No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate Galaxies
We present Gemini/GNIRS spectroscopic observations of 4 z-band (z~7) dropout galaxies and VLT/XSHOOTER observations of one z-band dropout and 3 Y-band (z~8-9) dropout galaxies in the Hubble Ultra Deep Field, which were selected with Wide Field Camera 3 imaging on the Hubble Space Telescope. We find...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2012
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| _version_ | 1797054364619112448 |
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| author | Caruana, J Bunker, A Wilkins, S Stanway, E Lacy, M Jarvis, M Lorenzoni, S Hickey, S |
| author_facet | Caruana, J Bunker, A Wilkins, S Stanway, E Lacy, M Jarvis, M Lorenzoni, S Hickey, S |
| author_sort | Caruana, J |
| collection | OXFORD |
| description | We present Gemini/GNIRS spectroscopic observations of 4 z-band (z~7) dropout galaxies and VLT/XSHOOTER observations of one z-band dropout and 3 Y-band (z~8-9) dropout galaxies in the Hubble Ultra Deep Field, which were selected with Wide Field Camera 3 imaging on the Hubble Space Telescope. We find no evidence of Lyman-alpha emission with a typical 5-sigma sensitivity of 5X10^-18erg/cm^2/s, and we use the upper limits on Lyman-alpha flux and the broad-band magnitudes to constrain the rest-frame equivalent widths for this line emission. Accounting for incomplete spectral coverage, we survey 3.0 z-band dropouts and 2.9 Y-band dropouts to a Lyman-alpha rest-frame equivalent width limit > 120Ang (for an unresolved emission line); for an equivalent width limit of 50Ang the effective numbers of drop-outs surveyed fall to 1.2 z-band drop-outs and 1.5 Y-band drop-outs. A simple model where the fraction of high rest-frame equivalent width emitters follows the trend seen at z=3-6.5 is inconsistent with our non-detections at z=7-9 at the ~ 1-sigma level for spectrally unresolved lines, which may indicate that a significant neutral HI fraction in the intergalactic medium suppresses the Lyman-alpha line in z-drop and Y-drop galaxies at z > 7. |
| first_indexed | 2024-03-06T18:56:15Z |
| format | Journal article |
| id | oxford-uuid:11f1c29d-b030-4052-b052-925c74e38ec1 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:56:15Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | oxford-uuid:11f1c29d-b030-4052-b052-925c74e38ec12022-03-26T10:05:02ZNo Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate GalaxiesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:11f1c29d-b030-4052-b052-925c74e38ec1EnglishSymplectic Elements at Oxford2012Caruana, JBunker, AWilkins, SStanway, ELacy, MJarvis, MLorenzoni, SHickey, SWe present Gemini/GNIRS spectroscopic observations of 4 z-band (z~7) dropout galaxies and VLT/XSHOOTER observations of one z-band dropout and 3 Y-band (z~8-9) dropout galaxies in the Hubble Ultra Deep Field, which were selected with Wide Field Camera 3 imaging on the Hubble Space Telescope. We find no evidence of Lyman-alpha emission with a typical 5-sigma sensitivity of 5X10^-18erg/cm^2/s, and we use the upper limits on Lyman-alpha flux and the broad-band magnitudes to constrain the rest-frame equivalent widths for this line emission. Accounting for incomplete spectral coverage, we survey 3.0 z-band dropouts and 2.9 Y-band dropouts to a Lyman-alpha rest-frame equivalent width limit > 120Ang (for an unresolved emission line); for an equivalent width limit of 50Ang the effective numbers of drop-outs surveyed fall to 1.2 z-band drop-outs and 1.5 Y-band drop-outs. A simple model where the fraction of high rest-frame equivalent width emitters follows the trend seen at z=3-6.5 is inconsistent with our non-detections at z=7-9 at the ~ 1-sigma level for spectrally unresolved lines, which may indicate that a significant neutral HI fraction in the intergalactic medium suppresses the Lyman-alpha line in z-drop and Y-drop galaxies at z > 7. |
| spellingShingle | Caruana, J Bunker, A Wilkins, S Stanway, E Lacy, M Jarvis, M Lorenzoni, S Hickey, S No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate Galaxies |
| title | No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate
Galaxies |
| title_full | No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate
Galaxies |
| title_fullStr | No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate
Galaxies |
| title_full_unstemmed | No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate
Galaxies |
| title_short | No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate
Galaxies |
| title_sort | no evidence for lyman alpha emission in spectroscopy of z gt 7 candidate galaxies |
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