pyhesdm

Local Universe Dispersion Measure (DM) Model Computed from HESTIA Simulation

This package provides a Python interface to a DM model for the local universe within 120 Mpc, as introduced in Huang et al.(2024).

This package is designed to calculate the DM contribution from specific components for given Galactic coordinates. The model considers the following components: the Milky Way disk, the Milky Way halo, the intra-group medium (IGrM), the intergalactic medium (IGM), and the halos. The DM models for the Milky Way disk, Milky Way halo (D < 0.2 Mpc) and the IGrM (0.2 Mpc < D < 3.4 Mpc) are all-sky projected model, while the DM model for the IGM and halos (3.4 Mpc < D < 120 Mpc) are 3D spherical models.

The Milky Way disk DM model is the NE2001 model. If you require the NE2001 model in 3D and with higher resolution, please use pygedm (doi:10.1017/pasa.2021.33). The DM models for the Milky Way halo and the IGrM are computed from the HESTIA simulation (Libeskind et al., 2020). The DM model for the IGM is computed based on the Hamlet reconstructed density field (Valade et al., 2022). The DM model for the galaxy and group halos are from the NEDLVS catalog (doi:10.26132/NED8) and the 2MASS Galaxy Groups catalog (Tully et al., 2015).

Requirements

Before using this package, ensure that the following packages are installed:

1. ne2001-0.0.1
2. dust_extinction-1.5
3. linetools-0.3.2
4. mwprop-1.0.10
5. importlib_resources
6. healpy-1.17.3
7. FRB
   This package depends on the FRB package developed at https://github.com/FRBs/FRB, which is not available via PyPI.
   Please install it manually before using pyhesdm:

git clone https://github.com/FRBs/FRB.git
cd FRB
pip install .

Download

git clone git@github.com:yuxinhuang1229/pyhesdm.git

Test installation

setup.py automatically download NEDLVS catalog from its website. This catalog is used for calculating DM_halos.

python3 setup.py sdist bdist_wheel
pip3 install .

Usage

from pyhesdm.hestia_dm import Hestia_DM
from pyhesdm.dmhalos import NEDLVS_Tully_Halos

hesdm = Hestia_DM()
halos = NEDLVS_Tully_Halos()

# calculate MW halo DM
FRB20220319D = SkyCoord('02:08:42.7 +71:02:06.9', unit=['hourangle','deg'], frame='icrs')
hesdm.get_mwhalo(FRB20220319D.galactic.l,FRB20220319D.galactic.b)
>> 39.368945 pc/cm^3

# calculate DM_IGM and its uncertainty
virgo = SkyCoord("12h27m 12d43m", frame='icrs')
dmigm, dmstd = hesdm.get_dmigm(virgo.galactic.l,virgo.galactic.b)
print(dmigm, dmstd)
>> 24.231488 pc/cm^3  2.021273 pc/cm^3

# calculate DM_halos
halos.get_dmhalos(lon=virgo.galactic.l, lat=virgo.galactic.b)
>> 618 objects are identified along the ray
>> 226 objects already have masses
>> 4  groups/clusters found within 5Mpc.
>> <DM_halos> =  71.72133087498753 pc/cm^3
>> <DM_halos>_specz =  70.33314714677843 pc/cm^3
>> <DM_halos>_photoz =  1.388183728209114 pc/cm^3
>> <DM_halos>_grp =  55.07165041895517 pc/cm^3
>> 125.4048 pc/cm^3