Edge Of Disk Research Articles

A tell-tale tracer for externally irradiated protoplanetary disks: Comparing the [C I] 8727 line and ALMA observations in proplyds

The evolution of protoplanetary disks in regions with massive OB stars is influenced by externally driven winds that deplete the outer parts of these disks. The winds have previously been studied via forbidden oxygen emission lines, which also arise in isolated disks in low-mass star-forming regions (SFRs) with weak external UV fields in photoevaporative or magnetic (internal) disk winds. It is crucial to determine how to disentangle external winds from internal ones. Here, we report a proxy for unambiguously identifying externally driven winds with a forbidden line of neutral atomic carbon We compare for the first time the spatial location of the emission in the and lines traced by VLT/MUSE-NFM with the ALMA Band 7 continuum disk emission in a sample of 12 proplyds in the Orion Nebula Cluster (ONC). We confirm that the emission is co-spatial with the disk emission, whereas that of is emitted both on the disk surface and on the ionization front of the proplyds. We show for the first time that the line is also co-spatial with the disk surface in proplyds, as seen in the MUSE and ALMA data comparison. The peak emission is compatible with the stellar location in all cases, apart from one target with high relative inclination with respect to the ionizing radiation, where the peak emission is located at the disk edge in the direction of the ionizing radiation. To verify whether the line is detected in regions where external photoevaporation is not expected, we examined VLT/X-Shooter spectra for young stars in low-mass SFRs. Although the and 6300 lines are well detected in all these targets, the total detection rate is $ in the case of the line. This number increases substantially to a $ detection rate in sigma -Orionis, a region with higher UV radiation than in low-mass SFRs, but lower than in the ONC. The spatial location of the line emission and the lack of its detection in isolated disks in low-mass SFRs strongly suggest that this line is a tell-tale tracer of externally driven photoevaporative winds, which agrees with recent excitation models.

A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE)

We examine the prevalence of truncated star-forming discs in the Virgo cluster down to M* ≃ 107 M⊙. This work makes use of deep, high-resolution imaging in the Hα+[N II] narrow-band from the Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) and optical imaging from the Next Generation Virgo Survey (NGVS). To aid in the understanding of the effects of the cluster environment on star formation in Virgo galaxies, we take a physically motivated approach to define the edge of the star-forming disc via a drop-off in the radial specific star formation rate profile. A comparison with the expected sizes of normal galactic discs provides a measure of how truncated star-forming discs are in the cluster. We find that truncated star-forming discs are nearly ubiquitous across all regions of the Virgo cluster, including beyond the virial radius (0.974 Mpc). The majority of truncated discs at large cluster-centric radii are of galaxies likely on their first infall. As the intra-cluster medium density is low in this region, it is difficult to explain this population with solely ram-pressure stripping. A plausible explanation is that these galaxies are undergoing starvation of their gas supply before ram-pressure stripping becomes the dominant quenching mechanism. A simple model of starvation shows that this mechanism can produce moderate disc truncations within 1−2 Gyr. This model is consistent with ‘slow-then-rapid’ or ‘delayed-then-rapid’ quenching, whereby the early starvation mode drives disc truncations without significant change to the integrated star formation rate, and the later ram-pressure stripping mode rapidly quenches the galaxy. The origin of starvation may be in the group structures that exist around the main Virgo cluster, which indicates the importance of understanding pre-processing of galaxies beyond the cluster virial radius.

JADES: Spectroscopic Confirmation and Proper Motion for a T-Dwarf at 2 kpc

Large area observations of extragalactic deep fields with the James Webb Space Telescope (JWST) have provided a wealth of candidate low-mass L- and T-class brown dwarfs. The existence of these sources, which are at derived distances of hundreds of parsecs to several kiloparsecs from the Sun, has strong implications for the low-mass end of the stellar initial mass function, and the link between stars and planets at low metallicities. In this letter, we present a JWST/NIRSpec PRISM spectrum of brown dwarf JADES-GS-BD-9, confirming its photometric selection from observations taken as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. Fits to this spectrum indicate that the brown dwarf has an effective temperature of 800–900 K (T5–T6) at a distance of 1.8–2.3 kpc from the Sun, with evidence of the source being at low metallicity ([M/H] ≤ −0.5). Finally, because of the cadence of JADES NIRCam observations of this source, we additionally uncover a proper motion between the 2022 and 2023 centroids, and we measure a proper motion of 20 ± 4 mas yr−1 (a transverse velocity of 214 km s−1 at 2.25 kpc). At this predicted metallicity, distance, and transverse velocity, it is likely that this source belongs either to the edge of the Milky Way thick disk or the galactic halo. This spectral confirmation demonstrates the efficacy of photometric selection of these important sources across deep extragalactic JWST imaging.

