A Keck Survey for Gravitationally Lensed Lyα Emitters in the Redshift Range 8.5 < z < 10.4: New Constraints on the Contribution of Low-Luminosity Sources to Cosmic Reionization

By D. Stark, Richard S. Ellis, J. Richard, Jean-Paul Kneib, Graham P. Smith, Michael R. Santos. 2007

146 citations recorded by the source corpus.

We discuss new observational constraints on the abundance of faint high-redshift Lyα emitters secured from a deep Keck near-infrared spectroscopic survey that utilizes the strong magnification provided by lensing galaxy clusters. In each of nine clusters, we have undertaken a systematic "blind" search for line emission with NIRSPEC in the J band within carefully selected regions that offer very high magnifications (≳10×-50×) for background sources with redshifts z ≃ 10. The high magnification enables the detection of emission at unprecedented flux limits (1041-1042 ergs s-1). As the comoving volumes probed are small, our survey is designed to address the important question of whether low-luminosity galaxies could provide the dominant ionizing flux at z ~ 10. Our survey has yielded six promising (>5 σ) candidate Lyα emitters that lie between z = 8.7 and z = 10.2. We carefully discuss the validity of our detections and the likelihood that the detected line is Lyα in light of earlier, apparently false, claims. Lower redshift line interpretations can be excluded, with reasonable assumptions, through the nondetection of secondary emission in further spectroscopy undertaken with LRIS and NIRSPEC. Nonetheless, as a result of our tests, we argue that at least two of our candidates are likely to be at z ≃ 10. Given the small survey volume, this suggests there is a large abundance of low-luminosity star-forming sources at z ≃ 8-10. While the predicted reionization photon budget depends upon a large number of physical assumptions, our first glimpse at the z ≃ 10 universe suggests that low-luminosity star-forming galaxies contribute a significant proportion of the UV photons necessary for cosmic reionization.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/1dd8f0a4c9bbf7bfaf17dd3eb6ab6ee78c7eea34

