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High-contrast Nulling Interferometry Techniques Project
"We are developing rotating-baseline nulling-interferometry techniques and algorithms on the single-aperture Hale and Keck telescopes at near-infrared wavelengths, aimed at the detection of faint emission close to bright stars. Our experiments are aimed at developing simple and robust nulling interferometer systems, that will be useful in the short term for unique observations of faint exozodiacal emission and exoplanets very close to nearby stars, and in the long term for refining and simplifying potential nulling-interferometer-based space missions. Here we propose significant sensitivity, stability, dispersion-reduction and statistical-analysis upgrades to our nulling interferometer systems so as to take our nulling work from the earlier ""basic physics demonstration"" phase to the ""ultimate limiting performance"" stage. Several planned upgrades to our nulling systems will enable forefront nulling capabilities at very low cost. First, we plan to improve the sensitivity of our Palomar Fiber Nuller by two orders of magnitude by replacing our current very modest detector with a much more sensitive IR camera inherited from the Palomar Testbed Interferometer. Second, we plan to improve our fringe stability through a series of upgrades. We will make use of the P3K extreme adaptive optics capability to come on line at Palomar mid-2011 to enable ~ 70 -100 nm stability between subapertures, and also extremely good fiber-coupling stability, together allowing very deep nulls to be measured. We will also upgrade our own post-adaptive optics fringe tracker and implement a novel fluctuation-tolerant fringe tracker algorithm. Third, we will further develop and test novel data reduction algorithms based on the statistics of the null-depth fluctuations to measure accurate astrophysical nulls to levels much deeper than our stabilization level would otherwise allow. Finally, we will also implement a number of dispersion reduction techniques to improve broadband operation an
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Laser frequency stabilization and stray light issues for LISA and other future multi-spacecraft missions Project
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"The Laser Interferometer Space Antenna (LISA) is a joint NASA/ESA project which will use laser interferometry between drag-free proof masses to measure gravitational waves from many galactic and cosmological sources. The same interferometer technology is also the key to future multi-spacecraft missions such as multi-aperture telescope missions. These missions could include several spacecraft all separated by potentially 10s of km, flying in a fixed formation with sub-wavelength variations in their distances. These multi-aperture or distributed aperture telescopes will revolutionize the angular resolution in the infrared, optical, and even X-ray band. This proposal addresses two components which are both critical to these missions. The first component introduces a new technique to stabilize the laser frequency to an optical reference cavity. Laser frequency noise will be the limiting factor for most of the distributed aperture telescope missions; in contrast, LISA can trade frequency noise against ranging precision. This new technique is based on heterodyne interferometry which is also used to measure changes in the distances between the spacecraft. Because of this similarity, this technology can easily be integrated into the payload. It requires the same photo detectors and digital signal processing systems that are used for the interferometry. It utilizes to a large degree existing components, reducing R&D time and cost for all interferometric space missions. We have already started initial proof of principle experiments and have reached already a performance remarkably close to the performance of the standard and long time-favored modulation/demodulation technique. Now we propose to study this technique in more detail, study the limiting noise sources experimentally and theoretically, and push it to the limitations of the reference cavity itself. The expected final fractional frequency noise should be better than 0.01ppt for measurement times of a 1000s. This
Infrared Interferometry of Auroral Ionosphere-Thermosphere Energetics Project
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 The FWMI prototype development is underway at USU/SDL. To develop the FWMI, USU/SDL is leveraging the successful implementation of a rocket-borne Michelson interferometer/spectrometer system that was designed by USU/SDL in the early 1980s and flown multiple times on sounding rockets. This sensor was designated the Rocket-Borne Field-Widened Interferometer-II (RBFWI-2). Utilizing modern designs, technologies, and components, the new prototype FWMI will significantly enhance the original RBFWI-2 to meet three technical goals: (1) extended spectral coverage, (2) higher spectral resolution, and (3) extended dynamical range. USU/SDL also intends to achieve large reductions in mass, volume, and power. The resultant prototype FWMI will then be a pathfinder for future missions that focus on addressing key scientific objectives and critical supporting science questions in auroral ionosphere-thermosphere energetics.

