Low-velocity Component Research Articles

Forbidden emission line spectro-imaging of the RU Lupi jet and low-velocity component

The first images of the jet and low-velocity component (LVC) from the strongly accreting classical T Tauri star RU Lupi are presented. Adaptive optics-assisted spectro-imaging of forbidden emission lines was used. The main aim of the observations was to test the conclusion from a recent spectro-astrometric study that the narrow component (NC) of the LVC traces a magnetohydrodynamic (MHD) disk wind, and to estimate the mass-loss rate in the wind. The structure and morphology support a wind origin for the NC. The upper limit to the launch radius and semi-opening angle of the wind in emission are estimated to be 2 au and circ $, in agreement with MHD wind models for high accretors. The height of the wind-emitting region, a key parameter for the derivation of the mass-loss rate, is estimated for the first time at sim 35 au, giving $ M out $ = 2.6 times 10$^ $. When compared to the derived mass-accretion rate of $ M acc $ = 1.6 times 10$^ $, the efficiency in the wind is too low for the wind to contribute significantly to the angular momentum removal.

Jets from the Upper Scorpius Variable Young Star System 2MASS J16075796-2040087 via KECK/HIRES Spectro-astrometry

2MASS J16075796-2040087 is an ∼5 Myr young star in Upper Sco with evidence for accretion bursts on a timescale of about 15 days and, uncommonly for its age, outflows traced by multicomponent forbidden emission lines (FELs). The accretion bursts may be triggered by a companion at ∼4.6 au. We analyze HIRES spectra optimised for spectro-astrometry to better understand the origin of the several FEL velocity components and determine whether a magnetohydrodynamic (MHD) disk wind is present. The FEL high-velocity component (HVC) traces an asymmetric, bipolar jet ∼700 au long. The jet’s position angle ∼ 277° is not perpendicular to the disk. The lower-velocity emission, classified previously as a disk wind low-velocity component, is found to have more in common with the HVC and overall it is not possible to identify an MHD disk wind component. The spectro-astrometric signal of the low-velocity emission resembles those of jets and its density and ionisation fraction fall into the range of HVCs. We suggest a scenario where the accretion bursts due to the close companion power the jets past the age where such activity ends around most stars. The low-velocity emission here could come from a slow jet launched near the close companion and this emission would be blended with emission from the MHD wind.

Early Planet Formation in Embedded Disks (eDisk)

We present the results of the observations made within the ALMA Large Program called Early Planet Formation in Embedded disks of the Class 0 protostar GSS30 IRS3. Our observations included the 1.3 mm continuum with a resolution of 0″.05 (7.8 au) and several molecular species, including 12CO, 13CO, C18O, H2CO, and c-C3H2. The dust continuum analysis unveiled a disk-shaped structure with a major axis of ~200 au. We observed an asymmetry in the minor axis of the continuum emission suggesting that the emission is optically thick and the disk is flared. On the other hand, we identified two prominent bumps along the major axis located at distances of 26 and 50 au from the central protostar. The origin of the bumps remains uncertain and might be an embedded substructure within the disk or the temperature distribution and not the surface density because the continuum emission is optically thick. The 12CO emission reveals a molecular outflow consisting of three distinct components: a collimated component, an intermediate-velocity component exhibiting an hourglass shape, and a wider angle low-velocity component. We associate these components with the coexistence of a jet and a disk wind. The C18O emission traces both a circumstellar disk in Keplerian rotation and the infall of the rotating envelope. We measured a stellar dynamical mass of 0.35 ±0.09 M⊙.

