Merger?

• by ramberts

  I'm not very good at these types of galaxies this close together. Is this a merger, what are some things to look for? To me there looks like a more dense area between, but I'm not sure if it's overlap, noise or tidal tails. Elliptical and lenticular galaxies are tough for me to tell if there is interaction, are there some key things to look for?

  Posted April 11, 2015 11:05 AM

• by Capella05 moderator in response to ramberts's comment.

  Hi @ramberts

  I don't think they are merging, but I agree it is sometimes difficult to tell!

  My amateur reasoning (without resorting to external sources):

  • The colour of the galaxies are different, suggesting that the galaxies are at different distances.
  • When looking at the respective individual galaxies there does not appear to be any distortion / disturbance - suggesting there is no interaction.
  • (try covering one of the galaxies and analysing it, and then do the same for the other - also useful when looking at gravitational lenses)
  • Both galaxies seem to exhibit an outer halo, but personally, I feel it is just by line of sight that they look connected.
  • There is no star formation - this is usually a tell tale sign of interaction.

  Posted April 11, 2015 12:10 PM

• by ramberts

  Thank you for your response Capella, that helps a lot! The color differences I thought of, but It looked to me like there was a lot going on tin the middle, but that makes sense since they are close together in the picture and ellipticals and lenticualrs can have large halo regions.

  Posted April 12, 2015 7:36 AM

• by Capella05 moderator

  No worries 😃

  Posted April 12, 2015 1:20 PM