Outflow Velocity Research Articles

Mutual impact of temperature and voltage on electro-osmotic dewatering process of mine tailings – a numerical study

Temperature and voltage are critical operational parameters that significantly influence the efficiency of the electro-osmosis dewatering process. Despite their importance, there is a lack of comprehensive research to evaluate their combined effects on enhancing electro-osmotic dewatering process efficiency. In this study, mutual effects of temperature and voltage on electro-osmotic dewatering of tailings were investigated using numerical simulation. To validate the model, output data were compared with experimental results on thermal electro-osmotic dewatering of red mud. The results indicated that increase in temperature from 25 °C to 35 °C and 25 °C to 45 °C resulted in a 12% and 27% increase in electric current, and 25% and 50% increase in fluid outflow velocity, respectively. Additionally, electric current and fluid outflow velocity increased by about 50% and 100% for all considered temperatures when voltage increased from 10.5 V to 15.75 and 10.5 V to 21 V, respectively. Furthermore, the results proved that increase in temperature was more effective than voltage in enhancing Joule’s heating-induced dewatering. The study also revealed that increase in distance between electrodes by more than 1 m decreases the efficiency of electro-osmotic dewatering.

The First Combined Hα and Rest-UV Spectroscopic Probe of Galactic Outflows at High Redshift

We investigate the multiphase structure of gas flows in galaxies. We study 80 galaxies during the epoch of peak star formation (1.4 ≤ z ≤ 2.7) using data from the Keck/Low-Resolution Imaging Spectrometer (LRIS) and the Very Large Telescope/K-Band Multi-Object Spectrograph (KMOS). Our analysis provides a simultaneous probe of outflows using UV emission and absorption features and Hα emission. With this unprecedented data set, we examine the properties of gas flows estimated from LRIS and KMOS in relation to other galaxy properties, such as star formation rate (SFR), SFR surface density (ΣSFR), stellar mass (M *), and main-sequence offset (ΔMS). We find no strong correlations between outflow velocity measured from rest-UV line centroids and galaxy properties. However, we find that galaxies with detected outflows show higher averages in SFR, ΣSFR, and ΔMS than those lacking outflow detections, indicating a connection between outflow and galaxy properties. Furthermore, we find a lower average outflow velocity than previously reported, suggesting greater absorption at the systemic redshift of the galaxy. Finally, we detect outflows in 49% of our LRIS sample and 30% in the KMOS sample and find no significant correlation between outflow detection and inclination. These results may indicate that outflows are not collimated and that Hα outflows have a lower covering fraction than low-ionization interstellar absorption lines. Additionally, these tracers may be sensitive to different physical scales of outflow activity. A larger sample size with a wider dynamic range in galaxy properties is needed to further test this picture.

GA-NIFS: JWST/NIRSpec IFS view of the z ∼ 3.5 galaxy GS5001 and its close environment at the core of a large-scale overdensity

