skytag

Annotate transient sources or galaxies with the percentage credibility region they reside within on a given HealPix sky map.

Documentation for skytag is hosted by Read the Docs (development version and main version). The code lives on github. Please report any issues you find here. If you want to contribute, pull requests are welcomed! true

Features

• A command-line tool to report the credibility region a sky-location is found within on a HealPix skymap.
• Providing a MJD will also return the time since the map event.
• A python interface to provide the same functionality reported above, but can handle large lists of sky-locations or transient events.
• works well in conjunction with gocart.

Installation

The easiest way to install skytag is to use conda:

conda create -n skytag python=3.11 pip skytag -c conda-forge
conda activate skytag

To upgrade to the latest version of skytag use the command:

conda upgrade skytag -c conda-forge

It is also possible to install via pip if required:

pip install skytag

To check installation was successful run skytag -v. This should return the version number of the install.

Command-Line

Here is the command-line usage:

Usage:
    skytag <ra> <dec> <mapPath>
    skytag <ra> <dec> <mjd> <mapPath>

If you need an example skymap, download one from here.

For example, to find the probability of the location RA=170.343532, Dec=-40.532255 then run:

skytag 170.343532 -40.532255 bayestar.multiorder.fits

This returns:

This location is found in the 74.55 credibility region of the map.

If you also supply an MJD:

skytag 170.343532 -40.532255 60065.2232 bayestar.multiorder.fits

We get:

This transient is found in the 74.55 credibility region, and occurred 2.85564 days after the map event.

Finally, we can request the localised event distance for this specific sky-position be returned:

skytag -d 170.343532 -40.532255 bayestar.multiorder.fits

This transient is found in the 74.55% credibility region. At this sky-position the map event is localised to a distance of 75.03 (±19.72) Mpc.

Python API

To use skytag in your own Python code, see here.

gocart

skyTag works very well in conjunction with gocart, a tool to consume GCN Kafka alert streams and convert HealPix skymaps.

How to cite skytag

If you use skytag in your work, please cite using the following BibTeX entry:

@software{Young_skytag,
author = {Young, David R.},
doi = {10.5281/zenodo.7977906},
license = {GPL-3.0-only},
title = {{skytag}},
url = {https://github.com/thespacedoctor/skytag}
}