The Period-luminosity Relation for the Large Magellanic Cloud Cepheids Derived from Spitzer Archival Data

Using Spitzer archival data from the SAGE (Surveying the Agents of a Galaxy’s Evolution) program, we derive the Cepheid period-luminosity (P-L) relation at 3.6, 4.5, 5.8 and 8.0 microns for Large Magellanic Cloud (LMC) Cepheids. These P-L relations can be used, for example, in future extragalactic distance scale studies carried out with the James Webb Space Telescope. We also derive Cepheid period-color (P-C) relations in these bands and find that the slopes of the P-C relations are relatively flat. We test the nonlinearity of these P-L relations with the F statistical test, and find that the 3.6μm, 4.5μm and 5.8μm P-L relations are consistent with linearity. However the 8.0μm P-L relation presents possible but inconclusive evidence of nonlinearity. Subject headings: Cepheids — distance scale