We present JWST Near-Infrared Spectrograph (NIRSpec) observations in integral field spectroscopic (IFS) mode of the galaxy GS5001 at redshift z = 3.47, the central member of a candidate protocluster in the GOODS-S field. The data cover a field of view (FoV) of 4″ × 4″ (∼30 × 30 kpc2) and were obtained as part of the Galaxy Assembly with NIRSpec IFS (GA-NIFS) GTO programme. The observations include both high (R ∼ 2700) and low (R ∼ 100) spectral resolution data, spanning the rest-frame wavelength ranges 3700–6780 Å and 1300–11850 Å, respectively. These observations enable the detection and mapping of the main optical emission lines from [O II]λλ3726, 29 to [S III]λ9531. We analysed the spatially resolved ionised gas kinematics and interstellar medium properties, including obscuration, gas metallicity, excitation, ionisation parameter, and electron density. In addition to the main galaxy (GS5001), the NIRSpec FoV covers a close companion in the south, with three sub-structures with velocities blueshifted by ∼ − 150 km s−1 with respect to GS5001, and another source in the north redshifted by ∼200 km s−1. Optical line ratio diagnostics indicate star formation ionisation and electron densities of ∼500 cm−3 across all sources in the FoV. The gas-phase metallicity in the main galaxy is 12+log(O/H) = 8.45 ± 0.04, and slightly lower in the companions (12+log(O/H) = 8.34 − 8.42), consistent with the mass-metallicity relation at z ∼ 3. We find peculiar line ratios (high log[N II]/Hα = [−0.45, −0.3], low log[O III]/Hβ = [0.06, 0.10]) in the northern part of GS5001. These could be attributed to either higher metallicity, or to shocks resulting from the interaction of the main galaxy with the northern source. We identify a spatially resolved outflow in the main galaxy, traced by a broad symmetric component in Hα and [O III], with an extension of about 3 kpc. We find maximum outflow velocities of ∼400 km s−1, an outflow mass of (1.7 ± 0.4)×108 M⊙, a mass outflow rate of 23 ± 5 M⊙ yr−1, and a mass loading factor of 0.23. These properties are compatible with star formation being the driver of the outflow. Our analysis of these JWST NIRSpec IFS data therefore provides valuable, unprecedented insights into the interplay between star formation, galactic outflows, and interactions in the core of a z ∼ 3.5 candidate protocluster.

Ubiquitous radio emission in quasars: Predominant AGN origin and a connection to jets, dust, and winds

We present a comprehensive study of the physical origin of radio emission in optical quasars at redshifts z < 2.5. We focus particularly on the associations between compact radio emission, dust reddening, and outflows identified in our earlier work. Leveraging the deepest low-frequency radio data available to date (LoTSS Deep DR1), we achieve radio detection fractions of up to 94%, demonstrating the virtual ubiquity of radio emission in quasars, and a continuous distribution in radio loudness. Through our analysis of radio properties, combined with spectral energy distribution modelling of deep multiwavelength photometry, we establish that the primary source of radio emission in quasars is the active galactic nucleus (AGN), rather than star formation. Modelling the dust reddening of the accretion disc emission shows a continuous increase in radio detection in quasars as a function of the reddening parameter E(B − V), suggesting a causal link between radio emission and dust reddening. Confirming previous findings, we observe that the radio excess in red quasars is most pronounced for sources with compact radio morphologies and intermediate radio loudness. We find a significant increase in [O III] and C IV outflow velocities for red quasars not seen in our control sample, with particularly powerful [O III] winds in those around the threshold from radio-quiet to radio-loud. Based on the combined characterisation of radio, reddening, and outflow properties in our sample, we favour a model in which the compact radio emission observed in quasars originates in compact radio jets and their interaction with a dusty, circumnuclear environment. In particular, our results align with the theory that jet-induced winds and shocks resulting from this interaction are the origin of the enhanced radio emission in red quasars. Further investigation of this model is crucial for advancing our understanding of quasar feedback mechanisms and their role in galaxy evolution.

Role of Ion Dynamics in Electron‐Only Magnetic Reconnection

AbstractStandard magnetic reconnection couples with both ions and electrons on different scales. Recently, a new type of magnetic reconnection, electron‐only reconnection without the coupling of ions, has been observed in various plasma environments. Standard reconnection typically has a reconnection outflow velocity of about one Alfvén speed. According to the scaling analysis, the electron outflow velocity is expected to be about one electron Alfvén speed in electron‐only reconnection. However, observations and simulations both find that the electron outflows are much slower than the electron Alfvén speed. In this letter, by performing two‐dimensional particle‐in‐cell simulations, we show that this is because ions play a role in electron‐only reconnection. The ions move slower than the electrons in the outflow direction, and such charge separation forms an in‐plane Hall electric field, which prevents the electrons from being accelerated to the electron Alfvén speed in electron‐only reconnection.

