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| Paper: |
MegaPipe 2.0: 10000 Square Degrees of CFHT MegaCam Imaging |
| Volume: |
523, Astronomical Data Analysis Software and Systems XXVIII |
| Page: |
649 |
| Authors: |
Gwyn, S. D. |
| Abstract: |
MegaPipe, the MegaCam data processing pipeline at the CADC, has been
upgraded to version 2.0 and has processed over 10000 square degrees of
the sky. MegaPipe has been operating since 2008. It was originally
intended to increase the usage of archival MegaCam data by calibrating
and stacking the images as they became public. That focus expanded to
include processing data from the CFHT Large Programs such as the NGVS,
OSSOS, VESTIGE and CFIS, as well as PI data. MegaPipe 2.0 represents
several improvements. The advent of GAIA means that the astrometric
calibration is considerably more accurate. The public release of
Pan-STARRS allows photometric calibration of images even if they
were taken under non-photometric conditions, by using the PS1 stars as
in-field standards. Together this means that almost every MegaCam
image can be astrometrically/photometrically calibrated to sufficient
accuracy to allow stacking (30 mas and 0.01 magnitudes
respectively). MegaPipe 2.0 also introduces an improvement to the
stacking method. MegaPipe previously only stacked images that were
centred on more or less the same part of the sky, which limited the
number of images that could be stacked. MegaPipe 2.0 instead stacks on
a grid of 10000x10000 pixel tiles, each half a degree square, evenly
covering the whole sky. The result is that twice as much sky area can
be stacked. There are now over 10000 square degrees of imaging in both
the ugriz filters as well as the narrow band filters. The data is
available for download at:
http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/megapipe/access/graph.html |
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