gdpyc is a Python 2/3 package for calculating Hydrogen column density and optical extinction. gdpyc offers functionalities similar to the nh tool included in HEASoft, or on-line web services like HEASARC’s nH or IRSA’s Galactic Dust Reddening and Extinction.
This package uses HEALpix maps provided by NASA’s LAMBDA service. Please cite the original papers and authors of the surveys if you use this tool for your research (see sections Surveys and References below).
Dependencies
gdpyc depends on:
numpy
astropy
astropy-healpix
regions
Certain functionalities also requiere:
healpix
matplotlib
Installation
gdpyc can be easily installed using pip:
pip install gdpyc
Example
A simple example of using gdpyc:
>>> from gdpyc import GasMap, DustMap
>>> from astropy.coordinates import SkyCoord
>>> coords = SkyCoord(34.0, -5.0, unit='deg')
>>> GasMap.nh(coords, nhmap='DL')
<Quantity 1.9278499e+20 1 / cm2>
>>> GasMap.nh(coords, nhmap='LAB')
<Quantity 1.9802036e+20 1 / cm2>
>>> DustMap.ebv(coords, dustmap='Planck13')
'0.027179038520908336'
>>> DustMap.extinction(coords, dustmap='SFD', filters='SDSS_r')
<Table length=1>
SDSS_r
float64
--------------------
0.049108389441137615
>>> GasMap.plot_map('HI4PI')
Surveys
gdpyc includes several HI and dust surveys with nH and E(B - V) estimations. We created low resolution HEALPix maps for all surveys (NSIDE=64 ~ 1 degree pixels) by degrading the original maps using the ud_grade tool from healpy. Only low resolution maps are included in the installation. If the user asks for high resolution maps (hires parameter, see API documentation), they are downloaded as needed and stored for future use.
HI surveys
DL: Composite all-sky map of neutral Hydrogen column density (NHI), formed from the Leiden/Dwingeloo survey data [1] and the composite NHI map of [2]. The two datasets are not matched in sensitivity or resolution; note that discontinuities exist in the constructed composite map.
DL high resolution data (oversampled), NSIDE=512 ~ 0.11 deg.
LAB: Observations of 21-cm emission from Galactic neutral Hydrogen over the entire sky, merging the Leiden/Dwingeloo Survey [1] of the sky north of -30° with the Instituto Argentino de Radioastronomia Survey [3], [4] of the sky south of -25°. [5]
LAB high resolution data (oversampled), NSIDE=512 ~ 0.11 deg. [6]
HI4PI: The HI 4-PI Survey (HI4PI) is a 21-cm all-sky survey of neutral atomic Hydrogen. It is constructed from the Effelsberg-Bonn HI Survey (EBHIS) and the Galactic All-Sky Survey (GASS). [7]
HI4PI high resolution data, NSIDE=1024 ~ 0.06 deg.
Dust surveys
SFD: All-sky map of Galactic reddening, E(B - V), from a composite 100 micron map formed from IRAS/ISSA maps calibrated using DIRBE observations. [8]
SFD high resolution data (undersampled), NSIDE=512 ~ 0.11 deg.
Planck13: All-sky map of Galactic reddening, E(B - V), using Planck-HFI and IRAS data, for extra-galactic studies. [9]
Planck13 high resolution data, NSIDE=2048 ~ 0.03 deg.
Extinction values for different filters are estimated using the E(B - V) conversion factors presented in [10], assuming an extinction to reddening ratio R=3.1 Additional factors for 2MASS, Spitzer-IRAC and WISE filters are from IRSA’s Galactic Dust Reddening and Extinction service.
References
1 maintainer
Release files for gdpyc 1.2
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| gdpyc-1.2.tar.gz | 1.3 MB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| gdpyc-1.2-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 2.6 MB
Release files / gdpyc-1.2.tar.gz
| Download URL | gdpyc-1.2.tar.gz |
|---|---|
| Size | 1.3 MB |
| Tags | Source |
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| Download URL | gdpyc-1.2-py3-none-any.whl |
|---|---|
| Size | 1.3 MB |
| Tags | Python 3 |
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