When researching my target audience i felt it appropriate to visit examples of sites that you would typically find Arctic Monkey's products being sold, so i went to HMV's website and found that they had categorised them in "rock and pop" other artists in this category are Take That, Britney Speares, and Robbie Williams. A set of artists that I'm fairly sure an indie band would not normally want to be grouped with, this showed me that although they are an indie band they are very mainstream now. This would suggest to me that there audience has grown which it undoubtedly has but due to the fact that they are no longer an underground band a lot of fans may have responded negatively to their recent amount of success.
When on the NME website I took a screenshot of a page that told me about artists similar to Arctic Monkeys. This would have been put on the site to attract members of a similar audience so I felt it was appropriate to put on here.
I then did the same thing with the HMV site and here is the screen shot for that

Then to help me gauge the how many of either gender like my band I went onto their website and decided to check out their forum posts to see how many I could identify as male or female. Unfortunately due to online screen names there would be no way for me to do this, and the site does not give out personal information of their users, however I did again take a screen shot to show just how many users there are.

From this we see that the site has nearly 800 topics in the forum and each topic could have anything up to 9,634 posts on it, and thats only the first page of discussions. If we average out each topic to having say around 4,000 posts on it, with 747 topics that means that the site could have anything up to or around 2,988,000 comments on it, and rising. If we then do the same thing for the amount of times each post has been viewed (which is the number in the second column) and we average this out to around 17,000, means that the forum could have been viewed in one way or another 12,699,000 times.
All of this shows me just how popular this band have become and possibly just how wide their range of audience is.
When analysing the NME magazine for my digipak research i noted that this magazine was consistent with the music websites suggested artists for fans of Arctic Monkeys, which in turn suggests to me that this is the sort of magazine my advert would be featured in.