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Cheshire cat galaxy group,  SDSS J1038+4849, gravitational lens, 



    
        

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Cheshire cat galaxy group, SDSS J1038+4849, gravitational lens

Getting plate-solving status, please wait...
Cheshire cat galaxy group,  SDSS J1038+4849, gravitational lens, 



    
        

            Morten la Cour

Cheshire cat galaxy group, SDSS J1038+4849, gravitational lens

Acquisition details

Dates:
March 16, 2021
Frames:
374×300(31h 10′)
Integration:
31h 10′
Avg. Moon age:
2.82 days
Avg. Moon phase:
8.75%

Basic astrometry details

Astrometry.net job: 4465660

Resolution: 1533x1140

File size: 778.7 KB

Locations: Halsnæs, Hundested, Denmark

Data source: Backyard

Description

This iconic target represent a gravitational lens, where the two foreground galaxies SDSS J1038+4849 lens four background galaxies into arc shaped structures, where the weakest is ABmag 23.55. The entire lens is known as Hubble's smiling lens. More data about this lens and several others can be found here https://www.researchgate.net/publication/231037045_GeminiGMOS_Spectroscopy_of_26_Strong_Lensing_Selected_Galaxy_Cluster_Cores

This image is taken in several nights in Feb->March 2021 from a SQM-L 21.3->21.6 sky in Denmark. The elevation is 17 above sea level.

The electron flux into the 4.54x4.54 micron pixels from the weakest arc is 0.65 electron pr minute. The background flux was 92.5 electrons pr pixels. The pixel resolution of the setup is 0.846 "/pix, and the gain is 0.156 electrons/ADU. Hence with a QE of 60% this corresponds to an photon flux of the weakest arc of 1.5 photon/min on a background of 215.4 photons/min. Some integration time is needed in order to obtain a resonable image.

The image is assembled from 321 300s L + 24 600s RGB subs. Also around 35 5s RDB subs were included to improve star colour. Drizzle integration in PI. The final image is resampled 200% to a resolution of 0.22 2/pix. The lens itself is around 20” in diameter.

Comments

Histogram

Cheshire cat galaxy group,  SDSS J1038+4849, gravitational lens, 



    
        

            Morten la Cour