Fluxes (TTOOLS API)

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uk.ac.starlink.ttools.func
Class Fluxes

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

public class Fluxes
extends Object
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
`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
`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. V_J~=V_AB+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. B_J~=B_AB+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. Bj_J~=Bj_AB+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. R_J~=R_AB+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. I_J~=I_AB+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. g_J~=g_AB+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. r_J~=r_AB+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. i_J~=i_AB+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. Rc_J~=Rc_AB+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. Ic_J~=Ic_AB+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. J_Vega~=J_AB+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. H_Vega~=H_AB+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. K_Vega~=K_AB+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