Class Fluxes

java.lang.Object
uk.ac.starlink.ttools.func.Fluxes

public class Fluxes extends Object
Functions for conversion between flux and magnitude values. Functions are provided for conversion between flux in Janskys and AB magnitudes.

Some constants for approximate conversions between different magnitude scales are also provided:

  • Constants JOHNSON_AB_*, for Johnson <-> AB magnitude conversions, from Frei and Gunn, Astronomical Journal 108, 1476 (1994), Table 2 (1994AJ....108.1476F).
  • Constants VEGA_AB_*, for Vega <-> AB magnitude conversions, from Blanton et al., Astronomical Journal 129, 2562 (2005), Eqs. (5) (2005AJ....129.2562B).
Since:
30 Jun 2006
Author:
Mark Taylor
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final double
    Approximate offset between Johnson and AB magnitudes in B band.
    static final double
    Approximate offset between Johnson and AB magnitudes in Bj band.
    static final double
    Approximate offset between Johnson and AB magnitudes in g band.
    static final double
    Offset between Johnson and AB magnitudes in g' band (zero).
    static final double
    Approximate offset between Johnson and AB magnitudes in i band.
    static final double
    Approximate offset between Johnson and AB magnitudes in I band.
    static final double
    Approximate offset between Johnson and AB magnitudes in Ic band.
    static final double
    Offset between Johnson and AB magnitudes in i' band (zero).
    static final double
    Approximate offset between Johnson and AB magnitudes in r band.
    static final double
    Approximate offset between Johnson and AB magnitudes in R band.
    static final double
    Approximate offset between Johnson and AB magnitudes in Rc band.
    static final double
    Offset between Johnson and AB magnitudes in r' band (zero).
    static final double
    Offset between Johnson and AB magnitudes in u' band (zero).
    static final double
    Approximate offset between Johnson and AB magnitudes in V band.
    static final double
    Offset between Johnson and AB magnitudes in z' band (zero).
    static final double
    Approximate offset between Vega (as in 2MASS) and AB magnitudes in H band.
    static final double
    Approximate offset between Vega (as in 2MASS) and AB magnitudes in J band.
    static final double
    Approximate offset between Vega (as in 2MASS) and AB magnitudes in K band.
  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    abToJansky(double magAB)
    Converts AB magnitude to flux in Jansky.
    static double
    fluxToLuminosity(double flux, double dist)
    Converts flux to luminosity given a luminosity distance.
    static double
    janskyToAb(double fluxJansky)
    Converts flux in Jansky to AB magnitude.
    static double
    luminosityToFlux(double lumin, double dist)
    Converts luminosity to flux given a luminosity distance.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • JOHNSON_AB_V

      public static final double JOHNSON_AB_V
      Approximate offset between Johnson and AB magnitudes in V band. VJ~=VAB+JOHNSON_AB_V.
      See Also:
    • JOHNSON_AB_B

      public static final double JOHNSON_AB_B
      Approximate offset between Johnson and AB magnitudes in B band. BJ~=BAB+JOHNSON_AB_B.
      See Also:
    • JOHNSON_AB_Bj

      public static final double JOHNSON_AB_Bj
      Approximate offset between Johnson and AB magnitudes in Bj band. BjJ~=BjAB+JOHNSON_AB_Bj.
      See Also:
    • JOHNSON_AB_R

      public static final double JOHNSON_AB_R
      Approximate offset between Johnson and AB magnitudes in R band. RJ~=RAB+JOHNSON_AB_R.
      See Also:
    • JOHNSON_AB_I

      public static final double JOHNSON_AB_I
      Approximate offset between Johnson and AB magnitudes in I band. IJ~=IAB+JOHNSON_AB_I.
      See Also:
    • JOHNSON_AB_g

      public static final double JOHNSON_AB_g
      Approximate offset between Johnson and AB magnitudes in g band. gJ~=gAB+JOHNSON_AB_g.
      See Also:
    • JOHNSON_AB_r

