Arp-Madore observations

[Martin Meredith]

The Arp-Madore (AM) catalogue is less well-known than Arp's collection of peculiar galaxies and galaxy groups. It isn't too surprising why: most of the catalogue members are not so easy to see from mid-Northern latitudes (the most northerly member of the catalogue has a declination of a mere -21 degrees 43 minutes). The clue is in the full name of the accompanying book: A Catalogue of Southern Peculiar Galaxies and Associations (1987), Cambridge University Press, the full text of which is (legally!) available at this link in HTML format: http://ned.ipac.caltech.edu/level5/SPGA_Atlas/frames.html

For Northern hemisphere observers, capturing more than a handful of AM catalogue members is going to be a challenge. From the UK for instance most Arp-Madore objects don't rise more than 16 degrees above the horizon at culmination. However, EEVA is made for exactly this kind of challenge! The full catalogue contains 5846 galaxies or groups of galaxies so the situation isn't so bad: there are 174 entries down to -23 degrees and as many as 1285 down to -30 degrees. Quite a few are members of the NGC and IC catalogies too. And there are some real beauties (as well as plenty of very faint/small objects!).

One of the things I like about the AM catalogue is the existence of brief but tantalising notes, such as 

rare/distinctive,hi.s.br. linear object

irregular/disturbed,chaotic spiral w. app. comp'n

interacting; ring; close triple

that make me just want to go out and observe them to see if I can spot these features. And from my experience so far it is sometimes really hard to to do, making it a seriously fun pursuit...

I've set up this thread so that anyone can post their Arp-Madore observations (visual, night vision as well as EEVA) all in one place.

Similarly, if anyone has any Arp-Madore resources, anecdotes, historical references, etc, please feel free to write about them too. And in case this all sounds very Northern-centric, of course it would be fabulous to hear from anyone who has access to the full Southern sky!

You can find the full catalogue here https://vizier.u-strasbg.fr/viz-bin/VizieR-3 but I've spent a few hours mangling that into what I hope is a slightly more useful and augmented format as a comma-separated value format file that can be loaded into spreadsheets etc here: ArpMadoreReduced.csv

In a while I'll start to post some of my recent observations of Arp-Madore objects. Is anyone up for the challenge?

cheers

Martin

[Martin Meredith]

This is AM 0831-224. (Note that the names are an abbreviation of the RA/Dec). This catalogue takes you into some strange places -- I think this is the first time I've observed in Pyxis.

The entry reads: "companion,edge-on sb w. 5 app. comp's" i.e. type Sb with 5 apparent companion galaxies. One of the companions is the Sa type galaxy near the bright star at around 2 o'clock. Two of the other companions are visible but rather faint. What I like about the main galaxy (which is actually NGC 2613) is that it is embedded in a star-rich field, somewhat unusually for galaxies. Some hint of spiral arms is apparent along with quite an extended halo and very bright stellar-like core. This is a rather bright galaxy (mag 11.1) at an estimated 73 million light years distance. The galaxy is very similar in appearance to NGC 3771 in Pegasus if memory serves (next to the 'deer lick' group). It is a massive galaxy whose rotational properties have been studied for a while.

 

Edited April 4, 2020 by Martin Meredith

[Mike JW]

Fascinating. I only heard of this list a few days ago. Looks like I shall have to move along way south! 

Wonderful idea to set up a thread devoted this list. Mike

[Martin Meredith]

Thank you Mike. Yes, there are many advantages to being a little further south from an astronomical point of view!

Here's another AM object (actually, there are 2 AMs here: more on that in a moment).

This is the central region of Abell 1060, better known as the Hydra Cluster, which in turn is part of the Hydra-Centaurus supercluster. The chain of galaxies snake their way between the two bright beacon stars. These stars are HR 4162, mag 4.9, M1 type with a high colour index (1.6) and therefore worth revisiting one day for a look in colour; and HD 91964, mag 6.7 type K4/5, again with a colour index of 1.5. It is a real challenge to control these stars and at the same time see the fainter parts of the galaxies. 

