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Paper: Observation of the Halo of the Edge-On Galaxy IC 5249
Volume: 165, The Third Stromlo Symposium: The Galactic Halo
Page: 187
Authors: Yock, Philip; Pennycook, Glen; Rattenbury, Nicholas; Koribalski, Baerbel; Muraki, Yasushi; Yanagisawa, Toshi; Jugaku, Jun; Dodd, Richard
Abstract: Optical photometry and HI synthesis observations of the southern edge-on Sc,d galaxy IC 5249 are reported. The rotation curve rises linearly out to a radius of 7 kpc, and then appears to flatten out at 100 km s^{-1}. The HI mass out to 24.5 kpc is 6 x 109Modot, or 10% of the total mass out to this radius. The colour, central surface brightness, scale height and scale length of the disk of IC 5249 are R-I approx0.4, muR=20.5+/-0.1 mag arcsec^{-2}, 620+/-40 pc and 12 kpc, respectively. Additional light to that predicted by an exponential disk is present at distances greater than 3 kpc from the disk. At 6 kpc the surface brightness is mu_R approx 28 mag arcsec^{-2}. The measured distribution of surface brightness in the halo is consistent, within large statistical uncertainties, with that expected for a tracer of dark matter. If the tracer consists entirely of red dwarfs with mass 0.2Modot, then their spatial density at galactocentric radius 8.5 kpc in IC 5249 is (1.15+/-0.7) x 10^6 kpc^{-3}. This is about 7 x the local Galactic density of such stars. At this density, they would contribute about 10% of the mass of IC 5249. This is an upper limit to the total mass of stars in IC 5249 with mass >= 0.2Modot.
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