Discovery of an Enormous Lyα Nebula in a Massive Galaxy Overdensity at z = 2.3

Cai, Zheng; Fan, Xiaohui; Yang, Yujin; Bian, Fuyan; Prochaska, J. Xavier; Zabludoff, Ann I.; McGreer, Ian D.; Zheng, Zuduo; Green, Richard; Cantalupo, Sebastiano; Frye, Brenda; Hamden, Erika; Jiang, Linhua; Kashikawa, Nobunari; Wang, Ran

doi:10.3847/1538-4357/aa5d14

Cited by 154 publications

(182 citation statements)

References 87 publications

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“…At z ∼ 2 − 3, luminous LAEs are known to have counterparts in multiwavelength data (e.g., X-ray and radio) and/or extended Lyα haloes (e.g., Steidel et al 2000;Ouchi et al 2008;Cantalupo et al 2014;Cai et al 2017). A recent study, for example, has confirmed that there are excesses found in Lyα LFs at log L(Lyα) [erg s…”

Section: Introductionmentioning

confidence: 72%

SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14–21 deg2 sky

Konno

Ouchi

Shibuya

et al. 2017

Publications of the Astronomical Society of Japan

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We present the Lyα luminosity functions (LFs) at z = 5.7 and 6.6 derived from a new large sample of 1266 Lyα emitters (LAEs) identified in total areas of 14 and 21 deg2, respectively, based on the early narrowband data of the Subaru/Hyper Suprime-Cam survey. Together with careful Monte Carlo simulations that account for the incompleteness of the LAE selection and the flux estimate systematics in the narrowband imaging, we have determined the Lyα LFs with unprecedentedly small statistical and systematic uncertainties in a wide Lyα luminosity range of 1042.8–43.8 erg s−1. We obtain best-fit Schechter parameters of $L^{*}_{\mathrm{Ly}\alpha } = 1.6^{+2.2}_{-0.6} \ (1.7^{+0.3}_{-0.7}) \times 10^{43}\:\mathrm{erg}\:\mathrm{s}^{-1}$, $\phi ^{*}_{\mathrm{Ly}\alpha } = 0.85^{+1.87}_{-0.77} \ (0.47^{+1.44}_{-0.44}) \times 10^{-4}\:\mathrm{Mpc}^{-3}$, and $\alpha = -2.6^{+0.6}_{-0.4} \ (-2.5^{+0.5}_{-0.5})$ at z = 5.7 (6.6). We confirm that our best-estimate Lyα LFs are consistent with the majority of the previous studies, but find that our Lyα LFs do not agree with the high number densities of LAEs recently claimed by Matthee/Santos et al.’s studies that may overcorrect the incompleteness and the flux systematics. Our Lyα LFs at z = 5.7 and 6.6 show an indication that the faint-end slope is very steep (α ≃ −2.5), although it is also possible that the bright-end LF results are enhanced by systematic effects such as the contribution from AGNs, blended merging galaxies, and/or large ionized bubbles around bright LAEs. Comparing our Lyα LF measurements with four independent reionization models, we estimate the neutral hydrogen fraction of the intergalactic medium to be $x_\mathrm{H\,{\small I}} = 0.3 \pm 0.2$ at z = 6.6, which is consistent with the small Thomson scattering optical depth obtained by Planck 2016.

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Section: Introductionmentioning

confidence: 72%

SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14–21 deg2 sky

Konno

Ouchi

Shibuya

et al. 2017

Publications of the Astronomical Society of Japan

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185

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“…The center of the MAMMOTH-I Nebula was classified by Cai et al (2017b) as 'source B'. 1 We adopt their terminology, and associate region B with the central group of galaxies, which is surrounded by diffuse light in the HST imaging.…”

Section: The Central Group (B)mentioning

confidence: 99%

“…In this paper, we present observations of extended molecular gas across a radio-quiet ELAN, namely the MAMMOTH-I Nebula at z = 2.3. The MAMMOTH-I Nebula is one of the most extreme ELANe found to date, with Lyα emission stretching across ∼440 kpc (Cai et al 2017b). It is located in the extreme galaxy overdensity BOSS1441, which traces a proto-cluster (Cai et al 2017a;Arrigoni Battaia et al 2018b;Mukae et al 2019).…”

