2008/05/17 by W. Gieren, G. Pietrzyński, G. Pietrzynski +11
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy #Astrophysics #Cepheid variable #Distance modulus #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Infrared #Local Group #Metallicity #Photometry (optics) #Physics #Red-giant branch #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/589994
latex, 6 figures. accepted to ApJ
arxiv created 2008/05/17 · openalex publication_date 2008/08/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We have obtained deep images in the near-infrared J and K filters for several fields in the Local Group galaxy WLM. We report intensity mean magnitudes for 31 Cepheids located in these fields, which we previously discovered in a wide-field optical imaging survey of WLM. The data define tight period-luminosity relations in both near-infrared bands, which we use to derive the total reddening of the Cepheids in WLM and the true distance modulus of the galaxy from a multiwavelength analysis of the reddened distance moduli in the VIJK bands. From this, we obtain the values E ( B − V ) = 0.082 ± 0.02 and ( m − M ) 0 = 24.924 ± 0.042 mag, with a systematic uncertainty in the distance of about ±3%. This Cepheid distance agrees extremely well with the distance of WLM determined from the I -band tip of the red giant branch (TRGB) method by ourselves and others. Most of the reddening of the Cepheids in WLM (0.06 mag) is produced inside the galaxy, demonstrating again the need for an accurate determination of the total reddening and/or the use of infrared photometry to derive Cepheid distances which are accurate to 3% or better, even for small irregular galaxies like WLM.