Ginga Specific Software: Program NH
Program nh determines the Galactic hydrogen density in a
specified direction of the sky. This is calculated using an
interpolation of data taken from Marshall & Clark (1984). This
covers the entire sky and uses various 21-cm surveys for its source
(Stark et al. 1984; Clearly, Heiles & Haslam 1979; Heiles
& Clearly 1979).
A data file containing the Galactic hydrogen density values (the
default is $XACAL/nh2x2.dat).
Nh requires three input parameters. The QX parameter system
is used to read these parameters.
| GNG_RA |
The Right Ascension in degrees (1950.0 equinox). |
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| GNG_DEC |
The Declination angle in degrees (1950.0 equinox). |
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| GNG_SNH |
The name of the file containing the Galactic hydrogen density
values (the default is $XACAL/nh2x2.dat) |
Nh returns one input parameter. The QX parameter system is
used to display this parameters.
| GNG_NH |
The Galactic hydrogen column density (in units of 1021 hydrogen atoms cm-2). |
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