QSO MUSEUM I: a sample of 61 extended Ly α-emission nebulae surroundingz∼ 3 quasars

Abstract

Motivated by the recent discovery of rare Enormous Lyman-Alpha Nebulae (ELAN) around z ∼ 2 quasars, we have initiated a long-term observational campaign with the MUSE/VLT instrument to directly uncover the astrophysics of the gas around quasars. We present here the first 61 targets of our effort under the acronym QSO MUSEUM (Quasar Snapshot Observations with MUse: Search for Extended Ultraviolet eMission). These quasars are characterized by a median redshfit of z = 3.17 (3.03 < z < 3.46), absolute i magnitude in the range −29.67 ≤ M i (z = 2) ≤ −27.03, and different levels of radio-loudness. This sample unveils diverse specimens of Lyα nebulosities extending for tens of kiloparsecs around these quasars (on average out to a maximum projected distance of 80 kpc) above a surface brightness SB> 8.8×10 −19 erg s −1 cm −2 arcsec −2 (2σ ). Irrespective of the radio-loudness of the targets, the bulk of the extended Lyα emission is within R < 50 kpc, and is characterized by relatively quiescent kinematics, with average velocity dispersions of σ Lyα < 400 km s −1 . Therefore, the motions within all these Lyα nebulosities have amplitudes consistent with gravitational motions expected in dark matter halos hosting quasars at these redshifts, possibly reflecting the complexity in propagating a fast wind on large scales. Our current data suggest a combination of photoionization and resonant scattering as powering mechanisms of the Lyα emission. We discover the first z ∼ 3 ELAN, which confirms a very low probability (∼ 1%) of occurrence of such extreme systems at these cosmic epochs. Finally, we discuss the redshift evolution currently seen in extended Lyα emission around radio-quiet quasars from z ∼ 3 to z ∼ 2, concluding that it is possibly linked to a decrease of cool gas mass within the quasars' CGM from z ∼ 3 to z ∼ 2, and thus to the balance of cool vs hot media. Overall, QSO MUSEUM opens the path to statistical and homogeneous surveys targeting the gas phases in quasars' halos along cosmic times.

Gas filaments of the cosmic web located around active galaxies in a protocluster

“…MUSE PSFs are stable during long exposures (e.g., 43). We selected a subset of the cube spanning 150 spectral pixels, or 187.5 Å, within which we mask the wavelength range where the redshifted Ly α emission line was expected (4940.4 Å-5002.9 Å) (see (44) for more details). After PSF subtraction, we proceeded to subtract the continuum of the remaining sources using the CUBEBKGSUB procedure in CUBEXTRACTOR, which is based on a fast medianfiltering approach.…”

How cold gas continuously entrains mass and momentum from a hot wind

“…Absorption line measurements of bright background sources such as quasars (Werk et al 2014;Prochaska et al 2017;Ho et al 2017) or (stacks of) galaxies (Steidel et al 2010;Rubin et al 2017) paired with the knowledge of a foreground galaxies as well as direct emission maps (Hennawi et al 2015;Wisotzki et al 2016;Arrigoni Battaia et al 2019) all draw a picture of large amounts of cold gas in the circumgalactic medium of distant and galaxies (also see review by Tumlinson et al 2017).…”

A Giant Lyα Nebula and a Small-scale Clumpy Outflow in the System of the Exotic Quasar J0952+0114 Unveiled by MUSE∗

“…The reduction of the J0952+0114 data comprises a combination of recipes from the standard ESO MUSE Data Reduction Software (DRS, pipeline version 1.6, Weilbacher 2015) and from CubExtractor software package (CubEx in brief, S. Cantalupo 2019, in preparation; the reader is referred to B16, M18; Arrigoni Battaia et al 2019;Cantalupo et al 2019-hereafter A19 and C19-for a description). We employed MUSE scibasic and MUSE scipost routines to perform standard calibration steps on the raw data: master bias, (initial) master flat-fielding, twilight, illumination corrections; wavelength and flux calibrations.…”