Package uk.ac.starlink.ttools.func

Class Fluxes

  • public class Fluxes
extends java.lang.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 double JOHNSON_AB_B
      Approximate offset between Johnson and AB magnitudes in B band.
      static double JOHNSON_AB_Bj
      Approximate offset between Johnson and AB magnitudes in Bj band.
      static double JOHNSON_AB_g
      Approximate offset between Johnson and AB magnitudes in g band.
      static double JOHNSON_AB_gPrime
      Offset between Johnson and AB magnitudes in g' band (zero).
      static double JOHNSON_AB_i
      Approximate offset between Johnson and AB magnitudes in i band.
      static double JOHNSON_AB_I
      Approximate offset between Johnson and AB magnitudes in I band.
      static double JOHNSON_AB_Ic
      Approximate offset between Johnson and AB magnitudes in Ic band.
      static double JOHNSON_AB_iPrime
      Offset between Johnson and AB magnitudes in i' band (zero).
      static double JOHNSON_AB_r
      Approximate offset between Johnson and AB magnitudes in r band.
      static double JOHNSON_AB_R
      Approximate offset between Johnson and AB magnitudes in R band.
      static double JOHNSON_AB_Rc
      Approximate offset between Johnson and AB magnitudes in Rc band.
      static double JOHNSON_AB_rPrime
      Offset between Johnson and AB magnitudes in r' band (zero).
      static double JOHNSON_AB_uPrime
      Offset between Johnson and AB magnitudes in u' band (zero).
      static double JOHNSON_AB_V
      Approximate offset between Johnson and AB magnitudes in V band.
      static double JOHNSON_AB_zPrime
      Offset between Johnson and AB magnitudes in z' band (zero).
      static double VEGA_AB_H
      Approximate offset between Vega (as in 2MASS) and AB magnitudes in H band.
      static double VEGA_AB_J
      Approximate offset between Vega (as in 2MASS) and AB magnitudes in J band.
      static double VEGA_AB_K
      Approximate offset between Vega (as in 2MASS) and AB magnitudes in K band.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      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 Detail

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

      • 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:
        Constant Field Values

    • Method Detail

      • 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