Galaxy of the Month Archive 2020

In this series of articles we draw your attention to galaxies particularly worthly of an observer's time.

• NGC 969 in Triangulum

  December 2020 - Galaxy of the Month

  NGC 969 is part of a trio of galaxies along with NGC 974 and NGC 970 in Triangulum. NGC 969 and 974 were discovered by John Herschel in November 1827 using his 18.3” reflecting telescope. NGC 970 was discovered by Bindon Stoney using the 72” at Birr in September 1850. On the same night he though he saw another object, which was added to the NGC as NGC 971 but this was later shown to be just a star. Some sources however still attribute this number to the faint companion galaxy to NGC 970, including for instance Megastar 5.

  NGC 969 and 974 are listed as part of a 5 galaxy group, listed as WBL 077, that also includes NGC 978, but not NGC 970 as that would appear to be much further in the background. NGC 970 is also listed as an interacting pair in the extended Vorontsov-Velyaminov (VV) catalogue as VV 1034. I am puzzled however because although the WBL catalogue listing does not include NGC 970 as part of the group NASA/IPAC Extragalactic Database (NED) does include it as WBL 077-3.

  Interestingly although NGC 978 is not listed as part of the trio it probably should be as it fits in the same high power field. It too was discovered by John Herschel in 1827. It is also listed as an interacting galaxy in the VV catalogue as VV 1035. It would appear to be interacting with the galaxy listed as NGC 978B. NGC 974 is also gravitationally interacting as it is showing what appears to be long tidal tails or extended spiral arms in deep images.

  The group lies at a distance of perhaps 200 million light-years from us. NGC 969 is classified as an S0, a, lenticular galaxy but shows what appears to be a bar so perhaps SB0 might be a better classification for it. Perhaps surprisingly there does not seem to be a lot of research done specifically on this group. Both NGC 978 and its companion are listed as lenticulars but in the PanSTARRS image it appears there may be a third galaxy associated, either that or there is a knot in NGC 978B.

  Observationally the group maybe a challenge as the brightest galaxy (NGC 969) is around 13th magnitude and then it goes fainter. However, as John Herschel saw them all then (at least the main three) I would hope that a 40cm should be able to pick them up. NGC 970 is likely to be much tougher as that required the Birr 72” to find.

  The main trio is very compact and will take high power if the seeing and condition will allow it. I would be interested to know what power would be needed to visually split NGC 978 and 978B, my suspicion is probably over 300x. I note that the Night Sky Observer's Guide (NSOG) suggests that NGC 969, NGC 974 and NGC 978 should be visible in 30/35cm scopes but suggest that to split NGC 978 A and B would require a 55cm scope at medium power. UK observations by Mark Stuart suggest a 35cm is required for NGC 969 but it was not very prepossessing. He also reported observations of NGC 974 and 978 with the same and larger telescopes that also suggested they did not show much detail.

  Owen Brazell - Galaxy Section Director

• NGC 833 in Cetus

  November 2020 - Galaxy of the Month

  NGC 833 is part of a quartet of galaxies including NGC 833, 835, 838 and 839 that together make up the galaxy group Hickson 16.

  All four were discovered by William Herschel on the same night in November 1785. NGC 833 is also included in the Vorontsov-Velyaminov extended catalogue of interacting galaxies as VV 1007. The original VV catalogue had only 852 members but was extended by his students by adding an extra 1162 systems. The group is also known as Arp 318 and that may consist of the 4 galaxies in the Hickson 16 group as well as NGC 848, which appears to be at the same distance as the others.

  NGC 848 is somewhat fainter than the others and was discovered by Ormond Stone in 1885 and then independently by Swift in 1886. NGC 848 appears to have undergone strong gravitational interactions as well. Arp described it as a part of his group of galaxies with faint, diffuse streamers, peculiar galaxies.

