0th magnitude of the IRC photometric bands

Oth magnitude of the IRC photometric bands

Last Update : 07/11/12

These numbers are derived based on the standard definition (see Fazio et al. 2004, ApJS, 154, 10) and the IRC calibration is made based on $\nu I_\nu$=constant, which is different from the 0th magnitude definition system. Users need to apply color corrections when they use the IRC fluxes on the magnitude system.

The definition is given for in-band flux divided by its band width (either micron or hertz). However, the corresponding wavelength or frequency is NOT the reference wavelength (say 7um for S7), but it is the isophotal wavelength, which is also listed in the file (for S7, it is 7.116um). Since by our definition, the IRC data are calibrated based on Fnu*nu=constant, you cannot make any conversion unless you know the spectrum of your object. We can calculate the Vega-flux in our system. It is different from the number in the 0-th magnitude table.

Table. 0th magnitude of the IRC photometric bands

 Filter Bandwidth  In-Band  Flam(iso) lam(iso)   Bandwdth  Fnu(iso)  nu(iso)  TranUnc.
           um       W/cm2   W/cm2/um     um        Hz        Jy        Hz         %
         Unc(Bwd) Unc(InBd) Unc(Fli)  Unc(lis)   Unc(Bw)   Unc(Fni)  Unc(nis) 
           um         %     W/cm2/um     um        Hz        Jy        Hz
 N2     7.134E-01 2.268E-14 3.179E-14 2.338E+00 3.794E+13 5.978E+02 1.305E+14 5.000E+00
        2.580E-03 1.495E+00 4.889E-16 9.649E-03 8.764E+10 8.935E+00 1.132E+12
 N3     8.699E-01 8.627E-15 9.917E-15 3.189E+00 2.513E+13 3.433E+02 9.507E+13 5.000E+00
        3.756E-03 1.517E+00 1.564E-16 1.306E-02 7.215E+10 5.200E+00 7.850E+11
 N4     1.529E+00 4.687E-15 3.065E-15 4.329E+00 2.391E+13 1.960E+02 7.006E+13 5.000E+00
        7.255E-03 1.533E+00 4.918E-17 1.713E-02 7.650E+10 2.996E+00 5.663E+11
 S7     1.752E+00 7.737E-16 4.416E-16 7.116E+00 1.011E+13 7.654E+01 4.269E+13 5.000E+00
        1.190E-02 1.578E+00 7.589E-18 3.160E-02 4.419E+10 1.209E+00 3.496E+11
 S9W    4.104E+00 8.563E-16 2.086E-16 8.610E+00 1.570E+13 5.453E+01 3.583E+13 5.000E+00
        2.566E-02 1.555E+00 3.497E-18 3.665E-02 5.905E+10 8.449E-01 2.878E+11
 S11    4.123E+00 4.002E-16 9.705E-17 1.045E+01 1.092E+13 3.664E+01 2.921E+13 5.000E+00
        2.775E-02 1.629E+00 1.711E-18 4.674E-02 5.143E+10 5.904E-01 2.403E+11
 L15    5.980E+00 1.191E-16 1.992E-17 1.558E+01 7.178E+12 1.659E+01 1.952E+13 5.000E+00
        5.347E-02 1.705E+00 3.834E-19 7.512E-02 4.266E+10 2.799E-01 1.679E+11
 L18W   9.971E+00 1.027E-16 1.030E-17 1.839E+01 8.352E+12 1.230E+01 1.678E+13 5.000E+00
        8.445E-02 1.697E+00 1.953E-19 8.665E-02 4.557E+10 2.042E-01 1.391E+11
 L24    5.346E+00 2.298E-17 4.298E-18 2.289E+01 3.010E+12 7.633E+00 1.320E+13 5.000E+00
        6.748E-02 1.941E+00 9.951E-20 1.332E-01 2.668E+10 1.471E-01 1.285E+11


Field description:
   (1) band name
   (2) band width (in um)
   (3) in-band flux (W/cm2)
   (4) in-band flux/band width (um)
   (5) isophotal wavelength (see Fazio et al. 2004)
   (6) band width (in Hz)
   (7) in-band flux/band width (Hz) => Jy
   (8) isophotal frequency
	
   The first row is the value and the second is the uncertainty
   (as indicated, either in physical units or %).

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