On the origin of M81 group extended dust emission
Abstract
Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over of order a few arcminute scales the far-infrared (Herschel 250 &\mu&m) emission correlates spatially very well with a particular narrow velocity (2-3 km/s) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light back scattered off dust in our galaxy. Ultra-violet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arc minute scales and that at smaller scales there can be quite large dust temperature variations.
Cite
@article{arxiv.1010.4770,
title = {On the origin of M81 group extended dust emission},
author = {J. I. Davies and C. D. Wilson and R. Auld and M. Baes and M. J. Barlow and G. J. Bendo and J. J. Bock and A. Boselli and M. Bradford and V. Buat and N. Castro-Rodriguez and P. Chanial and S. Charlot and L. Ciesla and D. L. Clements and A. Cooray and D. Cormier and L. Cortese and E. Dwek and S. A. Eales and D. Elbaz and M. Galametz and F. Galliano and W. K. Gear and J. Glenn and H. L. Gomez and M. Griffin and S. Hony and K. G. Isaak and L. R. Levenson and N. Lu and S. Madden and B. O'Halloran and K. Okumura and S. Oliver and M. J. Page and P. Panuzzo and A. Papageorgiou and T. J. Parkin and I. Perez-Fournon and M. Pohlen and N. Rangwala and E. E. Rigby and H. Roussel and A. Rykala and N. Sacchi and M. Sauvage and B. Schulz and M. R. P. Schirm and M. W. L. Smith and L. Spinoglio and J. A. Stevens and S. Srinivasan and M. Symeonidis and M. Trichas and M. Vaccari and L. Vigroux and H. Wozniak and G. S. Wright and W. W. Zeilinger},
journal= {arXiv preprint arXiv:1010.4770},
year = {2015}
}
Comments
6 pages, 4 figures, accepted for publication in MNRAS