Version 1 of the notebook was written by Manon Gilles (Exoplanet Team, IAP, France).
Version 1 of the tool EuclidExtractor was written by Manon Gilles, with inputs from Henry Joy McCracken, Clotilde Laigle, the help of the VIS team, and the Exoplanet Team of IAP.
This notebook will guide you through the EuclidExtractor code and give you some informations on the Euclid Galactic Bulge Survey EGBS data. The commands needed to use it in the terminal are explained in the last part of the notebook.
This repository is subject to the terms and conditions defined in file LICENSE.txt, which is part of this source code package. No part of the package, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the file LICENSE.txt.
The EGBS data were acquired between March 23 and 24, 2025, during a one-time survey of the Galactic Bulge.
Most of the calibrated-frames contents are detailed in : http://st-dm.pages.euclid-sgs.uk/data-product-doc/dm10/visdpd/dpcards/vis_calibratedquadframe.html
Data explanation:
-
EUC_VIS_SWL-BKG-{obsid}-{dither}-{expnum}_*.fits
background image of the corresponding calibrated frame, generated by GnuAstro NoiseChisel. -
EUC_VIS_SWL-DET-{obsid}-{dither}-{expnum}_*_sci.fits
science image of the calibrated frame -
EUC_VIS_SWL-DET-{obsid}-{dither}-{expnum}_*_flg.fits
flag map of the calibrated frame -
EUC_VIS_SWL-DET-{obsid}-{dither}-{expnum}_*_rms.fits
noise map of the calibrated frame. It contains the quadratic sum of the image photon noise (square root of the science image) and the readout noise. -
EUC_VIS_SWL-WGT-{obsid}-{dither}-{expnum}_*.fits
VIS calibrated exposure weight map. It's the master PRNU image with all invalid pixels set to 0.
The scientific data has an observation identifier obsid = 067070. The other data used to calculate the PSF has an identifier obsid = 067068 / 067071.
The exposure number is always the same, expnum = 1. It usually changes for Euclid data, but not for EGBS data, which only has a single 400 s exposure.
Each field was observed 16 times at 4 slightly different positions, each observed 4 times.
It is possible to determine the field of observation based on the dither number. As illustrated in the image below:
- 0:15 -> field 1
- 16:31 -> field 2
- 32:47 -> field 3
- 48:63 -> field 4
- 64:79 -> field 5
- 80:95 -> field 6
- 96:111 -> field 7
- 112:127 -> field 8
- 128:143 -> field 9
From the VIS team: https://euclid.roe.ac.uk/issues/31852
Each field (a focal-plane array) is divided into 144 quadrants (36 CCDs, each made of 4 quadrants), as shown in the image below:
From Euclid Quick Data Release (Q1) : VIS processing and data products (Euclid Collaboration: H. J. McCracken et al. 2025)
The data was processed by the VIS ground-segment team at IAP. The PSF file was generated with PSFEx. The resulting PSF is a 21x21 array that can be calculated for different options.
The file EuclidRedmine_32876_EGBS_400s-PSF_PSFEx_model.pdf explains how the PSF was processed by the VIS Team and what are each file is. The PSF file was generated with PSFEx. The resulting PSF is a 21x21 array that can be calculated for different options using EuclidExtractor.py.
This version from 2026-02-23 was written by Manon Gilles (Exoplanet Team, IAP, France), with inputs from Henry Joy McCracken, Clotilde Laigle, the help of the VIS team, and the Exoplanet Team of IAP.
Please see the Jupyter Notebook EuclidExtractor/Euclid_data_extraction.ipynb, written by Manon Gilles, for more details on usage and fonctions.
Please note: The calibration source catalogues are intended for calibration purposes and are not suitable for statistical analyses. For further details, please refer to the Q2 paper.