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Quality of stellar radial velocities improved in DR6

Up to Spectra

The wavelength calibration of the SDSS spectra is problematic in the blue, because of a dearth of strong lines in the calibration lamps and in the nighttime sky. This led to systematic errors at the level of 10-15 km/s (i.e., 0.15-0.25 pixels) in the wavelength calibration at the extreme blue end, which was affecting both stellar model fits and the determination of radial velocities. More robust fitting algorithms brought these problems under control in DR6 and beyond.

The identity of the actual template stars are tabulated below. The 'Template Number' corresponding to the highest cross correlation peak match for any spectrum may be found under the keyword 'BESTTEMP' in the PDU header of a SDSS spSpec-$mjd-$plate-$fiberid.fit file.

Template numberSp TypePlateMJDFiberID
1sdO59352026265
2sdB30151942431
3sdB39051900115
4BHB48051989112
5A30051666128
6early F289519905
7early G30651637295
8late F27351957304
9G31051990356
10G/K39651816605
11early M40251793204
12M36751997593

Last modified: Sun Jul 15 14:47:10 CEST 2007