Object of the Week, December 15, 2013 – starburst galaxy NGC 1569 (Arp 210)

[Uwe Glahn]

NGC 1569 (Arp 210, UGC 3056)

Camelopardalis

RA 04 30 49.1
DEC +64 50 53

Type: Galaxy IBm

Size: 3.7’ x 1.8’

Mag: 11.2vmag (13.1mag SB)


Discovered in 1788 by F.W. Herschel with his famous 18.7” Speculum Metal Reflector (~ modern 16” Reflector) he described his new nebula as “pretty bright, small, extended, brighter Nucleus in the middle, 9.5 star 1’ north”

The first look in the data and the historical description shows a “normal” small galaxy. Arp catalogued the galaxy under number 210 which means the subgroup “galaxies – irregularities, absorption and resolution”.

Looking at deep pictures shows the irregularity morphology. And indeed, today NGC 1569 counts as a starburst galaxy with a starburst rate which is 100 times larger than that of our galaxy. The reason for that is the membership to the Maffei 1 Group (IC 342 Group) and the interactions between them.

The results of this interaction are the real interesting issue for us amateur astronomers. The galaxy shows large and bright super star clusters (SSC) mainly two prominent ones – SSC NGC 1569A and NGC 1569B. They belong to the brightest ones (beside e.g. M 82 and NGC 6946) and are in reach of the 10”-12” telescope class. Bigger aperture shows more smaller and fainter SSC.

deep amateur picture (Bernd Gährken)
http://www.astrode.de/2ds18a9b.jpg

HST + NIRSPEC SCAM (University of Virginia)
http://www.astro.virginia.edu/class/whittle/astr553/Topic11/t11_n1569_hst.jpg

animated gif -HST overlay (Bernd Gährken)
http://www.astrode.de/ngc1569vgl1.gif

Some visual amateur observations
- sketch with 12", 375x-500x, NELM 6m5+ (Christian Rausch) (http://www.licht-stimmungen.de/01_sub_pages_astro/Zeichnungen/Galaxien/NGC1569_112012.html)
- sketch with 16", 488x, NELM 6m5+ (Uwe Glahn) (http://www.deepsky-visuell.de/Zeichnungen/NGC1569.htm)
- sketch with 27", 586x, NELM 6m5+ (Uwe Glahn) (http://www.deepsky-visuell.de/Zeichnungen/NGC1569_27.htm)


And remember,

“Give it a go and let us know!
Good luck and great viewing!”

[Howard B]

Hi Uwe,

My only observation of NGC 1569 is from 2005 with 28 inch at 654x:

"This object was a tip from Tom (Osypowski) - very nice! An unusual galaxy so it seems this may be be a couple of galaxies in mid-merger. There are three bright core areas so maybe three galaxies are merging. Great sight regardless, best at 654x. High surface brightness takes magnification well." No SQM reading.

I had little idea what I was seeing were super star clusters, so my musings about the nature of 1569 were simply guesses based on what my brain was capable of at 2 am on that long ago morning. This is another good one to revisit on a dark, serene night especially since I now have a better idea what's there to see. I remember being intrigued by this object at the time and curious to find out more but it slipped away until now, so many thanks Uwe!

997 998

[Uwe Glahn]

Hi Howard,

seems that you catch both SSC A and B plus the SSC number 10 or perhaps the conglomerate of 6,7,9,10.

I'm not sure yet if the seeing is the most important factor here to catch the SSC, quasi a M57 ZS effect. I remember very good that it was always hard to detect both brighter cluster with my old 16". I did not note the seeing in the past. It was amazing how easy the SSC were in Christians 12" f/5 under good but not perfect conditions. It easily can be, that the clusters are in reach of a 10" or maybe a 8". Jens Bohle (http://www.jens-bohle.de/extragalaktische_kugelsternhaufen.htm) noted 14,8vmag for A and 15,5vmag for B.