An Eddington-limited Accretion Disk Wind in the Narrow-line Seyfert 1 PG 1448+273

PG 1448+273 is a luminous, nearby (z = 0.0645), narrow-line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. Previous X-ray observations of PG 1448+273 with XMM-Newton in 2017 and NuSTAR in 2022 revealed the presence of an ultrafast outflow, as seen through its blueshifted iron (Fe) K absorption profile, where the outflow velocity appeared to vary in the range 0.1−0.3c. In this work, new X-ray observations of PG 1448+273 are presented, in the form of four simultaneous XMM-Newton and NuSTAR observations performed in 2023 July and August. The X-ray spectra appeared at a similar flux in each observation, making it possible to analyze the mean 2023 X-ray spectrum at high signal-to-noise ratio. A broad (σ = 1 keV) and highly blueshifted (E = 9.8 ± 0.4 keV) Fe K absorption profile is revealed in the mean spectrum. The profile can be modeled by a fast, geometrically thick accretion disk wind, which reveals a maximum terminal velocity of v ∞ = −0.43 ± 0.03c, one of the fastest known winds in a nearby active galactic nucleus. As a result, the inferred mass outflow rate of the wind may reach a significant fraction of the Eddington accretion rate.

Exploring the Central Region of NGC 1365 in the Ultraviolet Domain

Active galactic nuclei (AGN) feedback and its impact on their host galaxies are critical to our understanding of galaxy evolution. Here, we present a combined analysis of new high resolution ultraviolet (UV) data from the Ultraviolet Imaging Telescope (UVIT) on AstroSat and archival optical spectroscopic data from the Very Large Telescope/MUSE, for the Seyfert galaxy, NGC 1365. Concentrating on the central 5 kpc region, the UVIT images in the far- and near-UV show bright star-forming knots in the circumnuclear ring as well as a faint central source. After correcting for extinction, we found the star formation rate (SFR) surface density of the circumnuclear 2 kpc ring to be similar to other starbursts, despite the presence of an AGN outflow, as seen in [O iii] 5007 Å. On the other hand, we found fainter UV and thus lower SFR in the direction southeast of the AGN relative to northwest in agreement with observations at other wavelengths from JWST and Atacama Large Millimeter/submillimeter Array. The AGN outflow velocity is found to be lesser than the escape velocity, suggesting that the outflowing gas will rain back into the galaxy. The deep UV data have also revealed diffuse UV emission in the direction of the AGN outflow. By combining [O iii] and UV data, we found the diffuse emission to be of AGN origin.

Thermodynamic Evolution of Plumes

Plumes are considered to play an important role in the origin of the solar wind. However, an understanding of their thermodynamic evolution is not complete. Here, we perform a detailed study of a plume inside a coronal hole throughout its lifetime, using the observations from the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager. We find that the plume’s formation is preceded by frequent occurrences of small-scale jets and jetlets at its base, leading to the gradual development of plume haze. The plume rapidly developed within the first 6 hr into its well-known morphology. Light curves from all extreme ultraviolet channels exhibit a similar profile, suggesting its multithermal nature and intensity modulation over its lifespan. Moreover, the photospheric magnetic field dynamics at the plume’s base are highly correlated with its light curve in 171 Å. We calculate outflow velocities, observed prominently in the 171 Å passband and mildly in the 193 and 211 Å passbands, with median speeds lower in higher temperature bands but occasionally comparable to the respective sound speeds. When data are averaged over larger spatial scales, the plume appears isothermal along its length, with constant temperature throughout its lifetime. However, an analysis of the differential emission measure at full resolution reveals the presence of higher-temperature plasma, indicating internal temperature structures within the plume. These results provide new insights into the formation, dynamics, and thermal properties of coronal plumes, placing tighter constraints on models to understand their thermodynamic evolution and potential role in the solar wind.

AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy

We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multiwavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AGN STORM 2) Project. The campaign revealed an unexpected and transient obscuring outflow, never before seen in this source. Of our four XMM-Newton/NuSTAR epochs, one fortuitously taken during a bright X-ray state has strong narrow absorption lines in the high-resolution grating spectra. From these absorption features, we determine that the obscurer is in fact a multiphase ionized wind with an outflow velocity of ∼5200 km s−1, and for the first time find evidence for a lower ionization component with the same velocity observed in absorption features in the contemporaneous Hubble Space Telescope spectra. This indicates that the UV absorption troughs may be due to dense clumps embedded in diffuse, higher ionization gas responsible for the X-ray absorption lines of the same velocity. We observe variability in the shape of the absorption lines on timescales of hours, placing the variable component at roughly 1000 R g if attributed to transverse motion along the line of sight. This estimate aligns with independent UV measurements of the distance to the obscurer suggesting an accretion disk wind at the inner broad line region. We estimate that it takes roughly 200 days for the outflow to travel from the disk to our line of sight, consistent with the timescale of the outflow's column density variations throughout the campaign.

MICONIC: JWST/MIRI MRS observations of the nuclear and circumnuclear regions of Mrk 231

We present JWST/MIRI MRS spatially resolved ∼5 − 28 μm observations of the central ∼4 − 8 kpc of the ultraluminous infrared galaxy and broad absorption line quasar Mrk 231. These are part of the Mid-Infrared Characterization of Nearby Iconic galaxy Centers (MICONIC) program of the MIRI European Consortium guaranteed time observations. No high excitation lines (i.e., [Mg V] at 5.61 μm or [Ne V] at 14.32 μm) typically associated with the presence of an active galactic nucleus (AGN) are detected in the nuclear region of Mrk 231. This is likely due to the intrinsically X-ray weak nature of its quasar. Some intermediate ionization potential lines, for instance, [Ar III] at 8.99 μm and [S IV] at 10.51 μm, are not detected either, even though they are clearly observed in a star-forming region ∼920 pc south-east of the AGN. Thus, the strong nuclear mid-infrared (mid-IR) continuum is also in part hampering the detection of faint lines in the nuclear region. The nuclear [Ne III]/[Ne II] line ratio is consistent with values observed in star-forming galaxies. Moreover, we resolve for the first time the nuclear starburst in the mid-IR low-excitation line emission (size of ∼400 pc, FWHM). Several pieces of evidence also indicate that it is partly obscured even at these wavelengths. At the AGN position, the ionized and warm molecular gas emission lines have modest widths (W80 ∼ 300 km s−1). There are, however, weak blueshifted wings reaching velocities v02 ≃ − 400 km s−1 in [Ne II]. The nuclear starburst is at the center of a large (∼8 kpc), massive rotating disk with widely-spread, low velocity outflows. Given the high star formation rate of Mrk 231, we speculate that part of the nuclear outflows and the large-scale non-circular motions observed in the mid-IR are driven by its powerful nuclear starburst.

A fast-rotator post-starburst galaxy quenched by supermassive black-hole feedback at z = 3

