We present a multiwavelength morphological analysis of star-forming clouds and filaments in the central (≲50 kpc) regions of 16 low-redshift (z < 0.3) cool core brightest cluster galaxies. New Hubble ...Space Telescope imaging of far-ultraviolet continuum emission from young (≲10 Myr), massive (≳5 M⊙) stars reveals filamentary and clumpy morphologies, which we quantify by means of structural indices. The FUV data are compared with X-ray, Lyα, narrow-band Hα, broad-band optical/IR, and radio maps, providing a high spatial resolution atlas of star formation locales relative to the ambient hot (∼107–8 K) and warm ionized (∼104 K) gas phases, as well as the old stellar population and radio-bright active galactic nucleus (AGN) outflows. Nearly half of the sample possesses kpc-scale filaments that, in projection, extend towards and around radio lobes and/or X-ray cavities. These filaments may have been uplifted by the propagating jet or buoyant X-ray bubble, or may have formed in situ by cloud collapse at the interface of a radio lobe or rapid cooling in a cavity's compressed shell. The morphological diversity of nearly the entire FUV sample is reproduced by recent hydrodynamical simulations in which the AGN powers a self-regulating rain of thermally unstable star-forming clouds that precipitate from the hot atmosphere. In this model, precipitation triggers where the cooling-to-free-fall time ratio is t
cool/t
ff ∼ 10. This condition is roughly met at the maximal projected FUV radius for more than half of our sample, and clustering about this ratio is stronger for sources with higher star formation rates.
Abstract
To advance our understanding of the fuelling and feedback processes which power the Universe’s most massive black holes, we require a significant increase in our knowledge of the molecular ...gas which exists in their immediate surroundings. However, the behaviour of this gas is poorly understood due to the difficulties associated with observing it directly. We report on a survey of 18 brightest cluster galaxies lying in cool cores, from which we detect molecular gas in the core regions of eight via carbon monoxide (CO), cyanide (CN) and silicon monoxide (SiO) absorption lines. These absorption lines are produced by cold molecular gas clouds which lie along the line of sight to the bright continuum sources at the galaxy centres. As such, they can be used to determine many properties of the molecular gas which may go on to fuel supermassive black hole accretion and AGN feedback mechanisms. The absorption regions detected have velocities ranging from −45 to 283 km s−1 relative to the systemic velocity of the galaxy, and have a bias for motion towards the host supermassive black hole. We find that the CN N = 0 − 1 absorption lines are typically 10 times stronger than those of CO J = 0 − 1. This is due to the higher electric dipole moment of the CN molecule, which enhances its absorption strength. In terms of molecular number density CO remains the more prevalent molecule with a ratio of CO/CN ∼10, similar to that of nearby galaxies. Comparison of CO, CN, and H i observations for these systems shows many different combinations of these absorption lines being detected.
We present Atacama Large Millimeter/submillimeter Array and Multi-Unit Spectroscopic Explorer observations of the brightest cluster galaxy in Abell 2597, a nearby (z = 0.0821) cool core cluster of ...galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxy's core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning "fountain," wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scales.
Adeno-associated viral vector 9 (AAV9) has recently been shown to penetrate the blood-brain barrier via intravascular administration, making it a good candidate for diffuse gene delivery. However, ...the potential side effects of systemic delivery are unknown. Intrathecal viral vector administration may be more invasive than intravenous injections, but it requires far less vector and it can be performed on an outpatient basis, making it an ideal route of delivery for clinical translation. A total of 12 domestic farm pigs (<20 kg) underwent a single-level lumbar laminectomy with intrathecal catheter placement for AAV9 delivery. Animals were perfused and the tissue was harvested 30 days after treatment. Gene expression was assessed by anti-green fluorescent protein immunohistochemistry. Although a single lumbar injection resulted in gene expression limited to the lumbar segment of the spinal cord, three consecutive boluses via a temporary catheter resulted in diffuse transduction of motor neurons (MNs) throughout the cervical, thoracic and lumbar spinal cords. We now present the first successful robust transduction of MNs in the spinal cord of a large animal via intrathecal gene delivery using a self-complementary AAV9. These promising results can be translated to many MN diseases requiring diffuse gene delivery.
