FaucherSpiral

class gammapy.astro.population.FaucherSpiral

Bases: gammapy.astro.population.LogSpiral

Milky way spiral arm used in Faucher et al (2006).

Reference: https://ui.adsabs.harvard.edu/abs/2006ApJ…643..332F

Attributes Summary

k
r_0
spiralarms
theta_0

Methods Summary

__call__(self, radius[, blur, random_state])	Draw random position from spiral arm distribution.
radius(self, theta, spiralarm_index)	Radius for a given angle.
theta(self, radius, spiralarm_index)	Angle for a given radius.
xy_position(self[, theta, radius, …])	Compute (x, y) position for a given angle or radius.

Attributes Documentation

k = <Quantity [4.25, 4.25, 4.89, 4.89] rad>

r_0 = <Quantity [3.48, 3.48, 4.9 , 4.9 ] kpc>

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

theta_0 = <Quantity [1.57, 4.71, 4.09, 0.95] rad>

Methods Documentation

__call__(self, radius, blur=True, random_state='random-seed')

Draw random position from spiral arm distribution.

Returns the corresponding angle theta[rad] to a given radius[kpc] and number of spiralarm. Possible numbers are:

• Norma = 0,

• Carina Sagittarius = 1,

• Perseus = 2

• Crux Scutum = 3.

Parameters

random_state{int, ‘random-seed’, ‘global-rng’, RandomState}

Defines random number generator initialisation. Passed to get_random_state.

Returns

Returns dx and dy, if blurring= true.

radius(self, theta, spiralarm_index)

Radius for a given angle.

Parameters

thetaarray_like

Angle (deg)

spiralarm_indexint

Spiral arm index

Returns

radiusarray_like

Radius (kpc)

theta(self, radius, spiralarm_index)

Angle for a given radius.

Parameters

radiusarray_like

Radius (kpc)

spiralarm_indexint

Spiral arm index

Returns

thetaarray_like

Angle (deg)

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

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

Parameters

thetaarray_like

Angle (deg)

radiusarray_like

Radius (kpc)

spiralarm_indexint

Spiral arm index

Returns

x, yarray_like

Position (x, y)