AbstractThe most massive galaxies in the Universe stopped forming stars due to the time-integrated feedback from central supermassive black holes (SMBHs). However, the exact quenching mechanism is not yet understood, because local massive galaxies were quenched billions of years ago. Here we present JWST/NIRSpec integral-field spectroscopy observations of GS-10578, a massive, quiescent galaxy at redshift z = 3.064 ± 0.002. From its spectrum, we measure a stellar mass M⋆ = 1.6 ± 0.2 × 1011 M⊙ and a dynamical mass Mdyn = 2.0 ± 0.5 × 1011 M⊙. Half of its stellar mass formed at z = 3.7–4.6, and the system is now quiescent, with a current star-formation rate of less than 19 M⊙ yr−1. We detect ionized- and neutral-gas outflows traced by [O iii] emission and Na i absorption, with mass outflow rates 0.14–2.9 and 30–100 M⊙ yr−1, respectively. Outflow velocities reach vout ≈ 1,000 km s−1, comparable to the galaxy escape velocity. GS-10578 hosts an active galactic nucleus, evidence that these outflows are due to SMBH feedback. The neutral outflow rate is higher than the star-formation rate. Hence, this is direct evidence for ejective SMBH feedback, with a mass loading capable of interrupting star formation by rapidly removing its fuel. Stellar kinematics show ordered rotation, with spin parameter $${\lambda }_{{{{R}}}_{{\rm{e}}}}=0.62\pm 0.07$$ λ R e = 0.62 ± 0.07 , meaning GS-10578 is rotation-supported. This study presents direct evidence for ejective active galactic nucleus feedback in a massive, recently quenched galaxy, thus helping to clarify how SMBHs quench their hosts. The high value of $${\lambda }_{{{{R}}}_{{\rm{e}}}}$$ λ R e implies that quenching can occur without destroying the stellar disk.

H_3^+ absorption and emission in local (U)LIRGs with JWST NIRSpec: Evidence for high H_2 ionization rates

We study the $3.4-4.4$ fundamental rovibrational band of H$_3^+$, a key tracer of the ionization of the molecular interstellar medium (ISM), in a sample of 12 local ($d$$<$400\,Mpc) (ultra)luminous infrared galaxies ((U)LIRGs) observed with JWST NIRSpec. The P, Q, and R branches of the band are detected in 13 out of 20 analyzed regions within these (U)LIRGs, which increases the number of extragalactic H$_3^+$ detections by a factor of 6. For the first time in the ISM, the H$_3^+$ band is observed in emission; we detect this emission in three regions. In the remaining ten regions, the band is seen in absorption. The absorptions are produced toward the $3.4-4.4$ hot dust continuum rather than toward the stellar continuum, indicating that they likely originate in clouds associated with the dust continuum source. The H$_3^+$ band is undetected in Seyfert-like (U)LIRGs where the mildly obscured X-ray radiation from the active galactic nuclei might limit the abundance of this molecule. For the detections, the H$_3^+$ abundances, $N($H$_3^+$) H (0.5--5.5)times 10$^ imply relatively high ionization rates, $ H_2 $, of between 3times 10$^ $ and $>$4times 10$^ $, which is lower than the molecular outflow velocities measured using other tracers such as OH\,119 or rotational CO lines. This suggests that H$_3^+$ traces gas close to the outflow-launching sites before it has been fully accelerated. We used nonlocal thermodynamic equilibrium models to investigate the physical conditions of these clouds. In seven out of ten objects, the H$_3^+$ excitation is consistent with inelastic collisions with H$_2$ in warm translucent molecular clouds kin $sim 250--500\,K and H_2 )$sim 10$^ $). In three objects, dominant infrared pumping excitation is required to explain the absorptions from the (3,0) and (2,1) levels of H$_3^+$ detected for the first time in the ISM.

