Messier 77 was one of six galaxies studied by
Carl Seyfert in 1943 as examples of a new class of galaxies that now bears his name (the other galaxies in Seyfert's initial list were NGC 1275, 3516, 4051, 4151, and 7469).
Seyfert galaxies are closely related to quasars (which were not discovered until the late 1950s), with very luminous "active" galactic nuclei that are now understood to be powered by the accretion of matter onto their super-massive blackholes. Seyferts are
characterized by very prominent and strongly-broadened emission lines in their spectra. M77 is one of the closest and brightest Seyferts, was one of the very first galaxies to have its spectrum measured, and the first to be found with emission lines, which were discovered in 1908 by then-graduate student Edward Fath.
I found the image processing for M77 to be extremely challenging, mostly owing to the very high surface-brightness of the galaxy's core and tightly-wound disk relative to its expansive ring-like outer spirals. I needed an excruciating amount of trial and error to find a way to compress the dynamic range so as to bring out the intricate small-scale structures in the core and disk, without getting a result that looked too harsh (here's hoping that that's not the case here!), while keeping the colour from getting washed out.
The image is the result of just under 17 hours of exposures that passed my cuts on image quality (about 70% of the full telescope time), divided about equally between luminance and RGB (all unbinned). I took part of the data in January 2021, with most of it collected in the fall of 2021 and January of this year (eight nights in all). The final image scale is about 0.62"/pixel, and the FOV is just over 26' on a side.
Incidentally, the phrase
"The Original Six" carries special meaning for aficionados of one of the
two national sports of Canada.
Comments