Companion detection limits with adaptive optics coronagraphy

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 5 sigma level and as high as 12 in a 1 s exposure. This represents a substantial gain over similar techniques without adaptive optics.