  The group is at a distance of about 160 million light-years. All of the galaxies in the group show signs of interactions and most of the galaxies in the group are mild AGN’s either LINER’s or Seyfert 2 types. There are suggestions that a number of galaxies in the group may have undergone major merger events in the relatively recent past.

  The group is also part of a larger conglomeration of seven galaxies catalogued as LGG 49 which also includes NGC 873 as well, which I am slightly surprised about as it is at least 2 degrees away from the others on the sky.

  NGC 838 and 839 are probably star burst dominated galaxies as they show no signs of the expected continuum of an AGN in X-Ray observations. Observations with the XMM—Newton satellite however suggested that NGC 839 is probably an obscured AGN. Hickson 16 is thought to have one of the highest concentrations of starburst/AGN activity in the local universe. Interestingly all the galaxies in the group appear to be spirals.

  As one of the brighter Hickson groups the core group of HCG 16 should be visible with difficulty in 20-cm but relatively easily in say 37-cm. The galaxy group, including NGC 848, is pretty tight so should be visible in a medium power hyperwide eyepiece, say 250x. The Night Sky Observer's Guide (NSOG) suggests that perhaps 30-cm is required to see them well, although there is no mention of NGC 848 so this may be more difficult to find, perhaps not a surprise as it was missed by Herschel. NGC 835 is the brightest member of the group.

  For observers from the southern UK the group only just makes the 30 degree line so it is best to catch when within two hours of the meridian.

  The group (as Hickson 16) made the Deep Sky Forum (DSF) forum object of the week in 2014. There are also observations of the group at Adventures in Deep Space. For owners of large telescopes there are a number of other faint and probably unrelated galaxies in the field.

  Owen Brazell - Galaxy Section Director

• NGC 128 Group in Pisces

  October 2020 - Galaxy of the Month

  The small group of galaxies around NGC 128 in Pisces, also designated as LGG 6, was first discovered by William Herschel who found NGC 128 itself along with NGC 125 in 1790 using his 18.7” 20 foot reflecting telescope. NGC 126, NGC 127 and NGC 130 had to wait until 1850 when Bindon Stoney discovered them whilst examining the area using Lord Rosse’s 72” telescope.

  The LGG 6 group is composed of 11 galaxies including NGC 128, NGC 126, NGC 127 and NGC 130. Nearby MCG +0-2-45 is also associated with the group.

  NGC 128 itself appears to be interacting with NGC 127 and there is a tidal tail between the two. NGC 128 itself is an interesting galaxy as, although it is classified as a lenticular, it shows a boxy or peanut shaped nucleus with a strange X form. This could be the result of a previous merger or the ongoing interaction between itself and NGC 127. Although NGC 125 is also a disturbed galaxy it does not appear to be associated with NGC 128.

  NGC 125 appears to be a form of shell galaxy. This is shown up well in the image on the CHART32 website. Deep images suggest that NGC 126 also shows some sign of tidal tails so it is also undergoing a gravitational interaction, probably also with NGC 128. It appears that NGC 130 is also interacting with NGC 128 as well.

  There were some suggestions that NGC 125 might also be part of the group but its recession velocity is much larger than the others. The possibility remains however that NGC 128 and 125 have interacted in the past. The interaction of NGC 128 with NGC 127 is thought however to be a relatively recent phenomenon and has produced a counter rotating disk of stars in NGC 128 aligned with NGC 127.

  The interacting part of the group was also catalogued in the Vorontsov-Velyaminov of interacting galaxies as VV 894. The group also makes it into the WBL catalogue of poor clusters as WBL 10 and that group includes NGC 125 but not some of the others included in LGG 6. The group lies at a distance of perhaps 190 million light years from us.

  The group may be a tough one to observe with smaller telescopes. The Night Sky Observer's Guide (NSOG) suggests that only NGC 125 and NGC 128 will be visible in 10-12” scopes whilst the others may need telescopes in the 20” class to see, at least from UK skies. Observations with a 22cm from the UK suggest that NGC 128 was hard and that NGC 125 was not seen. Using a 37cm scope under mediocre skies showed NGC 128 as an edge on and NGC 125 as a circular patch. The other galaxies were not seen.

