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What is the name of the predominantly blue spiral galaxy at center-top of this image of Hickson Compact Group 7?

I've found a few articles mentioning the group, but they never seem to list the names of the galaxies contained therein.

Photo of HCG7

Photo of HCG7 sourced from Wikipedia

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3 Answers 3

up vote 6 down vote accepted

Using Google Sky, the three galaxies can be identified, and the blue spiral galaxy at center-top is NGC 197. I had to rotate the Google Sky image about 45 degrees to get the same orientation. An annotated version is:

enter image description here

The Hubble image from the question can be annotated as:

enter image description here

The orientation of the three main galaxies and the five features (F1 through F5) support that it is indeed the same part of the sky. The only difference is that F5 appears to be double in the Google Sky version. Also, the positions correspond to what is listed in the Polish Wikipedia entry for Hickson Compact Group 7. Even weaker features can be discerned by comparing the two images. For instance, two small galaxies and a star near the midpoint of NGC 192 and NG 196.

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Quoting from a paper*, "Group 7 in the Hickson catalog consists of four galaxies: three barred spirals, NGC 192, NGC 201 and NGC 197 (members A, C and D), and one barred lenticular, NGC 196 (B)." From Best of AOP: NGC 197, it looks like it's NGC 197.

*Paper is Konstantopoulos et al. (2010) in ApJ. Arxiv version here.

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From the original Hickson paper it's clear that Stuart has the right list of NGCs for individual galaxies within HCG 7, but I disagree with his breakdown of which is which. From this image I think it is clear that the three galaxies in the question image are the three big galaxies on the right. (The left one is quite face-on while the right one is somewhat edge-on, a better match IMO for the question image.)

From the geometry of the triangle that those three make, it is clear that you have to rotate the question image 90 degrees counterclockwise to get to my image. This makes the blue galaxy NGC 197, not 201.

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Ah, I was misoriented because the HST shot doesn't present a wide field. I've corrected my post after looking more into it and looking in Starry Night. –  Stuart Robbins Sep 15 '11 at 16:11
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