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Stellar tidal streams

I came across a pilot study on stellar tidal streams [1] when I was working with Prof. Jeremy. With the help of amateur astronomers and some serious observing time, of the order of 8-10 hours per galaxy, the authors constructed images of galaxies with extremely faint features visible!

It is common knowledge that the Andromeda galaxy and our own milky way galaxy are approaching each other and will eventually collide, leading to a very dynamical interaction. When such interactions occur on a much smaller scale, for example between a galaxy and a satellite/dwarf galaxy, one can expect the dwarf galaxy to be tidally disrupted by the bigger central galaxy, creating extended tidal streams. Given the extremely low surface brightness of said tidal streams, they are very hard to observe but they provide a valuable insight into the properties of the progenitor dwarf galaxy and the central galaxy.

The amount of literature on stellar tidal streams has been steadily rising over the last decade as we push the lower boundary of the observable magnitude limit. Extremely deep observations of LSB galaxies have revealed that most early type spiral galaxies have tidal features associated with them, previously too faint to observe. In [1], the authors have studied 8 LSB spiral galaxies and [2] has produced a much larger catalog of 92 LSB (low surface brightness) galaxies. Many more serendipitous discoveries of tidal structures have come, for example [3] and [4].

Understanding tidal interactions between galaxies can lead to a fundamental insight into many astrophysical problems, including but not limited to how star formation can be triggered by galactic collisions, studying the distribution of dark matter in the halo of the LSB galaxies [5], [6] and [7] and maybe even solving the dwarf galaxy problem.

I am following the work of the authors and I thought it was interesting enough to share with you folks, whoever is reading out there, today.

[1] Martinez-Delgado et al. 2000
[2] Duc et al 2014
[3] Bernard et al 2014
[4] Slater et al. 2014
[5] Bonaca et al. 2014
[6] Pearson et al. 2014
[7] Price-Whelan et al. 2014
[8] Fostel et al. 2014

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