM to catch transient objects in their earliest phas- es and monitor their rapid evolution. Spectral coverage from the optical to NIR, both in imaging and spectroscopy, is cru- cial for high-redshift sources in general, and high-redshift transients in particular. With April 2017