* 20151007: This file is from Nov, 1996 so is mainly of pedagogical value. * Wilson etal, 1972, ApJ, 177, 533. changed to .., 523 and units added * table values from Mountain et al, 1985 * Thanks to Jason Spyromilio for comments. Some recent papers on fundemental calibration using Vega are: Bohlin, Ralph C.; Gordon, Karl D.; Tremblay, P.-E, 2014, Techniques and Review of Absolute Flux Calibration from the Ultraviolet to the Mid-Infrared http://adsabs.harvard.edu/abs/2014PASP..126..711B Bohlin, R. C.; Gilliland, R. L., 2004, Hubble Space Telescope Absolute Spectrophotometry of Vega from the Far-Ultraviolet to the Infrared http://adsabs.harvard.edu/abs/2004AJ....127.3508B * * refs: * Hayes, 1970, Ap J, 159, 65 * Hayes and Latham, 1975, Ap J, 197, 593-601 * Koornneef, J., AA, 128, 84(1983) * Mountain et al, 1985, AA, 151, 399. * Oke and Gunn, 1983, Ap J, 266, 713. * Oke and Schild, 1970, Ap J, 161, 101. * Wilson etal, 1972, ApJ, 177, 523. * * The absolute calibration of Vega (alpha Lyrae) from * Hayes and Latham, 1975, Ap J, 197, 593-601 is * based on improved extinction corrections to data published * by Hayes, 1970, Ap J, 159, 65 and Oke and Schild, 1970, Ap J, 161, 101 * * For IR calibration see Koornneef, J., AA, 128, 84(1983) * Wilson etal, 1972, ApJ, 177, p533 and * Mountain et al, 1985, AA, 151, 399. * * The monochromatic flux reaching the Earth's atmosphere from Vega at * 5556ang is * * 3.39**-9 ergs cm-2 s-1 A-1 * 3.50**-20 ergs cm-2 s-1 Hz-1 * 948 photons cm-2 s-1 A-1 * * m(lam)-m(5556)=-2.5log(Flam(lam)/Flam(5556)) * therefore Flam(lam)= Flam(5556)*10**( /-2.5) * * Some useful cgs to SI conversions * * 1 Jy= 10**-23 ergs cm-2 Hz-1 = 10**-26 W m-2 Hz-1 * 1 W m-2 Hz-1 = 10**3 ergs sec-1 cm-2 Hz-1 * * AB magnitudes defined by Oke and Gunn(1983) * AB=-2.5log(Fnu) -48.60 * where 48.60 comes from 2.5log(Fnu(5556)) from above we get 48.63 * the difference is due to the different assumed zero-point for * alpha-lyrae. * The AB system is not actually zero-pointed on alpha Lyrae * For convenience to that the numbers are similar it is * zero-pointed on an assumed flux for alpha Lyrae which has since * been superseded, if you know what I mean! * * needs column with m-AB * * * waveband effective wavelength (needs to be checked) * U 3400ang * B 4400 * V 5500 * R 6500 * I 8000 * * * * * Wave- Mag Flam Fnu Fnu * length ergs cm-2 ergs cm-2 Jansky's * (ang) s-1 A-1 s-1 Hz-1 * 3300.0 1.137 3.3812E-09 1.2282E-20 1.2282E+03 9.0848E+14 14.958 1.1158E-05 3350.0 1.145 3.2569E-09 1.2192E-20 1.2192E+03 8.9493E+14 14.952 1.0911E-05 3400.0 1.129 3.2088E-09 1.2373E-20 1.2373E+03 8.8176E+14 14.945 1.0910E-05 3450.0 1.115 3.1569E-09 1.2533E-20 1.2533E+03 8.6899E+14 14.939 1.0891E-05 3500.0 1.097 3.1186E-09 1.2743E-20 1.2743E+03 8.5657E+14 14.933 1.0915E-05 3571.0 1.077 3.0515E-09 1.2980E-20 1.2980E+03 8.3954E+14 14.924 1.0897E-05 3636.0 1.059 2.9926E-09 1.3197E-20 1.3197E+03 8.2453E+14 14.916 1.0881E-05 4036.0 -0.299 8.4839E-09 4.6097E-20 4.6097E+03 7.4281E+14 14.871 3.4241E-05 4167.0 -0.278 7.8064E-09 4.5213E-20 