Central wavelengths and zero points

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Here is a large collection of central wavelengths and zero points, useful for converting between flux densities and magnitudes, which then enables adding points into an SED, or making a color-mag diagram (depending on whether you are starting from mags or flux densities).

band     wavelength (um)    zero point (Jy)
 J            1.235          1594
 H            1.662          1024
 Ks           2.159            666.7  Kshort not Johnson K!  http://www.ipac.caltech.edu/2mass/releases/allsky/doc/sec6_4a.html

(note that http://irsa.ipac.caltech.edu/Missions/2mass.html has/had 2.17 um, which isn't right)

 I1           3.6             280.9    http://irsa.ipac.caltech.edu/Missions/spitzer.html
 I2           4.5             179.7
 I3           5.8             115.0
 I4           8.0              64.13
 M1           24                7.14
 M2           70                0.775
 M3          160                0.159
 W1           3.4             309.54      http://irsa.ipac.caltech.edu/Missions/wise.html
 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        see below (3631 Jy for all)    !! 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
 ukidss Z      0.8817        2232 ?             Hewett 2006, MNRAS, 367, 454
 ukidss Y      1.0305        2026 ?
 ukidss J      1.2483        1530 ?
 ukidss H      1.6313        1019 ?
 ukidss K      2.2010         631 ?
 iphas rprime  0.624         3173.3
 iphas ha      0.656         2974.4
 iphas iprime  0.774         2515.7 
 PanSTARRS g   0.4810         see below (3631 Jy for all) 
 PanSTARRS r   0.6170
 PanSTARRS i   0.7520
 PanSTARRS z   0.8660
 PanSTARRS y   0.9620
 denis i       0.778         2499              Fouque et al. 2000, A&AS, 141, 313
 denis J       1.221         1595
 denis Ks      2.144          665 
 akari band 1   9                   !! Akari reports things already in flux densities. 
 akari band 2  18                      Generally, don't trust any other Akari bands, unless you are sure the source is really there.
 IRAS band 1   12              28.3        http://irsa.ipac.caltech.edu/IRASdocs/exp.sup/ch6/C2a.html
 IRAS band 2   25               6.73
 IRAS band 3   60               1.19
 IRAS band 4  100               0.43 
 MSX Band A     7.76                        http://irsa.ipac.caltech.edu/data/MSX/docs/MSX_psc_es.pdf for 10,000K BB
 MSX Band B1    4.29                  !! MSX should already be in flux density
 MSX Band B2    4.35
 MSX Band C    11.99
 MSX Band D    14.55
 MSX Band E    20.68
 Herschel/PACS "blue"     70   0.7961  should already be in flux density, but these come from [1] and [2]
 Herschel/PACS "green"   100   0.3868
 Herschel/PACS "red"     160   0.1500
 Herschel/SPIRE "short"  250   0.06   should already be in flux density, but these vome from [3], which may not be very accurate.
 Herschel/SPIRE "medium" 350   0.03
 Herschel/SPIRE "long"   500   0.01
 Gaia DR2 (NOT DR1!) G   0.673  (fluxes provided in catalog are in electrons!)
 Gaia DR2 (NOT DR1!) BP  0.532
 Gaia DR2 (NOT DR1!) RP  0.797


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; same thing for Pan-STARRS. For AB mags, you always use a flat reference spectrum, so the zero point is 3631 Jy for all bands.

More on filters and bandpasses

For advanced folks (and, frankly, my own future reference): If you have measurements from one of the USNO plate scans of the POSS plates... Monet et al. 2003, AJ, 125, 984 reports these transformations from SDSS EDR photometry [Section 8. eqn 2b-2e].

"B" magnitudes:
O = g* + 0.08 + 0.452(g* -r*), sigma = 0.34
J = g* + 0.06 + 0.079(g* - r*), sigma = 0.33
"R" magnitudes:
E = r* - 0.20 - 0.086(g* - r*), sigma = 0.30
F = r* - 0.09 - 0.109(g* - r*), sigma = 0.26
"I" magnitudes:
N = i* - 0.44 -0.164(r* -i*), sigma =0.31

Thanks to Peregrine McGehee for the following inversion of these formulae:

   g* - r * = ([Bmag - Rmag]  +0.22)/1.37
   g* = Bmag - 0.07 - 0.27(g* - r*)
   r* = g* - (g* - r*)
   i* = (Imag - 0.44 +0.16r* )/1.16

http://adsabs.harvard.edu/full/1991PASP..103..661R says that the wavelengths are : 1950 POSS red 6500A, blue 4100A. 2nd gen, blue 4800A, red 6500A, NIR 8500 A.


See also http://adsabs.harvard.edu/abs/2014arXiv1412.1474M "Revised Filter Profiles and Zero Points for Broadband Photometry" Mann and von Braun, 2015, PASP, 127, 102 for lots of discussion including revised wavelengths and zero points, even more than are listed here.

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