  

  The group is fairly tight so the use of high power is recommended in order to pick up the fainter members. They should all fit in the field of a modern hyperwide eyepiece at 350x. The fainter MCG member of the group is still close by and will again fit in the same field as the others when using a power around 260x. This is likely to be a challenge however for telescopes in the 20”+ class.

  Owen Brazell - Galaxy Section Director

• NGC 7585 in Aquarius

  September 2020 - Galaxy of the Month

  The small group of galaxies around NGC 7585 (NGC 7576 and NGC 7592) in Aquarius were all discovered by William Herschel. He found NGC 7585 and NGC 7592 in September 1784 but NGC 7576 had to wait until the following year in October 1785 to be picked up, although Herschel did not spot that NGC 7592 was a double galaxy.

  NGC 7585 was later added by Halton Arp to his catalogue of Peculiar galaxies as Arp 223 and by Vorontsov-Velyaminov to his interacting galaxy catalogue as VV 1973. Arp did not spot that NGC 7592 was also an interacting pair although Vorontsov-Velyaminov did and it is classified as VV 731.

  NGC 7585 appears to be a shell galaxy although Arp catalogued in his group of galaxies with amorphous spiral arms. The suggestion is that it is the result of the merger of two galaxies. Its current classification is fairly complex as (R’) SA0 +(s) pec. The suggestion is it is probably a lenticular galaxy.

  The three galaxies in the field do not seem to be related, although NGC 7576 is also a disturbed galaxy, possibly a rare ring one. NGC 7592 is a much more distant object. NGC 7585 itself maybe 145 million light-years away or so. NGC 7576 is, by some measurements, at a similar distance. The RC2 suggests they are a non-interacting pair. NGC 7576 does show up quite brightly in the ultraviolet GALEX survey which normally suggests some kind of star formation activity. Only the nucleus of NGC 7585 shows up in the UV. Both galaxies show up well in the infrared WISE images. Hubble has looked at NGC 7585 and in the near infra-red views with the NIC instrument a strong bar appears to show up.

  Perhaps surprisingly given the nature of the group not much individual research appears to have been done on them. NGC 7592 on the other had has had a lot of work done and the interacting pair have been well imaged in various wavebands by Hubble and shown to be Seyfert type AGN’s. Unfortunately I can’t find a colour processed version of the Hubble images of NGC 7592.

  Observational from UK latitudes these galaxies will be a challenge as they do not rise much above the 30 degree altitude line and will be best observed when on the meridian. Although Luginbuhl and Skiff (L&S) does suggest that NGC 7585 will be visible in good skies with a 25cm Night Sky Observers Guide (NSOG) Vol 1 suggests they are more of a challenge for 30cm+. UK observations of NGC 7585 with 25cm suggest it is not very impressive. I suspect that probably 40cm plus would be needed to see NGC 7592 well and to split them perhaps 55cm plus. None of these galaxies were bright enough to make it into the Herschel I or II lists although NGC 7585 did make it into the Herschel 3 list. The NGC 7585/7576 pair are close enough together to make it into the same field of a modern hyperwide eyepiece at perhaps 260x.

  The Arp 223 pair was also covered in the DeepSkyForum (DSF) Object of the Week for October 20th.

  Owen Brazell - Galaxy Section Director

• NGC 6269 in Hercules

  August 2020 - Galaxy of the Month

  For the August GOM we move to the constellation of Hercules and the small faint group of galaxies around NGC 6269. NGC 6269 is part of a small group of galaxies in Hercules, including NGC 6263, NGC 6264 and NGC 6265, that were originally discovered by Albert Marth using William Lassell’s 48” speculum metal telescope from Malta. The group were independently rediscovered by Stephan in 1871 using the 30” Foucault reflector at Marseille.

