Dr. James E. Rhoads Profile

Dr. James E. Rhoads

Research Astrophysicist at NASA Goddard Space Flight Ctr

SPIE Involvement:

Author

Publications (6)

SPIE Journal Paper | 8 February 2024

Spectral characterization of the Grism and Prism slitless spectrometers for the Nancy Grace Roman Space Telescope

Evan Bray, Mateo Batkis, Victor J. Chambers, Margaret Dominguez, Bente Eegholm, Guangjun Gao, Qian Gong, Wesley Halliday, Elias Howe, Jeffrey Kruk, Eliot Malumuth, Sangeeta Malhotra, Catherine Marx, James Rhoads, Maxime Rizzo, Joshua E. Schlieder, Laurie Seide, Eric R. Switzer, Jay Voris

JATIS, Vol. 10, Issue 01, 014003, (February 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.1.014003

KEYWORDS: Prisms, Cameras, Linear filtering, Point spread functions, Polarization, Optical fabrication, Diffraction, Sensors, Spectral models, Diffraction gratings

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Proceedings Article | 13 December 2020 Presentation

Calibration strategies for the Nancy Grace Roman Space Telescope Wide Field Instrument

Susana Deustua, Stefano Casertano, Chris Hirata, Daniel Scolnic, Rebekah Hounsell, Robert Hill, Sangeeta Malhotra, James Rhoads, Maxime Rizzo, David Rubin, Edward Wollack, Jeff Kruk

Proceedings Volume 11443, 114430E (2020) https://doi.org/10.1117/12.2562604

KEYWORDS: Calibration, Infrared telescopes, Infrared radiation, Space telescopes

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Proceedings Article | 22 August 2018 Presentation + Paper

ATLAS probe for the study of galaxy evolution with 300,000,000 galaxy spectra

Robert Content, Yun Wang, Massimo Roberto, Mark Dickinson, Henry Ferguson, Lynne Hillenbrand, Wesley Fraser, Peter Behroozi, Jarle Brinchmann, Andrea Cimatti, Emanuele Daddi, Christopher Hirata, Michael Hudson, J. Davy Kirkpatrick, Robert Barkhouser, James Bartlett, Robert Benjamin, Ranga Chary, Charlie Conroy, Megan Donahue, Olivier Doré, Peter Eisenhardt, Karl Glazebrook, George Helou, Sangeeta Malhotra, Lauro Moscardini, Zoran Ninkov, Alvaro Orsi, Michael Ressler, James Rhoads, Jason Rhodes, Alice Shapley, Stephen Smee

Proceedings Volume 10698, 106980I (2018) https://doi.org/10.1117/12.2313082

KEYWORDS: Spectrographs, Space telescopes, Digital micromirror devices, Mirrors, Cameras, Galactic astronomy, Prisms, Sensors, Telescopes, Galaxy evolution

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ATLAS (Astrophysics Telescope for Large Area Spectroscopy) Probe is a mission concept for a NASA probe-class space mission with primary science goal the definitive study of galaxy evolution through the capture of 300,000,000 galaxy spectra up to z=7. It is made of a 1.5-m Ritchey-Chretien telescope with a field of view of solid angle 0.4 deg². The wavelength range is at least 1 μm to 4 μm with a goal of 0.9 μm to 5 μm. Average resolution is 600 but with a possible trade-off to get 1000 at the longer wavelengths. The ATLAS Probe instrument is made of 4 identical spectrographs each using a Digital Micro-mirror Device (DMD) as a multi-object mask. It builds on the work done for the ESA SPACE and Phase-A EUCLID projects. Three-mirror fore-optics re-image each sub-field on its DMD which has 2048 x 1080 mirrors 13.6 μm wide with 2 possible tilts, one sending light to the spectrograph, the other to a light dump. The ATLAS Probe spectrographs use prisms as dispersive elements because of their higher and more uniform transmission, their larger bandwidth, and the ability to control the resolution slope with the choice of glasses. Each spectrograph has 2 cameras. While the collimator is made of 4 mirrors, each camera is made of only one mirror which reduces the total number of optics. All mirrors are aspheric but with a relatively small P-V with respect to their best fit sphere making them easily manufacturable. For imaging, a simple mirror to replace the prism is not an option because the aberrations are globally corrected by the collimator and camera together which gives large aberrations when the mirror is inserted. An achromatic grism is used instead. There are many variations of the design that permit very different packaging of the optics. ATLAS Probe will enable ground-breaking science in all areas of astrophysics. It will (1) revolutionize galaxy evolution studies by tracing the relation between galaxies and dark matter from the local group to cosmic voids and filaments, from the epoch of reionization through the peak era of galaxy assembly; (2) open a new window into the dark universe by mapping the dark matter filaments to unveil the nature of the dark Universe using 3D weak lensing with spectroscopic redshifts, and obtaining definitive measurements of dark energy and modification of gravity using cosmic large-scale structure; (3) probe the Milky Way's dust-shrouded regions, reaching the far side of our Galaxy; and (4) characterize asteroids and other objects in the outer solar systems.

Proceedings Article | 11 August 2010 Paper

Design and implementation of the NUV/optical widefield Star Formation Camera for the Theia Observatory

Paul Scowen, Rolf Jansen, Matthew Beasley, Daniella Calzetti, Steve Desch, Alex Fullerton, John Gallagher, P. Douglas Lisman, Steven Macenka, Sangeeta Malhotra, Mark McCaughrean, Shouleh Nikzad, Robert O'Connell, Sally Oey, Deborah Padgett, James Rhoads, Aki Roberge, Oswald H. W. Siegmund, Stuart Shaklan, Nathan Smith, Daniel Stern, Jason Tumlinson, Rogier Windhorst, Robert Woodruff

Proceedings Volume 7731, 77314Y (2010) https://doi.org/10.1117/12.857475

KEYWORDS: Sensors, Galactic astronomy, Stars, Cameras, Staring arrays, Imaging systems, Space telescopes, Silicon, Optical filters, Astronomy

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Proceedings Article | 21 July 2010 Paper

Multiband filters for near-infrared astronomical applications

James Rhoads, Sangeeta Malhotra, Paul Scowen, Ron Probst, Don McCarthy

Proceedings Volume 7735, 77356C (2010) https://doi.org/10.1117/12.856737

KEYWORDS: Optical filters, Bandpass filters, Image filtering, Cameras, Astronomy, Coating, Smoothing, Optical coatings, Boxcar filters, Astronomical imaging

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Proceedings Article | 12 July 2008 Paper

The Star Formation Observatory (SFO) mission to study cosmic origins near and far

Paul Scowen, Rolf Jansen, Matthew Beasley, Brian Cooke, Shouleh Nikzad, Oswald Siegmund, Robert Woodruff, Daniela Calzetti, Steven Desch, Alex Fullerton, John Gallagher, Sangeeta Malhotra, Mark McCaughrean, Robert O'Connell, Sally Oey, Debbie Padgett, James Rhoads, Aki Roberge, Nathan Smith, Daniel Stern, Jason Tumlinson, Rogier Windhorst

Proceedings Volume 7010, 70103Z (2008) https://doi.org/10.1117/12.788038

KEYWORDS: Stars, Galactic astronomy, Sensors, Spectroscopy, Imaging spectroscopy, Observatories, Quantum efficiency, Microchannel plates, Silicon, Planets

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Showing 5 of 6 publications

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