The carnegie hubble program

The Leavitt law at 3.6 μm and 4.5 μm in the large magellanic cloud

Victoria Scowcroft, Wendy L. Freedman, Barry F. Madore, Andrew Monson, S. E. Persson, Mark Seibert, Jane R. Rigby, Laura Sturch

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

The Carnegie Hubble Program is designed to improve the extragalactic distance scale using data from the post-cryogenic era of Spitzer. The ultimate goal is a determination of the Hubble constant to an accuracy of 2%. This paper is the first in a series on the Cepheid population of the Large Magellanic Cloud, and focusses on the period-luminosity (PL) relations (Leavitt laws) that will be used, in conjunction with observations of Milky Way Cepheids, to set the slope and zero point of the Cepheid distance scale in the mid-infrared. To this end, we have obtained uniformly sampled light curves for 85 LMC Cepheids, having periods between 6 and 140 days. PL and period-color relations are presented in the 3.6 μm and 4.5 μm bands. We demonstrate that the 3.6 μm band is a superb distance indicator. The cyclical variation of the [3.6]-[4.5] color has been measured for the first time. We attribute the amplitude and phase of the color curves to the dissociation and recombination of CO molecules in the Cepheid's atmosphere. The CO affects only the 4.5 μm flux making it a potential metallicity indicator.

Original languageEnglish (US)
Article number76
JournalAstrophysical Journal
Volume743
Issue number1
DOIs
StatePublished - Dec 10 2011

Fingerprint

Magellanic clouds
color
luminosity
Hubble constant
light curve
recombination
cryogenics
metallicity
dissociation
slopes
atmospheres
atmosphere
curves
programme
molecules
indicator

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Scowcroft, V., Freedman, W. L., Madore, B. F., Monson, A., Persson, S. E., Seibert, M., ... Sturch, L. (2011). The carnegie hubble program: The Leavitt law at 3.6 μm and 4.5 μm in the large magellanic cloud. Astrophysical Journal, 743(1), [76]. https://doi.org/10.1088/0004-637X/743/1/76
Scowcroft, Victoria ; Freedman, Wendy L. ; Madore, Barry F. ; Monson, Andrew ; Persson, S. E. ; Seibert, Mark ; Rigby, Jane R. ; Sturch, Laura. / The carnegie hubble program : The Leavitt law at 3.6 μm and 4.5 μm in the large magellanic cloud. In: Astrophysical Journal. 2011 ; Vol. 743, No. 1.
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Scowcroft, V, Freedman, WL, Madore, BF, Monson, A, Persson, SE, Seibert, M, Rigby, JR & Sturch, L 2011, 'The carnegie hubble program: The Leavitt law at 3.6 μm and 4.5 μm in the large magellanic cloud', Astrophysical Journal, vol. 743, no. 1, 76. https://doi.org/10.1088/0004-637X/743/1/76

The carnegie hubble program : The Leavitt law at 3.6 μm and 4.5 μm in the large magellanic cloud. / Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Monson, Andrew; Persson, S. E.; Seibert, Mark; Rigby, Jane R.; Sturch, Laura.

In: Astrophysical Journal, Vol. 743, No. 1, 76, 10.12.2011.

Research output: Contribution to journalArticle

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