Clinical characteristics of disc hemorrhages depending on their locations and glaucoma progression in myopic patients

This study aimed to investigate clinical characteristics and glaucoma progression in eyes with disc hemorrhage (DH) in the region of peripapillary atrophy (PPA) or DH in temporal region among glaucoma patients with myopia. One hundred ninety-six eyes of 196 glaucoma patients with myopia who were observed at least 4 years and had more than six visual field (VF) tests were included. Eyes with DHs located in the optic disc region at the superotemporal or inferotemporal locations were defined as typical DH. PPA area, disc ovality ratio, and disc torsion were measured. Length of γ-zone PPA, distance from disc edge to fovea, angle of scleral bending were measured using optical coherence tomography. Comparison of baseline characteristics between eyes with and without DH in PPA/DH in temporal region showed similar axial length (26.95 ± 1.60 mm; 26.82 ± 1.07 mm). γ-zone PPA was longer and angle of scleral bending was larger in eyes with DH in PPA/DH in temporal region (both p ≤ 0.001). Longer γ-zone PPA (β = 1.001; p = 0.018) and larger angle of scleral bending (β = 1.033; p = 0.008) were associated with presence of DH in PPA/DH in temporal region using logistic regression analysis. Eyes with DH in PPA/DH in temporal region had a smaller mean deviation slope of VF, a larger disc ovality ratio, a longer γ-zone PPA, and a larger PPA area when compared to those of eyes typical DH. VF progression was associated with absence of DH in PPA/DH in temporal region (p = 0.030) and larger angle of scleral bending (p = 0.019) using Cox proportional hazards model. DH in PPA/DH in temporal region was associated with stretching and deformation of sclera that may be result from myopic changes. Associated factors with VF progression was the degree of scleral deformation, not the presence of DH in PPA/DH in temporal region, showing that DH related to scleral deformation may possess clinical significance in glaucoma with myopia.

Electromagnetic signatures from accreting massive black hole binaries in time domain photometric surveys

We study spectral and time variability of accreting massive black hole binaries (MBHBs) at milli-parsec separations surrounded by a geometrically thin circumbinary disc. To this end, we present the first computation of the expected spectral energy distribution (SED) and light curves (LCs) from 3D hyper-Lagrangian resolution hydrodynamic simulations of these systems. We modelled binaries with a total mass of $10^6$ M$_ eccentricities of $e=0,\, 0.9$, and a mass ratio of $q=0.1,\, 1$. The circumbinary disc has an initial aspect ratio of 0.1, features an adiabatic equation of state, and evolves under the effect of viscous heating, black-body cooling, and self gravity. To construct the SED, we considered black-body emission from each element of the disc and we added a posteriori an X-ray corona with a luminosity proportional to that of the mini-discs that form around each individual black hole. We find significant variability of the SED, especially at high energies, which translates into LCs displaying distinctive modulations of a factor of $ 2$ in the optical and of $ 10$ in UV and X-rays. We analysed in detail the flux variability in the optical band that will be probed by the Vera Rubin Observatory (VRO). We find clear modulations on the orbital period and half of the orbital period in all systems. Only in equal-mass binaries, we find an additional, longer-timescale modulation, associated with an over-density forming at the inner edge of the circumbinary disc (commonly referred to as a lump). When considering the VRO flux limit and nominal survey duration, we find that equal-mass, circular binaries are unlikely to be identified, due to the lack of prominent peaks in their Fourier spectra. Conversely, unequal-mass and/or eccentric binaries can be singled out up to $z 0.5$ (for systems with bol $ erg s$^ $) and $z 2$ (for systems with bol $ erg s$^ $). Identifying electromagnetic signatures of MBHBs at separations of $ $ pc is of paramount importance to understand the physics of the gravitational wave (GW) sources of the future Laser Interferometer Space Antenna, and to pin down the origin of the GW background (GWB) observed in pulsar timing arrays.