Section: Introductionmentioning

confidence: 99%

The Cold Circumgalactic Environment of MAMMOTH-I: Dynamically Cold Gas in the Core of an Enormous Lyα Nebula

Emonts

Cai

Prochaska

et al. 2019

ApJ

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The MAMMOTH-I Nebula at redshift 2.3 is one of the largest known Lyα nebulae in the Universe, spanning ∼440 kpc. Enormous Lyα nebulae like MAMMOTH-I typically trace the densest and most active regions of galaxy formation. Using sensitive low-surface-brightness observations of CO(1-0) with the Very Large Array, we trace the cold molecular gas in the inner 150 kpc of the MAMMOTH-I Nebula. CO is found in four regions that are associated with either galaxies or groups of galaxies that lie inside the nebula. In three of the regions, the CO stretches up to ∼30 kpc into the circum-galactic medium (CGM). In the centermost region, the CO has a very low velocity dispersion (FWHM CO ∼ 85 km s −1 ), indicating that this gas is dynamically cold. This dynamically cold gas coincides with diffuse restframe optical light in the CGM around a central group of galaxies, as discovered with the Hubble Space Telescope. We argue that this likely represents cooling of settled and enriched gas in the center of MAMMOTH-I. This implies that the dynamically cold gas in the CGM, rather than the obscured AGN, marks the core of the potential well of this Lyα nebula. In total, the CO in the MAMMOTH-I Nebula traces a molecular gas mass of M H2 ∼ 1.4 (α CO /3.6) × 10 11 M , with roughly 50% of the CO(1-0) emission found in the CGM. Our results add to the increasing evidence that extended reservoirs of molecular gas exist in the CGM of massive high-z galaxies and proto-clusters.

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“…Warren & Møller 1996;Weatherley et al 2005;Cucciati et al 2014;Fumagalli et al 2016a;Bielby et al 2016;Péroux et al 2017;Cai et al 2017). However, due to the difficulty in mapping neutral hydrogen in emission at high redshift, until recently it has proven challenging to study in detail the connection between gas and galaxies inside overdensities beyond z 2.…”

Section: Introductionmentioning

confidence: 99%

Witnessing galaxy assembly in an extended z≈3 structure

Fumagalli

Mackenzie

Trayford

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present new observations acquired with the Multi Unit Spectroscopic Explorer instrument on the Very Large Telescope in a quasar field that hosts a high columndensity damped Lyα absorber (DLA) at z ≈ 3.25. We detect Lyα emission from a nebula at the redshift of the DLA with line luminosity (27 ± 1) × 10 41 erg s −1 , which extends over 37±1 kpc above a surface brightness limit of 6×10 −19 erg s −1 cm −2 arcsec −2 at a projected distance of 30.5±0.5 kpc from the quasar sightline. Two clumps lie inside this nebula, both with Lyα rest-frame equivalent width > 50 Å and with relative lineof-sight velocities aligned with two main absorption components seen in the DLA spectrum. In addition, we identify a compact galaxy at a projected distance of 19.1 ± 0.5 kpc from the quasar sightline. The galaxy spectrum is noisy but consistent with that of a star-forming galaxy at the DLA redshift. We argue that the Lyα nebula is ionized by radiation from star formation inside the two clumps, or by radiation from the compact galaxy. In either case, these data imply the presence of a structure with size 50 kpc inside which galaxies are assembling, a picture consistent with galaxy formation in groups and filaments as predicted by cosmological simulations such as the eagle simulations.

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Discovery of an Enormous Lyα Nebula in a Massive Galaxy Overdensity at z = 2.3

Cited by 154 publications

References 87 publications

SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14–21 deg2 sky

SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14–21 deg2 sky

The Cold Circumgalactic Environment of MAMMOTH-I: Dynamically Cold Gas in the Core of an Enormous Lyα Nebula

Witnessing galaxy assembly in an extended z≈3 structure

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