88 research outputs found
Keck/Palomar Cosmic Web Imagers (KCWI/PCWI) Reveal an Enormous Ly Nebula in an Extremely Overdense QSO Pair Field at
Enormous Ly nebulae (ELANe) represent the extrema of Ly
nebulosities. They have detected extents of kpc in Ly and
Ly luminosities erg s. The ELAN population is an
ideal laboratory to study the interactions between galaxies and the
intergalactic/circumgalactic medium (IGM/CGM) given their brightness and sizes.
The current sample size of ELANe is still very small, and the few
ELANe discovered to date are all associated with local overdensities of active
galactic nuclei (AGNs). Inspired by these results, we have initiated a survey
of ELANe associated with QSO pairs using the Palomar and Keck Cosmic Web
Imagers (PCWI/KCWI). In this letter, we present our first result: the discovery
of ELAN0101+0201 associated with a QSO pair at . Our PCWI discovery
data shows that, above a 2- surface brightness of
\sbunit, the end-to-end size of ELAN0101+0201 is kpc. We have
conducted follow-up observations using KCWI, resolving multiple Ly
emitting sources within the rectangular field-of-view of
projected kpc, and obtaining their emission line profiles at high
signal-to-noise ratios. Combining both KCWI and PCWI, our observations confirm
that ELAN0101+0201 resides in an extremely overdense environment. Our
observations further support that a large amount of cool (K) gas
could exist in massive halos (MM) at .
Future observations on a larger sample of similar systems will provide
statistics of how cool gas is distributed in massive overdensities at
high-redshift and strongly constrain the evolution of the intracluster medium
(ICM).Comment: Submitted to Astrophysical Journal Letter, 9 pages, 4 figures,
Comments Welcom
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
Exploring HeII1640 emission line properties at
Deep optical spectroscopic surveys of galaxies provide us a unique
opportunity to investigate rest-frame ultra-violet (UV) emission line
properties of galaxies at . Here we combine VLT/MUSE Guaranteed
Time Observations of the Hubble Deep Field South, Ultra Deep Field, COSMOS, and
several quasar fields with other publicly available data from VLT/VIMOS and
VLT/FORS2 to construct a catalogue of HeII1640 emitters at
. The deepest areas of our MUSE pointings reach a line
flux limit of 3.110-19 erg/ s/ cm. After discarding broad line
active galactic nuclei we find 13 HeII1640 detections from MUSE with
a median MUV = and 21 tentative HeII1640 detections from
other public surveys. Excluding Ly, all except two galaxies in our
sample show at least one other rest-UV emission line, with
CIII]1907,1909 being the most prominent. We use
multi-wavelength data available in the Hubble legacy fields to derive basic
galaxy properties of our sample via spectral energy distribution fitting
techniques. Taking advantage of the high quality spectra obtained by MUSE
(h of exposure time per pointing), we use photo-ionisation
models to study the rest-UV emission line diagnostics of the
HeII1640 emitters. Line ratios of our sample can be reproduced by
moderately sub-solar photo-ionisation models, however, we find that including
effects of binary stars lead to degeneracies in most free parameters. Even
after considering extra ionising photons produced by extreme sub-solar
metallicity binary stellar models, photo-ionisation models are unable to
reproduce rest-frame HeII1640 equivalent widths ( 0.2 - 10
A), thus additional mechanisms are necessary in models to match the observed
HeII1640 properties.Comment: Accepted to A&A, 31 pages, 17 figure
Direct evidence of AGN feedback: a post-starburst galaxy stripped of its gas by AGN-driven winds
Post-starburst E+A galaxies show indications of a powerful starburst that was quenched abruptly. Their disturbed, bulge-dominated morphologies suggest that they are merger remnants. The more massive E+A galaxies are suggested to be quenched by active galactic nucleus (AGN) feedback, yet little is known about AGN-driven winds in this short-lived phase. We present spatially resolved integral field unit spectroscopy by the Keck Cosmic Web Imager of SDSS J003443.68 + 251020.9, at z = 0.118. The system consists of two galaxies, the larger of which is a post-starburst E+A galaxy hosting an AGN. Our modelling suggests a 400 Myr starburst, with a peak star formation rate of 120 Mâ yr^(â1). The observations