The Carnegie Hubble Program: The Distance And Structure Of The SMC As Revealed By Mid-Infrared Observations Of Cepheids

Victoria Scowcroft, Wendy L. Freedman, Barry F. Madore, Andy Monson, S. E. Persson, Jeff Rich, Mark Seibert, Jane R. Rigby

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Using Spitzer observations of classical Cepheids we have measured the true average distance modulus of the Small Magellanic Cloud (SMC) to be $18.96\pm {0.01}_{\mathrm{stat}}\pm {0.03}_{\mathrm{sys}}$ mag (corresponding to $62\pm 0.3$ kpc), which is 0.48 ± 0.01 mag more distant than the LMC. This is in agreement with previous results from Cepheid observations, as well as with measurements from other indicators such as RR Lyrae stars and the tip of the red giant branch. Utilizing the properties of the mid-infrared Leavitt Law we measured precise distances to individual Cepheids in the SMC, and have confirmed that the galaxy is tilted and elongated such that its eastern side is up to 20 kpc closer than its western side. This is in agreement with the results from red clump stars and dynamical simulations of the Magellanic Clouds and Stream.
Original languageEnglish
Article number49
Pages (from-to)1-10
Number of pages10
JournalAstrophysical Journal
Issue number2
Early online date5 Jan 2016
Publication statusPublished - 10 Jan 2016

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