2006/10/02 by Robin L. Fingerhut, Henry Lee, Marshall L. McCall +1 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/509862
published as Astrophys.J.655:814-830,2007 · Accepted for publication in the Astrophysical Journal
arxiv created 2006/10/02 · openalex publication_date 2007/01/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We have obtained spectra of H II regions in the heavily obscured spiral galaxy Maffei 2. The observations have allowed for a determination of the Galactic extinction of this galaxy using a correlation between extinction and hydrogen column density observed among spiral galaxies. The technique reveals that the optical depth of Galactic dust at 1 μm obscuring Maffei 2 is τ 1 = 2.017 ± 0.211, which implies that A V = 5.58 ± 0.58 mag, significantly higher than observed for the giant elliptical Maffei 1 despite its similar latitude. For comparison, we apply the same technique to IC 342, a neighboring spiral to Maffei 2 but with more moderate obscuration by Galactic dust, owing to its higher Galactic latitude. For this galaxy, we obtain τ 1 = 0.692 ± 0.066, which agrees within errors with the value of 0.639 ± 0.102 derived from the reddening estimate of Schlegel et al. (1998). We therefore adopt the weighted mean of τ 1 = 0.677 ± 0.056 for the extinction of IC 342, which implies that A V = 1.92 ± 0.16 mag. A new distance estimate for Maffei 2 of 3.34 ± 0.56 Mpc is obtained from a self-consistent Tully-Fisher relation in I adjusted to the NGC 4258 maser zero point. With our new measurement of M I , Maffei 2 joins Maffei 1 and IC 342 as one of three giant members of the nearby IC 342/Maffei Group of galaxies. We present the revised properties of all three galaxies based on the most accurate extinction and distance estimates to date, accounting for shifts in the effective wavelengths of broadband filters as this effect can be significant for highly reddened galaxies. The revised distances are consistent with what would be suspected for the Hubble Flow, making it highly unlikely that the galaxies interacted with the Local Group since the big bang.