MNRAS-2014-Wilkins-1038-50.pdf (5.19 MB)
High-redshift galaxies and low-mass stars
journal contribution
posted on 2023-06-08, 23:03 authored by Stephen WilkinsStephen Wilkins, Elizabeth R Stanway, Malcolm N BremerThe sensitivity available to near-infrared surveys has recently allowed us to probe the galaxy population at z ˜ 7 and beyond. The existing Hubble Wide Field Camera 3 (WFC3) and Visible and Infrared Survey Telescope for Astronomy (VISTA) Infrared Camera (VIRCam) instruments allow deep surveys to be undertaken well beyond 1?µm – a capability that will be further extended with the launch and commissioning of the James Webb Space Telescope (JWST). As new regions of parameter space in both colour and depth are probed, new challenges for distant galaxy surveys are identified. In this paper, we present an analysis of the colours of L- and T-dwarf stars in widely used photometric systems. We also consider the implications of the newly identified Y-dwarf population – stars that are still cooler and less massive than T-dwarfs for both the photometric selection and spectroscopic follow-up of faint and distant galaxies. We highlight the dangers of working in the low-signal-to-noise regime, and the potential contamination of existing and future samples. We find that Hubble/WFC3 and VISTA/VIRCam Y-drop selections targeting galaxies at z ~ 7.5 are vulnerable to contamination from T- and Y-class stars. Future observations using JWST, targeting the z ~ 7 galaxy population, are also likely to prove difficult without deep medium-band observations. We demonstrate that single emission line detections in typical low-signal-to-noise spectroscopic observations may also be suspect, due to the unusual spectral characteristics of the cool dwarf star population.
History
Publication status
- Published
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- Published version
Journal
Monthly Notices of the Royal Astronomical SocietyISSN
0035-8711Publisher
Wiley-BlackwellExternal DOI
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1Volume
439Page range
1038-1050Department affiliated with
- Physics and Astronomy Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2015-11-04First Open Access (FOA) Date
2015-11-04First Compliant Deposit (FCD) Date
2015-11-04Usage metrics
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