ARP GALAXIES

[Martin Meredith]

Nice -- One of the clearest images (EEVA-style) that I've seen of the bridge, and great to see it in a wider context.

BTW Arp 104 is where this thread started so I hope that doesn't mean we're done with the complete catalogue 🙂

Martin

[AKB]

1 hour ago, Martin Meredith said:

I hope that doesn't mean we're done with the complete catalogue

Not a chance!

Here's Arp 162 / NGC 3414, also from last night.  This is mag 11, classified as S0(bar,mult) and has a "diffuse, diagonal filament", clearly seen.  Apparently considered to be 'a "box" or "X" galaxy by Whitmore and Bell (1988)' ... that's something I'm going to have to look up, unless someone here can shed more light on this.

Nearby, we have other delights:

• NGC 3418, S0-a(bar), mag 14.2 at 66 Mly
• NGC 3400, SBa(bar,ring) off to the right in the wide field
• FGC 135A, mag 15.4 at 74 Mly
• a couple of quasars
• dozens of other PGC galaxies

 

 

[Martin Meredith]

Good luck with googling x box galaxy...

I've come across box galaxies a couple of times. I forget what they signify exactly but the X refers to the shape made by the central region, as in NGC 128 (part of VV894)

[Mike JW]

Look up peanut and box shaped galactic bulges.

My Arp 162 does not show any more details but I have picked up mag 18/19 PGC around it.

Mike

Edited April 3, 2022 by Mike JW
added info

[AKB]

2 hours ago, Mike JW said:

peanut and box shaped galactic bulges.

Aha!

Title: The nature of 'box' and 'peanut' shaped galactic bulges
Authors: Shaw, M. A.
Journal: Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711), vol. 229, Dec. 15, 1987, p. 691-706.
Bibliographic Code: 1987MNRAS.229..691S

 

Quote

By box-shaped we mean bulges
whose light distributions show a pronounced cut-off in both galactocentric distance and Z-height,
and hence give the appearance of being square. Peanut-shaped bulges show similar features hut
also possess a depression in isophotal shapes along the minor (rotation) axis of the galaxy, thereby
giving the semblence of a 'figure-of-eight' when viewed in the plane perpendicular to this axis.

Many thanks!

MUCH better than:

16 hours ago, Martin Meredith said:

Good luck with googling x box galaxy...

Quote

Buy MARVEL'S GUARDIANS OF THE GALAXY for X box

 

[Mike JW]

It took me awhile to find the suitable phrase to eliminate chocolate, mobiles, X box.......

From my reading box shaped galactic bulges seem to be associated with bars, also likely to be associated with merger of a small companion which results in stuff flying about leading to bulge that is more of a box shape. I have read that it might just be a line of sight thing in visual wavelengths.

[AKB]

Two for the price of one... Arp 296 and 299.

First of all, the wide field (1º x 0.75º) shows:

• CGCG291-076, top left, Sm(diffuse) mag 14 at 81 Mly
• multple star 11271+5905, half way down RHS, mag 12/13
• PGC 35218, Sbc, mag 15.9 and PGC 2583396, mag 17.1 at 1300 Mly

 

Arp 296

This is PGC 35345 'and companion' which is marked in the atlas as SDSS J1 12850.64+583336.7, but here shown as PGC 2580146 and also, curiously, outside the boundary marked here for the Arp.  Ostensibly, 'double galaxies with long filaments'  Arp notes a "straight filament almost to attachment with arm of spiral". There's nothing visible joining the on any of the plates but the smaller galaxy does at least align towards the other.

 

Arp 299

Again, more confusion.  The main components are shown in the atlas as NGC3690E, NGC 2690W, and IC 694 (to the top right of the group), respectively show there as VV 18a,b, and c.  My worry is that these are labelled in Jocular as VV 118, so is something wrong here?

Arp notes "bright internal knots", and others (Hibbard and Yun, 1999) have studied optical tails beyond Arp's field to the north and south-west.  They're shown as quite extensive in the atlas, but the image there seems to be from a 24" f5 Newtonian, so absolutely no sign of that here.

 

 

   

Edited April 3, 2022 by AKB

[Mike JW]

Hi Tony, my view is the whole of the DSO databases need sorting out and for there to be a final agreed nomenclature.

Leaving that thought to one side. Below is my shot from a year ago and labelled according to NED.

Arp thought IC 694 was part of the main collision of the two galaxies but it is 40 million lyrs further out so currently not involved in the interaction.

VV118 is the notation for the area and given a classification as 'N' = three or more galaxies in a tight group. So which are the three galaxies ? note NED identifies 118e and 118d but does not identify a, b or  c. Your info suggests IC 694 is 'a' which leaves the two NGC 3690 as 'b' and 'c'. I have seen info that labels either of the NGCs as IC 694 and Jocular labels NGC 3690 W as IC 694.  By the way  another reference source suggests IC 694 is VV 118c and not 'a' as in your source. To me this make sense as the two NGCs are the brightest and thus should be 'a and b' 

In reality there are two galaxies carving each other up with the third galaxy (IC 694) currently not in the mix (but might have been in the past because it has very active star formation). VV 118 - ignoring what is now known about IC 694, is thus three tight galaxies and the extras are in fact just part of the big two galaxies (p of g).

