From M100 to NGC 7331: A multiband study and physical parameters in nearby galaxies

Bertua Marasca, J. C.; Dávila Gutiérrez, H.; Huaman Ticona, V.; Mosquera Hadatty, J. I.; Ramírez Valadez, A. A.
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Abstract

We study five nearby galaxies (M100/NGC 4321, NGC 1300, M 74, M 60, and NGC 7331) by combining multiband imaging (optical, UV, NIR, and X-rays) with simple photometric measurements to show how each spectral window traces different physical components: UV/blue emphasizes recent star formation (Gil de Paz et al. 2007), NIR outlines the old stellar mass and internal structure (Elmegreen et al. 2004; Ryder et al. 1998), and X-rays reveal compact sources and hot gas (Palumbo et al. 1981; Kaaret 2001; ESA 2005). For M100 we present a multiband mosaic with X-ray contours including the SN 1979C region (Kaaret 2001). We compare isophotal morphology in NGC 1300 (barred) and M 74 (unbarred), quantify ellipticity and equivalent radius in M 60 (Tonry & Schneider 1988), and illustrate a Tully–Fisher distance estimate for NGC 7331, discussing assumptions (inclination, internal corrections) and consistency with classical scales (Rubin et al. 1965; HST Key Project 2000). Our results underscore that a “layered” view reduces interpretative biases and that straightforward integrations of public data with open-source software yield robust introductory-level physical diagnostics (Knapen et al. 1999).