Diabetic Papillopathy and Papillophlebitis

Diabetic papillopathy is a rare ocular finding in patients with diabetes mellitus. Optic disc edema accompanying minimal visual changes caused by diabetic papillopathy distinguishes it from other optic neuropathies. The pathophysiology of diabetic papillopathy is still not clearly understood. Patients with diabetic papillopathy tend to be asymptomatic, but they may present to the clinic with mild blurred vision. Diagnosis can be made by excluding other possible causes of optic disc swelling. Diabetic papillopathy is essentially a diagnosis of exclusion. For this reason, the differential diagnoses in these patients need to be well known. There are no proven treatment options for diabetic papillopathy. However, since these patients often recover on their own, following the patients without treatment seems to be a reasonable approach for now. Papillophlebitis is a rare condition look like as incomplete central retinal vein occlusion due to optic disc edema and hemorrhages at the disc edge. It typically occurs in young, healthy women with acute, painless unilateral vision loss or blurred vision, optic disc edema, and retinal vein engorgement. Diagnosis is made by excluding other possible causes. There is no evidence-based, accepted treatment method for papillophlebitis.

IMPACTS OF POSTERIOR STAPHYLOMA ON PARAPAPILLARY MICROVASCULATURE AND ATROPHY IN HIGH MYOPIC EYES: A MATCHED COHORT STUDY WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

We aimed to evaluate the impacts of the different types of posterior staphyloma (PS) in high myopia on parapapillary microvasculature and parapapillary atrophy (PPA, i.e., γ-zone and δ-zone) with optical coherence tomography angiography. This cross-sectional study included 152 high myopic eyes (152 participants) with γ-zone. After matching, high myopic eyes were stratified into PS (n = 33) and non-PS (n = 33) groups. PS types, parapapillary microvasculature characteristics, the prevalence of non-juxtapapillary microvasculature dropout (NJ-MvD), the longest radial width from the optic disc edge to retinal pigment epithelium atrophy edge (PPA-w), γ-zone, and δ-zone with changes in visual field and best-corrected visual acuity (BCVA) were evaluated and analyzed. According to Curtin's classification, we identified five types of PS included: primary types I, II, III, and compound types VII, and IX. Eyes with type II showed a higher optic disc tilted ratio and larger PPA-w compared to other primary PS. Subjects with type IX were the oldest. Eyes with types VII and IX had wider γ-zone and δ-zone, worse visual field outcomes, poorer BCVA, and a higher incidence of NJ-MvD compared to primary PS. Choroidal and intrascleral vessels were associated with NJ-MvD and were located near or connected to the circle of Zinn-Haller. Eyes with high myopia and PS show wider PPA, affecting the γ-zone and δ-zone, and are at a higher risk of developing NJ-MvD. Specifically, eyes with PS types VII and IX are more susceptible to visual field damage and decreased BCVA. These results highlight the importance of impact of PS on PPM and PPA in high myopia.

A CFD‐PBM‐ANN framework to simulate the liquid–liquid two‐phase flow in a pulsed column

AbstractCFD‐PBM numerical simulation is a powerful tool in the research of droplet swarm behavior. In this work, an artificial neural network (ANN) based droplet breakage frequency function is established based on the directly measured data from our previous studies. Then, the weights and biases of ANN are embedded into the CFD‐PBM code in the form of matrices and vectors. For the first time, a CFD‐PBM‐ANN simulation framework is established. Simulation results are in good agreement with the experimental data under different operation conditions. The cumulative droplet size distribution decreases with the increase of interfacial tension and pulse intensity. It is also found by the simulation that the droplet breakage frequency is relatively high at the edge of disc and doughnut plate, which is accordant with the distribution of turbulent energy dissipation and velocity gradient.

Sunspot Group Detection and Classification by Dual Stream Convolutional Neural Network Method

The automatic detection and analysis of sunspots play a crucial role in understanding solar dynamics and predicting space weather events. This paper proposes a novel method for sunspot group detection and classification called the dual stream Convolutional Neural Network with Attention Mechanism (DSCNN-AM). The network consists of two parallel streams each processing different input data allowing for joint processing of spatial and temporal information while classifying sunspots. It takes in the white light images as well as the corresponding magnetic images that reveal both the optical and magnetic features of sunspots. The extracted features are then fused and processed by fully connected layers to perform detection and classification. The attention mechanism is further integrated to address the “edge dimming” problem which improves the model’s ability to handle sunspots near the edge of the solar disk. The network is trained and tested on the SOLAR-STORM1 data set. The results demonstrate that the DSCNN-AM achieves superior performance compared to existing methods, with a total accuracy exceeding 90%.

