Object of the Week, June 30th, 2019 - NGC 6070 & Friends

[Paul Alsing]

Object of the Week, June 30th, 2019 - NGC 6070, UGC 10230, MCG 0-41-4, PGC/LEDA 57345, in SERPENS CAPUT

R.A.: 16h09m58.9s ec.: +00°42'34" (2000)
Size: 3.2'x 1.7'
Magnitude: 12.40 B; SB 13.7
Morphology; SA(s)cd (as per NED)

Apologies for what is probably the most over-due OOTW ever. I was in an area of California that had very weak cell service and internet, and I was unable to post in a timely manner until today.

NGC 6070 was discovered by William Herschel on May 3rd, 1786 and is located in a beautiful field in Serpens. It presents to us in an intermediate orientation, not being quite face-on. The magnitude 6.7 variable star HD 145204 lies only about 8 arcminutes to the northwest (PA 326°), so it is best to get this guy out of the field of view while observing the galaxy.
NGC 6070 is the brightest member of a trio, with NGC 6070B (LEDA 1174983 - a double galaxy) and NGC 6070C (LEDA 1175364) being NE about 4.3 and 5.5 arcminutes respectively. However, these ‘B’ & ‘C’ designations seem to depend on where you look or who you ask, with NED using ‘B’ & ‘C’ for the faint companions and Wolfgang Steinicke's Revised NGC and IC Catalogue …

http://spider.seds.org/ngc/revngcic.cgi?NGC6070

… using ‘A’ & ‘B’ instead. Dr. Harold Corwin discusses these suffixed NGC/IC numbers here…

http://haroldcorwin.net/ngcic/niposintro.html

… where he says “…I discourage the use of these numbers -- all the objects have other more appropriate names that we would do better to adopt instead. Most of these suffixed numbers come to us from three sources: Gerard de Vaucouleurs's 1956 survey of southern Shapley-Ames galaxies, Eric Holmberg's 1937 list of double and multiple galaxies, and a list of galaxies in the far northern sky found by Philip Keenan, also published in 1937.”
While it is hard to argue with Dr. Corwin, it sure is easy to just say “NGC 6070B” when talking about a companion object… assuming we can all agree that it is “B” and not “C”… In any case, here is a copy/paste from SkyTools with a DSS overlay…

NGC 6070 & FRIENDS.jpg

I observed NGC 6070 & Friends this week while attending the Golden State Star Party (GSSP) near Adin, California, at an altitude of about 4500 ft. This location is in the corner of the state near both Oregon and Nevada, and is very sparsely populated, so the skies are nice and dark. In fact, the attendance of the star party is about 400 people, whereas Adin itself has about 250 residents! The skies here the last few nights have been somewhat variable. I have used a variety of telescopes, since I am literally surrounded by many wonderful instruments. I first looked through Jeff Gortatowsky’s nice 22” UC on Friday night. NGC 6070 was an easy object using this aperture, an oval disk of fairly even brightness with some mottling and a gradually brightening core. Helped by Megastar overlayed with RealSky, we knew the exact location of the companion galaxies, but the average seeing and transparency limited us to only ‘suspecting’ that we were seeing these faint guys. I wandered down to Alan Agrawal’s 24” f3.3 Star Structure, and we looked at it again. The view was essentially the same in the 24” as it was in the 22”.

Saturday night was not nearly as good as Friday night, so I was ‘inspired’ to wait another day to add to my observations of this galaxy trio.

Sunday night had good transparency, and the seeing was still only average, but I did get a good look through Bob Douglas’ 28” Star Structure. The view in this beast was markedly improved, probably because of both the increase in aperture and the good transparency. It was immediately obvious that there was structure in NGC 6070, as I could begin to make out an arm on the NE end of the galaxy and the mottling became more complex overall, and the companions went from ‘suspected’ to being held with direct vision. I have the feeling that had I spent a lot more time at the eyepiece I would absolutely dig out more details, but I did not want to interrupt Bob’s observing schedule by dominating his telescope. Thanks, Bob!

