Commissioning of the MIRAC-5 Mid-Infrared Instrument on the MMT

Rory Bowens; Jarron Leisenring; Michael R. Meyer; Taylor L. Tobin; Alyssa L. Miller; John D. Monnier; Eric Viges; Bill Hoffmann; Manny Montoya; Olivier Durney; Grant West; Katie Morzinski; William Forrest; Craig McMurtry

arXiv · 2412.10189

Commissioning of the MIRAC-5 Mid-Infrared Instrument on the MMT

Rory Bowens·Jarron Leisenring·Michael R. Meyer·Taylor L. Tobin·Alyssa L. Miller·John D. Monnier·Eric Viges·Bill Hoffmann·Manny Montoya·Olivier Durney·Grant West·Katie Morzinski·William Forrest·Craig McMurtry

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Abstract

We present results from commissioning observations of the mid-IR instrument, MIRAC-5, on the 6.5-m MMT telescope. MIRAC-5 is a novel ground-based instrument that utilizes a state-of-the-art GeoSnap (2 - 13 microns) HgCdTe detector with adaptive optics support from MAPS to study protoplanetary disks, wide-orbit brown dwarfs, planetary companions in the contrast-limit, and a wide range of other astrophysical objects. We have used MIRAC-5 on six engineering observing runs, improving its performance and defining operating procedures. We characterize key aspects of MIRAC-5's performance, including verification that the total telescope, atmosphere, instrument, and detector throughput is approximately 10%. Following a planned dichroic upgrade, the system will have a throughput of 20% and background limiting magnitudes (for SNR = 5 and 8 hour exposure times) of 18.0, 15.6, and 12.6 for the L', M', and N' filters, respectively. The detector pixels experience 1/f noise but, if the astrophysical scene is properly modulated via chopping and nodding sequences, it is less than 10% the Poisson noise from the observed background in an 85 Hz frame. We achieve close to diffraction-limited performance in the N-band and all bands are expected to reach diffraction-limited performance following the adaptive optics system commissioning. We also present an exposure time calculator calibrated to the on-sky results. In its current state, MIRAC-5 will be capable of achieving several scientific objectives including the observation of warm wide-orbit companions. Once the adaptive optics is commissioned and a coronagraph installed in 2025, MIRAC-5 will have contrast-limited performance comparable to JWST, opening new and complementary science investigations for close-in companions.

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Rory Bowens, Jarron Leisenring, Michael R. Meyer, Taylor L. Tobin, Alyssa L. Miller, John D. Monnier, Eric Viges, Bill Hoffmann, Manny Montoya, Olivier Durney, Grant West, Katie Morzinski, William Forrest, Craig McMurtry. 2024-12-13. Commissioning of the MIRAC-5 Mid-Infrared Instrument on the MMT. https://arxiv.org/abs/2412.10189

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