The XMM-Newton and NuSTAR view of IRASF11119+3257

Context. IRASF11119+3257 is an ultra-luminous infrared galaxy with a post-merger morphology, hosting a type-1 quasar at z = 0.189. It shows a prominent ultra-fast outflow (UFO) absorption feature (vout ∼ 0.25c) in its 2013 Suzaku spectrum. This is the first system in which the energy released by the UFO was compared to that of the known galaxy-scale molecular outflow to investigate the mechanism driving active galactic nuclei (AGN) feedback. Aims. In 2021, we obtained the first XMM-Newton long look of the target, coordinated with a simultaneous NuSTAR observation, with the goal of constraining the broad band continuum and the nuclear wind physical properties and energetics with an unprecedented accuracy. Methods. The new high-quality data allowed us to clearly detect at a confidence level P > 99.8% multiple absorption features associated with the known UFO at the 9.1 and 11.0 keV rest frames. Furthermore, an emission plus absorption feature at 1.1 − 1.3 keV reveals the presence of a blueshifted P-Cygni profile in the soft band. Results. We associate the two hard band features with blends of FeXXV and FeXXVI Heα-Lyα and Heβ-Lyβ line pairs and infer a large column (NH ∼ 1024 cm−2) of highly ionized (log ξ ∼ 5) gas outflowing at vout = 0.27 ± 0.01c. The 1.3 keV absorption line can be associated with a blend of Fe and Ne transitions, produced by a lower column (NH ∼ 3 × 1021 cm−2) and ionization (log ξ ∼ 2.6) gas component outflowing at the same speed. Using a radiative-transfer disk wind model to fit the highly ionized UFO, we derive a mass outflow rate comparable with the mass accretion rate and the Eddington limit (Ṁout = 4.25−0.73+1.11 M⊙/yr, ∼1.6 Ṁacc and ∼1.0 ṀEdd), and kinetic energy (Ėkin = 1.21−0.20+0.32 Lbol and ∼0.7LEdd) and momentum flux (Ṗout = 6.37−1.09+1.67 Lbol/c) among the highest reported in the literature. We measured an extremely low high-energy cutoff (Ecut ∼ 25 − 30 keV). This and several other cases in the literature suggest that a steep X-ray continuum may be related to the formation of powerful winds. We also analyzed the ionized [OIII] component of the large-scale outflow through optical spectroscopy and derived a large outflow velocity (vout ∼ 3000 km/s) and energetics comparable with the large-scale molecular outflows. Finally, we observe a trend of decreasing outflow velocity from forbidden optical emission lines of decreasing ionization levels, interpreted as the outflow decelerating at large distances from the ionizing source. Conclusions. The lack of a significant momentum boost between the nuclear UFO and the different phases of the large-scale outflow, observed in IRASF11119 and in a growing number of similar sources, can be explained by (i) a momentum-driven expansion, (ii) an inefficient coupling of the UFO with the host interstellar medium, or (iii) by repeated energy-driven expansion episodes with a low duty cycle, that average out on long timescales to produce the observed large-scale outflow.

Increasing particle-size by air-flow modification – An experimental study

Ambient particulate are characterize by submicron particles that may penetrate deep into the lungs, where they become harmful due to their morphology and composition, or due to their role as carriers of harmful chemicals or biological agents. Particle filtration technologies have in general a lower efficiency at diameter size around 0.1–0.3 μm. This study examines the concept of particle grouping as a means to overcome this size-gap, for improving air purification or filtration systems. The grouping manipulation is induced by a controlled rotating valve which creates a sinusoidal flow in the experimental tube, and by modules with varying diameter, forcing a wavy flow. Fine particles with a known size distribution which are introduced into the manipulated flow, exhibit groups of particles in the outflow, hence increase the effective size of the particles. Former successful studies were performed with high flow velocity and particle load of industrial duct and car engine outflow, while in the current study smaller particle loads representing ambient to indoor levels are in operation. Although the low velocity and particle load are challenging, this study shows a promising shift of the particle size distribution from a peak at 0.2–0.3 μm, towards larger particle diameters. Fine powder of dolomite is used in this study and preliminary results of adhesion experiments related to dolomite are also reported.

Numerical investigation of bimodal tip clearance effect on the lift-drag and flow characteristics of a hydrofoil

Tip leakage flow has adverse effect on energy conversion of the hydraulic machinery. The new tip clearance structure based on Bimodal Gaussian function is designed to reduce tip leakage vortex. The effects of bimodal structure with different amplitudes and arrangement positions on lift-drag and flow characteristics are studied. The results show that the maximum rise of the lift-drag ratio reaches 5.88% when the bimodal structure amplitude is equal to the tip clearance size. The bimodal structure reduces the outflow velocity at the peak and forms a smooth streamline, which weakens the entrainment with the mainstream. The location of the bimodal structure far away from leading edge helps to produce smooth streamlines and make the flow field smoother, and reduces the area of high turbulent kinetic energy region near leading edge and in tip clearance outflow region significantly. The arrangement position of bimodal structure close to leading edge can produce a low-speed zone or a recirculation zone in the mainstream, which can block the mainstream flow and reduce the energy characteristics of the hydrofoil.

