M63 with halo and hint of tidal stream

[Annehouw]

M63 has a remarkable halo and shows a few interesting tidal streams in really deep images. All of this is thought to be the result of mergers with companion  dwarf galaxies (as our own Milky Way has done and still is doing).  A fun fact is that the halo to total mass ratio is about 12 percent, which is the largest ratio in any galaxy known to date*

Unfortunately my Bortle 5 skies do not co-operate in showing the faintest of the faintest of stuff. The halo is OK, but there is only a hint of the brightest of the tidal streams (left side, going in an arc over the top and into the right side).

I spent about 22 hours in imaging this subject. Really bringing out the tidal streams would have taken double that or so. In view of the sparse amount of imaging time here (I have not taken a single exposure between november and march!), I think this should be final.

 

*Monthly Notices of the Royal Astronomical Society, Volume 454, Issue 4, 21 December 2015, Pages 3613–3621 (if you do an internet search with this string, you will find an interesting article on M63, its halo and tidal streams)

 

Edited May 14, 2020 by Annehouw

[tooth_dr]

Fantastic. I didn’t realise M63 had this!

[Annehouw]

...and here is a version processed specifically for the streams. Too noisy to be a nice picture, but it shows the phenomenon (discovered in 1979....). A few hours of processing produces a less grainy appearance 😉 

Edited May 17, 2020 by Annehouw

[tooth_dr]

2 hours ago, Annehouw said:

...and here is a version processed specifically for the streams. Too noisy to be a nice picture, but it shows the phenomenon (discovered in 1979....)

Wow again.  What kit are you using?  Just to see if this is doable lol

[Annehouw]

I am using my (now 20 years old) Hypergraph RC.  It is a 32cm F3.1/F9 system. I normally use in int the F3.1 configuration. See my avatar for a picture of it (in winter dress). Think of it as a sort of Celestron SC with a hyperstar lens (the camera is at the front). It is no longer made as the designer now only makes much bigger scopes for professional use. The speed of the system helps imaging from Bortle 5.  Still, it needs a lot of imaging time to overcome light pollution. I normally stick to targets that are close to zenith to maximize my chances.

I am fairly certain that you can image these streamers with a smaller and/or slower instrument provided you have dark skies. In the case of M63, there might be something else at play. You don't need a lot of exposure time to make a pretty picture of the galaxy. The brightness and the dust lanes, which to my eyes seem to hover in the halo above the plane of the galactic disc, are easily recorded. In astrophotography time is always scarce, so you have to decide when enough is enough. Most people probably do not know the extent of the halo and the streamers and hence stop imaging after a few hours.  To be honest, I did not know of the existence of the streamers. I wanted some of the halo extending from the galaxy disc, but found out that there is more and that's when I started looking for more information. 

[ollypenrice]

These outer parts really are difficult even from a dark site. Good going from Bortle 5. I know you like these tidal streams! 😁

Olly

[Annehouw]

Resurrecting this old thread...

Shortly after I first published this image of M63 showing the tidal stream, I was graciously given many hours of images by Oliver Penrice. Thank you very much, Olly! 

At that time, I was experiencing sort of a processing burnout. I had spent way to many hours behind the screen to bring out M63 and its halo and tidal stream. I have recovered though and I integrated this data into my earlier image. I have attached a inverted black and white version here for the sake of visibitity.

To celebrate this occasion, I did a fairly extensive astrophysical write-up on the subject of tidal streams. I tried to keep it popular, but it does cover a lot of ground in a few short paragraphs. You can find the final colour image and the write-up, with lots of links to further reading here: https://www.astrobin.com/ru40fg/F/