Circular motion of noncollinear spin textures in Corbino disks: Dynamics of Néel- versus Bloch-type skyrmions and skyrmioniums

Magnetic skyrmions are nanoscale magnetic whirls that can be driven by currents via spin torques. They are promising candidates for spintronic devices such as the racetrack memory, where a motion along the uniform current is typically desired. However, for spin torque nano-oscillators in Corbino disks, the goal is to achieve a circular motion, perpendicular to the radially applied current. As we show, based on analytical calculations and micromagnetic simulations, Bloch skyrmions engage in a circular motion with frequencies in the MHz range when driven by spin-orbit torques. In contrast, Néel skyrmions get stuck at the edges of the disk. Our analysis reveals that the antagonistic dynamics between Bloch- and Néel-type magnetic textures arise from their helicity. Furthermore, we find that skyrmioniums, which are topologically trivial variations of skyrmions, move even faster and allow an increase in the current density without being pushed toward the edges of the disk. When driven by spin-transfer torques instead, Bloch and Néel skyrmions no longer exhibit different dynamics. Instead, they move along a circular trajectory due to the skyrmion Hall effect caused by their topological charge. Consequently, the topologically trivial skyrmioniums inevitably become trapped at the disk edge in this scenario. To provide a comprehensive understanding, our paper also examines currents applied tangentially, further enriching our insights into skyrmion dynamics and appropriate current injection methods for skyrmion-based devices. Published by the American Physical Society 2024

Polarization Substructure in the Spiral-dominated HH 111 Disk: Evidence for Grain Growth

The HH 111 protostellar disk has recently been found to host a pair of spiral arms. Here we report the dust polarization results in the disk as well as the inner envelope around it, obtained with the Atacama Large Millimeter/submillimeter Array in continuum at λ ∼ 870 μm and ∼0.″05 resolution. In the inner envelope, polarization is detected with a polarization degree of ∼6% and an orientation almost everywhere parallel to the minor axis of the disk and thus likely to be due to the dust grains magnetically aligned mainly by toroidal fields. In the disk, the polarization orientation is roughly azimuthal on the far side and becomes parallel to the minor axis on the near side, with a polarization gap in between on the far side near the central protostar. The disk polarization degree is ∼2%. The polarized intensity is higher on the near side than the far side, showing a near–far side asymmetry. More importantly, the polarized intensity and thus polarization degree are lower in the spiral arms but higher in between the arms, showing an anticorrelation of the polarized intensity with the spiral arms. Our modeling results indicate that this anticorrelation is useful for constraining the polarization mechanism and is consistent with the dust self-scattering by the grains that have grown to a size of ∼150 μm. The interarms are sandwiched and illuminated by two brighter spiral arms and thus have higher polarized intensity. Our dust self-scattering model can also reproduce the observed polarization orientation parallel to the minor axis on the near side and the observed azimuthal polarization orientation at the two disk edges in the major axis. Further modeling work is needed to study how to reproduce the observed near–far side asymmetry in the polarized intensity and the observed azimuthal polarization orientation on the far side.

Properties of outer solar system pebbles during planetesimal formation from meteor observations

Observations of proto-planetary disks, as well as theoretical modeling, suggest that in the late stages of accretion leading up to the formation of planetesimals, particles grew to pebbles the size of 1-mm to tens of cm, depending on the location and ambient conditions in the disk. That is the same size range that dominates the present-day comet and primitive asteroid mass loss. Meteoroids that size cause visible meteors on Earth. Here, we hypothesize that the size distribution and the physical and chemical properties of young meteoroid streams still contain information about the conditions in the solar nebula during these late stages of accretion towards planetesimal formation. If so, they constrain where long-period (Oort Cloud) comets, Jupiter-family (Scattered Disk Kuiper Belt) comets, and primitive asteroids (Asteroid Belt) formed. From video and visual observations of 47 young meteor showers, we find that freshly ejected meteoroids from long-period comets tend to have low bulk density and are distributed with equal surface area per log-mass interval (magnitude distribution index χ ∼ 1.85), suggesting gentle accretion conditions. Jupiter-family comets, on the other hand, mostly produce meteoroids twice as dense and distributed with a steeper χ ∼ 2.15 or even χ ∼ 2.5, which implies that those pebbles grew from particles fragmenting in a collisional cascade or by catastrophic collisions, respectively. Some primitive asteroids show χ > 2.5, with most mass in small particles, indicating an even more aggressive fragmentation by processes other than mutual collisions. Both comet populations contain an admixture of compact materials that are sometimes sodium-poor, but Jupiter-family comets show a higher percentage (∼8% on average) than long-period comet showers (∼4%) and a wider range of percentages among comets. While there are exceptions in both groups, the implication is that most long-period comets formed under gentle particle growth conditions, possibly near the 30 AU edge of the Trans Neptunian Disk, while most Jupiter family comets formed closer to the Sun where pebbles reached or passed the fragmentation barrier, and primitive asteroids formed in the region where the cores of the giant planets formed. This is possible if the Scattered Disk represents all objects scattered by Neptune during its migration, while the present-day outer Oort cloud formed only during and after the time of the planet instability, well after the Sun had moved away from sibling stars.

