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ATLAS Survey

This is the ATLAS portal for the KiDS Survey Prodcution team. We want to use the ATLAS data to improve the KiDS survey photometric homogeneity (using overlaps) and (2) support KiDS science cases which are also applicable to ATLAS (for now just the KiDS Strong-Lensing project).

Status (last update 14 Apr 2015)

See ATLAS slides

We are producing u,g,r,i (not z!) ATLAS coadds re-using/adapting the KiDS pipeline.

Gaps in coadded data

Gaps between CCDs; in the release notes of ATLAS atlas_dr1.pdf: is written that in data observed before November 2011 the vertical gaps between the CCDs are not always filled in well because of the way the observations were executed. I suppose this is what you are seeing.

South-West secondary star diagnosis

Matt Owers notes:
- The issue I noted earlier with the small secondary star ~2” to the
southwest of brighter stars only appears in one g-band image. It is odd
that the secondary star is not the same brightness as the standard and I
can't really think what might cause this.

example case, g-band ATLAS data with rawfitsdata with DATE-OBS=set([datetime.datetime(2011, 9, 25, 1, 9, 10), datetime.datetime(2011, 9, 25, 1, 7, 35)]) :

Diagnosis: poor image quality in raw science exposures. 3 Figures below show a zoom in on an area in the example case:
Coadded calibrated image RawFitsData exposure 1 RawFitsData, exposure 2

The RawFitsData with the “secondary star” has DATE-OBS=2011-09-25T01:09:10.066.

DETECTION: most direct on RawScience. Probably using PSF anisotropy (high ellipticity with fixed PA) information. In absence of PSF anisotropy information of RawScienceFrames on can look at it for a ReducedScienceFrame with DATE-OBS=2011-09-25T01:09:10.066.

ASTROMETRY NOTE: this appears as one reason for bad astrometric residuals. See the correlated global astrometric parameters in the example case, g-band ATLAS data with rawfitsdata with DATE-OBS=set([datetime.datetime(2011, 9, 25, 1, 9, 10), datetime.datetime(2011, 9, 25, 1, 7, 35)]).

ATLAS tiles mapping onto Astro-WISE classes

(work in progress by Gijs)

Goal: define units of data for ATLAS in the same way as for KiDS. This ensures that whatever script/approach we develop that works on one will work for the other.

First the ATLAS observing strategy:

Now the mapping of it on Astro-WISE classes

KiDS survey operations handle on units of data:

For KiDS the mapping from survey tile to observing blocks to templates and exposures is straightforward:

For ATLAS>2011-10-31

Validation set: tile overlapping with SDSS

ATLAS data (1 pointing position) overlapping with SDSS (SEGUE):

The DATE_OBS for the RawScienceFrames is:
2013-06-02 00:45:26
2013-06-02 00:43:42
2013-02-11 07:10:16
2013-02-11 07:11:53
2012-05-20 02:03:29
2012-05-20 02:04:54
2013-02-03 07:02:43
2013-02-03 07:04:18

First production set: Cluster: APMCC917

The DATE_OBS for the RawScienceFrames is:
2011-09-29 05:58:21
2011-09-29 05:56:49
2011-09-25 01:06:04
2011-09-25 01:04:31
2011-09-29 04:57:25
2011-09-29 04:55:54
2011-09-24 05:45:24
2011-09-24 05:46:54
2011-09-29 05:59:54
2011-09-29 06:01:24
2011-09-25 01:07:35
2011-09-25 01:09:10
2011-09-29 04:58:55
2011-09-29 05:00:29
2011-09-29 06:04:26
2011-09-29 06:02:56
2011-09-25 01:12:12
2011-09-25 01:10:41
2011-11-29 02:39:18
2011-11-29 02:40:43
2011-12-05 01:45:05
2011-12-05 01:46:30
2011-08-22 07:39:28
2011-08-22 07:38:01
2011-11-28 01:40:30
2011-11-28 01:41:56
2011-11-29 02:42:31
2011-11-29 02:43:55
2011-12-05 01:50:15
2011-12-05 01:51:40
2011-08-22 07:40:54
2011-08-22 07:42:21
2011-11-29 02:45:41
2011-11-29 02:47:06
2011-12-05 01:54:03
2011-12-05 01:55:28
2011-11-19 01:47:03
2011-11-19 01:48:31
2011-09-25 05:46:51
2011-09-25 05:45:25
2011-12-13 01:41:51
2011-12-13 01:43:18
2011-09-27 06:20:29
2011-09-27 06:21:54
2011-11-19 01:50:18
2011-11-19 01:51:47
2011-09-25 05:48:19
2011-09-25 05:49:44
2011-12-13 01:45:26
2011-12-13 01:46:57
2011-11-19 01:53:37
2011-11-19 01:55:03
2011-09-25 05:52:38
2011-09-25 05:51:13
2012-10-14 01:30:26
2012-10-14 01:28:44
2012-09-13 03:10:12
2012-09-13 03:08:29
2012-06-24 08:25:34
2012-06-24 08:23:54
2012-10-16 00:59:05
2012-10-16 00:57:21
2012-10-14 01:34:23
2012-10-14 01:32:39
2012-09-13 03:14:14
2012-09-13 03:12:32
2012-06-24 08:29:40
2012-06-24 08:27:56
2012-10-16 01:03:02
2012-10-14 01:38:16
2012-10-14 01:36:37
2012-09-13 03:18:07
2012-09-13 03:16:27

Coadd QC

Report 2015-04-16: QC of 207 ATLAS coadds in SAMI cluster regions

QC check Nr OK Nr NOK
Cross-talk 207 0
Bg subtr. 206 1
Calibrations 207 0
Astrom 162 45
Photom 207 0
PSF difference 196 11
Overal verdict 156 51

Astrometry statistics

Data points: blue = u; green = g; red = r; magenta = i
Dashed lines: QC limits adopted in qcCoadd_ATLAS.py

PSF sizes and size variations

Data points: blue = u; green = g; red = r; magenta = i

Data in hand

coadds

VST-ATLAS pipeline description

We have a first draft pipeline. The VST-ATLAS pipeline is derived from the KiDS production pipeline.
A quick summary of the salient steps:

stepdescription
QC upon ingest not done, we simply take the most recent exposures of a field to be the right ones (not using ESO's QC (grade A,B,C)
Readnoise nightly OmegaCAM calibrations
Gainlinearity regularly (~ 3 per month) OmegaCAM calibrations
Flat-fielding and illumination correction re-using the calibrations made for KiDS
Fringe correction]] using same fringe maps as KiDS (not doing z)
Cross-talk done, using our general OmegaCAM configuration
Background subtraction row-by-row subtraction like KiDS
Hot pixels nightly OmegaCAM hotpixels (todo: check all are public)
Cold pixels regular (~2-3 per week) OmegaCAM calibrations
Satellite maps we do not know yet what is used (either single-frame based or 2-frame based
Photometric calibration done, nightly ZPTS as much as possible, except for u: forever
Chip-to-chip photometric corrections use fixed set (link to values will come)
Exposure-to-exposure photometric homogenization applied
Coadd-to-coadd photometric homogenization no applied
Astrometric calibration done, global
Automatic Coadd masks not done
Sourcelists not done
Manual Coadd Masks not done

References / handy links.

Scratch notes