Deep image of the Sombrero Galaxy and a swarm of globular clusters

[SkyViking]

Hi All,

Following on from my recent dabbling in globular clusters I decided to expand my globular collection slightly :P
I gathered some more data for my Sombrero galaxy image and managed to identify 136 globular clusters around it, with some down to magnitude 22+.
In the background numerous distant galaxies can be seen, many of them clumped together in groups. Also, what appears to be a faint tidal tail of the Sombrero is visible near the middle of the bottom edge of the image (between globulars #82 and #99). This is likely an ancient remnant trail of a captured dwarf galaxy.

Link to annotated full res image (1MB) is here: http://www.pbase.com/rolfolsen/image/143968106/original
(Including list with details of all 136 globulars)

Link to unannotated full res image (1MB) is here: http://www.pbase.com/rolfolsen/image/143968104/original

Image details:
Date: 19th April, 22nd and 24th May 2012
Exposure: LRGB: 210:17:17:17m, total 4hrs 21mins
Telescope: 10" Serrurier Truss Newtonian
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand

About the image:
The Sombrero galaxy, or Messier 104, is a giant Sa type disk galaxy viewed from just above its equatorial plane and outlined by a prominent dark rim of obscuring dust. The central bulge is unusually bright and extended, and orbiting the galaxy is one of the largest known populations of globular clusters, containing up to 1900 members. In comparison our own Milky Way galaxy has only around 150-200 such clusters. Nearby prime examples of these are Omega Centauri, Messier 4 and NGC6752.
Highlighted in this image are 136 of the Sombrero's brightest globulars, ranging in V magnitudes from 17.5 to 22+. The names and magnitude details of these clusters are given in the table (from SIMBAD). Some of these globulars are very large and one is classified as a separate Ultra Compact Dwarf galaxy, SUCD1, the closest known example of such an object. It is not known how the Sombrero amassed such a large number of globular clusters. This is normally a more typical feature of large elliptical galaxies. For example up to 12,000 globular clusters are orbiting the giant elliptical galaxy Messier 87.
The Sombrero Galaxy also contains a supermassive black hole of one billion solar masses - one of the most massive black holes among nearby galaxies. The galaxy lies some 30 million light years away in the direction of the constellation Virgo.

Hope you enjoy it. This was certainly a fun project, though surprisingly laborious to mark and match all these faint clusters.:lol:
Comments and critique welcome as usual.

Regards,
Rolf

[Octane]

Wow, looking fantastic!

H

[RobF]

Top stuff Rolf. Way beyond anyone else's Sombrero mapping notes I believe (Mike?). I'm not really familiar with Simbad - how the heck did you get it to cough up the detail for those globs by the way? When I look up M104 I don't see that data linked ? :question:

[alpal]

What great work you have acomplished.
That's a really interesting set of photos.

[jjjnettie]

:D Well done!! Who would have thought there were so many?

[Forgey]

Fantastic work Rolf !

[Liz]

Wow, fabulous stuff Rolf!! :thumbsup:

[jsmoraes]

Very good work. Excellent idea mark the clusters. I never saw one like. Congratulations:thumbsup:

[ngcles]

Hi Rolf & All,

Wow, that is quite incredible. Congratulations.

Best,

Les D

[multiweb]

Excellent work and presentation Rolf. Kudos to you. :thumbsup:

[Dennis]

I love these cosmic gems that you continue to dazzle us with; top work Rolf, a fabulous write up and excellent images.

Cheers

Dennis

[madbadgalaxyman]

Amazing image.

The Ultra-Compact Dwarf (UCD) galaxy is extremely obvious!

This new type of object was only first described in the year 2000, though there is some dispute as to who noticed them first..... and when.

"ultra-compact dwarf" is the exact way that the discoverers usually refer to these objects. But I suppose the dash in the name is somewhat unnecessary.

At least, the publication in the scientific literature, as a new type of galaxy, dates to the year 2000.

The newness of this discovery should make us aware that deep amateur images like Rolf's could well be hiding other surprises!

Here is a paper on UCD galaxies, illustrating how they compare to globular clusters and dwarf spheroidal galaxies:

[bkm2304]

Sorry, but I'm a but thick; ..which one is the UCD???

Richard the dim (mag 22.2).:question:

[Paul Haese]

Lovely image Rolf, heaps of detail and great colour. If there were anything to critique it is the noise. Get that under control and this is one hell of an image. Love the detail in the dust lanes. One imaging target I keep missing each year, you have made me put this higher up the list. Well done.

[strongmanmike]

Great stuff Rolf, you've got detail and depth there - no need to be aesthetically perfect IMO as seeing such info is much more interesting :thumbsup:. Excellent to know there are that many globs around M104 :eyepop: I knew there were a few...

