Mrk 205 and NGC 4319
12 21 44
+75 18 38
Mag 15.2 vis (Mrk 205)
Type: well, that is the question ... ;-)
This OOTW is going deep into the history books of cosmology. It is about a nice (at least on DSS) spiral galaxy, NGC 4319, and a quasi-stellar spot, Mrk 205, next to it. It is probably very special to astronomy, that tiny little specks such as Mrk 205 may cause large turmoil ...
Back to the year 1971. Edwin Hubble's theory of the expanding universe, reflected in a red shift correlating with distance appeared to be generally accepted. Well, not by everybody. Halton Arp took a deep photograph of NGC 4319 and Mrk 205 with the 200" Hale telescope, in which he suspected a "bridge" between the nearby spiral and the quasar, despite they had extremely different red shifts. His case was that they are close in space to each other and not a chance alignment along our line of sight. Arp was considering the hypothesis that the considerable red shift of the then new quasi-stellar objects or short quasars was not due to their distance from us. Instead, he suggested that they are objects being expelled from the nuclei of their "host galaxies" and that the red shift of their light had other reasons (such as, for instance, gravity). This was, of course, in strong disagreement to the general view of the scientific community, in particular Allan Sandage, leading to lasting controversies between the supporters of the two groups (with Arp's being certainly a minority).
If you are interested in this story and others, read the very interesting article about Arp's peculiar universe in Jeff Kanipe's and Dennis Webb's book about "The Arp Atlas of Peculiar Galaxies".
Here is an image of the galaxy group around NGC 4319 with on the DSS
And here a close up NGC 4319 with the quasar
The funny thing is: There is really something between NGC4319 and Mrk 205. Not distinct, but it is there. This HST Heritage image shows that the immediate environment of NGC 4319 is filled with matter, being outer parts of the spiral arms or perhaps as well some tidals due to interaction with other galaxies.
What can we see visually? Well, Mrk 205 is a quasar and there's not much to see except for a tiny stellar thing. During my first observation many years ago with my then 14" Dob, Mrk 205 was not easy and could be seen only with averted vision somewhat offset from NGC 4319 (more offset as suggested by the DSS image). With my 22" it is visible all the time, even with direct vision, if I recall it correctly. No, I did not see a bridge.
Last week, I revisited this group (almost at zenith during early evening) and also looked at the other galaxies. Neighboring NGC 4319 (no pun intended :-) ) is a small galaxy with a faint halo and not much structure at first sight. After some time, I suspected the northern spiral arm as an extremely faint arc offset from the main galaxy. Conditions were not overwhelming, so this should be easier under proper conditions. Unstructured NGC 4291 is situated WNW of 4319 and situated as one of the cornerstones of a quasi-rectangular asterism. There is another galaxy, NGC 4386, offset to the NE of the two other NGC galaxies.
"Give it a go and let us know what you think about red shifts, bridges, and all that stuff!"
Good luck and great viewing!