All this thinking/reading hopefully will keep dementia at bay? although sifting through the info might actually make me insane, certainly confused.

P.S. - last night I completed my current round of the UMA Arps - a fascinating collection of cosmic wonders.

Mike

[AKB]

22 hours ago, Mike JW said:

All this thinking/reading hopefully will keep dementia at bay?

Well, I certainly hope so! 

Thanks for all that – I turn to many of your posts to gain insight into what are, otherwise, just nice sights, and I do so again in reference this post, a similarly clarifying view of Arp 25 and 114.

 

Here's my observations of these objects from a recent night (April 1 – no joke.)  I can do little to add to your contribution except offer a wider field, dominated my two mag 8 stars HD 51141 (centre) and HD 47976 (top edge) and, hiding off on the LHS, (mag 15) galaxy UCG 3715.  Continuing the naming confusion, the Arp Atlas notes that some sources reverse the naming of NGC 2276 and NGC 2300.  Outside of the Arp grouping, other galaxies include (mag 14) IC 455 at 111 Mly, nicely flatish UGC 3661, and many others.

 

 

   

 

Edited April 4, 2022 by AKB

[Mike JW]

Hi Tony,

Thank you for your kind words. It works so well when we each contribute observations, thoughts, questions and our individual reading up on the object in question.  The quality of your shots as you know make me envious and they inspire me to take a look again at objects I have previously visited.

Mike

[AKB]

There are, of course, some very well-known objects which are Arps... M51 and M101 perhaps the most popular.  So whilst mooching around Canes Venatici at some other familiar favourites, I took a peek at NGC 4627, the dwarf elliptical galaxy, which is the 'calf' of NGC 4631, 'The Whale'.  Together these form Arp 281 (also VV 1156), 'Double galaxies with infall and attraction.'   Relatively featureless, NGC 4627 lies about 13,000 light-years from the wonderfully mottled NGC 4631, which is classed, now, as a barred spiral (used to be Sc?).  The Arp atlas has a splendid image by Robert Gendler using a 12.5" RC and 100 minutes of exposure, but the 10 minutes here captures just a little of that grandeur.

In the wide field, though, we also see NGCs 4656 [SBm(bar,mult) at a mere 17 Mly] and 4657, both part of the larger 4631 galaxy group (all part of VV 1560??.)  Also visible here are FGC 1490 (towards the middle of the LHS) and PGC 42953 (middle of bottom LH quadrant.)

 

 

   

Edited April 5, 2022 by AKB

[Mike JW]

Really interesting to see 4267 - never taken a look at it.

Mike

[catburglar]

Managed another session last night, first in a few weeks. I managed to get a couple of Arps in Leo (just after they transited the meridian which is a better part of my sky due to relatively lower levels of light pollution- but boy to I wish it was darker than it is...

First up is Arp 263- at first glance this looks like a case of David vs Goliath- the small ring galaxy left of and just below centre appears to be shredding the prominent galaxy wrapped around the bright star. However, the narrative in the Cambridge Photographic Atlas of Galaxies suggests that none of the galaxies in the field are responsible for this disruption and suggests that the disrupting galaxy has been entirely "consumed". The images shows a number of bright spots  representing regions of active star formation. 

 

Next up was Arp 316 (aka Gamma Leonis Group or Hickson 44)- or at least I managed to get 3 out of 4 members. The integral sign galaxy (NGC3187) clearly looks to be perturbed by the nearly edge on galaxy (NGC3190) close to centre (both are at circa 79Mly). The elliptical galaxy towards the edge of the field (NGC3193) seems to have distance estimates ranging between 65 Mly and 100+ Mly. This image (http://338arps.com/arp_316.htm) suggests that there is a bridge of material between 3190 and 3193, but it's not visible in my image or in the original Arp catalogue image (to my eyes at least).

[Mike JW]

I have been away on a trip, so just spotted your latest contribution - has fired me up to take another look at Arp 316. Last time I looked (2 years ago) I too failed to pick up the bridge and that was with the C11. I might do better with the 15" Dob.  Must look at Arp 263 with the 15.

Mike

[Martin Meredith]

I missed these too. Here's my Arp 263 from a couple of years ago.

BTW I've made use of a new feature that Steve (from Boulder) implemented in Jocular (thanks!), which is the ability to drag label positions. This will be in the next release. It really helps when there are a bunch of interesting galaxies in the field, as in this case with the CGCG catalogue members.

 

 

[catburglar]

It’s looking clear here for the early part of the night so I may get a chance to have another go at something between darkness and the anticipated arrival of clouds about midnight.🤞

[Mike JW]

Arp 263 - is called by some people the Loony Galaxy; I assume because of its chaotic state as a result of the merger. Interestingly so 91 H11 regions have been identified indicating the on going star formation. It is actually quite small at only 40,000lyrs across and is classified as IB(s)m pec. (s) = transition to a ring, Im = irregular magellanic  type, B = not sure what this refers to? a bar?