I don't think that is the tidal tail at the bottom though, I think that is a faint irregular dwarf galaxy? The tidal tail is lower down

I got my less extensive GC list straight from another image someone had compiled rather than from Simbad. Of course my full frame is a much larger field and we seem to have gone about as deep as each other (Mag 22 - wow!) so I'd be interested to know how many globs are in my field now :eyepop: I'll PM you :)

Mike

[mental4astro]

Daahhh, me too, :confused2:.

Is it No. 36 or 75? :help:

Oh, yeah, good work too, Rolf! :lol: :thumbsup:

[mental4astro]

Daahhh, found it! It's listed in the first link!

It is No. 75!

I was close, real close. :rolleyes:

Rolf, this image and list will proove quite handy when trying to visually nail any of these beasties! Fantastic excuse to NEED to get a bigger scope. So cool!!!!!!!!

[John Hothersall]

Thats great work picking up GC's so faint down to 22nd mag and a comprehensive list, this galaxy is rather unusual with several thousand GC unlike the Milkyways 158!

John.

[stevous67]

Well done and creative to pull out the very fine detail. Nice work.

Steve :thumbsup:

[Stevec35]

An impressive achievement to say the least.

Cheers

Steve

[Nikolas]

That is pretty awe inspiring.
What is it like to look at visually?

[alexandre]

Hello Rolf !


this is very beautiful, right on my screen, a bit too much noise around the galaxy!
But it's a good job!: Thumbsup:

see you soon;)
alex

[marco]

Almost missed this one! Amazing and painstaking work Rob, you deserves the accolades! Once again you show me what we can do with data colelcted with non professional telescopes!

Marco

[Shiraz]

Stunning project Rolf.
for interest, was the image taken with the new optics or the original? Either way, it is really high res. regards Ray

[atalas]

Great work!well done.

[madbadgalaxyman]

Here are some "Fast Facts" about the globulars of M104, taken from this preprint of a paper:
arxiv: 0909.4805 (which was published in the MNRAS around about year 2009).

(the authors are: Harris, Spitler, Forbes, and Bailin)
(Lee Spitler and Duncan Forbes are at Swinburne University)
(Australia's Duncan Forbes is one of the world authorities on Globular clusters. William Harris is virtually "Mr Globular"; he has worked on them all his long life.)

Q. How many globular clusters in total?
A. One estimate is 1,900
(As of 2009, M104 was the spiral galaxy with the largest known population of globular clusters.)

Q. How far away is M104?
A. A modern "compromise" distance is 9.0 megaparsecs (= 29.3 million light years).

Q. Do the globulars of M104 resemble the standard "old"(>= 8 billion years old) globular clusters of the Milky Way, M31, and other nearby galaxies?
A. Yes! Colours, sizes, & luminosities, are all very similar.
(I am not aware of any spectroscopy of the globulars of M104, so we could still get some surprises when it comes to age estimates, but then I am 3 years behind with my reading!)

Q. Are M104 and its globulars significantly affected by the dimming and reddening of its light by the dust within our own Galaxy?
A. No. The foreground Visual extinction is probably only about 0.15 magnitudes.

Q. How big are the globulars of M104, in angular terms, and in real physical dimensions?
A. The radius enclosing half of the total light is in the range 1-5 parsecs, for these clusters, which means that they are essentially stellar sources when seen with ground-based telescopes. But.....Hubble Space Telescope can partly resolve the globulars of M104. The absolute maximum angular dimension of one of these globulars is 0.1 arcsec for the faintest ones and about 0.5 arcsec for the very brightest ones.

Q. Can you see any of these clusters visually in a 20 inch telescope?
A. I believe that the answer to this question is a decisive "no!!"; in fact, I have already addressed this question in another forum, but I need to look it up.

Best regards,
from mad galaxy man

[TheDecepticon]

Nice 104! Great shot!:D

[madbadgalaxyman]

Further to previous post regarding the UCD galaxy associated with M104, this UCD was studied by Hau et al., in

2009, MNRAS, volume 394, p.97

(this paper is available as a preprint, at //arxiv.org)
(look for the preprint called....... arxiv: 0901.1693)

They find that the half-light diameter of the UCD is about three times that of one of the biggest "standard globulars" associated with M104.

Their mass estimate for the UCD is 33 million solar masses.
In comparison, the biggest "standard globular clusters" weigh in at 5-10 million solar masses.

Interestingly, they find no requirement for dark matter to hold together this UCD, and to stop it from dispersing. However, in my view, the internal kinematics of this object do need further study so as to confirm this finding.

The only distinguishing factor between the very smallest galaxies and the very largest globulars is often the fact that , by definition, dwarf galaxies would fall apart if it were not for the gravity of the unknown "dark matter".