The successful flight of RBFWI-2 established a solid foundation for the development of the prototype FWMI. Based on that heritage, the current effort focuses on the development of a new optical detector system, a new sensor signal-conditioning system based on modern electronics, as well as extending the displacement of the optics to increase spectral resolution. These new techniques and other modern technologies will be added to the proven RBFWI-2 legacy design to allow the prototype FWMI to serve as the foundation for a flight FWMI version capable of meeting the targeted instrument specifications that are summarized below:

1. Spectral bandpass of 1300-8100 cm-1

2. Spectral resolution of ≤ 1.0 cm-1

3. Dynamic range characterized by a 10-13 W cm-2 sr-1(cm-1)-1 NER.

Exoplanet Direct Imaging Project
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"We propose to develop high contrast coronagraphic techniques for segmented telescopes, providing an integrated solution for wavefront control and starlight suppression on complex aperture geometries. Developing this technology will enable direct imaging of exoplanets from space with significant cost savings relative to monolithic mirrors. Searching for nearby habitable worlds with direct imaging is one of the top scientific priorities established by the Astro2010 Decadal Survey. Achieving this ambitious goal will require 1010 contrast on a telescope large enough to provide angular resolution and sensitivity to planets around a significant sample of nearby stars. Lightweight segmented mirror technology allows larger diameter optics to fit in any given launch vehicle as compared to monolithic mirrors, making it a compelling option for future space telescopes. But until recently, it was believed that internal coronagraphs were incapable of yielding very high contrast on segmented telescopes. Recent developments now show that there is in fact a clear path to high contrast coronagraphy on segmented apertures. The key advances are (1) the demonstration of precision wavefront shaping with amplitude control using multiple deformable mirrors, and (2) improvements in coronagraph mask design that dramatically reduce transmission of segment-gap-scattered light. We propose a plan that will mature these technologies for coronagraphy with on-axis segmented mirror telescopes to TRL 4 by mid-decade with the following elements: 1. Numerical studies for coronagraph optimization and wavefront shaping to yield high-contrast point spread function dark zones. 2. Precision segment phasing concepts and algorithms that will improve the state of the art by one order of magnitude, and will be applicable to any segmented telescope. 3. A system-level demonstration integrating segment precision phasing, wavefront control and shaping, together with advanced coronagraphy. Success
shengnan Sun - Parkes observations for project P1349 semester 2025APRS 06
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We propose an investigation of pulsars with interpulse (IP) emissions using the Ultra-wide-bandwidth Low (UWL) receiver at the Parkes (Murriyang) telescope. We aim to explore the polarization and emission properties of these pulsars through the application of the rotating vector model (RVM). Polarization profiles will be obtained across a wide bandwidth spanning 704 MHz to 4032 MHz. Emission heights will be measured using both the delay-radius and geometrical methods to examine their frequency dependence and test the radius-to-frequency mapping (RFM) model. Spectral analyses of different profile components will be conducted to constrain pulsar emission properties, while pulse intensity modulations will be analyzed to identify potential phase-lock phenomena. Our study will provide more information on the understanding of the properties of pulsars with IP emissions.
Groundbased Observations at the NASA Infrared Telescope Facility (IRTF)
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This bundle collects data taken at IRTF and associated document files.
Joanne Dawson - Long-term project observations for project P1321 semester 2025APRS 01
