Go to sdss.org
DR7 Home
Where to Start
   Database (CAS)
   Files (DAS)
   Older Releases
About DR7
   Sky Coverage
   Data Processing
   Known Issues
   DR Papers

Spectroscopic signal to noise of galaxy samples

Up: Spectra

Distribution of signal to noise in 1052 DR4 regular survey plates

The SDSS uses two identical multi-object fiber spectrographs. Below is a comparison of the two spectrographs in each of the three bands that span the spectroscopes' range in wavelength. The histograms show (S/N)2 in bins of 2.

g-band r-band i-band

Signal to noise as a function of magnitude

Signal to noise in each of the three spectroscopic bands as a function of petrosian magnitude in that band, for DR1 objects. Clicking on the image will enlarge it. Links to contour histograms are under each plot. MAIN sample galaxies are in black and LRG's are in red. The sharp cutoff in MAIN galaxies in the r-band is a result of the magnitude limit placed on target galaxies. Note that all of the following plots are of S/N and not (S/N)2.

g-band r-band i-band
contour plot contour plot contour plot

Alternatively, one could ask how the signal-to-noise depends on the fiber magnitudes.

g-band r-band i-band
SN v. fibermag_g SN v. fibermag_r SN v. fibermag_i

Last modified: Tue Jul 26 21:14:23 CDT 2005