ARP GALAXIES

[Mike JW]

Arp 28 (NGC 7678) (VV 359 - a peculiar galaxy) is to be found in Pegasus. Dr Arp put it in his group of Spiral Galaxies with a heavy arm and it lies about 140 million lyrs away. Colour images show it to be quite blue - it is a starburst galaxy and a Seyfert 2 (luminous nucleus), classified as SAB(rs)c. The heavy arm is the straight/wide arm leading down to the star and I just picked up a couple of star forming regions. The arm going left to right/up also tends to be straight and again I picked up some of the star forming regions. The galaxy has an extensive fainter halo - hinted at in my shot. Presumably this galaxy has had a close encounter to cause the straightened arms and starburst.

 

Mike

[roelb]

My trials on Arp 28

Evo 8 @ F/5

ASI290MM

ASI533MC-Pro

[Mike JW]

Hi Roel,

As always , thank you for adding in your shots. I much prefer the monocrhome - some good detail in that shot.

Cheers,

Mike

[Mike JW]

Earlier in the thread I posted Arp 278. Last night I decided to revisit it to get a more detailed shot. The pair are both known as NGC 7253 and are spirals about the size of our galaxy.

As they smash into each other stars have been flung everywhere - pleased to get the triangular 'star sail' of disturbed star linking the two galaxies. Also delighted to get a hint of the twisted ends of the galaxies as yet more stars get flung about. Just picking up hints of the disrupted/lumpy central zones and also the dark lanes in both galaxies.

Well worth the revisit.

[roelb]

Here 2 images from Arp 278

Both with Evo 8 @ F/5

First with ASI290MM

Second with ASI533MC

[Mike JW]

Three for the price of one - Arps 48, 119 and 88 in one shot. Located in Pisces.

Arp 48 is bottom left. Arp 119 is the obvious central pair and Arp 88 is the very faint pair to the right.

Arp 48 is classed as spiral with low surface brightness                  Arp 119 is and elliptical disturbing a spiral

companion on its arm.

 

 

 

 

 

 

 

 

 

 

 

Arp 88 is a spiral with a high surface brightness companion 

on its arm.

 

 

 

 

 

 

 

 

 

 

Mike

[Martin Meredith]

Its a value-for-money field, that's for sure. Here's mine from 2020 (doesn't add anything to yours but interesting to see what a smaller scope can do, albeit with a longer exposure)

[Martin Meredith]

Not sure if we've had Arp 135 (NGC 1023 + 1023A) yet but here is a 5m capture from tonight.

This is now thought to be an interacting pair (Arp classified it as "nearby fragments" and it had also been hypothesised as an asymmetric spiral arm). See [1] for an early paper. The main galaxy is type SB(rs)0, and its companion (irregular Magellanic type?) lies at the right hand end in this shot. In Aladin the companion has a distinctly blue/grey tinge, making me wish I'd added some colour to this capture.

A 2022 paper [2] found 523 globular cluster candidates in NGC 1023, finds 2 spiral arms, and suggests that the centre has been displaced due to the interaction.

Following the chain of stars beyond at the right hand end there is a star which appears to be bathed in a fuzzy glow which, according to Aladin, is the mag 16.3 9(R) galaxy PGC 10169.

[1] 

[2] https://www.aanda.org/articles/aa/full_html/2022/08/aa42402-21/aa42402-21.html

 

[Mike JW]

Lovely to see this Arp again. By reducing the brightness I picked up hint of the arms around the core. Also my shot clearly shows PGC 10169 and always nice to pick up a quasar.

Mike

[catburglar]

My first night of EEVA for some time. Took a bit of fettling to get the reducer/camera/collimation sorted after my recent round of planetary observing with the SCT...

By the time 'd got everything working again, the skies were becoming hazy in the west and south, so I had to pick a target towards North- Arp 25 (aka NGC 2276) in Cepheus is an almost face on spiral that looks to have been distorted by an interaction with a near neighbour. The prominent star forming regions in the spiral arms also point to an interaction with a neighbouring galaxy. Wikipedia suggests that the interacting galaxy is the prominent elliptical galaxy NGC 2300 (aka Arp 114) at the 8 o'clock position in the screen capture. This seems unlikely to me given the different redshifts found in SIMBAD. Using a H_o value of 70.8 km/s/Mpc gives distance of 110Mly for Arp 25 and circa 88Mly for Arp 114.  Arp 25 is also home to 8 ultraluminous x-ray sources- one of them being an intermediate mass (50,000 solar mass) black hole according to a study with the Chandra observatory. Apparently this is thought to be captured from a previous collision with a dwarf galaxy.

 

[Mike JW]

Well done, good to take a look at the Arps and to ponder what is going on with the galaxies. It does seem to be uncertain as what is causing the disturbance.