4.5213E+03 7.1946E+14 14.857 3.2529E-05 4255.0 -0.263 7.3841E-09 4.4593E-20 4.4593E+03 7.0458E+14 14.848 3.1420E-05 4464.0 -0.238 6.5562E-09 4.3578E-20 4.3578E+03 6.7159E+14 14.827 2.9267E-05 4566.0 -0.199 6.0454E-09 4.2041E-20 4.2041E+03 6.5659E+14 14.817 2.7603E-05 4785.0 -0.153 5.2764E-09 4.0297E-20 4.0297E+03 6.2654E+14 14.797 2.5247E-05 5000.0 -0.103 4.6149E-09 3.8483E-20 3.8483E+03 5.9960E+14 14.778 2.3074E-05 5263.0 -0.050 3.9667E-09 3.6649E-20 3.6649E+03 5.6964E+14 14.756 2.0877E-05 5556.0 0.000 3.3992E-09 3.5000E-20 3.5000E+03 5.3960E+14 14.732 1.8886E-05 5840.0 0.062 2.9059E-09 3.3057E-20 3.3057E+03 5.1336E+14 14.710 1.6970E-05 6056.0 0.111 2.5830E-09 3.1599E-20 3.1599E+03 4.9505E+14 14.695 1.5643E-05 6436.0 0.167 2.1720E-09 3.0010E-20 3.0010E+03 4.6582E+14 14.668 1.3979E-05 6790.0 0.217 1.8636E-09 2.8659E-20 2.8659E+03 4.4153E+14 14.645 1.2654E-05 6800.0 0.219 1.8547E-09 2.8607E-20 2.8607E+03 4.4088E+14 14.644 1.2612E-05 7100.0 0.272 1.6203E-09 2.7244E-20 2.7244E+03 4.2225E+14 14.626 1.1504E-05 7550.0 0.361 1.3201E-09 2.5100E-20 2.5100E+03 3.9709E+14 14.599 9.9667E-06 7780.0 0.398 1.2015E-09 2.4259E-20 2.4259E+03 3.8535E+14 14.586 9.3480E-06 8090.0 0.429 1.0799E-09 2.3576E-20 2.3576E+03 3.7058E+14 14.569 8.7368E-06 8708.0 0.450 9.1425E-10 2.3124E-20 2.3124E+03 3.4428E+14 14.537 7.9613E-06 9700.0 0.484 7.1410E-10 2.2411E-20 2.2411E+03 3.0907E+14 14.490 6.9267E-06 10250.0 0.571 5.9027E-10 2.0686E-20 2.0686E+03 2.9249E+14 14.466 6.0503E-06 10400.0 0.586 5.6550E-10 2.0402E-20 2.0402E+03 2.8827E+14 14.460 5.8812E-06 10800.0 0.649 4.9483E-10 1.9252E-20 1.9252E+03 2.7759E+14 14.443 5.3441E-06 ************************************************************ *5556.0 0.000 3.3992E-09 3.5000E-20 * * 1 Jy= 10**-23 ergs cm-2 Hz-1 = 10**-26 W m-2 Hz-1 * 1 W m-2 Hz-1 = 10**3 ergs sec-1 cm-2 Hz-1 * * AB=-2.5log(Fnu) -48.60 * * Wave- Mag Flam Fnu Fnu * length ergs cm-2 ergs cm-2 Jansky's * (ang) s-1 A-1 s-1 Hz-1 ************************************************************ *Data for IR from Wilson et al, 1972, ApJ, 177, 523 ************************************************************ 12500.0 0.905 1.5200E-20 16500.0 1.382 0.9800E-20 22000.0 1.879 0.62E-20 35000.0 2.742 0.28E-20 48000.0 3.398 0.153E-20 ************************************************************ *Koornneef, J., AA, 128, 84(1983) J,H,K,L,M * * wave ergs cm^{-2} ergs cm^{-2} W m^{-2} Jy AB * s^{-1] A^{-1} s^{-1} Hz^{-1} Hz^{-1} ************************************************************************* 1.25 3.14e-10 1.635e-20 1.635e-23 1635 0.981 1.65 1.20e-10 1.090e-20 1.090e-23 1090 1.306 2.20 4.12e-11 0.665e-20 0.665e-23 665 1.843 3.60 6.41e-12 0.277e-20 0.277e-23 277 2.794 4.80 2.13e-12 0.164e-20 0.164e-23 164 3.363 ************************************************************************** *Data for IR from Mountain et al, 1985 ************************************************************************** 124000.0 30.6 ^-10 Wm^2um^-1 150000.0 15.6 200000.0 5.76 250000.0 2.54 300000.0 1.28 350000.0 0.719 400000.0 0.435 450000.0 0.280 500000.0 0.188