There are 6 NGC galaxies in this shot, labelled on the negative view, and one more just out of shot (and quite a few more in the Abell cluster itself). Hickson 48 is just over 0.5 degree north of the cluster (and Hickson 48 is the 7th most southerly member of that catalogue).

 

What does the Arp-Madore atlas say about this cluster? One 'peculiarity' of the way the data is laid out is that the same AM designation can occur multiple times (in spreadsheet terms, the same identifier can be found on multiple rows). Each row corresponds to one of the objects within the entity (cluster, double, triple etc). In this case there are three entries for AM 1034-271, and they read

cluster (core=dbl. e)
dust; irregular/disturbed; cluster,"cluster (disturbed sp.,m82-type)
peculiar disk; dust,large disturbed sp. w. pec. dust

I find that it isn't always easy to determine which description applies to the cluster and which to the members. The first line obviously does concern the cluster, with two ellipticals at its core (although NGC 3311 is considered to be an intermediate stage E-S0). I initially thought that the second line corresponded to NGC 3312 (type Sb) although it doesn't look very m82-like to me. Looking more closely at the coordinates, I'm now inclined to believe the description applies to NGC 3307 (type S0-a). It seems that the 3rd description denotes the large spiral NGC 3312.

 

Bonus Arp-Madore object!

What about NGC 3314? Well, this innocuous-looking galaxy is not part of AM 1034-271 at all, but has its own AM designation of 1034-272 with the description "rare/distinctive,spindle galaxy = projection?". This is actually the most intriguing object in the entire image. It was discovered as recently as 1999 to be two overlapping galaxies with no physical relationship -- a very rare occurrence for relatively bright galaxies. Given that the Arp-Madore catalogue was compiled prior to 1977, the description seems prescient. The foreground galaxy is a face-on spiral, designated NGC 3314a (type SBab, mag 14.1), against a tilted background spiral, NGC 3314b (type Sc, mag 13.5).

I would like to think that you can just about can make out a hint of the spiral in my shot (see this blowup too, where both the face-on circular structure and perhaps part of a spiral arm is visible):

 

To appreciate how really remarkable the coincidental line-up of these galaxies is, I really recommend taking a look at the beautiful Hubble photo here https://apod.nasa.gov/apod/ap110715.html

Thanks for looking

Martin

[Martin Meredith]

This time we're in Crater at around -23 degrees looking at Arp-Madore 1100-224 (*). This is listed as "close pair, pair of spirals + comp'ns." It isn't very clear to me what the 'companions' part of the description refers to, but we certainly have a pair of quite distinctly-oriented but actually quite similar spirals with a lot of visible structure.

The upper galaxy (N is up here) is NGC 3511, type SABc, quite bright at mag 11.5. This is a type intermediate between a barred (SB) and an unbarred (SA) spiral -- the c refers to how loose the spiral arms are -- in the case, quite loose.

The lower galaxy is mag 11.9 NGC 3513, type SBc, face-on, displaying a bright clear bar and what to my eye looks like an interesting 'overlapping' arms structure although I think it is an artefact -- again, quite loose.  You can imagine that if the two galaxies were oriented in the same way they might look quite similar.

Both galaxies are approximately 50 million light-years distant. Maybe they are included in the 'peculiar' category as potential 'interactees' although I haven't yet been able to find any evidence for this online (admittedly I haven't looked very hard...). The DSS image of NGC 3513 is incredibly blue though, suggesting ongoing intense star formation, perhaps due to an encounter between the two in the past. There are a couple of star-like points in the upper arm that are really bright and I wonder if they are foreground stars in our own galaxy or bright knots in the galaxy itself. Looking at the DSS image I'm inclined to favour the latter.

 

 

Martin

 

(*) Due to the way the catalogue names are based on coordinates, sometimes things which are part of the same AM description appear to have separate AM designations. This is a case in point. Here NGC 3513 is listed as AM 1100-225, but it is clear that the description applies to the pair of galaxies.