ABSTRACT
We present Atacama Large Millimetre/submillimetre Array observations of the brightest cluster galaxy Hydra-A, a nearby (z = 0.054) giant elliptical galaxy with powerful and extended radio ...jets. The observations reveal CO(1−0), CO(2–1), 13CO(2–1), CN(2–1), SiO(5–4), HCO+(1–0), HCO+(2–1), HCN(1–0), HCN(2–1), HNC(1–0), and H2CO(3–2) absorption lines against the galaxy’s bright and compact active galactic nucleus. These absorption features are due to at least 12 individual molecular clouds that lie close to the centre of the galaxy and have velocities of approximately −50 to +10 km s−1 relative to its recession velocity, where positive values correspond to inward motion. The absorption profiles are evidence of a clumpy interstellar medium within brightest cluster galaxies composed of clouds with similar column densities, velocity dispersions, and excitation temperatures to those found at radii of several kpc in the Milky Way. We also show potential variation in a ∼10 km s−1 wide section of the absorption profile over a 2 yr time-scale, most likely caused by relativistic motions in the hot spots of the continuum source that change the background illumination of the absorbing clouds.
Active galactic nuclei play a crucial role in the accretion and ejection of gas in galaxies. Although their outflows are well studied, finding direct evidence of accretion has proved very difficult ...and has so far been done for very few sources. A promising way to study the significance of cold accretion is by observing the absorption of an active galactic nucleus's extremely bright radio emission by the cold gas lying along the line of sight. As such, we present ALMA CO(1-0) and CO(2-1) observations of the Hydra-A brightest cluster galaxy (z = 0.054) which reveal the existence of cold, molecular gas clouds along the line of sight to the galaxy's extremely bright and compact mm-continuum source. They have apparent motions relative to the central supermassive black hole of between -43 and -4 km s-1 and are most likely moving along stable, low ellipticity orbits. The identified clouds form part of a ˜109 M⊙, approximately edge-on disc of cold molecular gas. With peak CO(2-1) optical depths of τ = 0.88 ^{+0.06}_{-0.06}, they include the narrowest and by far the deepest absorption of this type which has been observed to date in a brightest cluster galaxy. By comparing the relative strengths of the lines for the most strongly absorbing region, we are able to estimate a gas temperature of 42^{+25}_{-11} K and line of sight column densities of N_{CO}=2^{+3}_{-1}× 10 ^{17} {cm}^{-2} and N_{H2 }=7^{+10}_{-4}× 10 ^{20} {cm}^{-2}.
As the epidemic of gunshot injuries and firearm fatalities continues to proliferate in the United States, knowledge regarding gunshot wound (GSW) injury and management is increasingly relevant to ...health-care providers. Unfortunately, existing guidelines are largely outdated, written in a time that high-velocity weapons and deforming bullets were chiefly restricted to military use. Advances in firearm technology and increased accessibility of military grade firearms to civilians has exacerbated the nature of domestic GSW injury and complicated clinical decision-making, as these weapons are associated with increased tissue damage and often result in retained bullets. Currently, there is a lack of literature addressing recent advances in the field of projectile-related trauma, specifically injuries with retained bullets. This review aims to aggregate the available yet dispersed findings regarding ballistics, GSW etiology, and treatment, particularly for cases involving retained projectiles.
