The Dark Mystery of Galaxy X (Una Galassia di Materia Oscura) - via @SciShowSpace

Sources:
http://arxiv.org/pdf/0908.0334.pdf
http://arxiv.org/pdf/1502.01358v1.pdf
http://arxiv.org/pdf/1601.03381v1.pdf
http://lcogt.net/spacebook/cepheid-va...
http://www.skyandtelescope.com/astron...
http://earthsky.org/space/have-astron...
http://www.gemini.edu/node/12470
https://briankoberlein.com/2015/02/17...
https://www.youtube.com/watch?v=I9tel...
http://earthsky.org/space/a-nearby-da...

Images:
https://commons.wikimedia.org/wiki/Fi...
https://commons.wikimedia.org/wiki/Fi...