Evolution of the observed Lyαluminosity function fromz= 6.5 toz= 7.7: evidence for the epoch of reionization?

Clément, Benjamin; Cuby, Jean-Gabriel; Courbin, F.; Fontana, A.; Freudling, W.; Fynbo, J. P. U.; Gallego, J.; Hibon, Pascale; Kneib, Jean-Paul; Fèvre, O. Le; Lidman, C.; McMahon, R. G.; Milvang-Jensen, B.; Møller, P.; Moorwood, A. F. M.; Nilsson, K.; Pentericci, L.; Venemans, Bram; Villar, V.; Willis, Jon

doi:10.1051/0004-6361/201117312

Cited by 51 publications

(60 citation statements)

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“…1) as part of a Large ESO Programme (Prog-Id: 181.A-0485, PI: Cuby) and a HAWK-I science verification programme (Prog-Id: 60.A-9284(B), PI: Fontana). For details on the observations and data reduction we refer to Castellano et al (2010) and Clément et al (2012). The field is in the northern half of the GOODS-S field (centred at RA, Dec = 03 h 32 m 29 s , −27 d 44 m 42 s , J2000).…”

Section: Imaging Observationsmentioning

confidence: 99%

Emission-line-selected galaxies atz= 0.6–2 in GOODS South: Stellar masses, SFRs, and large-scale structure

Kochiashvili

Møller

Milvang-Jensen

et al. 2015

A&A

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We have obtained deep NIR narrow and broad (J and Y) band imaging data of the GOODS-South field. The narrow band filter is centered at 1060 nm corresponding to redshifts z = 0.62, 1.15, 1.85 for the strong emission lines Hα, [Oiii]/Hβ and [Oii], respectively. From those data we extract a well defined sample (M(AB) = 24.8 in the narrow band) of objects with large emission line equivalent widths in the narrow band. Via SED fits to published broad band data we identify which of the three lines we have detected and assign redshifts accordingly. This results in a well defined, strong emission line selected sample of galaxies down to lower masses than can easily be obtained with only continuum flux limited selection techniques. We compare the (SED fitting-derived) main sequence of star-formation (MS) of our sample to previous works and find that it has a steeper slope than that of samples of more massive galaxies. We conclude that the MS steepens at lower (below M = 10 9.4 M ) galaxy masses. We also show that the SFR at any redshift is higher in our sample. We attribute this to the targeted selection of galaxies with large emission line equivalent widths, and conclude that our sample forms the upper boundary of the MS. We briefly investigate and outline how samples with accurate redshifts down to those low stellar masses open a new window to study the formation of large scale structure in the early universe. In particular we report on the detection of a young galaxy cluster at z = 1.85 which features a central massive galaxy which is the candidate of an early stage cD galaxy, and we identify a likely filament mapped out by [Oiii] and Hβ emitting galaxies at z = 1.15.

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Section: Imaging Observationsmentioning

confidence: 99%

Emission-line-selected galaxies atz= 0.6–2 in GOODS South: Stellar masses, SFRs, and large-scale structure

Kochiashvili

Møller

Milvang-Jensen

et al. 2015

A&A

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“…We followed three peculiar objects selected as high-EW line emitters spectroscopically in a search for LAE candidates at z ∼ 7.7 using very deep optical data (Clément et al 2012). Had we used optical data that was shallower by approximately one magnitude, we would have selected these three objects as genuine LAE candidates at z ∼ 7.7.…”

Section: Discussion and Implication For High-z Surveysmentioning

confidence: 99%

“…Cuby et al (2007), Willis et al (2008) for pioneering searches at redshifts 8.8 with small format near IR detectors. With the advent of large mosaics of near IR arrays, more recent searches have been carried out at redshifts 7.3, 7.7 and 8.8 (Tilvi et al 2010;Hibon et al 2010Hibon et al , 2011Krug et al 2012;Clément et al 2012;Shibuya et al 2012;Milvang-Jensen et al 2013;Matthee et al 2014;Konno et al 2014). Thus far, only one of the LAE candidates from these searches has been confirmed spectroscopically at z ∼ 7.3.…”

Section: Introductionmentioning

confidence: 99%

“…To do so, we use the LAE samples from one of our previous studies (Clément et al 2012) in which we have selected high EW line emitting objects at low redshift that would have been selected as LAE candidates at z ∼ 7.7, if the optical observations had been one magnitude shallower. From VLT-X-Shooter spectroscopy, we investigate the nature of these objects.…”

Section: Introductionmentioning

confidence: 99%

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Narrowband selected high-redshift galaxy candidates contaminated by lower redshift [OIII] ultra-strong emitter line galaxies

