Kevin T. Hanna

GatirCam: Gemini mid-infrared imager

The University of Florida is developing the mid-IR imager, called GatirCam, to be used primarily, but not solely, at the southern hemisphere Gemini telescope at Cerro Pachon, Chile. Key features of GatirCam are its fully reflective optics, its very high mechanical rigidity, and the fact that the associated electronics are very similar to those is in use successfully on similar instrumentation. Design studies for GatirCam indicate that it will meet or exceed all critical requirements of image quality and performance. A low-resolution spectroscopic mode is also currently under consideration for implementation in GatirCam.

MARVELS-1b: A Short-period, Brown Dwarf Desert Candidate from the SDSS-III Marvels Planet Search

We present a new short-period brown dwarf (BD) candidate around the star TYC 1240-00945-1. This candidate was discovered in the first year of the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III, and we designate the BD as MARVELS-1b. MARVELS uses the technique of dispersed fixed-delay interferometery to simultaneously obtain radial velocity (RV) measurements for 60 objects per field using a single, custom-built instrument that is fiber fed from the SDSS 2.5 m telescope. From our 20 RV measurements spread over a ~370 day time baseline, we derive a Keplerian orbital fit with semi-amplitude K = 2.533 ± 0.025 km s^(–1), period P = 5.8953 ± 0.0004 days, and eccentricity consistent with circular. Independent follow-up RV data confirm the orbit. Adopting a mass of 1.37 ± 0.11 M_☉ for the slightly evolved F9 host star, we infer that the companion has a minimum mass of 28.0 ± 1.5 M_(Jup), a semimajor axis 0.071 ± 0.002 AU assuming an edge-on orbit, and is probably tidally synchronized. We find no evidence for coherent intrinsic variability of the host star at the period of the companion at levels greater than a few millimagnitudes. The companion has an a priori transit probability of ~14%. Although we find no evidence for transits, we cannot definitively rule them out for companion radii ≲ R_(Jup).

CanariCam: a multimode mid-infrared camera for the Gran Telescopio CANARIAS

The University of Florida is developing a mid-infrared camera for the 10.4-meter Gran Telescopio CANARIAS. CanariCam has four science modes and two engineering modes, which use the same 320 x 240-pixel, arsenic-doped silicon, blocked-impurity-band detector from Raytheon. Each mode can be remotely selected quickly during an observing sequence. The pixel scale is 0.08 arcsec, resulting in Nyquist sampling of the diffraction-limited point-spread-function at 8 μm, the shortest wavelength for which CanariCam is optimized. The total available field of view for imaging is 26 arcsec x 19 arcsec. The primary science mode will be diffraction-limited imaging using one of several available spectral filters in the 10 μm (8-14 μm) and 20 μm (16-25 μm) atmospheric windows. Any one of four plane gratings can be inserted for low and moderate-resolution (R = 100 - 1300) slit spectroscopy in the 10 and 20-μm regions. Insertion of appropriate field and pupil stops converts the camera into a coronagraph, while insertion of an internal rotating half-wave plate, a field mask, and a Wollaston prism converts the camera into a dual-beam polarimeter.

Performance of the FLAMINGOS Near-IR Multi-object Spectrometer and Imager and Plans for FLAMINGOS-2: a Fully Cryogenic Near-IR MOS for Gemini South

We report on the performance of FLAMINGOS, the worlds first fully cryogenic near-IR multi-object spectrometer. FLAMINGOS has a fast all refractive optical system, which can be used at telescopes slower than f/7.5. This makes FLAMINGOS a very efficient wide-field imager when used on fast small aperture telescopes and a high AW spectrometer using laser machined aperture masks for MOS spectroscopy. FLAMINGOS uses a 2048x2048 HgCdTe HAWAII-2 array by the Rockwell Science Center. The array is readout through 32 amplifiers, which results in low overheads for observations. We describe both the operating characteristics of the HAWAII-2 array and of the array controller and data acquisition system. FLAMINGOS has been in operation for about 1.5 years and is now in routine use on four telescopes: The Kitt Peak 4-m and 2.1-m, The 6.5-m MMT and the 8-m Gemini South Telescope. We will describe the operating characteristics of FLAMINGOS on each of these telescopes that deliver fields-of-view from 21x21 arcminutes to 2.7x2.7 arcminutes and pixels from 0.6 arcseconds to 0.08 arcseconds. While providing a large AW product for fast telescopes (i.e. f/8), FLAMINGOS becomes progressively less efficient on slower telescopes. Since nearly all large telescopes have fairly slow optical systems (f/12 or slower) the combination of large aperture and slow optical systems makes FLAMINGOS ill suited for optimal performance on current large aperture telescopes. Thus, we are beginning construction of FLAMINGOS-2, which will be optimized for performance on the f/16 Gemini South 8-m telescope. Similar to FLAMINGOS, FLAMINGOS-2 will be fully refractive using grisms, laser machined aperture masks and a 2048x2048 HgCdTe HAWAII-2 array. FLAMINGOS-2 will provide a 6.1 arcminute field-of-view with 0.18 arcsecond pixels. FLAMINGOS-2 will also be designed to except an f/32 beam from the Gemini South MCAO system.