Soft X-ray Spectrum Changes over the 35-Day Cycle in Hercules X-1 Observed with AstroSat SXT

Observations of the X-ray binary system Her X-1 by the AstroSat Soft X-ray Telescope (SXT) were carried out in 2020 through 2023 with the goals of measuring X-ray spectrum changes with the 35-day disk precession phase and measuring eclipses at different 35-day phases. Her X-1 exhibits a regular flux modulation with a period of ≃35 days with different intensity levels at various 35-day phases (called “states”). The four multi-day long observations were scheduled to cover most of these states. Each 35-day phase was determined using monitoring observations with the Swift Burst Alert Telescope (BAT). Nine eclipses were observed in the range of 35-day phases, with at least one eclipse during each observation. Data with dips were separated from data without dips. The variation in X-ray spectral parameters vs. 35-day phase shows the following: eclipse parameters are nearly constant, showing that the scattering corona does not change with 35-day phase; dips show an increase in covering fraction but not column density compared to non-dip data; the1 keV line normalization behaves similarly to the powerlaw normalization, consistent with an origin near the powerlaw emission region, likely the magnetospheric accretion flow from the inner disk onto the neutron star; and the blackbody normalization (area) is large (∼3×105 km2) during the Main High and Short High states, consistent with the inner edge of the accretion disk.

Inner dusty regions of protoplanetary discs – III. The role of non-radial radiation pressure in dust dynamics

ABSTRACT We explore the dynamical behaviour of dust particles that populate the surface of inner optically thick protoplanetary discs. This is a disc region with the hottest dust and is of a great importance for planet formation and dust evolution, but we still struggle to understand all the forces that shape this environment. In our approach, we combine results from two separate numerical studies, one is the wind velocity and density distributions obtained from magnetohydrodynamical simulations of accretion discs, and the other is a high-resolution multigrain dust radiation transfer. In our previous paper in the series, we described the methodology for utilizing these results as an environmental input for the integration of dust trajectories driven by gravity, gas drag, and radiation pressure. Now we have two improvements, we incorporate time changes in the wind density and velocity, and we implement the non-radial radiation pressure force. We applied our analysis on the Herbig Ae and T Tau stars. We confirm that the radiation pressure force can lead to dust outflow, especially in the case of more luminous stars. Additionally, it opposes dust accretion at the inner disc edge and reduces dust settling. These effects are enhanced by the disc wind, especially in the zone where the stellar and the disc magnetic fields meet. Our results suggest that dust grains can stay in the hottest disc region for an extended period and then end up ejected into the outer disc regions.