Pénin

Cuby

Clément

et al. 2015

A&A

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Context. Lyman-break galaxies (LBG) and narrowband (NB) surveys have been successful at detecting large samples of high-redshift galaxies. Both methods are subject to contamination from low-redshift interlopers. Aims. Our aim is to investigate the nature of low-redshift interlopers in NB Lyman-α emitters (LAE) searches. Methods. From previous HAWK-I NB imaging at z ∼ 7.7, we identify three objects that would have been selected as high-redshift LAEs had our optical data been one magnitude shallower (but still one to two magnitudes fainter than the near infrared data). We follow up these objects in spectroscopy with X-Shooter at the VLT. Results. Despite low quality data due to bad weather conditions, for each of the three objects we identify one, and only one emission line, in the spectra of the objects that we identify as the [OIII]5007 Å line. From this result, combined with spectral energy density fitting and tests based on line ratios of several populations of galaxies, we infer that the three objects are ultra-strong line emitters at redshifts ∼1.1. Conclusions. From this work and the literature we remark that the [OIII] line appears to be a common source of contamination in high-redshift LBG and LAE samples and we suggest that efforts be made to characterize with high accuracy the [OIII] luminosity function out to redshift ∼3 or higher.

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“…In the past few years, the knowledge of galaxies at ⩾ z 6.5 has tremendously improved through large samples of galaxy candidates at ⩾ z 6.5 discovered using both the narrowband imaging method (Lyα emitters [LAEs]; e.g., Kashikawa et al 2006;Hu et al 2010;Ouchi et al 2010;Clément et al 2012;Krug et al 2012)and Lyman break dropout method (Lyman break galaxies [LBGs]; e.g., Oesch et al 2010;Bouwens et al 2011;Yan et al 2011;Finkelstein et al 2012a;Ellis et al 2013). Bright LBG candidates at > z 7 have been routinely discovered based on the dropout method in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS;Grogin et al 2011;Koekemoer et al 2011) and Cluster Lensing And Supernova survey with Hubble (CLASH;) fields via deep imaging with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3).…”

Section: Introductionmentioning

confidence: 99%

LBT/LUCI SPECTROSCOPIC OBSERVATIONS OFz≃7 Galaxies GALAXIES

Bian

Stark

Fan

et al. 2015

ApJ

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We present deep near-infrared spectroscopic observations of 13 luminous  z 7 Lyman break galaxies (LBGs) ( - M 21 UV) and a  z 9.6 lensed LBG candidate, MACS1149-JD1, using the LBT/LUCI spectrograph in the multi-object mode and long-slit mode, respectively. Thez 7 galaxies are selected in one of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey/WIDE survey observations, the UKIRT Infrared Deep Sky Survey Ultra Deep Survey field, and MACS1159-JD1 is selected from the Cluster Lensing And Supernova survey with Hubble survey observations. With ∼4-5 hr integrations, the LBT spectra are sensitive to Lyα emission, with rest-frame equivalent width greater than 55 Å ( > EW 55 0 Å) atz 7 and 90 Å ( > EW 90 0 Å) at z 9.5. No Lyα emission is observed in any of the  z 7 LBGs. After correcting the spectroscopic incompleteness, our measurements place an upper limit on the Lyα emission fraction ofLy 0in luminous LBGs at  z 7. This result is consistent with the lack of Lyα emission in > z 7 LBGs in previous studies. Together with other measurements of the Lyα emission fraction in LBGs at  z 7, this study puts a strong constraint on the fraction of luminous  z 7 LBGs with large EW Lyα,3.2 . We estimate the expected Lyα emission fraction at  z 7 by extrapolating the evolution of the fraction at low redshifts and find that the observed Lyα emission fraction is lower than the expected Lyα emission fraction at the 89% significancelevel, consistent with expectations if Lyα emission in  z 7 LBGs has been suppressed by neutral hydrogen in the intergalactic medium or optically thick absorbers around the galaxies. We do not find any strong Lyα emission feature at the redshift range of  z 7.3-9.7 in the MACSJ1159-JD1 spectrum, either. This is consistent with the conclusion that Lyα emission in the galaxy has been highly suppressed.

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Evolution of the observed Lyαluminosity function fromz= 6.5 toz= 7.7: evidence for the epoch of reionization?

Cited by 51 publications

References 50 publications

Emission-line-selected galaxies atz= 0.6–2 in GOODS South: Stellar masses, SFRs, and large-scale structure

Emission-line-selected galaxies atz= 0.6–2 in GOODS South: Stellar masses, SFRs, and large-scale structure

Narrowband selected high-redshift galaxy candidates contaminated by lower redshift [OIII] ultra-strong emitter line galaxies

LBT/LUCI SPECTROSCOPIC OBSERVATIONS OFz≃7 Galaxies GALAXIES

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