NGC 6070 & FRIENDS from NOAO.jpg

As it always is, observing with the likes of the 3 folks who shared their telescopes with me, along with Jimi Lowrey, Steve Gottlieb, Howard Banich and Akarsh Simha, and many others here on “Dob Row”, is a real treat, and these times are cherished.

As always, give it a go and let us know.

[gdjsky01]

Best view I had was early in the evening (IIRC) Saturday the 30th(?) before the sky went to heck.
It was on Alan's 24" Star Structure. There, me and Charlie Wicks saw 6070 and two companions.
IIRC each companion took a position to the 6'oclock'ish (in a Dob) of a star that made a chain to the east(???). Not sure about that. I am using the photo above assuming east is left.

I think looking at the photo above you'd rotate it 170 to 180 or so degrees clockwise for the dob given the date and time. I believe we were seeing PGC 57350 and LEDA 1175374 because we could see the stars labeled 14.4, unlabeled (in the middle), and 15.2 Those were the chain I remember

At least that is what I recall. I forgot to to Alan what EP he was using. Saturday went to heck very quickly thereafter and Paul did not get a view. After that, it turned out to be a Star Party night.


Sorry I am not an expert observer with directions, distances, mags, etc.

[Steve Gottlieb]

This group reminds me a bit of NGC 7331 and companions, including the fact that the companions to NGC 6070 are much more distant at ~590 million l.y., compared to ~100 million l.y. for NGC 6070. Through my 24-inch (5 years back), I wrote ...

NGC 6070 appeared fairly bright, large, elongated 2:1 SW-NE, 2'x1', contains a large brighter core, fades out around the periphery. A very faint "star" near the northeast tip is actually a compact HII region labeled as region IV in the 2010 paper "Giant HII regions in NGC 7479 and NGC 6070". Located 8' SE of mag 6.7 HD 145204.

NGC 6070 is the brightest in a trio with NGC 6070B = CGCG 023-018 (double) 4.2' NE and NGC 6070C = LEDA 1175364 5.6' NE. NGC 6070B appeared very faint, small, elongated 2:1 ~N-S, low surface brightness. This is a close double system and the noted elongation suggests both systems were merged, but not individually resolved. NGC 6070C appeared extremely faint, very small, round, 12" diameter.

Through Jimi's 48-inch last May (during the Texas Star Party) much more detail was visible even in rather poor seeing...

At 375x NGC 6070 revealed three spiral arms or arcs of arms as well as a couple of HII knots. The galaxy appeared bright, large, elongated nearly 2:1 ~SW-NE, ~3'x1.5'. An inner spiral arm was visible on the NE side of the bright core. It showed a "hard" outer edge that defined the arm and contrasted with an obvious darker gap (dust) that was between this arm and an outer spiral arm. The outer arm seemed to emerge just north of the inner arm and gently curved counterclockwise towards the east and bending south near its tip. This outer arm ended at a very faint, small HII knot labeled as region I in the 2010 paper. Just outside the northeast curve of this arm was a second, slightly brighter HII knot, 6"-10" diameter (identified as region IV). Another inner spiral arc was symmetrically placed to the SW side of the core. It was pretty ill-defined, though, and lacked a sharp edge.

NGC 6070B is a close double system 4.3' NE of NGC 6070. The cores were easily resolved at 16" separation N-S. The southern component (NGC 6070B NED2) was larger and appeared fairly faint, round, 0.4' diameter, small bright core. The northern component (NGC 6070B NED1) was also fairly faint and round, but smaller - about 15" diameter. NGC 6070C, just 1.3' NE [PA 35°], was brighter than either component of NGC 6070B and appeared moderately bright, fairly small, round, 20" diameter, moderately high surface brightness.

[gdjsky01]

yes I mistyped. LEDA 1175364