Comparison of Hi and optical redshifts of galaxies - The impact of redshift uncertainties on spectral line stacking

dc.contributor.authorMaddox, Natasha
dc.contributor.authorHess, Kelley M.
dc.contributor.authorBlyth, S.-L.
dc.contributor.authorJarvis, Matt
dc.date.accessioned2018-02-06T12:28:25Z
dc.date.available2018-02-06T12:28:25Z
dc.date.issued2013
dc.description.abstractAccurate optical redshifts will be critical for spectral co-adding techniques used to extract detections from below the noise level in ongoing and upcoming surveys for Hi, which will extend our current understanding of gas reservoirs in galaxies to lower column densities and higher redshifts. We have used existing, high quality optical and radio data from the SDSS and ALFALFA surveys to investigate the relationship be- tween redshifts derived from optical spectroscopy and neutral hydrogen (Hi) spectral line observations.We find that the two redshift measurements agree well, with a negli- gible systematic offset and a small distribution width. Employing simple simulations, we determine how the width of an ideal stacked Hi profile depends on these redshift offsets, as well as larger redshift errors more appropriate for high redshift galaxy sur- veys. The width of the stacked profile is dominated by the width distribution of the input individual profiles when the redshift errors are less than the median width of the input profiles, and only when the redshift errors become large, 150 kms−1, do they significantly affect the width of the stacked profile. This redshift accuracy can be achieved with moderate resolution optical spectra. We provide guidelines for the number of spectra required for stacking to reach a specified mass sensitivity, given tele- scope and survey parameters, which will be useful for planning optical spectroscopy observing campaigns to supplement the radio data.en_US
dc.description.accreditationWeb of Science
dc.identifier.citationMaddox, N. et al. (2013). Comparison of Hi and optical redshifts of galaxies - The impact of redshift uncertainties on spectral line stacking. Monthly Notices of the Royal Astronomical Society, 433(3): 2613 - 2625en_US
dc.identifier.issn0035-8711
dc.identifier.urihttp://dx.doi.org/10.1093/mnras/stt934
dc.identifier.urihttp://hdl.handle.net/10566/3479
dc.language.isoenen_US
dc.privacy.showsubmitterFALSE
dc.publisherOxford University Pressen_US
dc.rightsThis is the pre-print version (From arXiv:1305.6154 ) of the article published online at: http://dx.doi.org/10.1093/mnras/stt934
dc.status.ispeerreviewedTRUE
dc.subjectGalaxiesen_US
dc.subjectDistances and redshiftsen_US
dc.subjectSurveyen_US
dc.subjectRadio linesen_US
dc.titleComparison of Hi and optical redshifts of galaxies - The impact of redshift uncertainties on spectral line stackingen_US
dc.typeArticleen_US

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