Mike

[catburglar]

9 hours ago, Mike JW said:

classified as IB(s)m pec. (s) = transition to a ring, Im = irregular magellanic  type, B = not sure what this refers to? a bar?

Mike- the description of type IB(s)m from https://ned.ipac.caltech.edu/level5/March14/Buta/Buta3.html suggests that you’re correct see the specific quote below.

A special hallmark of the VRHS is the recognition of the Magellanic Clouds as extreme late-type barred spirals of the type SB(s)m that show a characteristic one-armed asymmetry and offset bar (de Vaucouleurs & Freeman 1972). Magellanic irregulars form the last major stage along the VRHS, and are often barred (i.e., classified as type IBm or IB(s)m, implying a subtle spiral variety)

[Mike JW]

Arp 71 is in the Arp classification as a spiral with a high surface brightness companion. Quite possibly it is a line of sight pairing but is obviously part of the wider galaxy group. In this shot it is the pairing in the centre. However this area is rich in interest. The whole area is Abell 2151. Arp 71 is also  VV1791.

Arp 272 is nearby but Jocular has placed the label in correctly. It is where the VV220 label is placed. Arp 272 is a group of three galaxies

Off to the left is the galaxy labelled as Arp 272 in the shot above. It is in fact PGC 057073 and hoorah it is a ring galaxy (outer ring) - (R)SABs, also around the 500 million lyr mark.

and finally on the landscape image is VV 212, which is Arp 122. This pairing are interacting, or have been ( they are about 10 million lyrs apart). Arp grouped them as elliptical or elliptical like galaxy perturbing a spiral (the uppermost galaxy is the spiral that is being perturbed).

Abell 2151 is the whole of my landscape shot and beyond. Many galaxies are about the 500 million lyr mark. A total of 87 galaxies in the group.

and finally, there was me off to bed at 7pm to sleep/rest until just before 11pm. Then out I went into the light late spring/early summer skies of GB on a night of steady  skies and transparent (M13 just naked eye at the zenith). Packed it in at 1am and sorry to abandon the Milky Way going most the way down to Sag. Was it worth it? - absolutely but at my age I am wrecked and need a day to recover.

Mike

 

 

[Martin Meredith]

Abell 2151 is a marvellous group and is one of the few that has me hankering after a larger sensor. One could easily spend an hour or two in the this area alone.

You're right that Arp 272 appears to be wrongly labelled (also the case on my charts). Having checked the Kanipe & Webb Arp book it does mention a naming irregularity and that Arp's original atlas indicates NGC 6054, which is where Jocular places its circle, and indeed Simbad http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ngc+6054&submit=SIMBAD+search agrees with this (erroneous?) designation. All v interesting for the astro-historian no doubt! We're just fortunate to have so much to see in one shot.

Here's mine from earlier this month:

[Mike JW]

Really need Tony's set up for the wide field views in an observatory, then stroll across to the 20" Dob (in the roll off shed) with a suitable camera inserted to take a closer more detailed look and of course all of this gear under mag 7 skies!!!!!!

Abell 2151 - such beauty, awe inspiring.

Mike

[Martin Meredith]

I'm sure we must have had Arp 286 in Virgo before but its a new one for me (at least in the recent past where I've kept records...)

This is in the 'double galaxies with infall and attraction' category, and consists of NGC 5566, 5560 and 5569, in order of brightness.

NGC 5566 is SBab(bar, ring, mult) according to LEDA and SB(r)ab according to the Kanipe & Webb Arp book.

NGC 5560 is SB(bar, mult) for LEDA and SB(s)b pec for Kanipe & Webb

NGC 5569 is SABc(bar, mult) or SAB(rs) cd: -- take your pick.

Either way, this is a very interesting selection of barred spirals that fit easily along the narrow axis of the tiny ASI 290 sensor. 

I would have left this for longer but seeing was worse than 4.5" and detail didn't seem to be improving, but it is one to revisit as there is a lot of structure and extensive faint detail to extract. This image is quite noisy as I've tried to show the extent of the spiral arms in NGC 5566.

 

[Mike JW]

It is a while since I visited this beautiful group. Below is my shot from 2 years ago (pre jocular).

Mike
 

[M40]

Well this is my first on any group of galaxies, not a patch on you boys but I am well pleased. 

ARP286. This was 8 x 30 seconds with an ASI290MM using stellamira 85mm, asi studio, uv/ir cut filter. No processing, no darks, flats or bias frames (I really must learn how to do that)

Things can only get better

Edited June 21, 2022 by M40
spellign

[Mike JW]

Well done. My first attempts went straight into the bin. It makes for a lovely project to visit all the Arps in a year. I have done two rounds. First time with a smaller scope and not using Jocular. Second time using my 15" Dob and stacking the images in Jocular. What you have picked up with your set up is more than I could see visual in my former 20" Dob.

Have fun, enjoy the journey.

Mike