Abstract We present the first systematic search for UV signatures from radio source-driven active galactic nuclei (AGN) feedback in Compact Steep Spectrum (CSS) radio galaxies. Owing to their ...characteristic sub-galactic jets (1–20 kpc projected linear sizes), CSS hosts are excellent laboratories for probing galaxy scale feedback via jet-triggered star formation. The sample consists of seven powerful CSS galaxies, and two galaxies host to radio sources >20 kpc as the control, at low to intermediate redshifts ( z < 0.6). Our new Hubble Space Telescope images show extended UV continuum emission in six out of seven CSS galaxies, with five CSS hosts exhibiting UV knots cospatial and aligned along the radio-jet axis. Young (≲ 10 Myr), massive (≳ 5 M ⊙ ) stellar populations are likely to be the dominant source of the blue excess emission in radio galaxies at these redshifts. Hence, the radio-aligned UV regions could be attributed to jet-induced starbursts. Lower near-UV star formation rates compared to other indicators suggest low scattered AGN light contribution to the observed UV. Dust attenuation of UV emission appears unlikely from high internal extinction correction estimates in most sources. Comparison with evolutionary synthesis models shows that our observations are consistent with recent (∼1−8 Myr old) star-forming activity likely triggered by current or an earlier episode of radio emission, or by a confined radio source that has frustrated growth, due to a dense environment. While follow-up spectroscopic and polarized light observations are needed to constrain the activity-related components in the observed UV, the detection of jet-induced star formation is a confirmation of an important prediction of the jet feedback paradigm.
A three‐dimensional quantitative stratigraphic forward model is employed to investigate the controls leading to the Messinian events in the lacustrine Pannonian Basin of Central Paratethys, and the ...link between the Messinian salinity crisis in the Mediterranean and the late Miocene‐Pliocene stratigraphy of the Pannonian Basin. Subsurface geological data show that a prominent unconformity surface formed during Messinian time in the Pannonian Basin associated with a sudden forced regression, abrupt basinward shift of facies and a subsequent, prolonged lowstand normal regression. The lowstand prograding series filled up the shallow basin fast, while, at the same time, the marginal areas of the basin were subject to tectonic inversion. The Dionisos program used in this research is built on a nonlinear water‐driven sediment diffusion process, and it employs multiple sediment classes, basin flexure and compaction. Four different scenarios were built in the experiments to test possible basin histories with different rates and timing of tectonic inversion. Each scenario was modelled in two versions: including and not including a lake‐level fall in the Messinian. The results confirm that the Pannonian Basin in the study area has undergone a tectonic inversion since the Messinian, although the exact rates of uplift at different locations remain uncertain. The unconformity and the observed stratigraphic architecture and facies pattern could be modelled adequately only in the versions that applied a Messinian lake‐level fall. Our research concludes that the Messinian unconformity in the Pannonian Basin was caused by an absolute lake‐level drop, likely linked to the desiccation of the Mediterranean, followed by subsidence and normal regression in the basin centre and concomitant tectonic inversion and uplift along the basin margins.
Abstract
We present a case study of HE 0040-1105, an unobscured radio-quiet active galactic nucleus (AGN) at a high accretion rate of
λ
Edd
= 0.19 ± 0.04. This particular AGN hosts an ionized gas ...outflow with the largest spatial offset from its nucleus compared to all other AGNs in the Close AGN Reference Survey. By combining multiwavelength observations from the Very Large Telescope/MUSE, Hubble Space Telescope/Wide Field Camera 3, Very Large Array, and European VLBI Network, we probe the ionization conditions, gas kinematics, and radio emission from host galaxy scales to the central few parsecs. We detect four kinematically distinct components, one of which is a spatially unresolved AGN-driven outflow located within the central 500 pc, where it locally dominates the interstellar medium conditions. Its velocity is too low to escape the host galaxy’s gravitational potential, and may be re-accreted onto the central black hole via chaotic cold accretion. We detect compact radio emission in HE 0040-1105 within the region covered by the outflow, varying on a timescale of ∼20 yr. We show that neither AGN coronal emission nor star formation processes wholly explain the radio morphology/spectrum. The spatial alignment between the outflowing ionized gas and the radio continuum emission on 100 pc scales is consistent with a weak jet morphology rather than diffuse radio emission produced by AGN winds. >90% of the outflowing ionized gas emission originates from the central 100 pc, within which the ionizing luminosity of the outflow is comparable to the mechanical power of the radio jet. Although radio jets might primarily drive the outflow in HE 0040-1105, radiation pressure from the AGN may contribute to this process.
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