  NGC 6264, NGC 6265 and NGC 6269 are included as part of a 3 galaxy physical group catalogued as WBL 625. The group also appears to be known as AWM 5. NGC 6263 is not part of the group apparently.

  Marth also added two more galaxies found in the field in NGC 6271 and NGC 6722 whilst Stephan added NGC 6261, bringing a total of 7 NGC galaxies within a radius of 15 arc-seconds from NGC 6269. The majority of them lie on a line from NGC 6261 to NGC 6272.

  NGC 6269 itself is an elliptical with NGC 6265 being an S0 and NGC 6264 a spiral. The group around NGC 6269 appears to be embedded in a hot gas component found in X-Rays. It may be that NGC 6265 is a recent addition to the group and is having its gas stripped out by the RAM pressure interactions with the hot gas in the inter group medium as X-Ray observations done with Chandra shows a tail of material being stripped out of it. The NGC 6269 group also shows some of the characteristics of a fossil galaxy group. Fossil groups are where there is a cD galaxy, in this case NGC 6269, which has merged with most of the other galaxies in the group. Although NGC 6269 is not currently an AGN it is suggested that it does contain a billion solar mass black hole and there are suggestions that it was active in the past.

  Distance measurements to the group suggest it is about 120Mpc away. Interestingly the AWM 5 group definition includes a lot more galaxies than the WBL one, including NGC 6271 and 6272. The velocity maps from there suggest that there may be two clumps of galaxies in this cluster.

  Visually at 13th magnitude and fainter these galaxies are likely to be a challenge for any telescopes below 35cm, with NGC 6269 itself showing as a faint smudge. Using a modern hyperwide eyepiece at a medium power of, say 200x, will fit all the galaxies in this field in the same eyepiece FOV. Perhaps unsurprisingly the group does not appear in Night Sky Observer's Guide (NSOG) or the other observing handbooks. Owners of larger telescopes may well find other faint galaxies scattered in this field.

  This will be a challenging field to work on because of the faintness of the galaxies, many being around 15th magnitude, so it will be interesting to see how many can be picked out. It is interesting to note that Steve Gottlieb in his NGC note collection describes the whole group as very faint with his 17.5” reflector. Mark Stuart from the UK reports that NGC 6269 is on the edge with a 14” but does not report any of the other galaxies to be visible.

  Owen Brazell - Galaxy Section Director

• NGC 6340 in Draco

  July 2020 - Galaxy of the Month

  July comes and we are back to lengthening nights, although still no astronomical dark until August here in the UK.

  My choice for this month’s GOM is the strange galaxy NGC 6340 in Draco. Discovered by William Herschel in 1788, NGC 6348 has an anomalous appearance. It appears to be like a lenticular galaxy and the shape suggests that it was the result of a major merger between an elliptical and a spiral galaxy about 12 billion years ago.

  The bulge and inner part of the disk appear to be rotating in a different direction to the stellar disk. It also shows some signs of being a polar ring galaxy with material at right angles to the main disk.

  The distance is also somewhat uncertain but may be of the order of 62 million light-years.

  SIMBAD says it is part of a pair of galaxies but does not suggest what the other galaxy is. It could be one (or both) of the two IC objects in the field, IC 1251 and IC 1254, both galaxies, discovered by Edward Swift using a 16” refractor in 1890. It has been suggested that both IC 1251 and IC 1254 may be part of an interacting group with NGC 6340 as both of them show some signs of gravitational distortion. IC 1251 in particular appears to be furiously forming stars from its image in the UV from the GALEX satellite. If they are at the same distance as NGC 6340 then they are both quite small galaxies.

  NGC 6340 itself also shows some signs of an interaction/merger event perhaps within the last few hundred million years. NGC 6340 also appears to have a low activity AGN at its centre. The disk contains a ring of counter-rotating stars which is part of the reason that it has been suggested that it was involved in a major merger event. Currently NGC 6340 is classified as an S0-a galaxy. One of the best images of the group including NGC 6340 can be found on Adam Block's website.

