Astrophysical source population models (gammapy.astro.population
)¶
Introduction¶
The gammapy.astro.population
module provides a simple framework for population
synthesis of gamma-ray sources, which is useful in the context of surveys and
population studies.
Getting Started¶
The following example illustrates how to simulate a basic catalog including a spiral arm model.
import astropy.units as u
from gammapy.astro.population import make_base_catalog_galactic
max_age = 1E6 * u.yr
SN_rate = 3. / (100. * u.yr)
n_sources = int(max_age * SN_rate)
table = make_base_catalog_galactic(
n_sources=n_sources,
rad_dis='L06',
vel_dis='F06B',
max_age=max_age,
spiralarms=True,
)
The total number of sources is determined assuming a maximum age and a supernova
rate. The table returned is an instance of Table
which
can be used for further processing. The example population with spiral-arms is
illustrated in the following plot.
(Source code, png, hires.png, pdf)
Galactocentric spatial distributions¶
Here is a comparison plot of all available radial distribution functions of the surface density of pulsars and related objects used in literature:
(Source code, png, hires.png, pdf)
TODO: add illustration of Galactocentric z-distribution model and combined (r, z) distribution for the Besancon model.
Spiral arm models¶
Two spiral arm models of the Milky way are available:
(ValleeSpiral
and gammapy.astro.population.FaucherSpiral
)
(Source code, png, hires.png, pdf)
Velocity distributions¶
Here is a comparison plot of all available velocity distribution functions:
(Source code, png, hires.png, pdf)
Reference/API¶
gammapy.astro.population Package¶
Astrophysical population models.
Functions¶
add_observed_parameters (table[, obs_pos]) |
Add observable parameters (such as sky position or distance). |
add_observed_source_parameters (table) |
Add observed source parameters to the table. |
add_pulsar_parameters (table[, B_mean, ...]) |
Add pulsar parameters to the table. |
add_pwn_parameters (table) |
Add PWN parameters to the table. |
add_snr_parameters (table) |
Adds SNR parameters to the table. |
make_base_catalog_galactic (n_sources[, ...]) |
Make a catalog of Galactic sources, with basic source parameters. |
make_catalog_random_positions_cube ([size, ...]) |
Make a catalog of sources randomly distributed on a line, square or cube. |
make_catalog_random_positions_sphere (size[, ...]) |
Sample random source locations in a sphere. |
Classes¶
CaseBattacharya1998 ([amplitude, alpha, beta]) |
Radial distribution of the surface density of supernova remnants in the galaxy - Case & Battacharya 1998. |
Exponential ([amplitude, z_0]) |
Exponential distribution. |
FaucherKaspi2006 ([amplitude, r_0, sigma]) |
Radial distribution of the birth surface density of pulsars in the galaxy - Faucher-Giguere & Kaspi 2006. |
FaucherKaspi2006VelocityBimodal ([amplitude, ...]) |
Bimodal pulsar velocity distribution - Faucher & Kaspi (2006). |
FaucherKaspi2006VelocityMaxwellian ([...]) |
Maxwellian pulsar velocity distribution. |
FaucherSpiral |
Milky way spiral arm used in Faucher et al (2006). |
LogSpiral |
Logarithmic spiral. |
Lorimer2006 ([amplitude, B, C]) |
Radial distribution of the surface density of pulsars in the galaxy - Lorimer 2006. |
Paczynski1990 ([amplitude, r_exp]) |
Radial distribution of the birth surface density of neutron stars - Paczynski 1990. |
Paczynski1990Velocity ([amplitude, v_0]) |
Distribution by Lyne 1982 and adopted by Paczynski and Faucher. |
ValleeSpiral () |
Milky way spiral arm model from Vallee (2008). |
YusifovKucuk2004 ([amplitude, a, b, r_1]) |
Radial distribution of the surface density of pulsars in the galaxy - Yusifov & Kucuk 2004. |
YusifovKucuk2004B ([amplitude, a, b]) |
Radial distribution of the surface density of OB stars in the galaxy - Yusifov & Kucuk 2004. |