scholarly journals Titan: Atmospheric and surface features as observed with Nasmyth Adaptive Optics System Near-Infrared Imager and Spectrograph at the time of the Huygens mission

2007 ◽  
Vol 112 (E2) ◽  
Author(s):  
M. Hirtzig ◽  
A. Coustenis ◽  
E. Gendron ◽  
P. Drossart ◽  
M. Hartung ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Surface Features ◽  
Infrared Imager ◽  
Adaptive Optics System

scholarly journals The Surface of Titan from Adaptive Optics Observations

2002 ◽  
Vol 12 ◽  
pp. 629
Author(s):  
Seran G. Gibbard ◽  
Bruce A. Macintosh ◽  
Claire E. Max ◽  
Henry Roe ◽  
Imke de Pater ◽  
...  
Keyword(s):  
High Resolution ◽  
Solar System ◽  
Visible Light ◽  
Adaptive Optics ◽  
Surface Albedo ◽  
Near Infrared ◽  
High Resolution Spectroscopy ◽  
Surface Features ◽  
Infrared Wavelengths ◽  
Adaptive Optics System

AbstractSaturn’s largest moon Titan is the only satellite in the Solar System with a substantial atmosphere. Photolysis of methane creates a hydrocarbon haze in Titan’s atmosphere that is opaque to visible light. The new adaptive optics system on the 10–meter W. M. Keck Telescope enables us to observe Titan with a resolution of 0.04 arcseconds, or 20 resolution elements across the disk. By observing at near-infrared wavelengths that are methane band windows we can see through Titan’s hydrocarbon haze to the surface beneath. Recent adaptive optics images of Titan both in broadband (J, H, and K) filters and in narrowband filters that selectively probe Titan’s surface and atmosphere allow us to determine surface albedo and properties of the hydrocarbon haze layer. Future observations will include high-resolution spectroscopy coupled with adaptive optics to obtain spectra of individual surface features.

scholarly journals Companion Detection Limits with Adaptive Optics Coronagraphy

2004 ◽  
Vol 202 ◽  
pp. 99-102
Author(s):  
B. R. Oppenheimer ◽  
R. G. Dekany ◽  
M. Troy ◽  
T. Hayward ◽  
B. Brandl
Keyword(s):  
Adaptive Optics ◽  
Focal Plane ◽  
Near Infrared ◽  
Dynamic Range ◽  
Infrared Camera ◽  
Nearby Star ◽  
Point Spread ◽  
Spread Function ◽  
Adaptive Optics System ◽  
Circular Disks

We present a study of the Palomar Adaptive Optics System and the PHARO near infrared camera in coronagraphic mode. The camera provides two different focal plane occulting masks–opaque circular disks 0.43 and 0.97″ across. Three different pupil plane apodizing masks (Lyot masks) are also provided. The six different combinations of Lyot mask and focal plane mask suppress differently the point spread function of a bright star centered on the focal plane mask. We obtained images of the bright nearby star Gliese 614 with all six different configurations in the K filter. We measured the dynamic range achievable with these configurations. Within 2.5″, the dynamic range is at least 8 magnitudes at the 5σ level and as high as 12 in a 1 s exposure. This represents a substantial gain over similar techniques without adaptive optics.

scholarly journals Morphology of z ~ 1 galaxies from deep K-band AO imaging

2006 ◽  
Vol 2 (S235) ◽  
pp. 405-405
Author(s):  
Marc Huertas-Company ◽  
Daniel Rouan ◽  
Geneviève Soucail ◽  
Olivier Le Fèvre ◽  
Lidia Tasca
Keyword(s):  
Adaptive Optics ◽  
Spatial Resolution ◽  
Near Infrared ◽  
High Spatial Resolution ◽  
Integration Time ◽  
Early Type ◽  
Distant Galaxies ◽  
First Time ◽  
Concentration Asymmetry ◽  
Adaptive Optics System

AbstractWe present the results of observations of distant galaxies (z ~ 0.8) at high spatial resolution (~0.1"). We observed 7 fields of 1' × 1' with the NACO Adaptive Optics system (VLT) in Ks (2.2μm) band with typical V ~ 14 guide stars and 3h integration time per field. Observed fields are selected within the COSMOS survey area. We analyze the morphologies by means of B/D (Bulge/Disk) decomposition with GIM2D and CAS (Concentration-Asymmetry) estimators for 79 galaxies with magnitudes between Ks = 17 − 23 and classify them in three main morphological types (Late Type, Early Type and Irregulars). We obtain for the first time an estimate of the distribution of galaxy types at redshift z ~ 1 as measured from the near infrared at high spatial resolution.

