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Zeropoints (and sources) and monochromatic flux SED shape assumption

These zero points have been updated to those used in:Mayne, Harries and Rowe (in prep)
For the values used in Mayne and Harries (2010) click here
Filter set
Suffix
Zero Point
Monochromatic Flux info
Magnitude
Source
Response unit (e-/?)
Assumed SED
Central/Effective λ (μm)(2)
Δλ (μm)
Sources

Johnson U -14.18 VEGA Photons Flat 0.36 0.10 Central λ's & widths estimated from zero response limits.
B -15.30 0.46 0.18
V -14.86 0.585 0.21
R -15.11 0.71 0.30
I -14.58 0.81 0.20
J -14.26 1.23 0.36
H -13.49 1.62 0.44
K -13.09 2.18 0.56

Tycho Vt -15.09 VEGA Photons Flat 0.527 0.21 Central λ's & widths from Bessells (2005).
Bt -14.94 0.422 0.145

Bessell U -14.23 VEGA Photons Flat 0.37 0.11 Central λ's from Bessell et al (1998) & widths estimated from zero response limits.
B -15.32 0.44 0.18
V -14.86 0.55 0.21
R -15.09 0.64 0.29
I -14.57 0.80 0.20
J -13.92 1.22 0.36
H -13.65 1.63 0.96
K -12.71 2.19 0.36
L -11.74 3.45 0.72

SDSS u -12.43 Zero Magnitude flux of 3631 Jy Photons Flat 0.3555 0.0599 Central λ's & widths from Fukugita et al (1996)
g -14.22 0.473 0.1379
r -14.22 0.6261 0.1382
i -13.78 0.7672 0.1535
z -11.84 0.9097 0.137

2MASS J 15.73 Zero magnitude fluxes, J=1594, H=1024, Ks=666.7 (Jy) Photon(1) Flat 1.235 0.162 Central λ's & widths from Cohen et al (2003). Zero magnitude fluxes from 2MASS documentation
H 16.37 1.662 0.251
Ks 17.38 2.159 0.262

MKO J -13.48 VEGA Photons Flat 1.24 0.16 Central λ's & widths from Simons and Tokunaga (2002)
H -13.46 1.65 0.29
K -12.64 2.2 0.34

UKIRT Z -13.84 VEGA Photons Flat 0.8775 0.095 Central λ's & widths from Simons and Tokunaga (2002)
Y -13.46 1.02 0.1
J -14.01 1.28 0.42
H -13.29 1.65 0.45
K -12.82 2.2 0.66

IRAS 12 21.00 Zero magnitude fluxes, 12=28.3, 25=6.73, 60=1.19, 100=0.43 (Jy). Energy Flat 12.0 6.5 Central λ's & widths from Neugebauer et al (1984). Zero magnitude fluxes from IRAS explanatory supplement.
25 23.55 25.0 11.0
60 26.24 60.0 40.0
100 28.41 100.0 37.0

SCUBA(3) 450WB 0 None applied Energy 10,000K Black Body 443.0 138.92 Central λ's from JAC & widths estimated from zero response limits.
850WB 0 863.0 230.636

IRAC(4) 3.6 -10.15 Zero magnitude fluxes, 3.6=280.9, 4.5=179.7, 5.8=115.0, 8.0=64.9 (Jy). Photons Flat 3.55 1.2 Central λ's from Reach et al (2005) & widths estimated from zero response limits. Zero magnitude fluxes from from IRAC handbook
4.5 -9.70 4.493 1.56
5.8 -8.07 5.731 2.27
8.0 -8.55 7.872 4.69

MIPS 24 25.97 Zero magnitude fluxes, 24=7.17, 70=0.778, 160=0.160 (Jy). Energy 10,000K Black Body 23.68 14.20 Central λ's and zero magnitude fluxes from MIPS website, widths estimated from zero response limits.
70 29.62 71.42 61.06
160 32.48 155.9 99.83

CIT J -13.73 VEGA Photons Flat 1.25 0.24 Central λ's estimated using widths, which are from Elias et al (1982)
H -13.44 1.65 0.30
K -12.97 2.215 0.41

PACS blue -6.00 VEGA Photons Flat 70 90.5 Central λ's from PACS observers' manual
green -5.26 100 109
red -4.27 160 391.25

SPIRE 250 -3.16 VEGA Photons Flat 250 176.30 Central λ's from SPIRE observers' manual
350 1.87 350 281.26
500 0.0(5) 500 290.24

CFHT 12K (Mould) V -14.86 VEGA Photons Flat 0.5374 0.0974 Central λ's and widths from CFHT website
R -14.69 0.6581 0.1251
I -14.78 0.8223 0.2164

CFHT Mega Prime u* -14.33 VEGA Photons Flat 0.3743 0.0758 Central λ's and widths from CFHT website
g' -15.49 0.4872 0.1455
r' -14.76 0.6282 0.1219
i' -14.61 0.7776 0.1508
z' -15.07 1.1702 0.6868

WISE6,* W1 18.19022 Zero magnitude fluxes, W1=309.540, W2=171.787, W3=31.674, W4=8.363 Energy (Photons also available6) Fν∝ ν-2 3.40025 1.1183 Central λ's and widths from WISE website
W2 18.97940 4.65201 1.3781
W3 21.12111 12.80754 9.8183
W4 24.26880 22.37535 8.3906

(1) Not strictly an Energy summing system, but the dλ dependence has been included in the Response functions, see Cohen et al (2003) and the 2mass handbook. (2) Effective wavelengths will differ if the flux across the filter is not constant as described in Bessells (2005). Therefore, using literature effective wavelengths may result in monochromatic flux errors of around 1%. Formally for a photon counting system:λeff =∫ λ FλR(λ)dλ/(∫ FλR(λ)dλ)
-essentially weighted by wavelength. (3) SCUBA 2 filters will be similar to SCUBA.
(4) Gain required to convert from counts to DN used for IRAC.
(5) Wavelength longer than maximum in Vega spectrum (model and data).
(6) New Filters (beta version please email me with any problems). Both photon and energy counting responses are available at the WISE website, we have used energy counting. Therefore, our zero point magnitudes will differ from those published on the WISE website (these are photon counting zero points), we have, however, used the same zero magnitude fluxes.


Last modified: Fri Sep 18 13:16:33 BST 2009

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