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Interesting galaxies thread


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Galaxy season is upon us and we have threads collecting together galaxy groupings e.g. Arps, VVs, Shakhbazians, WBLs etc, but none for EEVA-style observations of isolated galaxies, so I propose to start one here.

Exemplars might include the well-known Messier galaxies, members of the NGC or IC catalogues, ultra-thin or face-on spirals, or indeed any galaxy that stands out for any reason. It might be embedded in an interesting star field, possess some astrophysical peculiarity or historical relevance, or simply be plain good-looking!

All observations or comments welcome

Martin

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So to get the ball rolling, here's one from very early yesterday, the final observation from a long session during which I observed 20-odd galaxies in a small region of the sky in and around Ursa Major and Draco. This is the galaxy NGC 3726, a late-stage spiral (spiral arms quite loose) which is seen almost face on. Apart from the bright core and knot-laden arms, this one stands out for its large and relatively bright halo. Two of the arms show interesting features: at the right hand side the arm appears to split into a tuning fork, while at the base there is a twig-like branching which seems quite unnatural to my eyes. No doubt high-resolution images will show what is going on, but part of the fun is trying to work it out without seeing the Hubble view. I'll see if I can find out more and add to the thread later.

Since getting the local plate-solving and annotation side going I've been enjoying seeing what else is in the field. I have the one million quasar catalogue loaded so inevitably in most fields there are a few quasars, but often they are too faint for my setup. Unusually, on this occasion there are 6 that I think I have just about caught a few photons from. Their magnitudes (mainly blue) and redshifts are shown. In fields with lots of quasars, detecting the faint points of light is an interesting pastime to see how deep your setup can reach on a given night. I tend to max out at around 20 most nights (at least for short exposures -- I never use long exposures so I can't say what my real limit is), but last night I might just have reached a little further than this (though the evidence for the mag 20.4 quasar is not very strong...).

  1979462772_NGC372614Mar21_13_37_41.jpg.743a63f4c0d2752119e5221359b8790d.jpg 

cheers

Martin

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Hi Martin,

I had just posted 3726 in my long report but here is a differently stretched shot with the jocular circles on it. I was totally focused in the other thread on the galaxy itself and did not even think about what else might have been caught. Interesting to see we picked up the same quasars and I had no idea there were PGC galaxies shining through 3726 (on the right hand side)

Mike

1218120684_NGC372614Mar21_18_20_49.png.16eb7c88351806a29d2ecfb907fc2656.png

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NGC 6503 is in Draco. The reason for posting this galaxy is because of its lonely position in space. It is a dwarf at just 30,000 lyrs across and is a near neighbour at 17 million lyrs away. It lies right at the edge of the Local Void ( a region about 150 million lyrs of no stars or galaxies). Its classification is SAcd - H11, LINER. Its black hole is being starved of material and so emits relatively little energy, hence the LINER designation. I read that our galaxy is slowly being pulled away from the Local Void, I do not know if 6503 is being pulled away as well - how sad to think of it all alone!!! There are some wonderful Hubble images of this galaxy. I was pleased to pick up some of the lumpiness of its appearance which coincides with H11 star forming regions.

687987085_NGC650320Mar21_19_21_03.png.86166973b598a114480e174570db422a.png

Mike

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3 hours ago, Mike JW said:

NGC 6503 is in Draco. The reason for posting this galaxy is because of its lonely position in space. It is a dwarf at just 30,000 lyrs across and is a near neighbour at 17 million lyrs away. It lies right at the edge of the Local Void ( a region about 150 million lyrs of no stars or galaxies). Its classification is SAcd - H11, LINER. Its black hole is being starved of material and so emits relatively little energy, hence the LINER designation. I read that our galaxy is slowly being pulled away from the Local Void, I do not know if 6503 is being pulled away as well - how sad to think of it all alone!!! There are some wonderful Hubble images of this galaxy. I was pleased to pick up some of the lumpiness of its appearance which coincides with H11 star forming regions.

687987085_NGC650320Mar21_19_21_03.png.86166973b598a114480e174570db422a.png

Mike

Lovely image Mike, and as you say, a lot of he "lumpiness" is showing. More data may mean more detail?

Edited by oldfruit
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  • 3 weeks later...

