FLAMINGOS I Imaging Sensitivity Estimates

Based on imaging performance with FLAMINGOS I during engineering time at KPNO and the MMT, we have estimated the sensitivity of FLAMINGOS I imaging on Gemini South for both point and uniform surface-brightness sources that give a signal-to-noise ratio (S/N) of 5 in a one-hour integration.

caution Important caveat: These estimates make unverified assumptions about the telescope and instrument performance. Commissioning tests in 2001B will be needed to verify sensitivities.

Like other visitor instruments FLAMINGOS I will not be supported in the Gemini Integration Time Calculator (ITC), however similar methods were used for these calculations. See the ITC help pages for more information on the calculation methods used.

The limiting magnitude depends on the observing conditions. In the table presented here we have assumed 50% (median) conditions for all categories. The meanings of the observing condition criteria are explained in detail in the observing condition constraints. The estimates are for observations at zenith, and can be scaled to higher airmass in a straightforward way. The individual exposures are long enough to be background-limited in all cases: 120 sec at J, 60 sec at H and 45 sec at K and 60 sec at Ks. See the detector page and background/saturation properties for more information.

All magnitudes listed below result in a S/N of 5 in a total integration time of 1 hour. Observations are assumed to be dithered and sky subtraction noise is included. All individual exposures include the source. For point sources we used an aperture of 1.4 times the FHWM seeing-squared (0.5 arcsec seeing, 58 pixels in area). For uniform surface brightness sources, an aperture with an area of 1 square arcsec is used.

Filter Center wavelength (Ám) Point Sources Extended Sources Individual Exposure
(mag) (mJy) (mag/arcsec2) (mJy/arcsec2) (sec)
J 1.20 23.00 1.0E-3 22.43 1.7E-3 120
H 1.64 22.26 1.3E-3 21.69 2.1E-3 60
K 2.20 22.08 9.7E-4 21.51 1.6E-3 45
K(short) 2.15 22.09 9.6E-4 21.52 1.6E-3 60


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Last update Aug 30, 2001 Michael Ledlow