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

Resolving the Formation of Protogalaxies. III. Feedback from the First Stars (2007, background): “…(SMBH) of mass ∼109M⊙ (Becker et al. 2001; Fan et al. 2002, 2006) and low-luminosity galaxies (Hu et al. 2002; Iye et al. 2006; Kashikawa et al. 2006; Bouwens & Illingworth 2006; Stark et al. 2007) at and above redshift 6 indicate that active star and BH formation began long before this epoch.”
z ~ 7-10 Galaxies in the HUDF and GOODS Fields: UV Luminosity Functions (2008, background): “…of course, is that the number of star-forming galaxy candidates at z ∼ 7 − 10 has been very small, of order ∼ 4 − 5 galaxies (Bouwens et al. 2004c; Bouwens et al. 2005; Bouwens & Illingworth 2006; Iye et al. 2006; Labbé et al. 2006; Mannucci et al. 2007; Stark et al. 2007b; Bradley et al. 2008).”
Gravitational lensing (2010, unknown): “The magnification by galaxy clusters as cosmic telescopes has recently been used in systematic searches for galaxies at very high redshift [54, 404, 457, 464] and for increasing the resolution in detailed studies of distant galaxies [468, 469].”
The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Lyα Emitters from z = 3.1 to 5.7 in the 1 deg2 Field: Luminosity Functions and AGN (2007, background): “Blind spectroscopy in cluster regions yielded candidates of gravitationally lensed LAEs that enable us to study intrinsically faint LAEs (Ellis et al. 2001; Santos et al. 2004; Stark et al. 2007).”
Studying reionization with Lyα emitters (2007, methodology): “Both Dijkstra et al. (2006) and Stark et al. (2007) find that this simple parameterization is able to provide adequate fits to the z = 5.7 and z = 6.6 luminosity functions even when fixing Fc.”
Measurements of the UV background at 4.6 < z < 6.4 using the quasar proximity effect (2010, background): “The bulk of the ionising photons atz > 6 that make up the UVB are believed to come from low-luminosity galaxies (Richard et al. 2006; Stark et al. 2007; Richard et al. 2008; c© 0000 RAS Srbinovsky & Wyithe 2010; Oesch et al. 2010).”
The physics of the intergalactic medium (2007, background): “Much improved Lyα emitter statistics are anticipated with current or upcoming narrow band surveys which may make it possible to realize these tests (Gardner et al., 2006; Horton et al., 2004; Ouchi et al., 2008; Stark et al., 2007b).”
HerMES: CANDIDATE GRAVITATIONALLY LENSED GALAXIES AND LENSING STATISTICS AT SUBMILLIMETER WAVELENGTHS (2012, background): “The magnification provided by gravitational lensing makes it an effective tool for identifying and studying intrinsically faint and typically distant galaxies (e.g. Stark et al. 2007; Richard et al. 2008, 2011).”
Resolved spectroscopy of gravitationally lensed galaxies: recovering coherent velocity fields in subluminous z ~ 2-3 galaxies (2009, background): “Over the past decade, using the growing archive of HST ACS and WFPC-2 images of rich clusters (e.g. Santos et al. 2004; Sand et al. 2005; Stark et al. 2007) and through specific projects such as the MAssive Cluster Survey (MACS, Ebeling et al. 2001) and Local Cluster Substructure Survey c© 0000…”
The luminosity function, halo masses and stellar masses of luminous Lyman-break galaxies at redshifts 5 < z < 6 (2008, methodology): “Moreover, at present, the highest-redshift galaxy with spectroscopic confirmation (z = 6.96; Iye et al. 2006) was identified using the narrow-band technique (see Stark et al. 2007a for candidate LAEs atz ≥ 8).”
STAR FORMATION RATES AND STELLAR MASSES OF z = 7–8 GALAXIES FROM IRAC OBSERVATIONS OF THE WFC3/IR EARLY RELEASE SCIENCE AND THE HUDF FIELDS (2009, unknown): “The overall results suggest the galaxies formed substantial amounts of stars at even earlier times, well into the epoch of reionization (Stark et al. 2007; Yan et al. 2006; Labbé et al. 2010).”
THE ABUNDANCE OF STAR-FORMING GALAXIES IN THE REDSHIFT RANGE 8.5–12: NEW RESULTS FROM THE 2012 HUBBLE ULTRA DEEP FIELD CAMPAIGN (2012, methodology): “Measures of the assembled stellar mass from Spitzer Space Telescope photometry at z ≃5-6 (Stark et al. 2007a; Eyles et al. 2007; González et al. 2010, 2011; Labbé et al. 2012) suggest that 1 Department of Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125;…”
STATISTICS OF 207 Lyα EMITTERS AT A REDSHIFT NEAR 7: CONSTRAINTS ON REIONIZATION AND GALAXY FORMATION MODELS (2010, background): “Moreover, beyond this epoch, only weak upper limits are placed on Lyα LF at z ≃ 8.8 (Willis & Courbin 2005; Cuby et al. 2007; Willis et al. 2008; Sobral et al. 2009; cf. Stark et al. 2007).”
Keck spectroscopy of faint 3 < z < 7 Lyman break galaxies – I. New constraints on cosmic reionization from the luminosity and redshift-dependent fraction of Lyman α emission (2010, background): “…targets, as well as the availability of associated Spitzer and Chandra data which provided valuable stellar masses and active galactic nuclei (AGN)-related properties (Eyles et al. 2005; Yan et al. 2006; Eyles et al. 2007; Stark et al. 2007a, 2009; González et al. 2010; Labbé et al. 2010).”
UV Luminosity Functions at z~4, 5, and 6 from the Hubble Ultra Deep Field and Other Deep Hubble Space Telescope ACS Fields: Evolution and Star Formation History (2007, background): “…with Model Results: The brightening we observe in M∗ from z ∼ 6 to z ∼ 4 (and plausibly from z ∼ 7.4) is almost identical to what one finds in the evolution of the halo mass function over this range (see also Stark et al. 2007c) assuming a constant proportionality between mass and light (see §5.2).”
A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems (2007, background): “15), and in fact, less by factors of 10–30 than the number density inferred by Stark et al. (2007) for z 8– 10 objects.”