  Although NGC 6340 is quite bright in terms of its total magnitude it is also quite large so may be a challenge to see in twilight skies. It has certainly been seen in a 25cm telescope from the UK but was not an easy catch. For those with larger telescopes the companions are the objects of interest. If these prove to be too easy then there are a number of other fainter galaxies in the field at around 16th magnitude to try for. These are almost certainly unrelated to NGC 6340 and are much further away.

  The NGC 6340 group is also well covered in the Cambridge Photographic Atlas of Galaxies, available from the Society.

  Owen Brazell - Galaxy Section Director

• NGC 5557 and Arp 199 in Boötes

  June 2020 - Galaxy of the Month

  Writing the galaxy of the month piece for June and July is often tricky as, certainly from the latitude of the UK, we never get any astronomical darkness during these months, and this won’t return until August. As such the choice has to be bright galaxies. For this month’s object I have chosen the elliptical galaxy NGC 5557 in Boötes.

  Discovered by William Herschel in May 1785, NGC 5557 is part of a group of galaxies catalogued as LGG 378 which includes the edge on spiral NGC 5529, covered in an earlier GOM piece. William on the same night also found the nearby galaxy NGC 5544 but did not spot it was a double nebula, this was left to his son John to find in 1827 when he saw it split in two and the second galaxy was catalogued as NGC 5545, The pair was also independently split by Bindon Stoney, one of Lord Rosse’s assistants in 1852 using the 72” at Birr. The pair is now known as Arp 199, although it was earlier noted to be an interacting pair and was catalogued as VV 210.

  Although looking fairly uninteresting to visual observers’ deep images show that in fact NGC 5557 is a shell galaxy with shells of gas and stars showing that in the last few (3-5) billion years or so NGC 5557 has undergone a number of interactions with other galaxies, and indeed merged with them. This is well illustrated in this image by Mark Hanson. Very deep images with the CFHT also show the presence of tidal tails and a number of dwarf galaxies accompanying NGC 5557. It has been suggested that some of these dwarf galaxies may have formed in the tidal tails. It has also been suggested that NGC 5557 may well have been formed from the merger of two spiral galaxies in the recent, astronomical, past.

  NGC 5557 is classified either as an E1 or E2 galaxy, so pretty much round as seen from our perspective. Distance estimates vary widely but it would seem to be at about 33 Mpc from us. Interestingly Lord Rosse thought that NGC 5557 was a spiral galaxy, one of his few misjudgements in that area.

  Although NGC 5557 is bright enough to show faintly in a 15cm telescope it will probably require something in the 25-30cm size to show its brighter core and surrounding haze, certainly from UK skies. Arp 199 lies perhaps 16’ away from it. I found that with a 37cm telescope under twilight skies that it was fairly easy, although admittedly the galaxy was overhead and not in the best position to view with a Dobsonian telescope. Both NGC 5557 and Arp 199 will appear in the same medium power field, say around 200x.

  NGC 5557 is bright enough to have made the Astronomical League’s Herschel 400 list. There is a bright star involved in the halo of NGC 5557 which could be confused with a SN so beware before reporting it. Arp 199 is a very tight pair and much fainter than NGC 5557 so will require larger telescopes and high power to split. The pair consists of two spirals. Arp 199 was covered in the DSF OOTW in 2014.

  Owen Brazell - Galaxy Section Director

• NGC 4567 and NGC 4568 in Virgo

  May 2020 - Galaxy of the Month

  From northern latitudes we get little or no astronomical dark from May to August so the targets for the GOM are going to be brighter ones and for this month I have chosen the galaxy pair NGC 4567 and NGC 4568, popularly known as the Siamese twins, or Butterfly Galaxies which were discovered by William Herschel in 1784 and then rediscovered by John Herschel in 1829.

  The interacting pair are part of the Virgo cluster and, perhaps surprisingly, did not make Arp’s catalogue, although they did make Vorontsov-Velyaminov’s catalogue of interacting galaxies as VV 219. The pair appear to be in the process of merging.

