The Araucaria Project. The Distance to the Local Group Galaxy WLM from Cepheid Variables discovered in a Wide-Field Imaging Survey

Abstract

We have conducted an extensive wide-field imaging survey for Cepheid variables in the Local Group irregular galaxy WLM. From data obtained on 101 nights, we have discovered 60 Cepheids which include 14 of the 15 Cepheid variables previously detected by Sandage and Carlson. Down to a period of 3 days, our Cepheid survey in WLM should be practically complete. Importantly, we have found for the first time a long-period Cepheid (P=54.2 days) in this galaxy, alleviating the puzzle that WLM with its many blue, massive stars does not contain Cepheids with periods longer than about 10 days. Our data define tight period-luminosity relations in V, I and the reddening-free Wesenheit magnitude ${\mathrm{W}}_{\mathrm{I}}$ which are all extremely well fit by the corresponding slopes of the LMC Cepheid PL relation, suggesting no change of the PL relation slope down to a Cepheid metal abundance of about -1.0 dex, in agreement with other recent studies. We derive a true distance modulus to WLM of 25.144 $\pm$0.03 (r) $\pm$0.07 (s) mag from our data, in good agreement with the earlier 24.92 $\pm$ 0.21 mag determination of Lee, Freedman and Madore (1993a) from Cepheid variables. The quoted value of the systematic uncertainty does not include the contribution from the LMC distance which we have assumed to be 18.50 mag, as in the previous papers in our project.

AJ accepted

References in corpus (6)

• A new Cepheid distance to the maser-host galaxy NGC 4258 and its implications for the Hubble Constant
• The Araucaria Project. VLT spectra of blue supergiants in WLM: classification and first abundances
• The Araucaria Project: Distance to the Local Group Galaxy NGC 3109 from Near-Infrared Photometry of Cepheids
• The Araucaria Project. Near-Infrared Photometry of Cepheid Variables in the Sculptor Galaxy NGC 55
• The Araucaria Project. The Distance to the Sculptor Group Galaxy NGC 55 from a Newly Discovered Abundant Cepheid Population
• The Araucaria Project. A Wide-Field Photometric Survey for Cepheid Variables in NGC 3109

Cited by in corpus (11)

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• The Araucaria Project. The Distance to the Sculptor Galaxy NGC 247 from Near-Infrared Photometry of Cepheid Variables
• High-precision distance measurements with classical pulsating stars
• The Araucaria Project. The Distance to the Local Group Galaxy WLM from Near-Infrared Photometry of Cepheid Variables
• The Astrophysical Distance Scale III: Distance to the Local Group Galaxy WLM using Multi-Wavelength Observations of the Tip of the Red Giant Branch, Cepheids, and JAGB Stars
• C stars in the outer spheroid of NGC 6822
• Carbon stars as standard candles -- III. Un-binned maximum likelihood fitting and comparison with TRGB estimations
• The Araucaria Project: The Distance to the Sculptor Group Galaxy NGC 247 from Cepheid Variables Discovered in a Wide-Field
• APEX CO(3-2) observations of NGC6822