Enjoy your EEVA journey - I have sold my gear - age catching up on me........time to move on.

Mike

[Bill S]

A bit of an Arpathon. Just a few hours of observing - picking up some objects that I have not looked at before or have not realised they were Arp galaxies.

Arp 89 NGC 2648. PGC 24469 is visible just to the side. Some interaction going on.

 

NGC 2375 interacting with 2735A. About 175 million light years away.

 

 

 

 

I like the long swirly arms on Arp 243. This is NGC 2623. Wikipedia tells us NGC 2623 is the result of two spiral galaxies that have merged. Scientists believe that this situation is similar to what will occur to the Milky Way, which contains the Solar System, and the neighbouring galaxy, the Andromeda Galaxy in four billion years. Something to look forward to!

 

Arp 247 is a galxy cluster IC 2338, UGC 04383 and IC 2339.

Arp 215 is NGC 2782. It is a Seyfert 2 galaxy. In other words an active galaxy - the 2 designation refers to spectral characteristics. They have a supermassive black hole with an active accretion disc.



Arp 315 is three galaxies – NGC 2830, 2831 and 2832 – from right to left. These, along with 80 more are part of Abell 779. Located about 300 million light years away.




Arp 283 is NGC 2798 and 2799 and they look to be interacting. About 85 million light years away.



Arp 202 is NGC 2719 and 2719A. 

NGC 3395 was the Webb Deep Sky Soc Galaxy of the Month for March 2023. Also known as Arp 270 and VV 246. The interesting article on the Webb DSS site (https://webbdeepsky.com/galaxies/2023/) explains that it is thought that the galaxies are in the early stages of interaction.

OK, that's quite enough for now!

 

[Mike JW]

Excellent collection and such good results. I have just checked against my archive of Arps and none of mine add anymore details, despite using the 15.

Mike

[Martin Meredith]

What a fantastic session (and great to see the Lodestar X2 delivering such excellent results -- it must be at around 10 years since it was released). I haven't done much EEVA recently, preferring some simple 10x50 binocular views, but your post inspires me to get the kit out under the stars again. Arp 283 is a particular favourite due to the placement of the pair of bright stars, echoing the galaxies and somehow emphasising the differential in distance.

Martin

[Martin Meredith]

Here is Arp 242 from last night, one of several I observed in Coma. Better known perhaps as The Mice, this pair of galaxies is classified as 'appearance of fission'. The two galaxy cores have some structure in the shot, and the fainter tail of NGC 4676B is an interesting challenge to pull out in this 5 minute view.

(Info on shot except for binning, which was 2x2; and ignore seeing estimate in favour of automatically estimated FWHM value)

[Bill S]

Arp 242. Ah yes Martin, I thought it looked familiar. Here's a shot from exactly 3 years ago. A bit longer exposure and I've inverted it to show the faint tail of NGC 4676B. Did a bit more Arp spotting last night and the night before. I must sort through them.

[Bill S]

And some more Arps (new to me) from a couple of recent sessions. Two nights observing in a row - amazing.

Arp 83

NGC 3799 and 3800. Bright arm probably due to tidal interaction. The disturbance may lead to more star formation.

 

Arp 263

Irregular galaxy. NGC 3239. Arp class Irregular clumps. Described as a bit of a train wreck. See also http://articles.adsabs.harvard.edu/full/1990PASP..102...41K

Arp 94

Arp 94 the large component, NGC 3227, is an unbarred spiral. NGC is a 3226 smaller dwarf elliptical galaxy.

NGC 3227 is a Seyfert with an active galactic nucleus.

Arp 232 is NGC 2911 and was classified by Arp as being neither spiral nor elliptical.

Arp 307 is NGC 2872, NGC 2873 and NGC 2874. The two larger ones were discovered by William Herschel but it took the 72-inch Birr telescope to see NGC 2873 for the first time.

 

 

Arp 335 – NGC 3509 was classed by Arp as Miscellaneous! It has been described as a possible double (i.e. merging) galaxy but this is debated. A fascinating shape.

 

Arp 43, which is IC 607, is a face on spiral galaxy. It’s rather small in my image but there certainly seems to be quite a lot of detail and it has a bright core.

 

An enjoyable couple of nights.

 

[Martin Meredith]

Another great haul Bill. I dug out my Arp 335 and turned the stretch well up to see if I could extract a bit more from the cores as well as the lower curved tail. There does seem to be quite a bit of detail though some might be foreground stars. There are loads of galaxies in the field, the labelled ones having mags ranging from 16.2 to 18.6. They seem to belong to very different groupings judging by their distance estimates, some around 360 MLyrs (same as the Arp galaxy itself) and others up to 1.6 billion Lyrs. The Saturn-like galaxy (PGC 93108) looks to be part of the Arp group, physically-speaking.