N i] 10400/10410 Å Lines as Possible Disk Wind Tracers in a Young Intermediate-mass Star

Abstract In this study, we performed high-resolution near-infrared (NIR) spectroscopy (R = 28,000; λ = 0.90–1.35 μm) with a high signal-to-noise ratio on HD 200775, a very young (∼0.1 Myr old) and massive intermediate-mass star (a binary star with a mass of about 10 M ⊙ each) with a protoplanetary disk. The obtained spectra show eight forbidden lines of three elements: two of [S ii] (10289 and 10323 Å), two of [N i] (10400 and 10410 Å), and four of [Fe ii] (12570, 12946, 12981, and 13209 Å). This is the first time that the [N i] lines are detected in a young stellar object with a doublet deblended. Gaussian fitting of the spectra indicates that all line profiles have low-velocity components and exhibit blueshifted features, suggesting that all lines originate from the disk winds (magnetohydrodynamic disk wind and/or photoevaporative wind). Based on the fit, the [N i] and [Fe ii] lines are categorized into narrow components, while the [S ii] lines are at the boundary between broad and narrow components. These forbidden lines are suggested to be very promising disk wind tracers among the existing ones because they are in the NIR-wavelength range, which can be observed from early stages with high sensitivities. Among these lines, [N i] lines would be a rather powerful probe for deriving the basic physical parameters of disk wind gases. However, the study of these lines herein is limited to one object; thus, further studies are needed to examine their properties.

Constraining Protoplanetary Disk Winds from Forbidden Line Profiles with Simulation-based Inference

Protoplanetary disks (PPDs) are sites of vigorous hydrodynamic processes, such as accretion and outflows, and ultimately establish the conditions for the formation of planets. The properties of disk outflows are often inferred through the analysis of forbidden emission lines. These lines contain multiple overlapping components, tracing different emission regions with different processes that excite them: a high-velocity component (tracing a jet), a broad low-velocity component (LVC; tracing inner disk wind), and a narrow LVC (tracing the outer disk wind). They are also heavily contaminated by background spectral features. All of these challenges call into question the traditional approach of fitting Gaussian components to the line profiles and cloud the physical interpretation of those components. We introduce a novel statistical technique to analyze emission lines in PPDs. Simulation-based inference is a computationally efficient machine-learning technique that produces posterior distributions of the parameters (e.g., magnetic field, radiation sources, and geometry) of a representative wind model when given a spectrum without any prior assumption about line shapes (e.g., symmetry). In this pathfinder study, we demonstrate that this technique indeed accurately recovers the parameters from simulated spectra without noise and background. Future work will provide an analysis of the observed spectra.

GIARPS High-resolution Observations of T Tauri stars (GHOsT)

Aims. This paper aims to revisit the kinematical and physical properties of the warm (T ~ 5000–10 000 K) atomic gas in the inner disk (<5 au) region of classical T Tauri stars (CTTs) and relate them to the properties of the outer dusty disk resolved with ALMA. We also want to define constraints for the mass-loss in the inner atomic winds and jets to assess their role in the evolution and dispersal of planet-forming disks. Methods. We used the high resolution (R = 115 000, ~2.6 km s−1) spectra of 36 CTTs observed as part of the GIARPS High-resolution Observations of T Tauri stars (GHOsT) project and analysed the profile and luminosity of the brightest optical forbidden lines, namely [O I] 630 nm, [O I] 557 nm, [S II] 406 nm, [S II] 673 nm, and [N II] 658 nm. Results. We decomposed the line profiles into different velocity components, and concentrated our analysis mostly on the so-called narrow low-velocity component (NLVC). We find that about 40% of sources display a NLVC peak velocity (Vp) compatible with the stellar velocity. These include the transitional disks (TD) and typically show a single low velocity component (LVC), lower mass accretion rates, and the absence of a jet. They therefore might represent later evolutionary stages where the emission from the disk is dominant with respect to the wind contribution. No difference in kinematical properties was instead found between sources with full disks and disks with substructures as resolved by ALMA. The [O I] 630 nm profiles peaking at the stellar velocity are well fitted by a simple Keplerian disk model, where the emission line region extends from ~0.01 au up to several tens of au in some cases. The [O I] emission is detected inside the sub-millimetre dust cavities of all the TDs. No correlation is found between Rkep, derived from the line half width at half maximum (HWHM), and the size of the dust cavity. We see an anti-correlation between the [O I] 557/630 nm ratio and Rkep, which suggests that the [O I] emitting region expands as the gas dominating the emission cools and becomes less dense. We confirmed previous findings that the line ratios observed in the LVC, if compared with a thermal single temperature and density model, imply ne ~ 106–108 cm−3 and Te ~ 5000–10 000 K, and additionally constrained the ionisation fraction in the NLVC to be xe < 0.1. We however discuss the limits of applying this diagnostic to winds that are not spatially resolved. Conclusions. The emission from the disk should be considered as an important contribution to the forbidden line emission in CTTs. Also, the clearing of warm atomic gas from the upper disk layers does not seem to follow the dispersal of the bulk of molecular gas and dust during late disk evolution. For the outflow component, we estimated the mass-loss for both the disk winds and jets. We conclude that without better knowledge of the wind geometry and spatial extent, and given the limitation of the diagnostics, the mass-loss rates in the wind traced by the blue shifted LVC cannot be constrained better than a factor of 100, with a Ṁwind/Ṁacc spanning between ~0.01 and more than 1. When compared with synthetic [O I] 630 nm images of X-ray photoevaporation models, the estimated Ṁwind represents a lower limit to the total mass-loss rate of the model, indicating that [O I] 630 nm is likely not the best tracer to probe mass-loss in low-velocity winds.

