The identification of post-starburst galaxies at z ˜ 1 using multiwavelength photometry: a spectroscopic verification

David T. Maltby, Omar Almaini, Vivienne Wild, Nina A. Hatch, William G. Hartley, Chris Simpson, Ross J. McLure, James Dunlop, Kate Rowlands, Michele Cirasuolo

Research output: Contribution to journalArticlepeer-review

Abstract

Despite decades of study, we still do not fully understand why somemassive galaxies abruptly switch off their star formation in the earlyUniverse, and what causes their rapid transition to the red sequence.Post-starburst galaxies provide a rare opportunity to study thistransition phase, but few have currently been spectroscopicallyidentified at high redshift (z > 1). In this paper, we present thespectroscopic verification of a new photometric technique to identifypost-starbursts in high-redshift surveys. The method classifies thebroad-band optical-near-infrared spectral energy distributions (SEDs) ofgalaxies using three spectral shape parameters (supercolours), derivedfrom a principal component analysis of model SEDs. When applied to themultiwavelength photometric data in the UKIDSS Ultra Deep Survey, thistechnique identified over 900 candidate post-starbursts at redshifts 0.5<z <2.0. In this study, we present deep optical spectroscopy fora subset of these galaxies, in order to confirm their post-starburstnature. Where a spectroscopic assessment was possible, we find themajority (19/24 galaxies; ˜80 per cent) exhibit the strong Balmerabsorption (H δ equivalent width Wλ > 5Å) and Balmer break, characteristic of post-starburst galaxies. Weconclude that photometric methods can be used to select large samples ofrecently-quenched galaxies in the distant Universe.
Original languageEnglish
Pages (from-to)L114-L118
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume459
Issue number1
Early online date3 Apr 2016
DOIs
Publication statusPublished - 11 Jun 2016

Keywords

  • methods: statistical
  • galaxies: fundamental parameters
  • galaxies: high-redshift
  • galaxies: photometry
  • galaxies: statistics
  • galaxies: stellar content

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