Difference between revisions of "Central wavelengths and zero points"

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Line 11: Line 11:
 
   I4          8.0              64.13
 
   I4          8.0              64.13
  
   M1          24                7.14
+
   M1          24                7.17
 
   M2          70                0.775
 
   M2          70                0.775
 
   M3          160                0.159
 
   M3          160                0.159

Revision as of 22:06, 3 April 2012

Here is a large collection of central wavelengths and zero points, useful for converting between flux densities and magnitudes, and for adding points into an SED.

band     wavelength (um)    zero point (Jy)
 J            1.25           1594
 H            1.65           1024
 Ks           2.17            666.7  Kshort not Johnson K!
 I1           3.6             280.9
 I2           4.5             179.7
 I3           5.8             115.0
 I4           8.0              64.13
 M1           24                7.17
 M2           70                0.775
 M3          160                0.159
 W1           3.4             309.54
 W2           4.6             171.79
 W3          12                31.676
 W4          22                 8.3635
 U           0.36            1755
 B           0.44            4000.87
 V           0.55            3597.28
 Rc          0.71            3080     !! Cousins R (not the same as Johnson R)!
 Ic          0.79            2432.84  !! Cousins I (not the same as Johnson I)!
 sloan u    2910*1d-4                 !! 2910 A, and there are 10^-4 um per A. (etc for rest)
 sloan g    4810*1d-4
 sloan r    6230*1d-4
 sloan i    7640*1d-4
 sloan z    9060*1d-4

BE CAREFUL to keep track of whether you are working with Vega-based magnitudes or AB mags. Vega magnitudes define things with respect to a Vega spectrum (see Units page), but some folks (largely extragalactic folks) define things with respect to a flat spectrum source instead, and those are AB mags. Most Sloan folks (even those folks working with stars) work in AB mags instead. For AB mags, you always use a flat reference spectrum, so the zero point is 3631 Jy for all bands.