      public static final double JOHNSON_AB_r
      Approximate offset between Johnson and AB magnitudes in r band. rJ~=rAB+JOHNSON_AB_r.
      See Also:
    • JOHNSON_AB_i

      public static final double JOHNSON_AB_i
      Approximate offset between Johnson and AB magnitudes in i band. iJ~=iAB+JOHNSON_AB_i.
      See Also:
    • JOHNSON_AB_Rc

      public static final double JOHNSON_AB_Rc
      Approximate offset between Johnson and AB magnitudes in Rc band. RcJ~=RcAB+JOHNSON_AB_Rc.
      See Also:
    • JOHNSON_AB_Ic

      public static final double JOHNSON_AB_Ic
      Approximate offset between Johnson and AB magnitudes in Ic band. IcJ~=IcAB+JOHNSON_AB_Ic.
      See Also:
    • JOHNSON_AB_uPrime

      public static final double JOHNSON_AB_uPrime
      Offset between Johnson and AB magnitudes in u' band (zero). u'J=u'AB+JOHNSON_AB_uPrime=u'AB.
      See Also:
    • JOHNSON_AB_gPrime

      public static final double JOHNSON_AB_gPrime
      Offset between Johnson and AB magnitudes in g' band (zero). g'J=g'AB+JOHNSON_AB_gPrime=g'AB.
      See Also:
    • JOHNSON_AB_rPrime

      public static final double JOHNSON_AB_rPrime
      Offset between Johnson and AB magnitudes in r' band (zero). r'J=r'AB+JOHNSON_AB_rPrime=r'AB.
      See Also:
    • JOHNSON_AB_iPrime

      public static final double JOHNSON_AB_iPrime
      Offset between Johnson and AB magnitudes in i' band (zero). i'J=i'AB+JOHNSON_AB_iPrime=i'AB.
      See Also:
    • JOHNSON_AB_zPrime

      public static final double JOHNSON_AB_zPrime
      Offset between Johnson and AB magnitudes in z' band (zero). z'J=z'AB+JOHNSON_AB_zPrime=z'AB.
      See Also:
    • VEGA_AB_J

      public static final double VEGA_AB_J
      Approximate offset between Vega (as in 2MASS) and AB magnitudes in J band. JVega~=JAB+VEGA_AB_J.
      See Also:
    • VEGA_AB_H

      public static final double VEGA_AB_H
      Approximate offset between Vega (as in 2MASS) and AB magnitudes in H band. HVega~=HAB+VEGA_AB_H.
      See Also:
    • VEGA_AB_K

      public static final double VEGA_AB_K
      Approximate offset between Vega (as in 2MASS) and AB magnitudes in K band. KVega~=KAB+VEGA_AB_K.
      See Also:
  • Method Details

    • abToJansky

      public static double abToJansky(double magAB)
      Converts AB magnitude to flux in Jansky.

      F/Jy=10(23-(AB+48.6)/2.5)

      Parameters:
      magAB - AB magnitude value
      Returns:
      equivalent flux in Jansky
    • janskyToAb

      public static double janskyToAb(double fluxJansky)
      Converts flux in Jansky to AB magnitude.

      AB=2.5*(23-log10(F/Jy))-48.6

      Parameters:
      fluxJansky - flux in Jansky
      Returns:
      equivalent AB magnitude
    • luminosityToFlux

      public static double luminosityToFlux(double lumin, double dist)
      Converts luminosity to flux given a luminosity distance.

      F=lumin/(4 x Pi x dist2)

      Parameters:
      lumin - luminosity
      dist - luminosity distance
      Returns:
      equivalent flux
    • fluxToLuminosity

      public static double fluxToLuminosity(double flux, double dist)
      Converts flux to luminosity given a luminosity distance.

      lumin=(4 x Pi x dist2) F

      Parameters:
      flux - flux
      dist - luminosity distance
      Returns:
      equivalent luminosity