# 1. Introduction¶

## 1.1. Physics goals¶

CLUMPY is dedicated to the calculation of $$\gamma$$-ray or neutrino signals from annihilating and decaying astrophysical Dark Matter. Dark matter haloes are present at many scales (sub-Galactic, Galactic, cluster scale). The Galactic centre is the obvious location for indirect detection of dark matter annihilation. However, it is plagued by a large background of astrophysical sources. Other potentially promising targets are dSphs, dark clumps of the Galactic halo, gradients of the smooth halo (towards but slightly offset the Galactic centre), galaxy clusters, or the overall diffuse extragalactic emission.

For this reason, several modules are available in CLUMPY, to deal with all the above situations. Each module is reached by using the appropriate flag in the command line. Specific formats for user-defined ASCII input files are also required, depending on the options used. Help for the various options and allowed parameters are designed to be self-explaining.

Specifically, CLUMPY addresses the following physics problems of indirect dark matter annihilation/decay signals:

J-factors: Calculate astrophysical J- and D-factors from a spherical or triaxial DM distribution in the Galaxy (smooth, mean and/or drawn subhaloes) and/or for extragalactic haloes; Calculate fluxes for Galactic and/or extragalactic contributions, combining the astrophysical factor and the particle physics factor; Perform a Jean analysis to reconstruct DM profiles from kinematic data ($$\chi^2$$ analysis or MCMC analysis) and to calculate the associated J-factors, i.e., integrating the collisionless Boltzmann equation in spherical symmetry, assuming steady-state and negligible rotational support. This relates the dynamics of a collisionless tracer population (e.g., stars in a dwarf spheroidal galaxy or galaxies in a galaxy cluster) to the underlying gravitational potential.

For a detailed description of the physics problem, go to Section 6.

## 1.2. Ingredients¶

J-factor and flux calculations require many inputs from particle physics, cosmology, structure formation, DM halo distributions, etc. This is detailed in this documentation and in the CLUMPY publications. These inputs are handled by parametrisations and their associated keywords, and they describe for instance:

(Sub-)haloes: Profile parametrisations (Zhao, NFW, Einasto, etc.), concentration-mass dependence (Bullock, Moliné, etc.),… Cosmology parameters, mass distribution (Press-Schechter, Tinker, etc.), absorption (Finke, Franceschini, etc.), … Light profile (Plummer, Zhao, etc.), anisotropy profile (constant, Osipkov, etc.), … Integration angle, smoothing (by Gaussian PSF), angular power spectrum (APS), …

## 1.3. Release history¶

We provide below as tarballs previous CLUMPY releases and bug fixes, and the associated publications. However, if not for specific demands, always use the last release version from the git repository!

## 1.4. Developers/contacts¶

For any question, or if you believe that you have a module that would be a bonus for a future CLUMPY release, feel free to contact us to discuss the matter:

Past contributors

• Vincent Bonnivard (Jeans analysis module in v2)
• Aldée Charbonnier (wrote unreleased v0)
• Emmanuel Nezri (particle physics module in v2)