Near-Infrared Observations of Neptune’s Tropospheric Cloud Layer with the Lick Observatory Adaptive Optics System

2001 ◽  
Vol 122 (3) ◽  
pp. 1636-1643 ◽  
Author(s):  
Henry G. Roe ◽  
Donald Gavel ◽  
Claire Max ◽  
Imke de Pater ◽  
Seran Gibbard ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Cloud Layer ◽  
Infrared Observations ◽  
Adaptive Optics System

scholarly journals Discovery of a Tight Brown Dwarf Companion to the Low Mass Star LHS 2397a

2003 ◽  
Vol 211 ◽  
pp. 261-264 ◽  
Author(s):  
Melanie Freed ◽  
Laird M. Close ◽  
Nick Siegler
Keyword(s):  
Adaptive Optics ◽  
Spectral Type ◽  
Proper Motion ◽  
Near Infrared ◽  
Mass Star ◽  
Infrared Photometry ◽  
Brown Dwarf ◽  
Dynamical Mass ◽  
Low Mass ◽  
Adaptive Optics System

Using the adaptive optics system, Hōkūpa'a, at Gemini-North, we have directly imaged a companion around the UKIRT faint standard M8 star, LHS 2397a (FS 129) at a separation of 2.96 AU. Near-Infrared photometry obtained on the companion has shown it to be an L7.5 brown dwarf and confirmed the spectral type of the primary to be an M8. We also derive a substellar mass of the companion of 0.068M⊙, although masses in the range (0.061 – 0.069) are possible, and the primary mass as 0.090M⊙ (0.089 – 0.094). Reanalysis of archival imaging from HST has confirmed the secondary as a common proper motion object. This binary represents the first clear example of a brown dwarf companion within 4 AU of a low mass star, and should be the first L7.5 to have a dynamical mass. As part of a larger survey of M8-M9 stars, this object may indicate that there is no “brown dwarf desert” around low mass primaries.

scholarly journals 9.5. The “double nucleus” of M31 in J, H, and K

1998 ◽  
Vol 184 ◽  
pp. 391-392
Author(s):  
P. Hinz ◽  
K. Hege ◽  
D. McCarthy ◽  
M. Lloyd-Hart ◽  
F. Melia
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Blind Deconvolution ◽  
Hubble Space Telescope ◽  
Wiener Filter ◽  
Diffraction Limit ◽  
Infrared Observations ◽  
Double Nucleus ◽  
Filter Algorithms ◽  
Adaptive Optics System

Hubble Space Telescope images of the nucleus of M31 show a double-peaked structure with the primary peak being offset from the center by approximately 0.5″. We observed the central 13″ of M31 in the J, H, and Ks passbands to determine the nuclear structure in the near-infrared. Observations were taken at the MMT Observatory, using a low-order adaptive optics system, FASTTRAC II (Gray et. al. 1995). The diffraction limit for the system is 0.25″ in K band. PSF images showed correction to 0.5″ FWHM. Uncorrected images showed the seeing to be about 1″. The images were deconvolved using several methods to check for consistency. We used Iterative-Blind Deconvolution, Richardson-Lucy, and Wiener filter algorithms, getting similar results for each. Measurements suggest the PSF in the deconvolved images is approximately 0.35″ FWHM.

scholarly journals Simulation Study of a Low-Light-Level Wavefront Sensor Driving a Low-Order, Near-IR Adaptive Optics System

1994 ◽  
Vol 158 ◽  
pp. 308-310
Author(s):  
David W. Tyler ◽  
Gary C. Loos
Keyword(s):  
Adaptive Optics ◽  
System Performance ◽  
Near Infrared ◽  
Light Level ◽  
Wavefront Sensor ◽  
High Fidelity ◽  
Low Light ◽  
Near Ir ◽  
Adaptive Optics System ◽  
Low Order

Two high-fidelity computer simulations are used to study low-order adaptive optics systems operating in the near-infrared. We study obtainable system performance using very dim reference sources at three IR wavelengths.

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