35 research outputs found
Too Influential or Too Inadequate? A Critical Discourse Analysis of Environmental Advertising
This study focused on how environmental advertising constructs messages and shapes reality for consumers. Guided by discourse theory, this study used critical discourse analysis to examine and thematize images of environmental advertisements, resulting in the four themes of personalizing, personification, time, and shock value over specifics. From these findings and their analysis, it became clear that today’s consumers of environmental advertising are in a predicament: these advertisements create unwarranted feelings of responsibility, blame, and pressure, while simultaneously falling short in offering substantive advice on how to make meaningful change. To address this twofold problem, this study created a guide to be a more critical consumer of media, as well as a suggested media campaign to offer a better approach to environmental advertising
Widespread QSO-driven outflows in the early Universe
We present the stacking analysis of a sample of 48 quasi-stellar objects (QSOs) at 4.5 < z < 7.1 detected by the Atacama Large
Millimetre Array (ALMA) in the [CII] \u3bb158 \ub5m emission line to investigate the presence and the properties of massive, cold outflows
associated with broad wings in the [CII] profile. The high sensitivity reached through this analysis allows us to reveal very broad
[CII] wings tracing the presence of outflows with velocities in excess of 1000 km s 121. We find that the luminosity of the broad [CII]
emission increases with LAGN, while it does not significantly depend on the star formation rate of the host galaxy, indicating that the
central active galactic nucleus (AGN) is the main driving mechanism of the [CII] outflows in these powerful, distant QSOs. From
the stack of the ALMA cubes, we derive an average outflow spatial extent of 3c3.5 kpc. The average atomic neutral mass outflow rate
inferred from the stack of the whole sample is M\u2d9out 3c 100 M yr 121, while for the most luminous systems it increases to 3c200 M yr 121.
The associated outflow kinetic power is about 0.1% of LAGN, while the outflow momentum rate is 3cLAGN/c or lower, suggesting that
these outflows are either driven by radiation pressure onto dusty clouds or, alternatively, are driven by the nuclear wind and energy
conserving but with low coupling with the interstellar medium. We discuss the implications of the resulting feedback effect on galaxy
evolution in the early Universe
Widespread {QSO}-driven outflows in the early Universe
We present the stacking analysis of a sample of 48 quasi-stellar objects (QSOs) at 4.5 < z < 7.1 detected by the Atacama Large Millimetre Array (ALMA) in the [CII] lambda 158 mu m emission line to investigate the presence and the properties of massive, cold outflows associated with broad wings in the [CII] profile. The high sensitivity reached through this analysis allows us to reveal very broad [CII] wings tracing the presence of outflows with velocities in excess of 1000 km s(-1). We find that the luminosity of the broad [CII] emission increases with L-AGN, while it does not significantly depend on the star formation rate of the host galaxy, indicating that the central active galactic nucleus (AGN) is the main driving mechanism of the [CII] outflows in these powerful, distant QSOs. From the stack of the ALMA cubes, we derive an average outflow spatial extent of similar to 3.5 kpc. The average atomic neutral mass outflow rate inferred from the stack of the whole sample is (M)over dot(out) similar to 100 M-circle dot yr(-1), while for the most luminous systems it increases to similar to 200 M(circle dot)yr(-1). The associated outflow kinetic power is about 0.1% of LAGN, while the outflow momentum rate is similar to L-AGN/C or lower, suggesting that these outflows are either driven by radiation pressure onto dusty clouds or, alternatively, are driven by the nuclear wind and energy conserving but with low coupling with the interstellar medium. We discuss the implications of the resulting feedback effect on galaxy evolution in the early Universe
Cold molecular outflows in the local Universe and their feedback effect on galaxies
We study molecular outflows in a sample of 45 local galaxies, both star
forming and AGN, primarily by using CO data from the ALMA archive and from the
literature. For a subsample we also compare the molecular outflow with the
ionized and neutral atomic phases. We infer an empirical analytical function
relating the outflow rate simultaneously to the SFR, , and galaxy
stellar mass; this relation is much tighter than the relations with the
individual quantities. The outflow kinetic power shows a larger scatter than in
previous, more biased studies, spanning from 0.1 to 5 per cent of , while the momentum rate ranges from 1 to 30 times ,
indicating that these outflows can be both energy-driven, but with a broad
range of coupling efficiencies with the ISM, and radiation pressure-driven. For
about 10 per cent of the objects the outflow energetics significantly exceed
the maximum theoretical values; we interpret these as 'fossil outflows'
resulting from activity of a past strong AGN, which has now faded. We estimate
that, in the stellar mass range probed here ( 10), less
than 5 per cent of the outflowing gas escapes the galaxy. The molecular gas
depletion time associated with the outflow can be as short as a few million
years in powerful AGN, however, the total gas (H+HI) depletion times are
much longer. Altogether, our findings suggest that even AGN-driven outflows
might be relatively ineffective in clearing galaxies of their entire gas
content, although they are likely capable of clearing and quenching the central
region
MUSE view of Arp220: Kpc-scale multi-phase outflow and evidence for positive feedback
Arp220 is the nearest and prototypical ULIRG, and shows evidence of pc-scale