  There have been two supernova seen in the pair with SN 2004cc and SN 2020fqv, discovered on March 31st 2020 at about magnitude 15, there is an image of the supernova at The Virtual Telescope Project.

  The galaxies are about 52-60 million light-years distant and if at that distance the two cores would be separated by only perhaps 20000 light-years. Surprisingly for two galaxies so close together they do not appear to be distorted that much by galactic tides so maybe this is just a projection effect or perhaps this is just a very early phase of the interaction as the highest rates of star formation appear to be in the overlap areas. A molecular collision front containing a number of large molecular clouds strung out in a large filament was also found in the overlap region in the CO bands using ALMA.

  Both galaxies are spirals with the rather exotic classification of SA(rs)bc. The GALEX UV image of the pair shows a number of large bright star forming regions, particularly in NGC 4567.

  The pair would also appear to be part of a subgroup in the Virgo cluster catalogued as LGG 285 which has 44 listed galaxies in it, although not the nearby NGC 4564.

  One of the best amateur images of this pair is at the CHART32 website which also shows the nearby lenticular galaxy NGC 4564 (another William Herschel discovery).

  Perhaps surprisingly the pair did not make either the H400 or H400 II lists but was added into the H400 III galaxy list, they were in general getting into pretty nondescript galaxies by then 😊

  Visually the pair can be a challenge in small telescopes as they are perhaps fainter than expected, even an observation with a 10” from UK skies suggested the pair was not so easy.

  Larger telescopes will show the pair relatively easily and start to show some of the structure evident in images. As they are so close together then high power may be useful. They galaxies make a pretty trio with NGC 4564 in a medium power field and using a modern hyperwide eyepiece (one of the advantages of the cost of these things).

  

  

  For those with larger telescopes there is also the faint galaxy IC 3578 at 15th magnitude in the same field, this was discovered by Frost photographically using a 24” refractor in 1904.

  Owen Brazell - Galaxy Section Director

  Observations

  We have an observation by Ivan Maly with his 20-inch, observing from a dark site in the Appalachian region of Pennsylvania.

• NGC 4410A in Virgo

  April 2020 - Galaxy of the Month

  This month’s challenge is the interacting group of galaxies around NGC 4410A. The main double galaxy NGC 4410 was discovered by John Herschel in 1828. Although the group has been listed as part of the Virgo cluster and lies within its spatial bounds on the sky it actually lies at a distance of perhaps 111 Mpc, far beyond the Virgo cluster. The other galaxies in the group include IC 790, sometimes called NGC 4410C, and PGC 40736, sometimes known as NGC 4410D. The galaxies are all interacting and show tidal tails.

  The group is also listed as WBL 408, a group of 9 galaxies which also includes NGC 4411. However there are some issues with this as some distance measurements place NGC 4411 at about 55 million light years so it would be part of the Virgo cluster not part of the 4410 group. Note that NGC 4411 is also known as IC 3339 because there were errors in the co-ordinates listed by the discoverers Bigourdan and Peters, and Dreyer thought they were two separate objects.

  The galaxy PGC 40745, sometimes known as NGC 4411B may be associated with NGC 4411A and thus part of the Virgo cluster.

  There is an excellent image of the group at Hanson Astronomy Photos and also at the Chilean Advanced Robotic Telescope website and a much deeper image at the Canada-France-Hawaii Telescope (CFHT) website. For an annotated image of all the galaxies in the area see the ManTrapSkies website.

  The group contains some X-ray emitting gas which may be related to the active nucleus of NGC 4410A. It is suggested that the group is in the process of evolving from a spiral rich group, which typically do not have a hot intra cluster medium, to an elliptical one via mergers. The strong UV emission from the group also meant it made Markarians catalogue as Mrk 1325. Perhaps surprisingly it did not make Arp’s catalogue, although it is in the extended Vorontsov-Velyaminov (VV) catalogue of interacting galaxies as VV 1537.