reveal stationary and outflowing gas, photoionized by the central AGN. We detect gas outflows to a distance of 17 kpc from the central galaxy, far beyond the region of the stars (âŒ3 kpc), inside a conic structure with an opening angle of 70 deg. We construct self-consistent photoionization and dynamical models for the different gas components and show that the gas outside the galaxy forms a continuous flow, with a mass outflow rate of about 24 Mâ yr^(â1). The gas mass in the flow, roughly 10^9Mââ , is larger than the total gas mass within the galaxy, some of which is outflowing too. The continuity of the flow puts a lower limit of 60 Myr on the duration of the AGN feedback. Such AGNs are capable of removing, in a single episode, most of the gas from their host galaxies and expelling enriched material into the surrounding circumgalactic medium
Centrotemporal spikes during NREM sleep: The promoting action of thalamus revealed by simultaneous EEG and fMRI coregistration
Benign childhood epilepsy with centrotemporal spikes (BECTS) has been investigated through EEG\u2013fMRI
with the aim of localizing the generators of the epileptic activity, revealing, in most cases, the activation of
the sensory\u2013motor cortex ipsilateral to the centrotemporal spikes (CTS). In this case report, we investigated
the brain circuits hemodynamically involved by CTS recorded during wakefulness and sleep in one boy with
CTS and a language disorder but without epilepsy. For this purpose, the patient underwent EEG\u2013fMRI
coregistration. During the \u201cawake session\u201d, fMRI analysis of right-sided CTS showed increments of BOLD signal
in the bilateral sensory\u2013motor cortex. During the \u201csleep session\u201d, BOLD increments related to right-sided
CTS were observed in a widespread bilateral cortical\u2013subcortical network involving the thalamus, basal
ganglia, sensory\u2013motor cortex, perisylvian cortex, and cerebellum.
In this patient, who fulfilled neither the diagnostic criteria for BECTS nor that for electrical status epilepticus
in sleep (ESES), the transition from wakefulness to sleep was related to the involvement of a widespread
cortical\u2013subcortical network related to CTS. In particular, the involvement of a thalamic\u2013perisylvian neural
network similar to the one previously observed in patients with ESES suggests a common sleep-related
network dysfunction even in cases with milder phenotypes without seizures. This finding, if confirmed in a
larger cohort of patients, could have relevant therapeutic implication
Unraveling the knots of gaseous Cosmic Web filaments at z 3 through H-alpha emission observations
Our cosmological model predicts that most of the matter in the universe is distributed in a network of filaments - the Cosmic Web - in which galaxies form and evolve. Because most of this material is very diffuse, its direct imaging has for long remained elusive, leaving many questions still open, e.g.: what are the morphological and kinematical properties of the Cosmic Web on both small (kpc) and large (Mpc) scales? How do galaxies get their gas from the Cosmic Web? Here, we tackle these questions with an innovative method to detect in emission the gaseous Cosmic Web using bright quasars as "cosmic flashlights". In particular, we propose to observe in H-alpha emission two fields at z~3 which contain the largest Cosmic Web filaments - over 4 cMpc in length - discovered so far in deep MUSE Ly-alpha emission searches around bright quasars. Because Ly-alpha is affected by radiative transfer which change both its spatial and spectral distribution, non-resonant H-alpha observations are fundamental in order to directly constrain both the filament densities and kinematics. The filament projected angular sizes are perfectly suited for NIRSpec-MOS which can trace the filaments over their full length capturing, at the same time, several embedded galaxies. Our H-alpha observations will probe structures within the filaments on scales smaller than a few physical kpc directly constraining both their density and kinematics. By relating these quantities to the kinematics and distance from associated galaxies, our result will be fundamental to informing a new generation of theoretical and numerical models in order to reveal the physics of intergalactic gas accretion and galactic outflows
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