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation

Massive infrared dark clouds (IRDCs) are considered to host the earliest stages of high-mass star formation. In particular, 70 μm dark IRDCs are the colder and more quiescent clouds. At a scale of about 5000 au using formaldehyde (H2CO) emission, we investigate the kinetic temperature of dense cores in 12 IRDCs obtained from the pilot Atacama Large Millimeter/submillimeter Array Survey of 70 μm dark High-mass clumps in Early Stages (ASHES). Compared to the 1.3 mm dust continuum and other molecular lines, such as C18O and deuterated species, we find that H2CO is mainly sensitive to low-velocity outflow components rather than to quiescent gas expected in the early phases of star formation. The kinetic temperatures of these components range from 26 to 300 K. The Mach number reaches about 15 with an average value of about 4, suggesting that the velocity distribution of gas traced by H2CO is significantly influenced by a supersonic nonthermal component. In addition, we detect warm line emission from HC3N and OCS in 14 protostellar cores, which requires high excitation temperatures (E u /k ∼ 100 K). These results show that some of the embedded cores in the ASHES fields are in an advanced evolutionary stage, previously unexpected for 70 μm dark IRDCs.

JWST detection of extremely excited outflowing CO and H2O in VV 114 E SW: A possible rapidly accreting IMBH

Mid-infrared (mid-IR) gas-phase molecular bands are powerful diagnostics of the warm interstellar medium. We report theJames WebbSpace Telescope detection of the COv = 1 − 0 (4.4 − 5.0 μm) and H2Oν2 = 1 − 0 (5.0 − 7.8 μm) ro-vibrational bands, both in absorption, toward the “s2” core in the southwest nucleus of the merging galaxy VV 114 E. All ro-vibrational CO lines up toJlow = 33 (Elow ≈ 3000 K) are detected, as well as a forest of H2O lines up to 130, 13(Elow ≈ 2600 K). The highest-excitation lines are blueshifted by ∼180 km s−1relative to the extended molecular cloud, which is traced by the rotational CO (J = 3 − 2) 346 GHz line observed with the Atacama Large Millimeter/submillimeter Array. The bands also show absorption in a low-velocity component (blueshifted by ≈30 km s−1) with lower excitation. The analysis shows that the bands are observed against a continuum with an effective temperature ofTbck ∼ 550 K extinguished withτ6 μmext ∼ 2.5−3(Ak ∼ 6.9 − 8.3 mag). The high-excitation CO and H2O lines are consistent withv = 0 thermalization withTrot ≈ 450 K and column densities ofNCO ≈ (1.7 − 3.5)×1019cm−2andNH2O ≈ (1.5 − 3.0)×1019cm−2. Thermalization of thev = 0 levels of H2O requires either an extreme density ofnH2 ≳ 109cm−3, or radiative excitation by the mid-IR field in a very compact (< 1 pc) optically thick source emitting ∼1010 L⊙. The latter alternative is favored, implying that the observed absorption probes the very early stages of a fully enshrouded active black hole (BH). On the basis of a simple model for BH growth and applying a lifetime constraint to the s2 core, an intermediate-mass BH (IMBH,MBH ∼ 4.5 × 104 M⊙) accreting at super-Eddington rates is suggested, where the observed feedback has not yet been able to break through the natal cocoon.

