Mapping the Lyα Emission around a z ∼ 6.6 QSO with MUSE: Extended Emission and a Companion at a Close Separation

Journal Article · Fri Oct 20 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA8DF4· OSTI ID:22875694

Farina, Emanuele P.; Venemans, Bram P.; Decarli, Roberto; Hennawi, Joseph F.; Walter, Fabian; Mazzucchelli, Chiara ^[1]; Bañados, Eduardo ^[2]; Cantalupo, Sebastiano ^[3]; Arrigoni-Battaia, Fabrizio ^[4]

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1. Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany)
2. The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
3. Institute for Astronomy, Department of Physics, ETH Zürich, Wolfgang-Pauli-Strasse 27, CH 8093, Zürich (Switzerland)
4. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748, Garching bei München (Germany)

We utilize the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope to search for extended Lyα emission around the z ∼ 6.6 QSO J0305−3150. After carefully subtracting the point spread function, we reach a nominal 5σ surface-brightness limit of SB{sub 5σ} = 1.9 × 10{sup −18} erg s{sup −1} cm{sup −2} arcsec{sup −2} over a 1 arcsec{sup 2} aperture, collapsing five wavelength slices centered at the expected location of the redshifted Lyα emission (i.e., at 9256 Å). Current data suggest the presence (5σ accounting for systematics) of a Lyα nebula that extends for 9 kpc around the QSO. This emission is displaced and redshifted by 155 km s{sup −1} with respect to the location of the QSO host galaxy traced by the [C II] 158 μm emission line. The total luminosity is L(Lyα) = (3.0 ± 0.4) × 10{sup 42} erg s{sup −1}. 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 Lyα emission is due to the fluorescence of the highly ionized optically thin gas. This scenario implies a high hydrogen volume density of n{sub H}∼6 cm{sup −3}. In addition, we detect a Lyα 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{sup −1}. The luminosity of the LAE is L(Lyα) = (2.1 ± 0.2) × 10{sup 42} erg s{sup −1} and its inferred star-formation rate is SFR ∼ 1.3 M {sub ⊙} yr{sup −1}. 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 favor the rapid build-up of supermassive black holes at early cosmic times.

• OSTI ID: 22875694
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 848; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
APERTURES
BLACK HOLES
BRIGHTNESS
CORRELATION FUNCTIONS
COSMOLOGY
DENSITY
FLUORESCENCE
GALAXIES
HYDROGEN
IONIZING RADIATIONS
LUMINOSITY
LYMAN LINES
NEBULAE
QUASARS
RED SHIFT
STARS
TELESCOPES
VELOCITY