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini

Stephen Eikenberry, Reba Bandyopadhyay, J. Greg Bennett, Aaron Bessoff, Matt Branch, Miguel Charcos, Richard Corley, Curtis Dewitt, John-David Eriksen, Richard Elston, Skip Frommeyer, Anthony Gonzalez, Kevin Hanna, Michael Herlevich, David Hon, Jeff Julian, Roger Julian, Nestor Lasso, Antonio Marin-Franch, Jose Marti, Charlie Murphey, S. Nicholas Raines, William Rambold, David Rashkin, Craig Warner Department of Astronomy, University of Florida, Gainesville, FL 32611

A new generation multi-object Doppler instrument for the SDSS-III Multi-object APO Radial Velocity Exoplanet Large-area Survey

We report performance of a new generation multi-object Doppler instrument for the on-going Multi-object APO Radial-velocity Exoplanet Large-area Survey (MARVELS) of the Sloan Digital Sky Survey III (SDSS-III) program. This instrument is based on dispersed fixed-delay interferomtry design. It consists of a multi-object fiber-feed, a thermally compensated monolithic fixed-delay interferometer, a high throughput spectrograph and a 4kx4k CCD camera. The spectrograph resolving power is R=11,000 and the wavelength coverage is 500-570 nm. The instrument is capable of measuring 60 stars in a single exposure for high to moderate precision radial velocity (3-20 m/s) measurements depending on the star magnitudes (V=7.6-12). The instrument was commissioned at the SDSS telescope in September 2008 and used to collect science data starting in October 2008. Observations of reference stars show that the measured photon noise limiting errors are consistent with the prediction for most of the measurements.

Design, performance, and early results from extremely high Doppler precision instruments in a global network

We report design, performance and early results from two of the Extremely High Precision Extrasolar Planet Tracker Instruments (EXPERT) as part of a global network for hunting for low mass planets in the next decade. EXPERT is a combination of a thermally compensated monolithic Michelson interferometer and a cross-dispersed echelle spectrograph for extremely high precision Doppler measurements for nearby bright stars (e.g., 1m/s for a V=8 solar type star in 15 min exposure). It has R=18,000 with a 72 micron slit and a simultaneous coverage of 390-694 nm. The commissioning results show that the instrument has already produced a Doppler precision of about 1 m/s for a solar type star with S/N~100 per pixel. The instrument has reached ~4 mK (P-V) temperature stability, ~1 mpsi pressure stability over a week and a total instrument throughput of ~30% at 550 nm from the fiber input to the detector. EXPERT also has a direct cross-dispersed echelle spectroscopy mode fed with 50 micron fibers. It has spectral resolution of R=27,000 and a simultaneous wavelength coverage of 390-1000 nm.

On-sky commissioning of Hamamatsu CCDs in GMOS-S

GMOS-S has been recently upgraded with Hamamatsu deep depletion CCDs, replacing the original EEV detector array. The new CCDs have superior quantum efficiency (QE) at wavelengths longer than 680nm, with significant sensitivity extending beyond 1 micron. Furthermore, the fringing level in GMOS-S data is now much lower due to the much thicker CCDs, additionally improving delivered sensitivity above that afforded by quantum efficiency alone. Soon after the Hamamatsu CCDs were installed in June 2014, some issues were noticed that impacted the ability to execute some science programs. In October 2015 the ARC controller electronics were upgraded and a cable was replaced, and since November 2015 GMOS-S has again been taking science data with the Hamamatsu detectors with no sign of the previous limitations. We present the results of the GMOS-S on-sky commissioning of the Hamamatsu detector array, and provide an update on the status of the GMOS-N portion of the project.

Improved red sensitivity deep depletion e2v devices for the Gemini North GMOS instrument

The GMOS-N instrument was upgraded with new CCDs in October 2011, improving the instrument sensitivity at both red and blue wavelengths. The deep depletion devices are manufactured by e2v (42-90 with multi-layer 3 coating) and extend the useful wavelength range of GMOS-N to 0.98 microns (compared to 0.94 microns previously). These detectors also exhibit much lower fringing than the original EEV detectors that had been in use since GMOS-N was commissioned in 2002. All other characteristics of the new detectors (readout speed, pixel size and format, detector controller, noise, gain) are similar to the original CCDs. Operating the new detectors in all amps mode (2 per CCD) has effectively improved the readout speed by a factor of 2. The new devices were selected to provide a quick and relatively simply upgrade route while technical issues with the Hamamatsu devices, originally planned for the upgrade, were investigated and resolved. We discuss the rationale for this interim upgrade, the upgrade process and attending issues. The new detectors have been used for science since November 2011. We present commissioning results illustrating the resulting gain in sensitivity over the original detector package. Gemini is still committed to installing Hamamatsu devices, which will further extend the useful wavelength range of GMOS to 1.03 microns, in both North and South GMOS instruments. We discuss the status of the Hamamatsu project and the current planned schedule for these future upgrades.

Characterization of deep-depletion Hamamatsu CCDs for the Gemini multi-object spectrograph

We have performed some initial characterization of back-illuminated deep-depletion CCDs from Hamamatsu Photonics. Three of these 2048×4096, three-side buttable devices will replace the current CCDs in the Gemini Multi-Object Spectrograph to improve the performance of the instrument in the red and near-infrared wavelengths. We describe our testing campaign and report on the results.