NGC 3423 is a classic spiral - SA(s)cd. it lies about 65 million lyrs away. It has plenty of H11 regions and I enjoy its lumpy appearance due its many star forming regions. The right hand shot indicates (yellow squares) the various mag 16/17 galaxies in the fov. The one indicated by the red lines is a quasar.

This galaxy would be a fine target for a bigger scope.

Testing out the STF 7"/ASI 174 MM camera with this shot - plenty of targets for this size scope.

Mike

1379041019_NGC342306Apr21_08_18_29.png.7d3a48652151963a2f5a989893739e36.png528692452_NGC342306Apr21_08_21_42.png.12b4ffe6366f1ec4009094e8e57a5b97.png

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Last year I posted an observation of NGC 4550. This is unusual and surprised me that it is rotating in two different directions.

 

I have been looking for other examples of this sort of thing.

NGC 4365 is an elliptical galaxy (E3) in Virgo. It's believed to be the result of a merger because it has a distinctly counter rotating core. It is very old, 12 billion years or so. Counter rotating disks are an active area of study and they can result from the merger mechanism (NGC  4365) or accretion (NGC 4550 above). See for example:

https://astrobites.org/2018/09/26/going-against-the-galactic-flow/

Here's my snapshot of it.

167476310_NGC436508Apr21_21_14_07.png.ab9eb55a1ff7743a9b73d38488bb1808.png

 

The smaller galaxy to the upper left is NGC 4370 and I think it looks a bit like a hamburger thanks to its noticeable dust lane. This galaxy has also been the subject of study as an example of of an Early Type Galaxy.  Early type galaxies is a bit of a misleading term because it relates to the original Hubble Tuning Fork diagram and the idea that distinctly spiral galaxies evolved from ellipticals. Just about the opposite of what we now believe. On the other hand ETGs may well be rather old so are early in that sense.

firefox_2021-04-08_21-42-15.thumb.png.098d8f61587ef86e8f536aa9379f3829.png

 

See for example:

https://www.aanda.org/articles/aa/pdf/2015/07/aa26147-15.pdf

Looking at my observation there are some other objects in the field. I was pleased to capture a mag 19 quasar:

python_2021-04-08_21-13-10.thumb.png.aa8aabf8cb3d4bc98a38e96abbbc954d.png

I think that's about enough of this one.

Cheers

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  • 2 weeks later...

What with all the focus on faint tiny stuff we don't see many Messier galaxies in these threads.

I've been going thru some of my recent captures and discovered a few. I sometimes forget how beautiful these can be -- especially M88 which is just hanging there in space. So here's a collage of 6 Messier galaxies live-combined in LRGB, 6-11min exposures. N is up in all cases except for M106 where I adjusted it for purely aesthetic reasons.

top row:

M108 type Sc, inclination 68 degrees, looking like an angry turbulent rotating bed of clouds

M88 type Sb  63 degrees -- surely the perfect inclination?

M105 (type E -- what more is there to say?)

bottom row:

M91 type Sc, appears face on but inclination is listed at 37 degrees, which I suppose explains the asymmetric halo

M106 type Sbc, looks like the Corryvreckan whirlpool, inclination 68 degrees (can this be right?); almost too large for the Lodestar with its extensive outer gas

M64  type SABa, inclination 64 degrees, fascinating inner 'eye' with tons of structure

1834924919_Screenshot2021-04-23at20_56_28.thumb.png.638739d19e812e730ca9d1c1e6967ed3.png

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Hello Martin

Yes, they are all very well worth a look. I'm going to have to do a bit more Jocular LRGB on some of the brighter galaxies. So much to see!

 

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Hi Martin,

Great idea to post a few of the Messier - never cease to fascinate me. As to Corryvreckan - I have felt the pull the currents of that monster on my boat and that was nowhere near the eye of the whirlpool.

Mike

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While looking around the wonderfully rich galaxy hunting ground of Virgo I came across NGC 4535 and decided it was quite pretty. I don't know if that makes it interesting.

