7.8 IR Sensitivity

7.8.1 Limiting Magnitudes

Table 7.10 presents the predicted limiting-magnitude performance of the WFC3 IR channel and compares it with that of the NIC3 camera. The calculations are based on an optimal extraction of a point source. The limiting ABMAG at a S/N of 10 was calculated for a 1-hour and a 10-hour exposure. The throughput curves for the WFC3 filters listed in column 2 were used; for NIC3, the most similar wide-band filter was used, and its name is given in column 3.

An Exposure Time Calculator (ETC) is available online. See Section 9.2.

Table 7.10: Limiting-magnitude performance of WFC3 compared with that of NIC3 based on on-orbit sensitivity from SMOV4. 

Band

Filter


 

Limiting magnitude
in 1 hr


 

Limiting magnitude
in 10 hrs

WFC3

NIC3


 

WFC3

NIC3


 

WFC3

NIC3

J

F110W

F110W


 

27.3

26.1


 

28.6

27.4

H

F160W

F160W


 

26.6

25.9


 

27.9

27.1

The table provides limiting ABMAGs at a S/N of 10 for the indicated WFC3 filters and for NIC3 with its most similar filters.