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Your search keyword '"Walter, Alex B."' showing total 9 results
Start Over Author "Walter, Alex B." Publication Type Magazines
9 results on '"Walter, Alex B."'

7. Stochastic Speckle Discrimination with Time-tagged Photon Lists: Digging below the Speckle Noise Floor

Author

Walter, Alex B., Bockstiegel, Clinton, Brandt, Timothy D., and Mazin, Benjamin A.

Abstract

We present an algorithm that uses the distribution of photon arrival times to distinguish speckles from incoherent sources, like planets and disks, in high-contrast images. Using simulated data, we show that our approach can overcome the noise limit from fluctuating speckle intensity. The algorithm is likely to be most advantageous when a coronagraph limits the coherent diffraction pattern in the image plane but the intensity is still strongly modulated by fast-timescale uncorrected stellar light, for example from atmospheric turbulence. These conditions are common at small inner working angles of highly corrected adaptive optics images and will allow probing of exoplanet populations at smaller angular separations. The technique requires a fast science camera that can temporally resolve the speckle fluctuations, and the detection of many photons per speckle decorrelation time. Because the algorithm directly extracts the incoherent light, standard differential imaging postprocessing techniques can be performed afterwards to further boost the signal.

Published
2019
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8. SCExAO, an instrument with a dual purpose: perform cutting-edge science and develop new technologies

Author

Close, Laird M., Schreiber, Laura, Schmidt, Dirk, Lozi, Julien, Guyon, Olivier, Jovanovic, Nemanja, Goebel, Sean, Pathak, Prashant, Skaf, Nour, Sahoo, Ananya, Norris, Barnaby, Martinache, Frantz, N'Diaye, Mamadou, Mazin, Ben, Walter, Alex B., Tuthill, Peter, Kudo, Tomoyuki, Kawahara, Hajime, Kotani, Takayuki, Ireland, Michael, Cvetojevic, Nick, Huby, Elsa, Lacour, Sylvestre, Vievard, Sébastien, Groff, Tyler D., Chilcote, Jeffrey K., Kasdin, Jeremy, Knight, Justin, Snik, Frans, Doelman, David, Minowa, Yosuke, Clergeon, Christophe, Takato, Naruhisa, Tamura, Motohide, Currie, Thayne, Takami, Hideki, and Hayashi, Masa

Published
2018
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9. DARKNESS: A Microwave Kinetic Inductance Detector Integral Field Spectrograph for High-contrast Astronomy

Author

Meeker, Seth R., Mazin, Benjamin A., Walter, Alex B., Strader, Paschal, Fruitwala, Neelay, Bockstiegel, Clint, Szypryt, Paul, Ulbricht, Gerhard, Coiffard, Grégoire, Bumble, Bruce, Cancelo, Gustavo, Zmuda, Ted, Treptow, Ken, Wilcer, Neal, Collura, Giulia, Dodkins, Rupert, Lipartito, Isabel, Zobrist, Nicholas, Bottom, Michael, Shelton, J. Chris, Mawet, Dimitri, van Eyken, Julian C., Vasisht, Gautam, and Serabyn, Eugene

Abstract

We present DARKNESS (the DARK-speckle Near-infrared Energy-resolving Superconducting Spectrophotometer), the first of several planned integral field spectrographs to use optical/near-infrared Microwave Kinetic Inductance Detectors (MKIDs) for high-contrast imaging. The photon counting and simultaneous low-resolution spectroscopy provided by MKIDs will enable real-time speckle control techniques and post-processing speckle suppression at frame rates capable of resolving the atmospheric speckles that currently limit high-contrast imaging from the ground. DARKNESS is now operational behind the PALM-3000 extreme adaptive optics system and the Stellar Double Coronagraph at Palomar Observatory. Here, we describe the motivation, design, and characterization of the instrument, early on-sky results, and future prospects.

Published
2018
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