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Register a new userMapping the invisible circumgalactic medium around a z $sim$ 4.5 radio galaxy with MUSE
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In this paper we present Multi Unit Spectroscopic Explorer (MUSE) integral field unit spectroscopic observations of the $sim70times30$ kpc$^2$ Ly$alpha$ halo around the radio galaxy 4C04.11 at $z = 4.5077$. High-redshift radio galaxies (HzRGs) are hosted by some of the most massive galaxies known at any redshift and are unique markers of concomitant powerful active galactic nucleus (AGN) activity and star formation episodes. We map the emission and kinematics of the Ly$alpha$ across the halo as well as the kinematics and column densities of eight HI absorbing systems at $-3500 < Delta v < 0$ km s$^{-1}$. We find that the strong absorber at $Delta v sim 0,rm km,s^{-1}$ has a high areal coverage ($30times30$ kpc$^2$), being detected across a large extent of the Ly$alpha$ halo, a significant column density gradient along the southwest to northeast direction, and a velocity gradient along the radio jet axis. We propose that the absorbing structure, which is also seen in CIV and NV absorption, represents an outflowing metal-enriched shell driven by a previous AGN or star formation episode within the galaxy and is now caught up by the radio jet, leading to jet-gas interactions. These observations provide evidence that feedback from AGN in some of the most massive galaxies in the early Universe may play an important role in redistributing material and metals in their environments.
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We present gravitational-arc tomography of the cool-warm enriched circumgalactic medium (CGM) of an isolated galaxy (``G1) at $z approx 0.77$. Combining VLT/MUSE adaptive-optics and Magellan/MagE echelle spectroscopy we obtain partially-resolved kinematics of MgII in absorption and [OII] in emission. The unique arc configuration allows us to probe 42 spatially independent arc positions transverse to G1, plus 4 positions in front of it. The transverse positions cover G1s minor and major axes at impact parameters of $approx 10-30$ kpc and $approx 60$ kpc, respectively. We observe a direct kinematic connection between the cool-warm enriched CGM (traced by MgII) and the interstellar medium (traced by [OII]). This provides strong evidence for the existence of an extended disc that co-rotates with the galaxy out to tens of kiloparsecs. The MgII velocity dispersion ($sigma approx 30-100$ km s$^{-1}$, depending on position) is of the same order as the modeled galaxy rotational velocity ($v_{rm rot} approx 80$ km s$^{-1}$), providing evidence for the presence of a turbulent and pressure-supported CGM component. We regard the absorption to be modulated by a galactic-scale outflow, as it offers a natural scenario for the observed line-of-sight dispersion and asymmetric profiles observed against both the arcs and the galaxy. An extended enriched co-rotating disc together with the signatures of a galactic outflow, are telltale signs of metal recycling in the $zsim 1$ CGM.
We demonstrate the presence of an extended and massive circumgalactic medium (CGM) around Messier 31 using archival HST COS ultraviolet spectroscopy of 18 QSOs projected within two virial radii of M31 (Rvir=300 kpc). We detect absorption from SiIII at -300<vLSR}<-150 km/s toward all 3 sightlines at R<0.2Rvir, 3 of 4 sightlines at 0.8<R/Rvir<1.1, and possibly 1 of 11 at 1.1<R/Rvir<1.8. We present several arguments that the gas at these velocities observed in these directions originates from the CGM of M31 rather than the Local Group or Milky Way CGM or Magellanic Stream. We show that the dwarf galaxies located in the CGM of M31 have very similar velocities over similar projected distances from M31. We find a non-trivial relationship only at these velocities between the column densities (N) of all the ions and R, whereby N decreases with increasing R. Singly ionized species are only detected in the inner CGM of M31 at R<0.2Rvir. At R<0.8 Rvir, the covering fraction is close to unity for SiIII and CIV (fc~60%-97% at the 90% confidence level), but drops to fc<10-20% at R>Rvir. We show that the M31 CGM gas is bound, multiphase, predominantly ionized (i.e., HII>>HI), and becomes more highly ionized gas at larger R. We estimate using SiII, SiIII, and SiIV a CGM metal mass of at least 2x10^6 Msun and gas mass of >3x10^9(Zsun/Z) Msun within 0.2 Rvir, and possibly a factor ~10 larger within Rvir, implying substantial metal and gas masses in the CGM of M31. Compared with galaxies in the COS-Halos survey, the CGM of M31 appears to be quite typical for a L* galaxy.
