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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Louisville

2013

Galaxies: dwarf

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Quantified H I Morphology – Vii. Star Formation And Tidal Influence On Local Dwarf H I Morphology., Benne W. Holwerda, N. Pirzkal, W. J. G. De Blok, S. -L. Blyth Oct 2013

Quantified H I Morphology – Vii. Star Formation And Tidal Influence On Local Dwarf H I Morphology., Benne W. Holwerda, N. Pirzkal, W. J. G. De Blok, S. -L. Blyth

Faculty Scholarship

Scale-invariant morphology parameters applied to atomic hydrogen maps (H i) of galaxies can be used to quantify the effects of tidal interaction or star formation on the interstellar matter (ISM). Here we apply these parameters, concentration, asymmetry, smoothness, Gini, M20, and the GM parameter, to two public surveys of nearby dwarf galaxies, the Very Large Array-ANGST and Local Irregulars That Trace Luminosity Extremes-The H i Nearby Galaxy Survey, to explore whether tidal interaction or the ongoing or past star formation is a dominant force shaping the H i disc of these dwarfs. Previously, H i morphological criteria were identified for …


The Occulting Galaxy Pair Ugc 3995 : Dust Properties From Hst And Califa Data., Benne W. Holwerda, W. C. Keel Aug 2013

The Occulting Galaxy Pair Ugc 3995 : Dust Properties From Hst And Califa Data., Benne W. Holwerda, W. C. Keel

Faculty Scholarship

UGC 3995 is an interacting and occulting galaxy pair. UGC 3995B is a foreground face-on spiral and UGC 3995A a bright background spiral with an AGN. We present analysis of the dust in the disc of UGC 3995B based on archival Hubble Space Telescope (HST) WFPC2 and PPAK IFU data from the CALIFA survey’s first data release. From the HST F606W image, we construct an extinction map by modeling the isophotes of the background galaxy UGC 3995A and the resulting transmission through UGC 3995B. This extinction map of UGC 3995B shows several distinct spiral extinction features. The radial distribution of …


Vlt/Vimos Observations Of An Occulting Galaxy Pair : Redshifts And Effective Extinction Curve., Benne W. Holwerda, T. Boker, J. J. Dalcanton, W. C. Keel, R. S. De Jong Jun 2013

Vlt/Vimos Observations Of An Occulting Galaxy Pair : Redshifts And Effective Extinction Curve., Benne W. Holwerda, T. Boker, J. J. Dalcanton, W. C. Keel, R. S. De Jong

Faculty Scholarship

We present Very Large Telescope/Visible Multiobject Spectrograph Integral Field Unit observations of an occulting galaxy pair previously discovered in Hubble Space Telescope (HST) observations. The foreground galaxy is a low-inclination spiral disc, which causes clear attenuation features seen against the bright bulge and disc of the background galaxy. We find redshifts of z = 0.064 ± 0.003 and 0.065 for the foreground and background galaxy, respectively. This relatively small difference does not rule out gravitational interaction between the two galaxies. Emission line ratios point to a star-forming, not active galactic nuclei dominated foreground galaxy. We fit the Cardelli, Clayton and …