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The atomic interstellar medium shows tiny-scale optical depth fluctuations on the scale of 0.1~10,000 AU, whose origin and nature are poorly understood. The existence of this Tiny-Scale Atomic Structure (TSAS) has significant implications, potentially calling into question our fundamental understanding of heating, cooling and dynamical processes in the interstellar medium. Yet observations remain sparse. This long-term project plans to search for temporal variations in HI absorption spectra seen against background pulsars to characterise TSAS in the Milky Way interstellar medium (ISM). These observations constitute the largest number of sightlines and densest temporal sampling ever performed in a single experiment, and will test predictions that TSAS is the tail end of a turbulent cascade, constrain its minimum size scale (down to resolutions of ~0.05 AU) and potentially provide the first direct measurements of pressures in "large" TSAS features of > 1000 AU. We make use of the phase-resolved spectral line mode that we have recently implemented on Parkes, which has cut data rates and processing times by factors of ~1000 compared to past studies. This is an expansion of our pilot P1321 to a long term study.
Joanne Dawson - Long-term project observations for project P1321 semester 2025APRS 20
공공데이터포털
The atomic interstellar medium shows tiny-scale optical depth fluctuations on the scale of 0.1~10,000 AU, whose origin and nature are poorly understood. The existence of this Tiny-Scale Atomic Structure (TSAS) has significant implications, potentially calling into question our fundamental understanding of heating, cooling and dynamical processes in the interstellar medium. Yet observations remain sparse. This long-term project plans to search for temporal variations in HI absorption spectra seen against background pulsars to characterise TSAS in the Milky Way interstellar medium (ISM). These observations constitute the largest number of sightlines and densest temporal sampling ever performed in a single experiment, and will test predictions that TSAS is the tail end of a turbulent cascade, constrain its minimum size scale (down to resolutions of ~0.05 AU) and potentially provide the first direct measurements of pressures in "large" TSAS features of > 1000 AU. We make use of the phase-resolved spectral line mode that we have recently implemented on Parkes, which has cut data rates and processing times by factors of ~1000 compared to past studies. This is an expansion of our pilot P1321 to a long term study.
Joanne Dawson - Long-term project observations for project P1321 semester 2025APRS 19
공공데이터포털
The atomic interstellar medium shows tiny-scale optical depth fluctuations on the scale of 0.1~10,000 AU, whose origin and nature are poorly understood. The existence of this Tiny-Scale Atomic Structure (TSAS) has significant implications, potentially calling into question our fundamental understanding of heating, cooling and dynamical processes in the interstellar medium. Yet observations remain sparse. This long-term project plans to search for temporal variations in HI absorption spectra seen against background pulsars to characterise TSAS in the Milky Way interstellar medium (ISM). These observations constitute the largest number of sightlines and densest temporal sampling ever performed in a single experiment, and will test predictions that TSAS is the tail end of a turbulent cascade, constrain its minimum size scale (down to resolutions of ~0.05 AU) and potentially provide the first direct measurements of pressures in "large" TSAS features of > 1000 AU. We make use of the phase-resolved spectral line mode that we have recently implemented on Parkes, which has cut data rates and processing times by factors of ~1000 compared to past studies. This is an expansion of our pilot P1321 to a long term study.
Joanne Dawson - Long-term project observations for project P1321 semester 2025APRS 21
공공데이터포털
The atomic interstellar medium shows tiny-scale optical depth fluctuations on the scale of 0.1~10,000 AU, whose origin and nature are poorly understood. The existence of this Tiny-Scale Atomic Structure (TSAS) has significant implications, potentially calling into question our fundamental understanding of heating, cooling and dynamical processes in the interstellar medium. Yet observations remain sparse. This long-term project plans to search for temporal variations in HI absorption spectra seen against background pulsars to characterise TSAS in the Milky Way interstellar medium (ISM). These observations constitute the largest number of sightlines and densest temporal sampling ever performed in a single experiment, and will test predictions that TSAS is the tail end of a turbulent cascade, constrain its minimum size scale (down to resolutions of ~0.05 AU) and potentially provide the first direct measurements of pressures in "large" TSAS features of > 1000 AU. We make use of the phase-resolved spectral line mode that we have recently implemented on Parkes, which has cut data rates and processing times by factors of ~1000 compared to past studies. This is an expansion of our pilot P1321 to a long term study.