Constant Surface Brightness Region Limiting Magnitudes

Table 7 lists the limiting magnitudes for imaging a constant surface brightness patch (such as a gas cloud). These limits were calculated by assuming a patch of area 1 arcsec$ ^2$ imaged on the detector. Then flux from the source and sky reaching the detector and the read noise in the patch were calculated.

Table 7: Constant surface brightness patch limiting magnitudes (Vega system): ShaneAO predicted (300s Fowler sample - 32 reads) for 8 (old laser) and 16 subapertures.
Filter ShARCS 8 ShARCS 16
  predicted predicted
K strehl 0.6 (LGS) 0.8 (LGS)
J 19.62 20.61
H 19.11 19.66
K 17.64 17.95
Ks 17.83 18.15

Figure 6: Constant surface brightness patches - Exposure time required to reach SNR=5 vs. magnitude (Vega system) in different filters for ShARCS 8 (ShARCS + old laser) and full ShaneAO (ShARCS 16).
Image exptVmag-csb

Figure 7: Constant surface brightness patches - SNR vs. magnitude for one 300s fowler exposure in different filters for ShARCS (8 or 16 subapertures).
Image snrVmag-csb

Srikar Srinath 2013-10-09