Projected WIRE Sensitivity

The background-limited sensitivity is given by the 64 sec flux density limits. This instrumental sensitivity will scale inversely with the square root of the cumulative exposure time spent on a WIRE field. The instrumental sensitivity is added in quadrature with the confusion-limited sensitivity to estimate WIRE's sensitivity at other exposure times. The confusion limits shown here apply only for regions of the sky at high Galactic latitude where confusion from stars and infrared "cirrus" are negligible.

Note: The background is dominated by zodiacal emission. The numbers below assume a high ecliptic latitude. Observations near the ecliptic plane will encounter a background about 3 times higher, which will raise the sensitivity limits by a factor of 1.7 in flux density.

Other key WIRE instrument parameters are listed on the WIRE Hardware page.

No Evolution Scenario
Exposure time	25 micron limit (SNR=5)	Areal density of detected galaxies	12 micron limit (SNR=5)
64 sec	5.7 mJy	13/sq deg	1.9 mJy
15 min	1.5 mJy	69/sq deg	0.51 mJy
75 min	0.69 mJy	180/sq deg	0.23 mJy
12.5 hr	0.25 mJy	580/sq deg	0.095 mJy
50 hr	0.17 mJy	906/sq deg	0.071 mJy
confusion limit	0.13 mJy	1200/sq deg	0.067 mJy

Moderate Density Evolution Scenario
Exposure time	25 micron limit (SNR=5)	Areal density of detected galaxies	12 micron limit (SNR=5)
64 sec	5.7 mJy	16/sq deg	1.9 mJy
15 min	1.5 mJy	88/sq deg	0.53 mJy
149 min	0.56 mJy	325/sq deg	0.22 mJy
22.4 hr	0.34 mJy	690/sq deg	0.16 mJy
confusion limit	0.30 mJy	750/sq deg	0.15 mJy

Projected WIRE Sample Size

No Evolution Scenario
Survey	Sky Coverage	25 micron flux limit (5 sigma)	# of sources
Moderate Depth	170 sq deg	0.69 mJy	30,000
Deep	8.3 sq deg	0.25 mJy	5,000
Ultra-deep	0.5 sq deg	0.17 mJy	500

Moderate Density Evolution Scenario
Survey	Sky Coverage	25 micron flux limit (5 sigma)	# of sources
Moderate Depth	830 sq deg	1.5 mJy	70,000
Deep	42 sq deg	0.56 mJy	14,000
Ultra-deep	1 sq deg	0.34 mJy	700

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Last Updated: 9/3/97