The MUSE Ultra Deep Field (MUDF). I. Discovery of a group of Ly$\alpha$ nebulae associated with a bright $z\approx 3.23$ quasar pair

Abstract

We present first results from Multi Unit Spectroscopic Explorer (MUSE) observations at the Very Large Telescope in the MUSE Ultra Deep Field (MUDF), a $\approx 1.2\times 1.4$ arcmin${}^2$ region for which we are collecting $\approx$200 hours of integral field spectroscopy. The $\approx 40$-hour observation completed to date reveals the presence of a group of three Ly$\alpha$ nebulae associated with a bright quasar pair at $z\simeq 3.23$ with projected separation of $\approx 500\mathrm{kpc}$. Two of the nebulae are physically associated with the quasars which are likely powering the Ly$\alpha$ emission, and extend for $\gtrsim 100\mathrm{kpc}$ at a surface brightness level of $\approx 6\times 10^{-19}\mathrm{erg}{\mathrm{s}}^{-1}\mathrm{c}{\mathrm{m}}^{-2}\mathrm{arcse}{\mathrm{c}}^{-2}$. A third smaller ($\approx$35 kpc) nebula lies at a velocity offset of $\approx 1550$ km s${}^{-1}$. Despite their clustered nature, the two large nebulae have properties similar to those observed in isolated quasars and exhibit no sharp decline in flux at the current depth, suggesting an even more extended distribution of gas around the quasars. We interpret the shape and the alignment of the two brighter nebulae as suggestive of the presence of an extended structure connecting the two quasar host galaxies, as seen for massive galaxies forming within gas-rich filaments in cosmological simulations.

MNRAS Letters in press, 3 figures, revised version: minor changes following proofs

References in corpus (12)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• The Circumgalactic Medium
• The MUSE second-generation VLT instrument
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• The large and small scale properties of the intergalactic gas in the Slug Ly-alpha nebula revealed by MUSE HeII emission observations
• Inspiraling Halo Accretion Mapped in Lyman-$\alpha$ Emission around a $z\sim 3$ Quasar
• XQ-100: A legacy survey of one hundred 3.5 < z < 4.5 quasars observed with VLT/XSHOOTER
• MUSE searches for galaxies near very metal-poor gas clouds at z~3: new constraints for cold accretion models
• Witnessing galaxy assembly in an extended z~3 structure
• A measurement of the z = 0 UV background from H$\alpha$ fluorescence
• Stacking the Cosmic Web in Fluorescent Lyman alpha Emission with MUSE
• The MUSE Data Reduction Pipeline: Status after Preliminary Acceptance Europe

Cited by in corpus (18)

• Gas filaments of the cosmic web located around active galaxies in a proto-cluster
• The REQUIEM Survey I: A Search for Extended Ly-Alpha Nebular Emission Around 31 z>5.7 Quasars
• MUSE Analysis of Gas around Galaxies (MAGG) -- II: Metal-enriched halo gas around z~1 galaxies
• MUSE Analysis of Gas around Galaxies (MAGG) -- III: The gas and galaxy environment of z = 3-4.5 quasars
• The MUSE Extremely Deep Field: the Cosmic Web in Emission at High Redshift
• The physical origins and dominant emission mechanisms of Lyman-alpha halos: results from the TNG50 simulation in comparison to MUSE observations
• MUSE Analysis of Gas around Galaxies (MAGG) -- I: Survey design and the environment of a near pristine gas cloud at z~3.5
• MUSE-ALMA Halos V: Physical properties and environment of z < 1.4 HI quasar absorbers
• J-PLUS: Unveiling the brightest-end of the Lyα luminosity function at 2.0<z<3.3 over 1000 deg^2
• MUSE-ALMA Haloes VII: Survey Science Goals & Design, Data Processing and Final Catalogues
• A Multiwavelength Study of ELAN Environments (AMUSE${}^2$). Mass budget, satellites spin alignment and gas infall in a massive $z\sim 3$ quasar host halo
• The MUSE Ultra Deep Field (MUDF). III. Hubble Space Telescope WFC3 Grism Spectroscopy and Imaging
• A search for dust and molecular gas in enormous Ly$\alpha$ nebulae at $z\approx 2$
• QSO MUSEUM II: Search for extended Ly$\alpha$ emission around eight $z\sim 3$ quasar pairs
• A Ly-alpha nebula at z~3.3
• ODIN: A New Lyman Alpha Blob Selection Method, Sample, and Statistical Analysis at $z\sim 3.1$
• Bayesian luminosity function estimation in multi-depth datasets with selection effects: A case study for $3<z<5$ Lyman $\alpha$ emitters
• The MUSE Ultra Deep Field (MUDF) VIII. The cool gas distribution surrounding galaxies at redshifts z ~ 0.5-2