  Observationally there are a number of galaxies that may be picked up in the area. At the recent (2020) Haw Wood Star Party I saw 5 galaxies in the area using my 22-inch but others using smaller telescopes saw 7. This may come from using a tablet program such as SkySafari at the telescope when you know there are other galaxies there and look for them rather than looking cold at the field. It also helps to have a driven scope that stops wind buffeting. To show that NGC 4410 is a double galaxy may require high power.

  NGC 4411a and b are face on spirals and are large and diffuse and as such much more difficult to see, they will however appear in the same field as NGC 4410 when using a modern hyperwide eyepiece at say 250x.

  Owen Brazell - Galaxy Section Director

• NGC 2889 in Hydra

  March 2020 - Galaxy of the Month

  For March’s GOM we stay in in the constellation of Hydra and look at the pair of galaxies NGC 2889 and NGC 2884. William Herschel discovered NGC 2889 in 1786 but it was left to Heinrich d’Arrest to discover NGC 2884 in 1865.

  Both of these galaxies appear to be spirals but whereas NGC 2889 is seen almost face on NGC 2884 is viewed at quite an angle. The two galaxies are listed as a pair but are not currently interacting, however distance measurements would suggest that the two galaxies may be an optical pair rather than a physical pair as NGC 2889 is listed as having a distance of about 61 Mpc whereas NGC 2884 is listed with a distance of maybe 50 Mpc. They could still be a pair however if there is a sufficiently large local component to their velocities as many distance velocity calculations are dependent on the Hubble flow being the dominant component of the velocity.

  NGC 2889 was home to SN 2007rb.

  Perhaps unsurprisingly there is not much research been done on either of these galaxies and what there is mostly concentrates on generic properties of the bar in NGC 2889. Deep images also suggest that NGC 2884 is a barred spiral, however NED gives it a classification as an S0/a (a lenticular galaxy) so there appears to be some confusion over its classification.

  The two galaxies are close enough together that they will fit in the same medium (150x) to high (270x) power field of view. However given that Herschel did not see NGC 2884 it may be much fainter than NGC 2889 so a high power may be better to pick it out. Night Sky Observer's Guide (NSOG) suggests that NGC 2889 will be visible faintly in 8-10 inch scopes whilst 16-18 will show more detail and bring out NGC 2884.

  Nearby is the asterism that was given the NGC number 2879 that was also found by d’Arrest on the same night he found NGC 2884. Unfortunately it is not a true fuzzy but merely a grouping of four stars. There are a number of other very faint galaxies in this field that are likely to be beyond all but the largest telescopes visually but are probably within the range of EAA systems.

  Owen Brazell - Galaxy Section Director

• NGC 2992 in Hydra

  February 2020 - Galaxy of the Month

  The pair of galaxies that make up the major components of the group associated with NGC 2992 and NGC 2993 were first discovered by William Herschel in 1785. They were later catalogued by Arp as Arp 245 and are also in the extended VV of interacting galaxies catalogue as VV 1311. Arp added the pair to his catalogue in the group of galaxies with the appearance of fission. The group lies perhaps 100 million light-years from us. Also close by is the galaxy RFGC 1621 which may also be associated with the group, although it is not part of the interacting pair.

  The main pair are seen perhaps 100 million years after the closest point of the encounter (perigalacticon) and the interaction has already drawn out tidal tails from both galaxies. Indeed there might already be a dwarf galaxy forming in the northern tidal tail of NGC 2992.

  NGC 2992 is also a Seyfert AGN, although a fairly mild one with a classification of 1.9. It is showing some signs of revived activity, perhaps due to infall of material on to its central black hole from merger products. Radio imaging shows bubbles of material coming out at right angles from the nucleus of NGC 2992 showing a classical biconical system. There may also be small scale spiral structure in the centre which could be fuelling the accretion disk around the central black hole.