Oh, and one more thing.......
the total visual (actually V-band) magnitude of the UCD is 17.6

[PeterM]

Just caught this today Rolf, OMG as jaw hits the ground, gobsmacked, but then I do like galaxies...

[midnight]

Thoroughly enjoyed your image Rolf and the effort gone into it.

Darrin...

[iceman]

That's quite an image Rolf, impressive indeed!

[SkyViking]

Thank you H :) Always glad to provide something interesting.


Thanks Rob, I used the CDS viewer: http://cdsweb.u-strasbg.fr/SimPlay/#target=M%20104&lp=true&rp=true&bp=true
On the right side you can turn on/off the various object types, globulars are under 'Other types'


Thank you, glad you liked it :)


Thanks JJJ, I was surprised with the numbers too!


Thank you Paula :)


Thanks Liz, glad you enjoyed it :)


Thanks very much Jorge, it certainly does put the galaxy in a different perspective when viewing it like this.


Thank you Les, I'm always glad to be able to show something a bit different :)


Thanks very much Marc! :)


Thank you Dennis, much appreciated. This one took a while to put together as you can imagine :P


Thank you Robert for your always thorough information - yes the UCD is apparently rather unique, it's very interesting.


Alex beat me to it :) but yes it's #75, it's the brightest on the list.


Thanks very much Paul, yes I pushed the data to the limit here to bring out the globulars. I'd prefer more hours on this one but it was not to be. I intend to gather more data in the future though so I can add to it. In the meantime I could maybe make a repro where the background is not stretched as much, really just to feature M104 itself.


Thank you Mike, and thanks for the discussion, yeah the tidal tail you imaged is further down and this is something else. Difficult to say what, so maybe a dwarf galaxy. It doesn't seem to be catalogued :shrug:




Thanks Alex, I see you found the UCD :) Good luck with the visual hunt, I'll look forward to the observation report... ;)


Thank you John, glad you enjoyed it. Yes M104 it is a rather unusual galaxy, and a beautiful one too.


Thanks Steve :)


Thanks very much Steve, it's always fun to go off the beaten path :)


Thanks Nikolas, visually it's quite nice in my 10" scope. I can see the dark dust lane easily and a bright core.


Thanks Alex, yes it was stretched to the max to show off the globulars. I need more data, so I'll collect it little by little.


Thanks a lot Marco, there is so much out there to look at and I think in most areas we as amateurs have only scratched the surface of what's possible.


Thank you Ray, this was taken with the old optics. I reused the optics when I built my new scope, but I'm planning to get a new primary mirror soon.


Thank you Louie :)


Thanks Graham! :)


Thanks very much Peter. There is nothing like a nice galaxy is there, I like them too :D


Thank you Darrin, quite an effort but it was worth it I think and I had fun doing it :)


Thank you Mike, glad you enjoyed it :)

[frenchbluehour]

WOW:) love these images :) inspiring indeed :)

[Suzy]

:scared2: Makes me weak in the knees seeing this. What an incredible, jaw dropping image!
I saw this pic a while back and it stuck in my head so I went searching for it and voila here I am now bringing up an old thread. :P
It's just been posted on the IIS facebook page, Rolf. And thanks for all the information you added- very informative and helped me no end when it came to sharing it. :lol:

[frenchbluehour]

Yes... FB that's where I just viewed these amazing images.. Didn't realise until now this was an old thread...

[Suzy]

Great avatar Nicole- W.W. is my all time hero! :D

Old threads are often worth bringing back up- its such a shame to see some great pics and info get buried- a resurrection brings it back to the attention to those who missed it. That's one of the great things about this forum- the search feature! :D Even tho the pic is a few years old, it still holds its own in being awesome. :D Glad you enjoyed the image on fb. ;):)

Rolf, Carl said on facebook that #75 is SUCD1.
And Whoa, digging around to find more info on SUCD1, I came across the Universe Today article (http://www.universetoday.com/95801/astrophoto-incredible-deep-view-of-globular-clusters-swarming-the-sombrero-galaxy/) on this image- congratulations & well done! Albeit belated lol.

[frenchbluehour]

Thanks Suzy .... :D .... WW is mine too..

[E_ri_k]

Wow, stunning image! The galaxy has a beautiful glow to it, lots of detail in that band of dust :thumbsup:
Erik

[ZeroID]

That ... is ... just ... insane ....

Thanks Rolf for the pic and information and Suzy for the 'resurrection' ..

Insane I say ...... just insane ...

[SpaceNoob]

wow! :D

crazy detail there.

[SkyViking]

Thanks Suzy, and thank you very much everyone for your comments. I'm actually hoping to redo this at some stage with a lot more imaging time. Hopefully I'll get around to it once my new 12.5" scope is ready.