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Thread: Object of the Week Dezember 3, 2017- UGC 3730 (Arp 141) - the collision pair

  1. #1
    Join Date
    Feb 2012

    Object of the Week Dezember 3, 2017- UGC 3730 (Arp 141) - the collision pair

    UGC 3730 = Arp 141, VV 123

    RA: 07 14 20
    DEC: +73 28 37
    MAG: 13.2b

    Type: interacting galaxies

    “High in the sky” or better “in the middle of nowhere” we find this interesting galaxy/galaxy pair.

    First scientist who draws attention to the pair was the Russian astronomer Vorontsov-Velyaminov in 1958 on the plates of the Palomar Survey. Before he published his first parts of his famous catalogue he sends this interesting object to the Burbidge’s which had access to the powerful 82-inch telescope of the McDonald Observatory. They first assume a collision or a formation stage between both galaxies [1959ApJ...130...23B].
    Later Sandage uses the even bigger power of the new 200-inch to study the pair and made the hypothesis that the companion part of the pair is only “condensing of the intergalactic medium” [1963ApJ...138..863S].
    Two years later, Limber picks up the idea of collision again [1965ApJ...142.1346L].
    Newer investigations of Delgado-Donate et al. spoke about interaction of this system. They present dwarf candidates, also brighter that 18mag and so perhaps a target for bigger amateur apertures. But sighting the paper [2003A&A...402..921D] I could not confirm such bright dwarfs from their chart.
    Not the bear Arp in mind I have to add that the system also find entry in his compilation. He catalogued the pair in the category “Material emanating from elliptical”.

    Nevertheless the origin of the system it presents a very exiting pair visually. I guess with around 13mag the brighter core could almost be visible in a 4-inch telescope. Larger telescopes show the fainter southern companion as a knot with the even fainter tails to the south.

    DSS blue 10'x10'

    PanSTARRS g-band 4'x4'

    200-inch Hale telescope

    sketch: 16", 360x, NELM 6m5+

    sketch:27", 419x-586x, NELM 7m0+

    As always, give it a go and let us know
    Clear Skies, uwe

    27" f/4,2

  2. #2
    Member Steve Gottlieb's Avatar
    Join Date
    Feb 2012
    Northern California
    Great object -- I'm surprised it hasn't been picked as an OOTW before!

    Here are my notes through Jimi's 48-inch as well as my 24" at a local site (light blue/green transition)

    48" (4/6/13): Arp 141 is an unusual interacting system, listed as a Ring galaxy with collider in Madore, Nelson and Petrillo's 2009 "Atlas and Catalog of Collisional Ring Galaxies". At the north end is VV 123B = Madore C1 (collider), which appeared bright, fairly small, round, 20" diameter, sharply concentrated with a very bright nucleus. This is the brightest component in the system. At the south edge of VV 123B (25" S of center) is VV 123A = Madore RN (Ring nucleus), which appeared fairly faint, small, irregularly round, 15" diameter. The ring component extends south of VV 123A and appeared as a faint, moderately large, oval haze, ~60"x30", mostly evident as a brighter arc or tail along the west side. This arc extends about as far south as a mag 14 star which is 1.5' SSW of VV 123B, though VV 123C, a small knot at the south end, was not resolved. Viewed at 488x and 610x.

    24" (1/25/14): at 375x, VV 123B appeared moderately bright, small, round, compact, 20" diameter, high surface brightness. VV 123A, situated just 25" S (nucleus of the Ring component) was cleanly resolved and appeared very faint, very small, round, 12" diameter, low surface brightness. The actual ring, extending south, was not seen.
    24" f/3.7 Starstructure
    18" f/4.3 Starmaster
    Adventures in Deep Space
    Contributing Editor, Sky & Tel

  3. #3
    Member Howard B's Avatar
    Join Date
    Feb 2012
    Portland, Oregon USA
    I agree this is a really cool object! I haven't seen it through my 28 inch yet so my only observation is through Jimi's 48 inch, the same night of Steve's report above:

    "Hey, this is really cool! An Arp that's also a ring galaxy and the ring is fairly easy to see. Averted vision brings out the ring best as well as a tiny star-like knot along the bottom part of the ring. 610x, 21.57 SQM."

    Arp141-UGC3730_crop.jpg Arp141-UGC3730_cropinvert.jpg
    28 inch f/4 alt-az Newtonian

  4. #4
    Join Date
    Apr 2012
    Eugene, OR
    I added this one to my Herschel Project observing for the night of the 10th:

    EAGLE'S RIDGE (spur road)

    MOON: 22 days (44% illuminated; rose at 12:56 AM)

    SEEING: 6

    SQM: 21.5 (at 11 PM)

    NELM: not checked
WEATHER CONDITIONS: temps in low 30s, breezy early

    All observations: 12.5" f/5 Discovery truss-tube Dobsonian, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV); 10mm Delos (158x, 0.5˚ TFOV) used for observation of Arp 141


    UGC 3730 (Arp 141): DeepSkyForum's Object of the Week for December 3rd: using 10mm Delos--difficult but obvious--1.0' long--radiating S from a 14th-mag star [actually one of the galactic nuclei in this colliding pair]--wedge-shaped--0.5' wide at the base--a couple of little knots within it, including one a third of the way down from the star to the base--along the edge of the base is brighter, with a knot at the end of the base--a knot on P side just off end of base--galaxy is definitely an irregular object--not consistently bright--isosceles triangle of 11th- and 12th-mag stars N slightly P galaxy; triangle 1' on two sides and 1.25' on long side--to P and SP is a Capricornus-shaped asterism made mostly of 10th- and 11th-mag stars--SF of the galaxy by 15' is a 9th-mag star

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