Evidence for photometric contamination in key observations of Cepheids in the benchmark galaxy IC 1613

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dc.creator Majaess, Daniel J.
dc.creator Turner, David Gerald, 1945-
dc.creator Gieren, W.
dc.creator Ngeow, C.
dc.date.accessioned 2018-03-27T12:55:22Z
dc.date.available 2018-03-27T12:55:22Z
dc.date.issued 2014-12
dc.identifier.issn 0004-6361
dc.identifier.uri http://library2.smu.ca/handle/01/27379
dc.description Publisher's Version/PDF
dc.description.abstract This study helps increase awareness of the pernicious effects of photometric contamination (crowding/blending), since it can propagate an undesirable systematic offset into the cosmic distance scale. The latest Galactic Cepheid Wesenheit (VI<sub>c</sub>) and Spitzer calibrations were employed to establish distances for classical Cepheids in IC 1613 and NGC 6822, thus enabling the impact of photometric contamination to be assessed in concert with metallicity. Distances (W<sub>VIc</sub>, [3.6]) for Cepheids in IC 1613 exhibit a galactocentric dependence, whereby Cepheids near the core appear (spuriously) too bright (r<sub>g</sub> &lt; 2'). That effect is attributed to photometric contamination from neighboring (unresolved) stars, since the stellar density and surface brightness may increase with decreasing galactocentric distance. The impact is relatively indiscernible for a comparison sample of Cepheids occupying NGC 6822, a result that is partly attributable to that sample being nearer than the metal-poor galaxy IC 1613. W<sub>VIc</sub> and [3.6] distances for relatively uncontaminated Cepheids in each galaxy are comparable, thus confirming that period-magnitude relations (Leavitt Law) in those bands are relatively insensitive to metallicity (&Delta;[Fe/H]&nbsp;≃ 1). en_CA
dc.description.provenance Submitted by Betty McEachern (betty.mceachern@smu.ca) on 2018-03-27T12:55:22Z No. of bitstreams: 1 Majaess_D_article_2014_c.pdf: 615854 bytes, checksum: 0a4e7e18543b172ea4533e1df7de579e (MD5) en
dc.description.provenance Made available in DSpace on 2018-03-27T12:55:22Z (GMT). No. of bitstreams: 1 Majaess_D_article_2014_c.pdf: 615854 bytes, checksum: 0a4e7e18543b172ea4533e1df7de579e (MD5) Previous issue date: 2014-12 en
dc.language.iso en en_CA
dc.publisher EDP Sciences en_CA
dc.relation.uri https://dx.doi.org/10.1051/0004-6361/201424444
dc.rights Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
dc.subject.lcsh Cepheids
dc.subject.lcsh Astronomy -- Observations
dc.title Evidence for photometric contamination in key observations of Cepheids in the benchmark galaxy IC 1613 en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Astronomy & Astrophysics 572, A64. (2014) en_CA
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Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
 
Published Version: https://dx.doi.org/10.1051/0004-6361/201424444
 
 

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