Edited April 6, 2020 by Martin Meredith

[Paul M]

On 05/04/2020 at 13:47, Martin Meredith said:

I would like to think that you can just about can make out a hint of the spiral in my shot (see this blowup too, where both the face-on circular structure and perhaps part of a spiral arm is visible):

 

To appreciate how really remarkable the coincidental line-up of these galaxies is, I really recommend taking a look at the beautiful Hubble photo here https://apod.nasa.gov/apod/ap110715.html

The spiral structure of the foreground galaxy must be visible in your image because  I could see what was happening before looking at the impressive image you linked to.

What strikes me about the Hubble image is how the foreground galaxy totally obliterates all detail from the galaxy behind it. Really brings home the density of the dark lanes. Looks like more dark material than star stuff!!

[RobertI]

A fascinating and useful introduction with some great resources, thank you Martin.

You've definitely got some structure of the foreground galaxy, I had to look at a version of the Hubble image which has the nearby star in order to orient myself, but there's definitely some structure there.

 

[Martin Meredith]

Thanks Paul and Rob. Here's another one from a few weeks ago that I enjoyed at the time due to the complex spiral arm structure that we are seeing practically face-on. This is NGC 2835 in Hydra, close to the border with Pyxis, classified in the Arp-Madore catalogue as a 3-armed spiral, and a rather loose one (type Sc). It is quite close at 37 million LYs and bright (mag 11.1, although with a moderate surface brightness of 22.7) and I imagine would be quite spectacular for us in the north if it were not at -22 degrees.

Also in the shot is the triple star B 1989. The closest component has a separation of 1" so no chance of me resolving it, but the other component is nicely-seen. 

 

 

 

 

 

[Xilman]

On 04/04/2020 at 19:00, Martin Meredith said:

The Arp-Madore (AM) catalogue is less well-known than Arp's collection of peculiar galaxies and galaxy groups.

...

ArpMadoreReduced.csvIn a while I'll start to post some of my recent observations of Arp-Madore objects. Is anyone up for the challenge?

Is AM-4 acceptable in this thread, or is it for galaxies only? Reference:

• Barry F. Madore and Halton C. Arp, 1982. A distant cluster in Hydra, AM-4. Publications of the Astronomical Society of the Pacific, Vol. 94, No. 2, p. 40-42 (Feb 1982) https://iopscience.iop.org/article/10.1086/130938/pdf which also includes a finder chart.

I am tracking down obscure globular clusters, both galactic and extra-galactic. Last night was spent imaging Segue 3 and various GCs in M31 and M33. I have got out as far as the Virgo Group in the past. AM-4 is on the to-do list. Balbinot-1  and HVGC-1 have already appeared on the members' pages at britastro.org

Edited November 8, 2020 by Xilman
fomratting and add HVGC-1; add link to pape

[Martin Meredith]

Sounds very interesting. I think it is best to keep this thread for the peculiar galaxies/groups, but there is a thread dedicated to GCs started by Mike JW which would welcome observations of AM-4 and other GCs.

Martin

[Xilman]

Thanks.  Could you post a link, please, because I have not yet found it?

[Martin Meredith]

 

[Xilman]

Thanks!

Unfortunately my work is very much not EEVA.  60-120 minute exposures and severe contrast stretching so that 20-22 mag stars become visible is almost certainly off-topic over there.

I will start a new thread.

Edited November 8, 2020 by Xilman

[Martin Meredith]

I think severe contrast stretching is definitely EEVA (at least potentially; I do it all the time). As for long exposures, I don't think anyone really minds here so long as the intent is observation/astrophysics rather than AP. I've gone nearly up to an hour trying (and failing) to spot z=6 quasars. I'm certainly interesting in hearing about your approach.

Martin

[Mike JW]

13 minutes ago, Martin Meredith said:

I think severe contrast stretching is definitely EEVA (at least potentially; I do it all the time). As for long exposures, I don't think anyone really minds here so long as the intent is observation/astrophysics rather than AP. I've gone nearly up to an hour trying (and failing) to spot z=6 quasars. I'm certainly interesting in hearing about your approach.

Martin

Agree = if the intent is observation, then that is what the EEVA threads are about. Mike