X-Ray Winds in Nearby-to-distant Galaxies (X-WING). I. Legacy Surveys of Galaxies with Ultrafast Outflows and Warm Absorbers in z ∼ 0–4

As an inaugural investigation under the X-ray Winds In Nearby-to-distant Galaxies (X-WING) program, we assembled a data set comprising 132 active galactic nuclei (AGNs) spanning redshifts z ∼ 0–4 characterized by blueshifted absorption lines indicative of X-ray winds. Through an exhaustive review of previous research, we compiled the outflow parameters for 583 X-ray winds, encompassing key attributes such as outflow velocities (V out), ionization parameters (ξ), and hydrogen column densities. By leveraging the parameters V out and ξ, we systematically categorized the winds into three distinct groups: ultrafast outflows (UFOs), low-ionization parameter (low-IP) UFOs, and warm absorbers (WAs). Strikingly, a discernible absence of linear correlations in the outflow parameters, coupled with distributions approaching instrumental detection limits, was observed. Another notable finding was the identification of a velocity gap around V out ∼ 10,000 km s−1. This gap was particularly evident in the winds detected via absorption lines within the ≲2 keV band, indicating disparate origins for low-IP UFOs and WAs. In cases involving Fe xxv/Fe xxvi lines, where the gap might be attributed to potential confusion between emission/absorption lines and the Fe K-edge, the possibility of UFOs and galactic-scale WAs being disconnected is considered. An examination of the outflow and dust sublimation radii revealed a distinction: UFOs appear to consist of dust-free material, whereas WAs likely comprise dusty gas. From 2024, the X-Ray Imaging and Spectroscopy Mission is poised to alleviate observational biases, providing insights into the authenticity of the identified gap, a pivotal question in comprehending AGN feedback from UFOs.

Using Ly α transits to constrain models of atmospheric escape

ABSTRACT Ly $\alpha$ transits provide an opportunity to test models of atmospheric escape directly. However, translating observations into constraints on the properties of the escaping atmosphere is challenging. The major reason for this is that the observable parts of the outflow often comes from material outside the planet’s Hill sphere, where the interaction between the planetary outflow and circumstellar environment is important. As a result, 3D models are required to match observations. Whilst 3D hydrodynamic simulations are able to match observational features qualitatively, they are too computationally expensive to perform a statistical retrieval of properties of the outflow. Here, we develop a model that determines the trajectory, ionization state, and 3D geometry of the outflow as a function of its properties and system parameters. We then couple this model to a ray tracing routine in order to produce synthetic transits. We demonstrate the validity of this approach, reproducing the trajectory of the outflows seen in 3D simulations. We illustrate the use of this model by performing a retrieval on the transit spectrum of GJ 436 b. The bound on planetary outflow velocity and mass-loss rates are consistent with a photoevaporative wind.

