VLT/VIMOS observations of an occulting galaxy pair: redshifts and effective extinction curve

dc.contributor.authorHolwerda, B. W.
dc.contributor.authorBoeker, T.
dc.contributor.authorDalcanton, J. J.
dc.contributor.authorKeel, W. C.
dc.contributor.authorde Jong, R. S.
dc.contributor.otherEuropean Space Agency
dc.contributor.otherUniversity of Washington
dc.contributor.otherUniversity of Washington Seattle
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.contributor.otherLeibniz Institut fur Astrophysik Potsdam (AIP)
dc.date.accessioned2018-09-21T20:02:19Z
dc.date.available2018-09-21T20:02:19Z
dc.date.issued2013
dc.description.abstractWe 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 Mathis extinction law to the spectra of individual fibres to derive slope (R-V) and normalization (A(V)). The normalization agrees with the HST attenuation map and the slope is lower than the Milky Way relation (R-V < 3.1), which is likely linked to the spatial sampling of the disc. We speculate that the values of R-V point to either coherent interstellar medium structures in the disc larger than usual (similar to 9 kpc) or higher starting values of R-V, indicative of recent processing of the dust. The foreground galaxy is a low stellar mass spiral (M-* similar to 3 x 10(9) M-circle dot) with a high dust content (M-dust similar to 0.5 x 10(6) M-circle dot). The dust disc geometry visible in the HST image would explain the observed spectral energy distribution properties of smaller galaxies: a lower mean dust temperature, a high dust-to-stellar mass ratio but relatively little optical attenuation. Ongoing efforts to find occulting pairs with a small foreground galaxy will show how common this geometry is.en_US
dc.format.mimetypeapplication/pdf
dc.identifier.citationHolwerda, B., Böker, T., Dalcanton, J., Keel, W., de Jong, R. (2013): VLT/VIMOS observations of an occulting galaxy pair: redshifts and effective extinction curve. Monthly Notices of the Royal Astronomical Society, 433(1). DOI: https://doi.org/10.1093/mnras/stt669
dc.identifier.doi10.1093/mnras/stt669
dc.identifier.orcidhttps://orcid.org/0000-0002-4884-6756
dc.identifier.orcidhttps://orcid.org/0000-0002-5666-7782
dc.identifier.orcidhttps://orcid.org/0000-0002-1264-2006
dc.identifier.urihttp://ir.ua.edu/handle/123456789/3928
dc.languageEnglish
dc.language.isoen_US
dc.publisherOxford University Press
dc.rights.licenseAttribution 4.0 International (CC BY 4.0)
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjecttechniques: imaging spectroscopy
dc.subjectgalaxies: distances and redshifts
dc.subjectgalaxies: dwarf
dc.subjectgalaxies: individual: 2MASX J00482185-2507365
dc.subjectgalaxies: ISM
dc.subjectgalaxies: spiral
dc.subjectDIGITAL-SKY-SURVEY
dc.subjectSPIRAL GALAXIES
dc.subjectSEEING GALAXIES
dc.subjectRADIATIVE-TRANSFER
dc.subjectOVERLAPPING GALAXIES
dc.subjectMASSIVE GALAXIES
dc.subjectDUST EXTINCTION
dc.subjectOPTICALLY THICK
dc.subjectSURVEY TREASURY
dc.subjectSTAR-FORMATION
dc.subjectAstronomy & Astrophysics
dc.titleVLT/VIMOS observations of an occulting galaxy pair: redshifts and effective extinction curveen_US
dc.typetext
dc.typeArticle
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