ValleeSpiral

class gammapy.astro.population.ValleeSpiral

Bases: gammapy.astro.population.LogSpiral

Milky way spiral arm model from Vallee (2008).

Reference: http://adsabs.harvard.edu/abs/2008AJ….135.1301V

Attributes Summary

bar_radius
m
p
r_0
r_sun
spiralarms
theta_0

Methods Summary

radius(theta, spiralarm_index)	Radius for a given angle.
theta(radius, spiralarm_index)	Angle for a given radius.
xy_position([theta, radius, spiralarm_index])	Compute (x, y) position for a given angle or radius.

Attributes Documentation

bar_radius = <Quantity 3. kpc>

m = 4

p = <Quantity 12.8 deg>

r_0 = <Quantity 2.1 kpc>

r_sun = <Quantity 7.6 kpc>

spiralarms = array(['Norma', 'Perseus', 'Carina Sagittarius', 'Crux Scutum'], dtype='<U18')

theta_0 = <Quantity -20. deg>

Methods Documentation

radius(theta, spiralarm_index)

Radius for a given angle.

Parameters:

theta : array_like

Angle (deg)

spiralarm_index : int

Spiral arm index

Returns:

radius : array_like

Radius (kpc)

theta(radius, spiralarm_index)

Angle for a given radius.

Parameters:

radius : array_like

Radius (kpc)

spiralarm_index : int

Spiral arm index

Returns:

theta : array_like

Angle (deg)

xy_position(theta=None, radius=None, spiralarm_index=0)

Compute (x, y) position for a given angle or radius.

Parameters:

theta : array_like

Angle (deg)

radius : array_like

Radius (kpc)

spiralarm_index : int

Spiral arm index

Returns:

x, y : array_like

Position (x, y)