Outflow Driven by a Protoplanet Embedded in the TW Hya Disk

Gas giant planets are formed by gas accretion onto planetary cores in protoplanetary disks. However, direct evidence of this process is still lacking, limiting our understanding of planetary formation processes. During mass accretion, planet-driven outflows may be launched, which could be observable by shock tracers such as sulfur monoxide (SO). We report the detection of SO gas in the protoplanetary disk around TW Hya in archival Atacama Large Millimeter/submillimeter Array observations. The SO J = 87 − 76 emission line is detected at a 6σ significance and localized to the southeast region of the disk with an arc-like morphology. The line center is redshifted with respect to the systemic velocity by ∼5 km s−1. The starting point of the SO emission is located at a planet-carved dust gap at 42 au. We attribute this to an outflow driven by an embedded protoplanet. Indeed, the observed morphology is well reproduced by a ballistic outflow model. The outflow velocity suggests that the outflow launching source has a mass of ∼4M ⊕ and the mass-loss rate is 3 × 10−8–1 × 10−6 M Jup yr−1. With the relation of mass-loss and mass-accretion rates established for protostars, we estimated the mass-accretion rate onto the protoplanet to be 3 × 10−7−1 × 10−5 M Jup yr−1, which matches theoretical predictions for a ∼4M ⊕ planet at this separation. The detection of planet-driven outflow provides us a unique opportunity to directly probe the earliest phase of gas giant planet formation.

Correlations of Plasma Properties Between the Upstream Magnetosheath and the Downstream Outflow Region of Magnetopause Reconnection

AbstractThe impact of upstream conditions on magnetopause reconnection has been an intriguing question in solar wind‐magnetosphere coupling. In this study, we conduct a statistical analysis of plasma properties in the reconnection outflow region and the associated upstream solar wind/magnetosheath. We observe that the normalized ion density (N/Nsw) decreases and the flow speed (V/Vsw) increases in the upstream magnetosheath with distance from the subsolar point, consistent with previous models and observations. The magnetic field strength (|B|), ion density (N), and ion bulk speed (|V|) in the upstream magnetosheath exhibit close correlations with those in the reconnection outflow region. This upstream‐downstream correlation likely arises from the process of forming reconnection outflows, where most upstream ions cross the separatrix and mix with ion outflow already accelerated near the X‐line. High‐speed part of reconnection outflow is mostly located on the magnetosphere side of the magnetopause current layer, with outflow velocities peaking close to the upstream magnetosheath Alfvén speed. The spatial extent of high‐speed outflow is greater in conditions of lower solar wind Alfvén Mach number (MA,sw). Additionally, the southward magnetic field in the magnetosheath and |B| of magnetopause current layer are larger in the cases of lower MA,sw. These findings indicate a close connection of plasma properties between the outflow region of magnetopause reconnection and the upstream magnetosheath.

Establishing an animal model for peritoneal catheter malfunction caused by omental wrapping using negative pressure suction: in vitro and in vivo exploration

Background This study aims to establish a simplified and effective animal model of catheter malfunction caused by omental wrapped using negative pressure suction. Method The peritoneal dialysis catheter outlet was linked to a negative-pressure (0-75mmHg) suction pump to intensify the negative pressure. Different negative pressures were tested for model construction in vitro. In vivo, a model of peritoneal catheter malfunction caused by omental wrapped was constructed in five beagles after catheter placement. Catheter drainage conditions and related complications were monitored before and after the model establishment. Results In the vitro experiment, the overall success rate of constructed models was 90% (36/40). The total malfunction rate was higher in 62.5 mmHg (10/10) and 75 mmHg (10/10) than in 12.5 mmHg (8/10) and 37.5 mmHg (8/10). The outflow velocity of dialysate at 62.5 mmHg was significantly lower than that at 12.5 mmHg and 37.5 mmHg, without a statistically significant difference compared to 75 mmHg. In the in vivo experiment, catheter outflow velocity increased, and residual fluid volume decreased after omental wrapped (99.6 ± 6.7 ml/min vs. 32.6 ± 4.6 ml/min at initial five minutes, p < 0.0001; 69.2 ± 16.3 ml vs. 581.0 ± 109.4 ml, p < 0.001). And the outflow velocity was finally below 2 ml/min. No severe related complications (such as infection, organ damage, or bleeding) were observed through laparoscopic examination and dialysate tests seven days post-operation. Conclusion Utilizing negative pressure suction to increase negative pressure around catheter tip is a simple, safe, and effective method for establishing an animal model of omental wrapped leading to catheter malfunction.