ARP 274 from Hubble

To celebrate my 18th birthday, I decided to process one of my favorite Hubble images! This was taken back in 2009 to celebrate the International Year of Astronomy by WFPC2. Given that it was taken by such a low-sensitivity sensor, this image actually had a whole lot of noise to deal with. I spent a while carefully removing hot pixels and cosmic rays to make the image look better. In case you’re wondering what exactly you’re looking at, here’s a little explanation about the galaxies:

Arp 274 is a system of three galaxies that appear to be partially overlapping in the image, although they may be at somewhat different distances. The spiral shapes of two of these galaxies appear mostly intact. The third galaxy at far left is more compact, but shows evidence of star formation. Two of the three galaxies are forming new stars at a high rate. This is evident in the bright blue knots of star formation that are strung along the arms of the galaxy on the right and along the small galaxy on the left. The largest component is located in the middle of the three. It appears as a spiral galaxy, which may be barred. The entire system resides at about 400 million light-years away from Earth in the constellation Virgo. The colours in this image reflect the intrinsic colour of the different stellar populations that make up the galaxies. Yellowish older stars can be seen in the central bulge of each galaxy. A bright central cluster of stars pinpoint each nucleus. Younger blue stars trace the spiral arms, along with pinkish nebulae that are illuminated by new star formation. Interstellar dust is silhouetted against the starry population. The pair of foreground stars on the right are inside our own Milky Way.

Data details:

All data was taken from the special Hubble proposal 11994: “HST Participation in the IYA 100 Hours of Astronomy”

Red: F814W, F656N
Green: F555W
Blue: F450W

Processing:

All processing was done in pixinsight.

Linear processing:
- The broadband channels were combined into an RGB image and then color calibrated
- the H-alpha data was contiuum subtracted using the broadband F555W filter
- The subtracted H-alpha data was added to the broadband RGB image
- A luminance image was extracted
- The NRGB image was denoised using TGV and MMT
- The luminance image was deconvolved using the RVC algorithm
- The luminance image was denoised
Non-linear Processing:
- The NRGB and lum images were stretched using GHS
- LRGB combination to combine lum and RGB
- Saturation increase of bright unsaturated areas
- HDR multiscale transformation
- Local Histogram equalization
- Saturation increase of bright unsaturated areas
- Noise reduction using MLT
- HDR multiscale transformation
- Sharpening using MMT and unsharpmask
- Curves transformation