In September, 2011, we imaged a bright supernova in M51 violating that galaxy in a 58 hour mega-exposure! Perusing through Astronomy Picture of the Day (APOD) on the night I was imaging the Comet Garradd-M71 rendezvous, I noticed that there is a new supernova discovered in spiral galaxy M101, originally dubbed PTY11kly, now named SN 2011fe. As it got dark on the first night at CAV, I see the Big Dipper sinking in the west and realize that I need to get equilibrated pronto to capture this object. Barry and I were operating the RC from the house when we downloaded the first 10-minute exposure and we immediately recognized the SN when compared to the Mt. Palomar Oschin image (link below). We gathered some luminance and color data but M101 set early. I do not see the bluish color in my data that the Palomar image shows. This supernova was discovered by the Palomar Transient Factory Sky Survey (link below) picked up by computer on August 24. It is a “type Ia” supernova caught early which apparently helps astronomers understand dark energy models better (link below). Being as M101 was so low this month, I needed to add M101 data captured in April 2010 to my current M101-SN data to create a 15 hour LRGB image. I didn’t realize until processing this data that M101 is one of the most prolific H-alpha galaxies. Some of these HII regions are so big and bright, they have their own NGC designations (see HII regions picture above). I had to work to populate the Whirlpool Galaxy with HII data taking 10 extra hours of H-alpha data alone. This M101 image has no added H-alpha data, only LRGB data! Some of these HII regions are huge, in particular NGC 5471, which is 2 orders of magnitude larger and brighter than the largest HII region in the Milky Way! I have also resolved this HII region into multiple stars or mega-star clusters. Also characteristic of M101 is the large bent arm which probably is the result of tidal interaction with other local galaxies. In my naiveté, I always thought M101 and M51 were part of our local Milky Way/Andromeda galaxy group. I now read that M101, M51 and, perhaps Sunflower Galaxy M63, are part of the separate “M101 galaxy group” (link below). These supernova have turned my focus to close Messier galaxies.
In my humble opinion, few things in the universe are more beautiful than a symmetrical face-on spiral galaxy. I remember as a teenager seeing professional images of M101 in Ursa Major and wondering why it was “defective” with one bent arm. Astronomer Chip Arp included M101 in his Atlas of Peculiar Galaxies (1966) as “Arp 26” because of that “heavy arm”. Wonder if Arp knew at that time that this is due to tidal interaction with another galaxy or galaxies?? Now that I (and the rest of the world) knows that this is the explanation for the strange arm in M101, I ponder which galaxy is responsible. Apparently, M101 is one of a group of about 9 galaxies (link below) and some people think it was an encounter with NGC 5474 (outside the field of my image) that caused the damage. Other people think it may be an interaction with biggies such as M63 or even M51! I add no clarity to this mystery by imaging M101, but I had fun this April at CAV ripping the blue arms and H-alpha regions using the RCOS for about 15 hours total at -25 degrees C. with the Apogee U16M. This is an LRGB image with 11 hours of luminance 1X1 and not enough RGB totaling about 4 hours at 2X2. Since I have weak color data, Tony Hallas helped me process this to enhance the color and keep color noise at bay. Also above, an inverted M101 image which also shows a bunch of NGC objects within the spiral arms of M101 accompanied by multiple distant galaxies including PGC 2469762 at 18th mag! One of these objects (NGC 5471) is a giant H-alpha conglomerate that also is very bright in ultraviolet light (see APOD link below). When I look at M101 visually through my 13-inch Dob, it is a faint smudge. My CCD detector sees a bit more!
http://apod.nasa.gov/apod/ap110826.html — M101 supernova APOD
http://www.astro.caltech.edu/ptf/ — Palomar Transient Factory website
http://en.wikipedia.org/wiki/SN_2011fe — SN 2011fe wiki info
http://www.robgendlerastropics.com/M101text.html — Interesting info on M101 – Gendler
http://www.robgendlerastropics.com/M101-HST-Gendler.html — Gendler’s amazing reprocess of Hubble Space Telescope M101!!!
http://www.atlasoftheuniverse.com/galgrps/m101.html – Galaxies in M101 Group – see perturbed NGC 5474.
http://www.daviddarling.info/encyclopedia/M/M101.html – Nice Spitzer IR image!
http://www.cosmicastronomy.com/m101-uv.htm – Amazing UV images of M101!
http://coolcosmos.ipac.caltech.edu/cosmic_classroom/multiwavelength_astronomy/multiwavelength_museum/m101.html – Multiwavelength Bonanza!!
http://apod.nasa.gov/apod/ap000610.html – WOW! The brightest UV source is NGC 5471!!