Defining New Image Overlays

In the previous tutorial, we managed to retreive some additional AllWISE data for Wolf 28 using proper motion correction. But how can we be sure that the returned data actually belongs to our target system? The best way to check this is to make use of ATK’s image overlays. Since we are using a user-defined alias to AllWISE (see previous tutorial), we first need to tell ATK how to generate an AllWISE overlay. We do this using the Overlays module, which we can once again access from the command line via the ATKoverlay tool.

To generate an overlay definition for a user-defined catalogue alias, we need to provide ATK with the name of the survey’s right ascension, declination, ID, and magnitude columns (if available) in Vizier:

ATKoverlay add allwise --ra RAJ2000 --dec DEJ2000 --id AllWISE --mags W1mag W2mag W3mag W4mag

Added scaled_detection overlay defintion for alias 'allwise'.

Since we provided magnitude columns, the overlay will be scaled with brightness (see here) - hence a ‘scaled_detection’ overlay definition has been generated. We can now generate images with AllWISE overlays just like we would with any survey that ATK supports out of the box!

from AstroToolkit.Tools import query

image = query(kind="image", survey="panstarrs", source=2552928187080872832, overlays=["allwise"], size=120).showplot()

Running panstarrs image query
source = 2552928187080872832
pos = None
size = 120

Plotting image data...

While we can already see that the detection lines up almost perfectly with our target source, we can make sure by hovering over the central detection (i.e. the one that pertains to Wolf 28) and comparing the object ID (J004910.78+052249.8) with that of the data that we retrieved in the previous tutorial. As expected, they match!