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View Full Version : Object of the Week - May 2, 2021 - An oddball in Canes Venatici



Clear Skies
May 2nd, 2021, 10:17 AM
Object: MCG+06-30-008 (http://aladin.u-strasbg.fr/AladinLite/?target=UGC%20%208440&fov=0.2502&survey=P%2fSDSS9%2fcolor) - PGC46969 - UGC8440
Constellation: Canes Venatici (https://en.wikipedia.org/wiki/Canes_Venatici)
R.A. / Dec. 13:25:36 +36°23m00s

In my hunt for a decent Object of the Week, I decided to let the dogs out. This week's object is an interesting galaxy that, despite its appearance, has managed to evade not only Arp, but Vorontsov-Vel'yaminov and Zwicky, too.

MCG+06-30-008 is in the southeastern part of Canes Venatici, 6 degrees to the east-southeast of the bright and beautiful double star "Cor Caroli" (Alpha Canum Venaticorum (https://en.wikipedia.org/wiki/Cor_Caroli)), that also goes by its double star designation STF1692.

A helpful lead-in feature to locate this galaxy is the mag. 6.1 variable star CL Canum Venaticorum (SAO63514), three quarters of a degree to the north-northwest. Can't miss it thanks to its M3 spectrum. From CL Canum, proceed due south until you run into a triplet of galaxies: NGC5143, NGC5141 & NGC5142 (https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_blue&r=13+24+56.28&d=%2B36+24+30&e=J2000&h=15.0&w=15.0&f=gif&c=none&fov=NONE&v3=), the latter two of which are a pair that goes by KPG 373. From there, go 8 minutes of arc to the east and you have found our object. It is flanked by two magnitude ten and a half-ish stars.

As images show, there is a lot going on with this week's OOTW. Distortion, likely due to interaction, presumably a merger, is evident.

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The DSS POSS2 Blue image (https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_blue&r=13+25+36.33&d=%2B36+22+52.4&e=J2000&h=15.0&w=15.0&f=gif&c=none&fov=NONE&v3=) reveals an irregular central blob without an obvious core but with a moderately bright nucleus. Branching off on the eastern side of the galaxy is a clearly distorted arm, running towards the north and elegantly curving towards the west. To the east of the galaxy, two faint streamers can be discerned.

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The SDSS image (http://skyserver.sdss.org/dr16/SkyServerWS/ImgCutout/getjpeg?TaskName=Skyserver.Chart.Image&ra=201.40138&dec=36.38122&scale=0.44&width=2045&height=2045&opt=&query=) tells us more, with a very faint superimposed star to the west-southwest of the nucleus and, further out west, some mottled structure. It is clear that NED's (http://ned.ipac.caltech.edu/byname?objname=PGC46969&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1) bland classification as a barred spiral galaxy of the Hubble type c variety, does not do this object justice.

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The DECaLS image (https://www.legacysurvey.org/viewer?ra=201.4002&dec=36.3805&zoom=13&layer=dr8) reveals further delicate details. A total of six streamers can be distinguished and the irregular blobs to the west are much clearer. These are reminiscent of some of the Shapley regions in the Large Magellanic Clouds (https://clearskies.eu/csog/downloads/other/#lmcregions), such as, for example, Shapley I (https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_red&r=05+22+18&d=-67+59+00&e=J2000&h=60&w=60&f=gif&c=none&fov=NONE&v3=) a.k.a. Constellation I.

Surprisingly, there is very limited information available for MCG+06-30-008. Even amateur images are less than a handful. I have as of yet not been able to find any paper or any survey that zooms in on this galaxy.

It will require some decent aperture to pick out the details of this galaxy, but as images show, there is plenty to discover.

As part of my collection of observing guides, the CSOG guide for this OOTW can be downloaded here (https://clearskies.eu/csog/downloads/dsfootw/).

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In the vicinity: in addition to KPG 373 and NGC5143 to the west, another KPG group is almost half a degree to the south-southeast. KPG 375 consists of NGC5149 & NGC5154 (https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_blue&r=13+26+18.87&d=%2B35+58+20.4&e=J2000&h=15.0&w=15.0&f=gif&c=none&fov=NONE&v3=). Nice bonus objects. If double stars are your thing, pan three quarters of a degree to the southwest of our object to find John Herschel's HJ530 (WDS13227+3556 (https://www.stelledoppie.it/index2.php?iddoppia=56730)).

Now go hunt that dog. And let us know!

akarsh
September 26th, 2021, 10:02 AM
Such an incredible find! I better put it on my list, although I don't expect much with my scope.