We present a study of the environment of 27 z=3-4.5 bright quasars from the MUSE Analysis of Gas around Galaxies (MAGG) survey. With medium-depth MUSE observations (4 hours on target per field), we characterise the effects of quasars on their surroundings by studying simultaneously the properties of extended gas nebulae and Lyalpha emitters (LAEs) in the quasar host haloes. We detect extended (up to ~ 100 kpc) Lyalpha emission around all MAGG quasars, finding a very weak redshift evolution between z=3 and z=6. By stacking the MUSE datacubes, we confidently detect extended emission of CIV and only marginally detect extended HeII up to ~40 kpc, implying that the gas is metal enriched. Moreover, our observations show a significant overdensity of LAEs within 300 km/s from the quasar systemic redshifts estimated from the nebular emission. The luminosity functions and equivalent width distributions of these LAEs show similar shapes with respect to LAEs away from quasars suggesting that the Lyalpha emission of the majority of these sources is not significantly boosted by the quasar radiation or other processes related to the quasar environment. Within this framework, the observed LAE overdensities and our kinematic measurements imply that bright quasars at z=3-4.5 are hosted by haloes in the mass range ~ 10^{12.0}-10^{12.5} Msun.
We present a study of the galaxy environment of 9 strong HI+CIV absorption line systems ($16.2<{rm log}(N({rm HI}))<21.2$) spanning a wide range in metallicity at $zsim4-5$, using MUSE integral field and X-Shooter spectroscopic data collected in a $zapprox 5.26$ quasar field. We identify galaxies within a 250 kpc and $pm1000$ km s$^{-1}$ window for 6 out of the 9 absorption systems, with 2 of the absorption line systems showing multiple associated galaxies within the MUSE field of view. The space density of Ly$alpha$ emitting galaxies (LAEs) around the HI and CIV systems is $approx10-20$ times the average sky density of LAEs given the flux limit of our survey, showing a clear correlation between the absorption and galaxy populations. Further, we find that the strongest CIV systems in our sample are those that are most closely aligned with galaxies in velocity space, i.e. within velocities of $pm500$ km s$^{-1}$. The two most metal poor systems lie in the most dense galaxy environments, implying we are potentially tracing gas that is infalling for the first time into star-forming groups at high redshift. Finally, we detect an extended Ly$alpha$ nebula around the $zapprox 5.26$ quasar, which extends up to $approx50$ kpc at the surface brightness limit of $3.8 times 10^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$. After scaling for surface brightness dimming, we find that this nebula is centrally brighter, having a steeper radial profile than the average for nebulae studied at $zsim3$ and is consistent with the mild redshift evolution seen from $zapprox 2$.
We utilize the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT) to search for extended Lyman-Alpha emission around the z~6.6 QSO J0305-3150. After carefully subtracting the point-spread-function, we reach a nominal 5-sigma surface brightness limit of SB = 1.9x10$^{-18}$ erg/s/cm$^2$/arcsec$^2$ over a 1 arcsec$^2$ aperture, collapsing 5 wavelength slices centered at the expected location of the redshifted Lyman-Alpha emission (i.e. at 9256 Ang.). Current data suggest the presence (5-sigma, accounting for systematics) of a Lyman-Alpha nebula that extends for 9 kpc around the QSO. This emission is displaced and redshifted by 155 km/s with respect to the location of the QSO host galaxy traced by the [CII] emission line. The total luminosity is L = 3.0x10$^{42}$ erg/s. Our analysis suggests that this emission is unlikely to rise from optically thick clouds illuminated by the ionizing radiation of the QSO. It is more plausible that the Lyman-Alpha emission is due to fluorescence of the highly ionized optically thin gas. This scenario implies a high hydrogen volume density of n$_H$ ~ 6 cm$^{-3}$. In addition, we detect a Lyman-Alpha emitter (LAE) in the immediate vicinity of the QSO: i.e., with a projected separation of 12.5 kpc and a line-of-sight velocity difference of 560 km/s. The luminosity of the LAE is L = 2.1x10$^{42}$ erg/s and its inferred star-formation-rate is SFR ~ 1.3 M$_odot$/yr. The probability of finding such a close LAE is one order of magnitude above the expectations based on the QSO-galaxy cross-correlation function. This discovery is in agreement with a scenario where dissipative interactions favour the rapid build-up of super-massive black holes at early Cosmic times.
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