P. Hickson et al., MULTINARROWBAND IMAGING - A NEW TECHNIQUE FOR MULTIOBJECT SPECTROPHOTOMETRY, Monthly Notices of the Royal Astronomical Society, 267(4), 1994, pp. 911-917
A technique is described which consists of repeated imaging of a field
through a series of narrowband filters. Photometry of each image then
provides low-resolution spectrophotometry of all detected objects. Fo
r faint objects this method is comparable in efficiency to slitless sp
ectroscopy, and can cover a larger wavelength range. The principal adv
antages of the method are simplicity, accuracy in crowded fields, accu
rate sky-subtraction, and the ability to measure many objects simultan
eously. In order to investigate the potential of determining galaxy mo
rphological type and redshift from multiband data, computer simulation
s are performed for a system of 40 bands having central wavelengths eq
ually spaced logarithmically from 400 to 1000 nm. Spectral energy dist
ributions of various galaxy types are redshifted, multiplied by the fi
lter transmission functions, and then degraded by random noise. These
simulated data are then compared with model spectral energy distributi
ons, sampled with the filters, for a range of Hubble type and redshift
, by means of a two-parameter, least-squares analysis. For a signal-to
-noise ratio of 10, the rms redshift error is less than 0.02 for all g
alaxy types, and the rms error in the morphological type code is less
than 0.14. The mean values of these errors are 0.009 and 0.11, respect
ively. For a signal-to-noise ratio of 3, the corresponding mean errors
are 0.06 and 0.6 for galaxies with redshift z < 0.5, and about half t
hese values for galaxies with 0.5 < z < 1.0.