High-resolution spectroscopy of the intermediate polar EX Hydrae

EX Hya is one of the best studied, but still enigmatic intermediate polars. We present phase-resolved blue VLT/UVES high-resolution (λ/Δλ ≃ 16.000) spectra of EX Hya taken in January 2004. Our analysis involves a unique decomposition of the Balmer line profiles into the spin-modulated line wings that represent streaming motions in the magnetosphere and the orbital-phase modulated line core that represents the accretion disk. Spectral analysis and tomography show that the division line between the two is solidly located at ∣υrad ∣ ≃ 1200 km s−1, defining the inner edge of the accretion disk at rin ≃ 7 × 109 cm or ∼10R1 (WD radii). This large central hole allows an unimpeded view of the tall accretion curtain at the lower pole with a shock height up to hsh ∼ 1R1 that is required by X-ray and optical observations. Our results contradict models that advocate a small magnetosphere and a small inner disk hole. Equating rin with the magnetospheric radius in the orbital plane allows us to derive a magnetic moment of the WD of μ1 ≃ 1.3 × 1032 G cm3 and a surface field strength B1 ∼ 0.35 MG. Given a polar field strength Bp ≲ 1.0 MG, optical circular polarization is not expected. With an accretion rate Ṁ = 3.9 × 10−11 M⊙ yr−1, the accretion torque is Gacc ≃ 2.2 × 1033 g cm2 s−2. The magnetostatic torque is of similar magnitude, suggesting that EX Hya is not far from being synchronized. We measured the orbital radial-velocity amplitude of the WD, K1 = 58.7 ± 3.9 km s−1, and found a spin-dependent velocity modulation as well. The former is in perfect agreement with the mean velocity amplitude obtained by other researchers, confirming the published component masses M1 ≃ 0.79 M⊙ and M2 ≃ 0.11 M⊙.

The First Estimation of the Ambipolar Diffusivity Coefficient from Multi-scale Observations of the Class 0/I Protostar, HOPS-370

Protostars are born in magnetized environments. As a consequence, the formation of protostellar disks can be suppressed by the magnetic field, efficiently removing the angular momentum of the infalling material. Nonideal MHD effects are proposed as one way to allow protostellar disks to form. Thus, it is important to understand their contributions to observations of protostellar systems. We derive an analytical equation to estimate the ambipolar diffusivity coefficient at the edge of the protostellar disk in the Class 0/I protostar, HOPS-370, for the first time, under the assumption that the disk radius is set by ambipolar diffusion. Using previous results of the protostellar mass, disk mass, disk radius, density and temperature profiles, and magnetic field strength, we estimate the ambipolar diffusivity coefficient to be 1.7−1.4+1.5×1019cm2s−1 . We quantify the contribution of ambipolar diffusion by estimating its dimensionless Elsässer number to be ∼1.7−1.0+1.0 , indicating its dynamical importance in this region. We compare our results to those of the chemical calculations of the ambipolar diffusivity coefficient using the Non-Ideal Magnetohydrodynamics Coefficients and Ionization Library, which are consistent with our results. In addition, we compare our derived ambipolar diffusivity coefficient to the diffusivity coefficients for ohmic dissipation and the Hall effect, and find ambipolar diffusion is dominant in our density regime. These results demonstrate a new methodology to understand nonideal MHD effects in observations of protostellar disks. More detailed modeling of the magnetic field, envelope, and microphysics, along with a larger sample of protostellar systems, is needed to further understand the contributions of nonideal MHD.

ALMA view of the L1448-mm protostellar system on disk scales: CH3OH and H13CN as new disk wind tracers

Protostellar disks are known to accrete; however, the exact mechanism that extracts the angular momentum and drives accretion in the low-ionization “dead” region of the disk is under debate. In recent years, magnetohydrodynamic (MHD) disk winds have become a popular solution. Even so, observations of these winds require both high spatial resolution (~10 s au) and high sensitivity, which has resulted in only a handful of MHD disk wind candidates to date. In this work we present high angular resolution (~30 au) ALMA observations of the emblematic L1448-mm protostellar system and find suggestive evidence for an MHD disk wind. The disk seen in dust continuum (~0.9 mm) has a radius of ~23 au. Rotating infall signatures in H13CO+ indicate a central mass of 0.4 ± 0.1 M⊙ and a centrifugal radius similar to the dust disk radius. Above the disk, we identify rotation signatures in the outflow traced by H13CN, CH3OH, and SO lines and find a kinematical structure consistent with theoretical predictions for MHD disk winds. This is the first detection of an MHD disk wind candidate in H13CN and CH3OH. The wind launching region estimated from cold MHD wind theory extends out to the disk edge. The magnetic lever arm parameter would be λϕ ≃ 1.7, in line with recent non-ideal MHD disk models. The estimated mass-loss rate is approximately four times the protostellar accretion rate (Ṁacc ≃ 2 × 10−6M⊙ yr−1) and suggests that the rotating wind could carry enough angular momentum to drive disk accretion.

