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LSST school workshop: Getting ready to do science with LSST data
Creating DCR-matched templates for image differencing (8973) - Mercredi 14 juin 2017 09:30 - 10:00

Creating DCR-matched templates for image differencing

The frequency-dependent spectral index of the atmosphere leads to spectrum-dependent distortions of sources away from zenith. While the effect of bulk refraction is easily corrected during astrometric calibration, this Differential Chromatic Refraction (DCR) introduces distortions that depend on the intrinsic spectrum of a source and vary with the parallactic angle and airmass of the observation. Past surveys have avoided DCR by restricting observations to low airmass, but LSST operations will require observations up to an airmass of 1.4 across the sky and up to 2 in some fields. With current image differencing techniques, we would have to choose between a high rate of false positive detections that would have to be culled with machine learning, or restrict template images to have similar airmasses and parallactic angles of the science image. However, the refraction of the atmosphere has been modeled for decades with increasing refinement, and we can use iterative forward modeling to estimate a sky model using that knowledge of the atmosphere to fit all observations of a patch simultaneously. We use this model to calculate new DCR-matched templates for image differencing, and find that it reduces the number of spurious source detections in DECam g-band images.

Ian SULLIVAN (University of Washington)

Toutes les vidéos de l'évenement LSST school workshop: Getting ready to do science with LSST data (35 videos)

00:57:52.63

2017-06-12

09:05 - 10:30 : Point sources and astrometry

00:19:33.76

2017-06-12

11:00 - 11:30 : Point sources and astrometry (cont.)

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2017-06-12

11:30 - 12:30 : Extended sources and galaxy photometry

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2017-06-12

14:00 - 15:00 : Extended sources and galaxy photometry (cont.)

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2017-06-12

15:00 - 15:30 : Image differencing

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2017-06-12

16:00 - 17:30 : Image differencing (cont.)

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2017-06-13

09:20 - 10:00 : PSF parameter estimation

00:39:50.93

2017-06-13

09:20 - 10:00 : Efficient multi-band deblending

00:36:08.77

2017-06-13

11:10 - 11:50 : LSST DM Processing of Crowded Fields

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2017-06-13

11:50 - 12:15 : Improved Point Source Detection in Crowded Fields using Probabili...

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2017-06-13

14:00 - 14:45 : Hyper Suprime-Cam Subaru Strategic Program

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2017-06-13

14:45 - 15:30 : HSC data meets LSST code

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2017-06-13

16:00 - 16:40 : Photometry extraction and validation using the HSC pipeline of HS...

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2017-06-13

16:40 - 17:20 : Reprocessing CFHT data with the LSST DM software stack

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2017-06-13

17:20 - 18:00 : Reprocessing CFHT Deep fields with the stack

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2017-06-14

09:00 - 09:30 : Joint astrometry

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2017-06-14

09:30 - 10:00 : Creating DCR-matched templates for image differencing

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2017-06-14

10:00 - 10:30 : Advances in astronomical image processing - Solving the problems ...

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2017-06-14

11:00 - 11:30 : LSST DM stack image differencing on CFHT images

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2017-06-14

14:00 - 14:35 : Dark Energy Survey - Status, Science, and Algorithmic Advancement...

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2017-06-14

14:35 - 15:10 : Forward Global Calibration of the Dark Energy Survey [remote pres...

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2017-06-14

15:10 - 15:45 : Photometric Calibration: lessons from CFHTLS

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2017-06-14

16:10 - 16:40 : PHOTOMETRYPIPELINE: An automated pipeline for calibrated photomet...

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2017-06-15

09:00 - 09:30 : LSST Data Management Overview

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2017-06-15

09:30 - 10:10 : What LSST Will Deliver: Images, Catalogs, Alerts, Services

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2017-06-15

10:10 - 10:40 : Qserv: A distributed shared-nothing database for the LSST catalog

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2017-06-15

11:10 - 11:40 : Scaling cloud for LSST catalog at IN2P3

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11:40 - 12:20 : LHC experiments : Petabytes to papers

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2017-06-15

12:20 - 12:50 : Exploring Spark and MongoDb for LSST

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2017-06-15

14:00 - 14:40 : Euclid - An update on the mission and its processing plan

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2017-06-15

14:40 - 15:20 : The Dark Energy Survey Data Management System [remote presentatio...

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2017-06-15

15:50 - 16:20 : Weak Lensing Data processing for the CFHTLenS and KiDS surveys [r...

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2017-06-15

16:20 - 17:00 : Lessons from a Large Survey: The First Decade of Pan-STARRS Obser...

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2017-06-15

17:00 - 17:10 : CosmoHub demonstration [spontaneous contribution]

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2017-06-15

17:10 - 17:20 : Workshop: Wrap up

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