First of all, I really like today's APOD!
M63. Photo: Thomas M. Bisque.
However, a picture like today's APOD often inspires me to find other pictures of the same object that shows different aspects and properties of the object in question. The first pictures of M63 that I can remember looked much like the picture at upper left: They were black and white pictures that showed M63 as an overexposed center surrounded by a relatively dark dusty disk with a spiral pattern and some scattered embedded bright knots. The next pictures to arrive were those that looked like the one at right: M63 was now in color, with a bright inner yellow ring with an inner dust lane, surrounding an even brighter yellow nuclear region. The outer ring was still dark and spiral-patterned with scattered knots embedded in it.
M63 in B, V and Hα. Photo: Subaru Telescope.
Interestingly, M63 really is
pretty much the same color all over, or relatively so. The Subaru Telescope image makes M63 look rather grey, with small splotches of pink from emission nebulas. The Hubble Telescope image, which enhances the blue and near infrared features of M63 because of the filters used, shows individual stars in the inner ring of M63 as blue grains of sand, scattered among, and alternating with, brown dust lanes.
M63 in infrared light. Photo: Spitzer/Médéric Boquien.
M63 in ultraviolet light. Photo: GALEX.
Let's take a look at M63 through infrared and ultraviolet filters. In the infrared Spitzer picture at left, we can see that many of the orange splotches correspond to red Hα nebulas seen in the Subaru Telescope image. But the two deep red sources at left in the Spitzer image can't be matched with anything in the Subaru image.
The ultraviolet image from GALEX shows the hot stars and other ultraviolet sources in M63. Just maybe, the two red sources at left in the Spitzer image can be matched with blue sources in the GALEX image. Note the outlying blue arms or stellar streams in the GALEX image, which demonstrates the fact that star formation is taking place well outside the luminous disk of M63.
Messier 63 Stellar Tidal Stream in the Halo.
Credit: Michele Trungadi / Giuseppe Donatiello (process)
Finally, take a look at this set of pictures of the nature of the halo of M63. The top right picture is by far the most interesting to me. M63 is surrounded by extended stellar streams. My guess is that these stellar streams are the remnants of small galaxies that have been cannibalized by M63.
Note in all pictures the small bulge and the small but bright core of M63. If we are to believe Wikipedia
, there might be a black hole in the center with a mass of almost a billion solar masses.