Python utilities and examples for accessing Gaia data using the Table Access Protocol (TAP)
Python
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Failed to load latest commit information.
code
examples
presentations
.gitignore
.travis.yml
LICENSE
README.md
setup.py

README.md

Gaia on TAP

Python utilities and examples for accessing ESA Gaia data using Table Access Protocol (TAP).

Authors

  • Andrew R. Casey (Monash University)

Installation

Install using pip:

pip install gaia-on-tap

Getting Started

The gaia.tap package includes two main functions for accessing Gaia data: query and cone_search. By default, both will return all retrieved sources as an astropy.table.Table object, so you can then write the results to disk or do something useful with them.

Select stars around M67

# Get all sources within 1 degree of M67

import astropy.coordinates as coord
from gaia.tap import cone_search


cluster = coord.SkyCoord.from_name("M67")

cluster_candidates = cone_search(cluster.ra.deg, cluster.dec.deg, 1.0)

Select hypervelocity star candidates in TGAS

This doesn't treat the errors correctly, but it's a useful example to show what you can do:

import gaia.tap

# Identify stars with tangential velocities exceeding 500 km/s, and reasonable parallaxes
hvs_candidates = gaia.tap.query(
    """ SELECT  * 
        FROM    gaiadr1.tgas_source
        WHERE   parallax_error/parallax < 0.2
          AND   (4.74 * SQRT(POWER(pmra, 2) + POWER(pmdec, 2)))/parallax > 500 """)

Authenticate using your ESA/Gaia Archive credentials

If you have an account with the ESA/Gaia archive, you can include your credentials so that you can upload or query private tables. This is done by having a file (e.g., credentials.yaml) like:

username: acasey
password: my-super-awesome-password

And then in the code:

import gaia

# Read in our credentials. You only have to do this once per Python session!
gaia.config.read("credentials.yaml")

# For any further queries use the authenticate flag, and the code will log you in automagically
sources = gaia.tap.query(" ... ", authenticate=True)

Upload a table to your local space on the ESA/Gaia archive

If you want to upload a VOtable and use it for cross-matches through the ESA/Gaia archive:

import gaia

# Read in our credentials. 
gaia.config.read("credentials.yaml")

# Upload our table, which we will ask ESA/Gaia to call 'my_table'
gaia.tap.upload("my_table", "/local/path/to/your/table.votable")

# Now use it!
# (Ensure that you use the authenticate=True flag so that you can access your private tables)
xmatched_sources = tap.query(
    """ SELECT  *
        FROM    gaiadr1.gaia_source as gaia,
                <YOUR_USERNAME>.my_table as my_table
        WHERE   1=CONTAINS(
                    POINT('ICRS', my_table.ra, my_table.dec),
                    CIRCLE('ICRS', gaia.ra, gaia.dec, 1.5/3600)
                )
    """, authenticate=True)

Resources