  Both NGC 2992 and NGC 2993 are connected by a faint tidal bridge as well as having their own tidal tails. RFGC 1621 appears to be a dwarf galaxy from its blue colours. Although observed with GALEX the pair do not seem to show the colours associated with new star formation. There is however a magnificent image of this pair at Adam Block's caelumobservatory website which does show new star formation in NGC 2993 as well as in the tidal tails. Both of these galaxies are catalogued as spirals, although of course they are now distorted from their encounter.

  Although not in the H400 lists NGC 2992 did make it into both Hartung’s Astronomical Objects for Southern Telescopes and Walter Scott Houston’s Deep Sky Wonders has also described the pair, although Houston does not say what size telescope was used. Night Sky Observer's Guide (NSOG) Volume 2 suggests that 12-14 inch telescopes should show the pair clearly and 20-22 inch telescopes may show the tidal tails, although I expect this is probably from a high altitude site. I am not sure if the small flat galaxy is visible given its magnitude of around 17. Given the closeness of the pair I think using a medium to high power eyepiece would be the choice for observing these. Unfortunately from the UK they never rise above the 1 airmass line so try and observe them on the meridian.

  Owen Brazell - Galaxy Section Director

  Observations

  We have an observation by Ivan Maly with his 20-inch, observing from a dark site in the Appalachian region of Pennsylvania.

• NGC 2563 in Cancer

  January 2020 - Galaxy of the Month

  The small group of galaxies around NGC 2563 was once through to be part of a larger group known as the Cancer I cluster however this has been shown just to be a collection of disparate groups of galaxies and is not a true cluster. The cluster is now better known as the NGC 2563 group.

  The brightest galaxies in the group, NGC 2562 and NGC 2563, were discovered by William Herschel in 1787. NGC 2560 and 2569 were discovered by d’Arrest in 1862 using the 11” refractor at Copenhagen and NGC 2570 by Copeland in 1873 using Lord Rosse’s 72” at Birr.

  The group is also catalogued as WBL 178, a group of 11 galaxies which also includes the galaxies NGC 2556 but not NGC 2569 and NGC 2570. The group is also included in the LGG catalogue as LGG 158, a group of 14 galaxies which includes the NGC galaxies 2558, 2562, 2557, 2563, 2556, 2560 and 2569, showing how different selection criteria can include different objects.

  A much deeper study has suggested that there may be as many as 64 members of this group, although many are small and faint. NGC 2563 is definitely the brightest cluster galaxy (BCG) for this group and most, if not all, of the galaxies in the core of the group are lenticulars which suggests this is quite an old group. It appears that galaxies on the outside edge may well be still joining the group as they are still gas rich spirals.

  The group is also bright in X-Rays and observations suggest that most of the gas has been stripped from the galaxies by RAM pressure stripping and there are signs of interactions within the group, although mostly from observations in the radio region in the 21cm band. The X-Ray emission is probably coming from the hot gas between the galaxies. The group appears to be about 228 million light-years from us.

  Observationally the core of the group is quite compact and will fit in the field of view of a medium power eyepiece. If we assume that all the galaxies in the LGG list are actually part of the group then the whole group spans about 45’ on the sky.

  There are observations of this group in the book 'Galaxies and How to Observe Them' by Steinicke and Jakiel and also in Night Sky Observer's Guide (NSOG) Volume 1 where they suggest the two brighter galaxies are targets for 12-14” telescopes. There is no individual coverage of the other galaxies in the group there although there is a sketch showing NGC 2560, NGC 2562 and NGC 2563. Luginbuhl and Skiff (L&S) suggest that a 25cm telescope maybe needed to show NGC 2562 and NGC 2563. There are many other fainter galaxies in the core of the group that large telescopes and EAA systems may pick up.

  Of particular interest is the galaxy UGC 4332, which appears to be undergoing some form of merger from the distortions visible in it. Observations of the fainter members of the group maybe hampered by the 6th magnitude star just south of it so the use of high power is recommended to keep it out of the field of view.

  Owen Brazell - Galaxy Section Director