HST, General Relativity and Einstein Ring

How to talk about relativity ?With a smile !

galaxies SDSSCGB 8842.3 and SDSSCGB 8842.4, strong gravitational lensing and Einstein ring. Reprocessed data from the Hubble Space Telescope

Mehdi Bozzo-Rey, [email protected]

Mehdi Bozzo-Rey: [email protected]

idea 1Gravity can be seen as a property of the space time geometry instead of a force


2 particles, no acceleration / force, parallel / straight trajectories.

2 particles + force (like gravitation) : massive structure at convergence point. Curved instead of straight trajectory

2 particles start in parallel but converge even if they are following the straightest path because the space is curved

http://www.einstein-online.info/elementary/generalRT/GeomGravity


idea 2If a structure is massive and compact enough it can curve the space time so the light emitted from a source can reach the observer using 2 different paths


http://www.einstein-online.info/spotlights/light_deflection

If the source, the lens and the observer are all aligned then what is called an Einstein ring can be observed.


where to get the data



loading the original fits data



something is not right ...



comparing with the fits preview from the HLA



How to fix it ?download the single exposures files: no luck

download the datasets from MAST: no luck

download individual files from MAST: no luck ...



Fits liberator will save us



opening the file with fits liberator



using fits liberator to export fits files as tiff files



And fits liberator saved the day !



loading all the datasets



IR data are not really usable



Who used the IR detector for shotgun target practice ?Nobody, but we have a death star and blobs !



WFC3 IR channel - death star



WFC3 IR channel - blobs



processing strategy use the WFPC2 images only Align the WFPC2 images combine the 3 images as RGB image:

Red: F814W Green: F606W Blue: F450W

standard processing

Option 2: use the WFC3 sub with F360W filter as luminance to create a LRGB picture



First step: crop



crop(2)


crop(3)


STF autostretch on the cropped images



dynamic alignment - Image registration section



dynamic alignment: F450W as reference



dynamic alignment: select the second image



dynamic alignment: control points - auto search



dynamic alignment - execution



dynamic alignment - registered image



last image to register / align



ready for channel combination !



channel combination



channel combination - RGB image


image flip


STF - autostretch


Dynamic Background Extraction


Dynamic crop


background neutralization


color calibration


sample format conversion


STF process reinjected in Histogram Transformation


channel extraction- masks creation


channel extraction - masks creation


working the masks with histogram transformation


finalizing masks creation


Wavelet transformHDR multiscale transform does not improve a lot the overall image, we will use wavelet transform instead (with luminance mask)


histogram transformation - background


curves transformation - background


starting point


final imageoriginal image :https://www.spacetelescope.org/images/potw1506a/


bonus 1: one ring to rule them all !http://www.spacetelescope.org/images/potw1151a/


how to get the dataDo the search with RA and DEC


LRG-3-757

Date post:	03-Mar-2016
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HST, General Relativity and Einstein Ring

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