 

64822015_NGC453523Apr21_21_01_52.png.eb7046af425f7930fbaa4d0d479f62df.png

 

This is a fine barred spiral (SAB(s)c) or SBc). It's about 54 million light years away and has the nickname The Lost Galaxy or The Lost Galaxy of Copeland. (Leland S. Copeland nicknamed it this in the 1950s because of its ghostly appearance in small telescopes.) Observations of Cepheid variables using the Hubble telescope have helped confirm its distance.

While reading up about this object I came across some posts that referred to it as McLeish's object.

e.g.

https://in-the-sky.org/data/object.php?id=NGC4535

I am convinced this is incorrect. McLeish's object is at declination -66 in Pavo. See for example:

https://ned.ipac.caltech.edu/level5/CATALOGS/naga.html

https://iopscience.iop.org/article/10.1086/301165/pdf

 

The galaxy is at a great angle for appreciating its shape. A fine example of a barred spiral in my opinion.

Bill

 

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I decided to have a look at this object using LRGB. It adds a bit to it perhaps but not a lot. Note that the subs were actually 15 seconds each. Always worth a look.

 

1079894155_NGC453530Apr21_22_29_34.png.edd0806974b68f4982fbdb306f84703d.png

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These are a couple of old favourites that I thought were worth a quick look in LRGB following  Martin Meredith's post earlier in this thread about fairly bright Messier galaxies,

M82 the Cigar Galaxy. I think it always looks a bit angry in colour. A starburst galaxy about 12 million light years away. Clearly many new stars being formed. It's suggested that gravitational interaction with M81 may be an important factor. 15 second subs whatever the snapshot says.

1802202270_Messier8230Apr21_22_33_14.png.bda8f174ffa78bb1723d2524aeecaca3.png

 

I had  a look at its neighbour, M81, while I was in the area. Bode's Galaxy also about 12 million light years away. 15 second subs again.

 

1439039308_Messier8130Apr21_22_34_15.png.4d2499f96fa9d3ac5309c5f903cebd5a.png

It's also quite an active galaxy but more obviously a grand design spiral.

Bill

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Hi Bill, you are quite right that M82 looks angry. I find it interesting to see colour but it sort of seems disappointing compared to non EEVA style  colour shots.. M81 in colour does add to the feel/interest with its blue tint, indicating the abundant star formation.

Mike

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Whilst in Virgo last night I wandered down to M104, so here is the classic view of it (well somebody had to add it into this thread).

183267460_Messier10402May21_08_34_10.png.f8a82c5599d72d10db0196a1b1bebf06.png

and whilst I was in Virgo I went to M 60, (with its partner NGC 4649 is Arp 116). There appears to be uncertainty as to the distance to this pairing, even discussion as to whether 4649 is in front or behind M60.

82239892_Messier6002May21_08_40_15.png.b6c35101742868a13e1375df28c36b8c.png

 

Mike

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NGC 3758

This is an object I was encouraged to look at by a fellow Lincoln Astronomy Society member.

For many years it has been classified as a Seyfert galaxy having an active galactic nucleus (AGN). In fact what makes it really interesting is that it has two cores. The galaxy must be the result of two galaxies merging and at this stage the two nuclei are separate. The galaxy itself is 425 million light years away and the cores are separated by 11,000 light years. The object is also classified as Makarian 739.

I was pleased that my equipment plus software allowed me to observe the two separate nuclei. The nature of this binary AGN has been clarified by several studies including the Swift satellite. Swift's  Burst Alert Telescope looking in X-rays showed that there is a second AGN, which was not apparent in visible, ultraviolet or radio wavelengths.

It has been speculated that eventually the AGNs will merge generating a gravitational wave outburst. (Not in our lifetimes.)

I observed in LRGB although I am not sure this adds a lot to monochrome in this case. The subs were actually 15 seconds each and so you can see I observed with 10 minutes of L with RGB added too. Five 15 second subs were enough to make out the two cores but more subs made things clearer. It's quite a small object so a fair bit of digital zoom has been applied to this snapshot.

 

50994460_NGC375801May21_15_18_58.png.60a8b494e8fc075d7f80d0c16ce42e77.png

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Really interesting capture and information -- thanks! Its amazing to thing that light takes 11000 years to pass from one core to the other. It really puts the distance into some kind of perspective.

[BTW I will try to sort out the exposure not getting recorded in the next release!]

Martin

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