6 research outputs found
GPI 2.0: Upgrades to the IFS including new spectral modes
The Gemini Planet Imager (GPI) is a high-contrast imaging instrument designed to directly image and characterize exoplanets. GPI is currently undergoing several upgrades to improve performance. In this paper, we discuss the upgrades to the GPI IFS. This primarily focuses on the design and performance improvements of new prisms and filters. This includes an improved high-resolution prism which will provide more evenly dispersed spectra across y, J, H and K-bands. Additionally, we discuss the design and implementation of a new low-resolution mode and prism which allow for imaging of all four bands (y, J, H and K-bands) simultaneously at Râ10. We explore the possibility of using a multiband filter which would block the light between the four spectral bands. We discuss possible performance improvements from the multiband filter, if implemented. Finally we explore the possibility of making small changes to the optical design to improve the IFSâs performance near the edge of the field of view
GPI 2.0: Upgrades to the IFS including new spectral modes
The Gemini Planet Imager (GPI) is a high-contrast imaging instrument designed
to directly image and characterize exoplanets. GPI is currently undergoing
several upgrades to improve performance. In this paper, we discuss the upgrades
to the GPI IFS. This primarily focuses on the design and performance
improvements of new prisms and filters. This includes an improved
high-resolution prism which will provide more evenly dispersed spectra across
y, J, H and K-bands. Additionally, we discuss the design and implementation of
a new low-resolution mode and prism which allow for imaging of all four bands
(y, J, H and K-bands) simultaneously at R=10. We explore the possibility of
using a multiband filter which would block the light between the four spectral
bands. We discuss possible performance improvements from the multiband filter,
if implemented. Finally we explore the possibility of making small changes to
the optical design to improve the IFS's performance near the edge of the field
of view.Comment: 8 pages, 5 figures, Proc. of SPIE Paper No. 11447-41
Final Design and On-Sky Testing of the iLocater SX Acquisition Camera: Broadband Single-Mode Fiber Coupling
Enabling efficient injection of light into single-mode fibers (SMFs) is a key
requirement in realizing diffraction-limited astronomical spectroscopy on
ground-based telescopes. SMF-fed spectrographs, facilitated by the use of
adaptive optics (AO), offer distinct advantages over comparable seeing-limited
designs, including higher spectral resolution within a compact and stable
instrument volume, and a telescope independent spectrograph design. iLocater is
an extremely precise radial velocity (EPRV) spectrograph being built for the
Large Binocular Telescope (LBT). We have designed and built the front-end fiber
injection system, or acquisition camera, for the SX (left) primary mirror of
the LBT. The instrument was installed in 2019 and underwent on-sky
commissioning and performance assessment. In this paper, we present the
instrument requirements, acquisition camera design, as well as results from
first-light measurements. Broadband single-mode fiber coupling in excess of 35%
(absolute) in the near-infrared (0.97-1.31{\mu}m) was achieved across a range
of target magnitudes, spectral types, and observing conditions. Successful
demonstration of on-sky performance represents both a major milestone in the
development of iLocater and in making efficient ground-based SMF-fed
astronomical instruments a reality.Comment: 18 pages, 17 figures. Accepted for publication in MNRA
GPI 2.0: Performance Evaluation of the Wavefront Sensor's EMCCD
The Gemini Planet Imager (GPI) is a high contrast imaging instrument that
aims to detect and characterize extrasolar planets. GPI is being upgraded to
GPI 2.0, with several subsystems receiving a re-design to improve the
instrument's contrast. To enable observations on fainter targets and increase
stability on brighter ones, one of the upgrades is to the adaptive optics
system. The current Shack-Hartmann wavefront sensor (WFS) is being replaced by
a pyramid WFS with an low-noise electron multiplying CCD (EMCCD). EMCCDs are
detectors capable of counting single photon events at high speed and high
sensitivity. In this work, we characterize the performance of the HN\"u 240
EMCCD from N\"uv\"u Cameras, which was custom-built for GPI 2.0. The HN\"u 240
EMCCD's characteristics make it well suited for extreme AO: it has low dark
current ( 0.01 e-/pix/fr), low readout noise (0.1 e-/pix/fr at a gain of
5000), high quantum efficiency ( 90% at wavelengths from 600-800 nm; 70% from
800-900 nm), and fast readout (up to 3000 fps full frame). Here we present test
results on the EMCCD's noise contributors, such as the readout noise,
pixel-to-pixel variability and CCD bias. We also tested the linearity and EM
gain calibration of the detector. All camera tests were conducted before its
integration into the GPI 2.0 PWFS system.Comment: 16 pages, 14 figures. Conference Proceedings for AO4ELT7, held in
June 2023 in Avignon, Franc
Accretion disk radii changes in IP Peg during outburst
The focus of this study is the change in accretion disk size in Dwarf Novae (DN), IP Peg. DN systems are a type of cataclysmic variable that experience periodic outbursts. These outbursts are caused by the release of gravitational potential energy from an increased rate of matter flow through the accretion disk. Throughout outburst, the radius of the accretion disk of the DN changes. Recent research done at Ball State University has suggested that the disk radius may not change as the disk instability model predicts. According to the disk instability model, the accretion disk should be at its largest radial size when the DN is at the peak of outburst. IP Peg in September and October of 2006 underwent outburst. It was found that during that particular outburst that the accretion disk was at its largest radial size on the decline from outburst and not peak. Further research into how the accretion disk changes with time is needed.Department of Physics and AstronomyThesis (M.S.