The contribution of high-redshift galaxies to cosmic reionization: new results from deep WFC3 imaging of the Hubble Ultra Deep Field

Bunker, Andrew J.; Wilkins, Stephen M.; Ellis, Richard S.; Stark, Daniel P.; Lorenzoni, Silvio; Chiu, Kuenley; Lacy, Mark; Jarvis, Matt J.; Hickey, Samantha

doi:10.1111/j.1365-2966.2010.17350.x

Cited by 204 publications

(233 citation statements)

References 72 publications

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“…Observationally however, this epoch is poorly studied. Still the current constraints strongly suggest that the EoR roughly straddled the redshift range of z ∼ 6-12 (Komatsu et al 2011;Fan, et al 2003Fan, et al , 2006Bolton & Haehnelt 2007;Theuns et al 2002;Bolton et al 2010;Oesch et al 2010;Bunker et al 2010).…”

Section: Epoch Of Reionizationmentioning

confidence: 99%

LOFAR: The LOw-Frequency ARray

Haarlem

Wise

Gunst

et al. 2013

A&A

2,101

783

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LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10-240 MHz and provides a number of unique observing capabilities. Spreading out from a core located near the village of Exloo in the northeast of the Netherlands, a total of 40 LOFAR stations are nearing completion. A further five stations have been deployed throughout Germany, and one station has been built in each of France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR achieves unparalleled sensitivity and angular resolution in the low-frequency radio regime. The LOFAR facilities are jointly operated by the International LOFAR Telescope (ILT) foundation, as an observatory open to the global astronomical community. LOFAR is one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. LOFAR's new capabilities, techniques and modus operandi make it an important pathfinder for the Square Kilometre Array (SKA). We give an overview of the LOFAR instrument, its major hardware and software components, and the core science objectives that have driven its design. In addition, we present a selection of new results from the commissioning phase of this new radio observatory.

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Section: Epoch Of Reionizationmentioning

confidence: 99%

LOFAR: The LOw-Frequency ARray

Haarlem

Wise

Gunst

et al. 2013

A&A

2,101

783

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“…Recently, observations of galaxies have been reported at z > 7 (Bouwens et al 2011;Bunker et al 2010;Vanzella et al 2011). The upcoming James Webb Space Telescope (JWST) will further enhance our ability to detect galaxies at higher redshift by exploring them with higher sensitivity and test our current understanding of early structure formation.…”

Section: Introductionmentioning

confidence: 99%

Lyman alpha emission from the first galaxies: implications of UV backgrounds and the formation of molecules

Latif

Schleicher

Spaans

et al. 2011

A&A

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The Lyman alpha line is a robust tracer of high redshift galaxies. We present estimates of Lyman alpha emission from a protogalactic halo illuminated by UV background radiation fields with various intensities. For this purpose, we performed cosmological hydrodynamics simulations with the adaptive mesh refinement code FLASH, including a detailed network for primordial chemistry, comprising the formation of primordial molecules, a multi-level model for the hydrogen atom as well as the photo-ionization and photo-dissociation processes in a UV background. We find that the presence of a background radiation field J 21 excites the emission of Lyman alpha photons, increasing the Lyman α luminosity up to two orders of magnitude. For a halo of ∼10 10 M , we find that a maximum flux of 5 × 10 −15 erg cm −2 s −1 is obtained for J 21 × f esc = 0.1, where f esc is the escape fraction of the ionizing radiation. Depending on the environmental conditions, the flux may vary by three orders of magnitude. For J 21 × f esc > 0.1 the Lyman alpha luminosity decreases as the atomic hydrogen abundance becomes rather small. The fluxes derived here can be probed using Subaru and the upcoming James Webb Space Telescope. The emission of Lyman alpha photons is extended and comes from the envelope of the halo rather than its core. In the center of the halo, line trapping becomes effective above columns of 10 22 cm −2 and suppresses the emission of Lyman alpha. In addition, cooling by primordial molecules may decrease the gas temperature in the central region, which further reduces Lyman α emission. In the central core, H 2 is photo-dissociated for a background flux of J 21 ≥ 1000. For weaker radiation fields, i.e. J 21 < 0.1, H 2 and HD cooling are particularly strong in the center of the halo, leading to gas temperatures as low as ∼100 K. We also performed a parameter study with different escape fractions of ionizing photons and explored the relative role of ionizing and dissociating radiation. We find that Lyman alpha emission depends more on the strength of the ionizing background. For a constant ionizing background, the Lyman α flux increases at least by an order of magnitude for stronger photodissociation.

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“…It is important to stress that while the advent of Wide Field Camera 3 (WFC3) on HST in 2009 has enabled extremely deep near-infrared imaging (up to λ 1.6 μm) which has revolutionised the study of galaxies at z 7−8, (Bouwens et al 2010;McLure et al 2010;Oesch et al 2009;Finkelstein et al 2010;Bunker et al 2010) the very small field-of-view offered by WFC3/IR coupled with its inability to observe in the K-band means that deep ground-based surveys such as UltraVISTA remain of crucial importance. In particular, the largest current (or indeed planned) WFC3/IR extragalactic survey is the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS; Grogin et al 2011;Koekemoer et al 2011), but even this 900-orbit 3-year HST Treasury Program will only cover 800 arcmin 2 .…”

Section: Introductionmentioning

confidence: 99%

UltraVISTA: a new ultra-deep near-infrared survey in COSMOS

McCracken

Milvang-Jensen

Dunlop

et al. 2012

A&A

780

712

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In this paper we describe the first data release of the UltraVISTA near-infrared imaging survey of the COSMOS field. We summarise the key goals and design of the survey and provide a detailed description of our data reduction techniques. We provide stacked, skysubtracted images in Y JHK s and narrow-band filters constructed from data collected during the first year of UltraVISTA observations. Our stacked images reach 5σ AB depths in an aperture of 2 diameter of ∼25 in Y and ∼24 in JHK s bands and all have subarcsecond seeing. To this 5σ limit, our K s catalogue contains 216 268 sources. We carry out a series of quality assessment tests on our images and catalogues, comparing our stacks with existing catalogues. The 1σ astrometric rms in both directions for stars selected with 17.0 < K s (AB) <

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The contribution of high-redshift galaxies to cosmic reionization: new results from deep WFC3 imaging of the Hubble Ultra Deep Field

Cited by 204 publications

References 72 publications

LOFAR: The LOw-Frequency ARray

LOFAR: The LOw-Frequency ARray

Lyman alpha emission from the first galaxies: implications of UV backgrounds and the formation of molecules

UltraVISTA: a new ultra-deep near-infrared survey in COSMOS

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