molecular outflows in its nuclear regions and strongly perturbed ionised gas
kinematics on kpc scales. It is therefore the ideal system for investigating
outflows and feedback phenomena in details. We investigate the feedback effects
on the Arp220 ISM, deriving a detailed picture of the atomic gas in terms of
physical and kinematic properties, with a spatial resolution never obtained
before (0.56", i.e. ~ 210 pc). We use optical IFS observations from VLT/MUSE-AO
to obtain spatially resolved stellar and gas kinematics, for both ionised ([N
II]6583) and neutral (Na ID5891,96) components; we also derive dust
attenuation, electron density, ionisation conditions and hydrogen column
density maps to characterise the ISM properties. Arp220 kinematics reveal the
presence of a disturbed, kpc-scale disk in the innermost nuclear regions, and
highly perturbed, multi-phase (neutral and ionised) gas along the minor-axis of
the disk, which we interpret as a galactic-scale outflow emerging from the
Arp220 eastern nucleus. This outflow involves velocities up to ~ 1000 km/s at
galactocentric distances of ~ 5 kpc, and has a mass rate of ~ 50 Msun/yr, and
kinetic and momentum power of ~ 1e43 erg/s and ~ 1e35 dyne, respectively. The
inferred energetics do not allow us to distinguish the origin of the outflows,
i.e. whether they are AGN-driven or starburst-driven. We also present evidence
for enhanced star formation at the edges of - and within - the outflow, with a
star formation rate SFR ~ 5 Msun/yr (i.e. ~ 2% of the total SFR). Our findings
suggest the presence of powerful winds in Arp220: they might be capable of
removing or heating large amounts of gas from the host ("negative feedback"),
but could be also responsible for triggering star formation ("positive
feedback").STFC
ER
Properties of the multiphase outflows in local (ultra)luminous infrared galaxies
Galactic outflows are known to consist of several gas phases, however, so far
the connection between these multiple phases has been investigated little and
only in a few objects. In this paper, we analyse MUSE/VLT data of 26 local
(U)LIRGs and study their ionised and neutral atomic phases. We also include
objects from the literature to obtain a total sample of 31 galaxies with
spatially resolved multi-phase outflow information. We find that the ionized
phase of the outflows has on average an electron density three times higher
than the disc ( 150 cm vs
500 cm), suggesting that cloud compression in the outflow is more
important that cloud dissipation. We find that the difference in extinction
between outflow and disc correlates with the outflow gas mass. Together with
the analysis of the outflow velocities, this suggests that at least some of the
outflows are associated with the ejection of dusty clouds from the disc. The
presence of dust in outflows is relevant for potential formation of molecules
inside them. We combine our data with millimetre data to investigate the
molecular phase. We find that the molecular phase accounts for more than 60
of the total mass outflow rate in most objects and this fraction is higher
in AGN-dominated systems. The neutral atomic phase contributes of the order of
10 , while the ionized phase is negligible. The ionized-to-molecular mass
outflow rate declines slightly with AGN luminosity, although with a large
scatter.STFC
ER
Recommended from our members
Cold molecular outflows in the local Universe and their feedback effect on galaxies
We study molecular outflows in a sample of 45 local galaxies, both star
forming and AGN, primarily by using CO data from the ALMA archive and from the
literature. For a subsample we also compare the molecular outflow with the
ionized and neutral atomic phases. We infer an empirical analytical function
relating the outflow rate simultaneously to the SFR, , and galaxy
stellar mass; this relation is much tighter than the relations with the
individual quantities. The outflow kinetic power shows a larger scatter than in
previous studies, spanning from 0.1 to 5~per cent of , while the
momentum rate ranges from 1 to 30 times , indicating that these
outflows can be both energy-driven, but with a broad range of coupling
efficiencies with the ISM, and radiation pressure-driven. For about 10~per cent
of the objects the outflow properties significantly exceed the maximum
theoretical values; we interpret these as "fossil outflows" resulting from
activity of a past strong AGN, which has now faded. We estimate that, in the
stellar mass range probed here ( 10), less than 5~per
cent of the outflowing gas escapes the galaxy. The molecular gas depletion time
associated with the outflow can be as short as a few million years in powerful
AGNs, however the total gas (H+HI) depletion times are much longer.
Altogether, our findings suggest that even AGN-driven outflows might be
relatively ineffective in clearing galaxies of their entire gas content,
although they are likely capable of clearing and quenching the central region.
Finally, we find no correlation between molecular outflow rate and radio power,
suggesting that on average radio jets do not play a major role in driving
massive molecular outflows in the luminosity range (log() = 41-46
erg s) probed here
Data Study Group Final Report: Bristol University – Applying AI and machine learning to reveal the molecular basis of heart disease
Automated actin filament detection in cryo electron microscopy images using image segmentation deep neural networks This report presents the output of the Cryo-EM challenge organised by The Alan Turing Institute and Jean Golding Institute as part of the Turing Data Study Group event in Bristol, August 2019. The aim of this challenge was to create an automated image processing workflow of actin filament identification, straightening, and extraction. This would be an important step towards detecting the troponin located on top of these actin filaments