Arp 92 (NGC 7603)


  10 inch Newtonian, StarlightXpress MX716, 100 minutes, 9.5' x 8.9'

  Although not obvious at first glance, Arp 92 is one of the strangest among the peculiars.  I haven't really tried to do a ranking but Arp 92 certainly has among the most, if not the most, citations in the astronomical literature.  When I checked, NED listed 249 references.  The class for Arp 92 is Spirals with Elliptical Galaxy Companions on Arms.  The Atlas note says "very faint connection shows better in red" and the red sensitivity of my CCD is the reason I captured as much as I did.  The primary, NGC 7603, is a Seyfert galaxy. The companion is best known as NGC 7603B.  Much controversy has arisen because 7603B certainly appears to be interacting with the primary but the redshift places it twice as far away.  More recently, two Spanish astronomers have imaged and acquired spectra of two emission objects (QSO's) with z values of 0.243 and 0.391, located right on the connecting filament.  These objects are marked in the left-hand false color image below.  A link to their article is provided below.  This link takes you to the abstract; click on the PDF file at the top of the page to go to the text.

          http://www.aanda.org/index.php?option=article&access=bibcode&bibcode=2002A%2526A...390L..15LPDF

While not as perplexing, Arp 92 also exhibits a very large halo, one that is difficult to explain unless it is involved in an interaction.  Some of this can be detected in the negative image but the right-hand false color image shows the extent of it much better.

The explanation for the non-standard image size is completely mundane.  I acquired the image over two separate nights and simply lined them up poorly.  The field shown is all that overlapped.

Atlas Image

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