51 research outputs found
Mapping the Lyman-Alpha Emission Around a z~6.6 QSO with MUSE: Extended Emission and a Companion at Close Separation
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
erg/s/cm/arcsec over a 1 arcsec 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 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 ~ 6 cm. 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 erg/s and its inferred
star-formation-rate is SFR ~ 1.3 M/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.Comment: 17 pages, 15 figures. Accepted for publication in Ap
Mapping the Lyman-Alpha Emission Around a z~6.6 QSO with MUSE: Extended Emission and a Companion at Close Separation
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
erg/s/cm/arcsec over a 1 arcsec 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 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 ~ 6 cm. 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 erg/s and its inferred
star-formation-rate is SFR ~ 1.3 M/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.Comment: 17 pages, 15 figures. Accepted for publication in Ap
The MUSE-Wide survey: A measurement of the Ly emitting fraction among galaxies
We present a measurement of the fraction of Lyman (Ly)
emitters () amongst HST continuum-selected galaxies at
with the Multi-Unit Spectroscopic Explorer (MUSE) on the VLT. Making
use of the first 24 MUSE-Wide pointings in GOODS-South, each having an
integration time of 1 hour, we detect 100 Ly emitters and find
for most of the redshift range covered, with 29
per cent of the Ly sample exhibiting rest equivalent widths (rest-EWs)
15\AA. Adopting a range of rest-EW cuts (0 - 75\AA), we find no evidence
of a dependence of on either redshift or UV luminosity.Comment: 10 pages, 5 figures (MNRAS, updated as per version in press
The MUSE Hubble Ultra Deep Field Survey X. Ly Equivalent Widths at
We present rest-frame Ly equivalent widths (EW) of 417 Ly
emitters (LAEs) detected with Multi Unit Spectroscopic Explorer (MUSE) on the
Very Large Telescope (VLT) at in the Hubble Ultra Deep Field.
Based on the deep MUSE spectroscopy and ancillary Hubble Space Telescope (HST)
photometry data, we carefully measured EW values taking into account extended
Ly emission and UV continuum slopes (). Our LAEs reach
unprecedented depths, both in Ly luminosities and UV absolute
magnitudes, from log(/erg s) 41.0 to 43.0 and
from Muv -16 to -21 (0.01-1.0 ). The EW values span the
range of 5 to 240 \AA\ or larger, and their distribution can be well
fitted by an exponential law exp(EW/). Owing to
the high dynamic range in Muv, we find that the scale factor, ,
depends on Muv in the sense that including fainter Muv objects increases
, i.e., the Ando effect. The results indicate that selection
functions affect the EW scale factor. Taking these effects into account, we
find that our values are consistent with those in the literature
within uncertainties at at a given threshold of Muv
and . Interestingly, we find 12 objects with EW \AA\
above uncertainties. Two of these 12 LAEs show signatures of merger
or AGN activity: the weak CIV emission line. For the remaining
10 very large EW LAEs, we find that the EW values can be reproduced by young
stellar ages ( Myr) and low metallicities ( ). Otherwise, at least part of the Ly emission in these LAEs
needs to arise from anisotropic radiative transfer effects, fluorescence by
hidden AGN or quasi-stellar object activity, or gravitational cooling.Comment: 22 pages, 12 figures, 9 tables, accepted for publication in A&A (MUSE
UDF Series Paper X
Ubiquitous giant Ly nebulae around the brightest quasars at revealed with MUSE
Direct Ly imaging of intergalactic gas at has recently
revealed giant cosmological structures around quasars, e.g. the Slug Nebula
(Cantalupo et al. 2014). Despite their high luminosity, the detection rate of
such systems in narrow-band and spectroscopic surveys is less than 10%,
possibly encoding crucial information on the distribution of gas around quasars
and the quasar emission properties. In this study, we use the MUSE
integral-field instrument to perform a blind survey for giant Ly
nebulae around 17 bright radio-quiet quasars at that does not suffer
from most of the limitations of previous surveys. After data reduction and
analysis performed with specifically developed tools, we found that each quasar
is surrounded by giant Ly nebulae with projected sizes larger than 100
physical kpc and, in some cases, extending up to 320 kpc. The circularly
averaged surface brightness profiles of the nebulae appear very similar to each
other despite their different morphologies and are consistent with power laws
with slopes . The similarity between the properties of all these
nebulae and the Slug Nebula suggests a similar origin for all systems and that
a large fraction of gas around bright quasars could be in a relatively "cold"
(T10K) and dense phase. In addition, our results imply that such gas
is ubiquitous within at least 50 kpc from bright quasars at
independently of the quasar emission opening angle, or extending up to 200 kpc
for quasar isotropic emission.Comment: 19 pages, 9 figures, 3 Tables, accepted to Ap
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