[Paul Alsing]

Hi Uwe,

I almost wrote about this guy last week, but decided instead to save him for a future O.O.T.W. However, you beat me to it! :P

My best view of this great object was again using the 82" @ McDonald Observatory in Ft. Davis, Texas. I wrote:

NGC 1569, Camelopardalis

"A dwarf irregular galaxy that may belong to the local group. This galaxy is home to several SSC’s, Super Star Clusters, that are very apparent in this telescope. The galaxy itself is a bright slash that fills most of the 5 arc-minute FOV, and the SSC’s show as 2 non-stellar bright regions aligned along the long axis of the galaxy. The literature suggests that these SSC’s have an absolute magnitude 3 mags brighter than Omega Centauri does."

I have otherwise observed NGC 1569 several times using my 25" f/5, but those views were not quite the same, although I could still see the SSC's within.

[Ivan Maly]

An object I would like to re-observe. Interesting information here, especially about the SSCs. Here are my notes from last winter.

January 9, 2013. Cherry Springs. 16”. Transparent by Clear Sky Clock in the evening, then above average. Clouds cleared after astronomical twilight. Zodiacal light to culminating Pisces. 0 deg. C, 70% humidity. Strong wind gusts, horrific seeing.

...

NGC 1569. IBm 5 Mly distant. Not in Herschel 400. Arp 210. Herschel’s class II. Wind too strong. The scope jerking in azimuth punched me in the eye with the 8 mm Ethos. 1 hr break in Steve’s observatory with the roof rolled on. Drinking tea and trading stories. Topic: “slapstick astronomy”. Example: melting the fabric of one’s tent by the heat of the campfire when trying to camp in winter on an unimproved remote dark site.

Wind now manageable. NGC 1569 is elongated S of a star at 45x (Pentax XW40). 225x (Ethos 8 mm) brings out a second star farther N. A similarly faint star is SE of the galaxy, and a fainter one SSE. The galaxy at the first glance looks like a comet with the tail pointing SE. This “comet” is gradually brightening to the galaxy’s core S of the bright star. The core ends abruptly on the NW side and appears pointed there. There is darkness beyond that point. The middle of the tail is wider than the core. To the NW of the core is a separated faint patch. It is symmetrical to the outer half of the tail. The tail extends more than half-way to the SE star. The patch cannot be held continuously, but the glimpses are persistent. The galaxy overall is elongated at least 5x1. 01:30.

[reiner]

Hi Uwe,
that's a really impressive starburst galaxy. I observed it during a few subsequent nights one year ago. I did not look specifically for superclusters, but I noted that the core of the starburst galaxy appears very structured. Overall, the galaxy appeared asymmetrical with the eastern part being fainter than the western half. There are as well a few start superimposed a bit off the core.

[Uwe Glahn]

Paul, Ivan and Reiner,

thanks for your input. I'm impressed that you Paul could detect the nonstellar character of these SSC's with the 82". Very cool.
I found another detailed observation this starburst galaxy from Andreas Domenico (http://www.andreas-domenico.de/deepsky/N1569.html). Very impressive detail for 18" aperture.

[FaintFuzzies]

Observation from my 22" scope (taken from my Arp book)

22" f/4.1 reflector @ 305, 327 and 458x

NGC 1569 - Bright dominant off-centered core with a double stellar nucleus arranged along the axis of the galaxy. I’m pretty sure that one is a star. Faint but obvious extension to the east, about 45” more. Total length is 1.8’ and 40” thick. The bright part is 1.1’ long. PA = 110º. A 9.5 magnitude star lies 45” north.

1013

[Marko]

What a bright 'treat' this object was and thanks for the tip. Observed in my 18" no problem even from the fairly bright sight I was at for the observation. It will be interesting to look again at a darker site in the 21.5 mag sort of range as it should expose more detail in the mottled areas.

[Dave Mitsky]

I observed the dwarf irregular galaxy NGC 1569 last night through two 16" Dobs, at my request, and my 10" f/4.7 Dob from one of the "local" dark sites that I frequent. NGC 1569 is a fine object and is set in an attractive star field.

The owner of one of the 16-inchers boosted the power quite a bit, which resulted in an interesting view. He also put NGC 1961 (http://martingermano.com/N1961group.htm), another interesting galaxy in Camelopardalis that's on the Herschel 400 list, into view.

I used magnifications of 40, 92, 133, and 267x while observing NGC 1569 with my telescope.

Dave Mitsky