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The variations of oxygen abundance and ionization parameter in HII regions are usually thought to be the dominant factors that produced …

We examine the connection between diffuse ionized gas (DIG), H II regions, and field O and B stars in the nearby spiral M101 and its …

Using deep, narrowband imaging of the nearby spiral galaxy M101, we present stellar age information across the full extent of the disk …

We present the spectra of two faint star-forming objects originally identified in our deep narrowband survey of the M101 Group. One is …

We present deep, narrowband imaging of the nearby spiral galaxy M101 and its satellite to analyze the oxygen abundances of their HII regions. We add to the narrowband data set of the M101 Group, consisting of Hα, Hβ, and [OIII] emission lines, the blue [OII]λ3727 emission line for the first time. Using the $R_{23}$ strong-line ratio, we estimate the oxygen abundances of ~720 HII regions throughout the M101 Group. M101 shows a strong abundance gradient, while the satellite galaxies present little or no gradient. There is some evidence for a flattening of the gradient in M101 beyond R ~ 14 kpc. Additionally, M101 shows signs of azimuthal abundance variations to the west and southwest. These features are explored in the context of the M101-NGC 5474 interaction.

Stellar feedback is fundamental to the modeling of galaxy evolution, as it drives turbulence and outflows in galaxies. Understanding …

We present deep, narrowband imaging of the spiral galaxy M101 and its group environment to search for star-forming dwarf galaxies and outlying HII regions. We find no large population of outlying HII regions or undiscovered star-forming dwarfs in the M101 Group, as most sources (93%) are consistent with being M101 outer-disk HII regions. The lack of any hidden population of low-luminosity star-forming dwarfs around M101 suggests a shallow faint-end slope (as flat at $\alpha ~ -1.0$) for the star-forming luminosity function in the M101 Group.

Starbursting dwarf galaxies are thought to be the prime candidate for exhibiting out- flow of material: they are undergoing massive …