Preliminary clinical observation and analysis of structural changes of optic nerve head in glaucoma patients after visual training

Objective: To investigate the effect of virtual reality visual training on remodeling optic nerve structures of glaucoma patients and analyze the influencing factors of visual training effect. Methods: A prospective non-randomized controlled trial was conducted. Glaucoma patients who presented to the Department of Ophthalmology, Beijing Shijitan Hospital between October 2021 and October 2022 were collected and divided into the training group or the control group according to their intentions. The training group accepted 3 months of visual training, while the control group did not. Optical coherence tomography was used to examine the disc edge area, cup volume, disc area, cup-to-disc ratio, and other parameters of the optic disc of both eyes of the patients at enrollment and after 3 months, and the changes of each parameter in the two groups were analyzed. Multivariate analysis was performed in the training group to investigate the effects of sex, age, visual field index, and mean defect on visual disc structure changes during visual training. Results: A total of 53 glaucoma patients (101 eyes) were included in the final analysis, among which the training group consisted of 27 cases (51 eyes), with 19 males and 8 females, and the age range was 48.0 (40.0, 61.0) years old. The control group comprised 26 cases (50 eyes), with 26 males and 11 females, and the age range was 54.0 (38.0, 63.0) years old. Compared with the control group, the deviation of cup volume was -0.006(-0.050, 0.015)mm3 (P<0.05), and the deviation of disc edge area was 0.00(-0.04, 0.05)mm2 (P<0. 05)in the visual training group after 3 months of visual training. The gender (OR=4.217, 95%CI=1.188-14.966) may be the influence factor of rim area. While,the mean defect (OR=1.526, 95%CI=0.245-9.491) was not that influential on rim area change. Conclusions: Visual training can increase the disc area and decrease the optic cup volume of the optic nerve in glaucoma patients. The rim area may be increased more easily after visual training in male glaucoma patients.

Emergence of hot corona and truncated disc in simulations of accreting stellar mass black holes

ABSTRACT Stellar mass black holes in X-ray binaries (XRBs) are known to display different states characterized by different spectral and timing properties, understood in the framework of a hot corona coexisting with a thin accretion disc whose inner edge is truncated. There are several open questions related to the nature and properties of the corona, the thin disc, and dynamics behind the hard state. This motivated us to perform 2D hydrodynamical simulations of accretion flows onto a $10 \, \mathrm{M}_\odot$ black hole. We consider a two-temperature plasma, incorporate radiative cooling with bremmstrahlung, synchrotron, and Comptonization losses and approximate the Schwarzschild space–time via a pseudo-Newtonian potential. We varied the mass accretion rate in the range $0.02 \le \dot{M}/\dot{M}_{\rm Edd} \le 0.35$. Our simulations show the natural emergence of a colder truncated thin disc embedded in a hot corona, as required to explain the hard state of XRBs. We found that as $\dot{M}$ increases, the corona contracts and the inner edge of the thin disc gets closer to the event horizon. At a critical accretion rate $0.02 \le \dot{M}_{\text{crit }}/\dot{M}_{\rm Edd} \le 0.06$, the thin disc disappears entirely. We discuss how our simulations compare with XRB observations in the hard state.

Discovery of Asymmetric Spike-like Structures of the 10 au Disk around the Very Low-luminosity Protostar Embedded in the Taurus Dense Core MC 27/L1521F with ALMA

Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations have revealed an increasing number of compact protostellar disks with radii of less than a few tens of astronomical units and that young Class 0/I objects have an intrinsic size diversity. To deepen our understanding of the origin of such tiny disks, we have performed highest-resolution configuration observations with ALMA at a beam size of ∼0.″03 (4 au) on the very low-luminosity Class 0 protostar embedded in the Taurus dense core MC 27/L1521F. The 1.3 mm continuum measurement successfully resolved a tiny, faint (∼1 mJy) disk with a major axis length of ∼10 au, one of the smallest examples in the ALMA protostellar studies. In addition, we detected spike-like components in the northeastern direction at the disk edge. Gravitational instability or other fragmentation mechanisms cannot explain the structures, given the central stellar mass of ∼0.2 M ⊙ and the disk mass of ≳10−4 M ⊙. Instead, we propose that these small spike structures were formed by a recent dynamic magnetic flux transport event due to interchange instability that would be favorable to occur if the parental core has a strong magnetic field. The presence of complex arc-like structures on a larger (∼2000 au) scale in the same direction as the spike structures suggests that the event was not single. Such episodic, dynamical events may play an important role in maintaining the compact nature of the protostellar disk in the complex gas envelope during the main accretion phase.