A New High-Contrast Imaging Program at Palomar Observatory


First Author:
Sasha Hinkley
Email: shinkley AT amnh.org
Columbia University
AMNH, Department of Astrophysics
New York, NY, United States
Coauthors:
Oppenheimer, Ben R., AMNH
Parry, Ian R., IoA, Cambridge
Brenner, Douglas, AMNH
Zimmerman, Neil, Columbia University
Hillenbrand, Lynne, Caltech
Sivaramakrishnan, Anand, AMNH
Soummer, Remi, STScI
Roberts, Lewis C., JPL
Dekany, Richard, Caltech
Beichman, Chas, NExScI
Bouchez, Antonin, Caltech
Roberts, Jenny, Caltech
Shao, Michael, JPL

Abstract
In July 2008, a new integral field spectrograph and a diffraction limited, apodized-pupil Lyot coronagraph was installed behind the adaptive optics system at the Hale 200-inch telescope at Palomar. This instrument serves as the basis of a long-term observational program in high-contrast imaging. The technical goal is to utilize the spectral nature of speckle noise to overcome it. The coronagraph alone will achieve an initial dynamic range of 10-4 to 10-5 at 1 arcsecond, without speckle noise suppression. Initial work indicates that spectral speckle suppression will provide significant improvement over this. Such sensitivity provides detection and low resolution spectra of young planets of several Jupiter masses around nearby stars. Priority targets will include those stars brighter than 8th magnitude and visible from the Northern Hemisphere with known circumstellar disks and planets, and those younger than 1 Gyr. In addition, several hundred survey stars within 25 pc will form the body of the target list. The spectrograph has a spectral resolution of 30-100 across the J and H bands (1.05 - 1.75 microns). The image plane is subdivided by a 200 x 200 element micro-lenslet array with a plate scale of 21 mas per lenslet, diffraction-limited at J-band. Our spatial resolution is twice that afforded by infrared HST observations, with an inner working angle 5 times smaller than HST can achieve through PSF subtraction. Moreover, through follow-up observations of Spitzer targets with a previously detected infrared excess (FEPS etc), this ground-based effort will complement the ongoing Spitzer mission. The addition of the integral field spectrograph will enable spatially resolved spectroscopic study of any imaged disks, complementing the coronagraphic observations of the disk structure. This system is the first of a new generation of apodized pupil coronagraphs combined with high-order adaptive optics and integral field spectrographs (e.g. GPI and SPHERE).
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