Line Profiles of Forbidden Emission Lines and What They Can Tell Us About Protoplanetary Disk Winds

Emission in forbidden lines of oxygen, neon, and other species are commonly used to trace winds from protoplanetary disks. Using Cloudy, we calculate such emission for parametrized wind models of the magnetothermal type, following Bai et al. These models share characteristics with both photoevaporative and magnetocentrifugal winds, which can be regarded as end members, and are favored by recent theoretical research. Both broad and narrow low-velocity components of the lines can be produced with plausible wind parameters, something that traditional wind models have difficulty with. Line luminosities, blueshifts, and widths, as well as trends of these with accretion luminosity and disk inclination, are in general accordance with observations.

GA-NIFS: The ultra-dense, interacting environment of a dual AGN at z ∼ 3.3 revealed by JWST/NIRSpec IFS (Corrigendum)

LBQS 0302-0019 is a blue quasar (QSO) at z ∼ 3.3, hosting powerful outflows, and residing in a complex environment consisting of an obscured AGN candidate, and multiple companions, all within 30 kpc in projection. We use JWST NIRSpec IFS observations to characterise the ionized gas in this complex system. We develop a procedure to correct for the spurious oscillations (or ‘wiggles’) in NIRSpec single-spaxel spectra, due to the spatial under-sampling of the point spread function. We perform a quasar-host decomposition with the QDeblend3D tools, and use multi-component kinematic decomposition of the optical emission line profiles to infer the physical properties of the emitting gas. The quasar-host decomposition allows us to identify i) a low-velocity component possibly tracing a warm rotating disk, with a dynamical mass Mdyn ∼10^11 Msun and a rotation-to-random motion ratio vrot/σ0 ∼2; ii) a spatially unresolved ionised outflow, with a velocity of ∼ 1000 km/s and an outflow mass rate of ∼10^4 Msun/yr. We also detect eight interacting companion objects close to LBQS 0302-0019. Optical line ratios confirm the presence of a second, obscured AGN at ∼20 kpc of the primary QSO; the dual AGN dominates the ionization state of the gas in the entire NIRSpec field-of-view. This work has unveiled with unprecedented detail the complex environment of this dual AGN, which includes nine interacting companions (five of which were previously unknown), all within 30 kpc of the QSO. Our results support a scenario where mergers can trigger dual AGN, and can be important drivers for rapid early SMBH growth.

5–12 pc resolution ALMA imaging of gas and dust in the obscured compact nucleus of IRAS 17578-0400

AbstractWe here present 0.02–0.04″ resolution ALMA observation of the compact obscured nucleus (CON) of IRAS 17578-0400. A dusty torus within the nucleus, approximately 4 pc in radius, has been uncovered, exhibiting a usually flat spectral index at ALMA band 3, likely due to the millimeter corona emission from the central supermassive black hole (SMBH). The dense gas disk, traced by 13CO(1-0), spans 7 pc in radius and suggests an outflow driven by a disk wind due to its asymmetrical structure along the minor axis. Collimated molecular outflows (CMO), traced by the low-velocity components of the HCN(3-2) and HCO+(3-2) lines, align with the minor axis gas disk. Examination of position-velocity plots of HCN(3-2) and HCO+(3-2) reveals a flared dense gas disk extended a radius of ∼60 pc, infalling and rotating at speeds of about 200 km s−1 and 300 km s−1 respectively. A centrifugal barrier, located around 4 pc from the dynamical center, implies an SMBH mass of approximately 108Mȯ, consistent with millimeter corona emission estimates. The CMO maintains a steady rotation speed of 200 km s−1 over the 100 pc scale along the minor axis. The projected speed of the CMO is about 80 km s−1, corresponding to around ∼500 km s−1, assuming an inclination angle of 80°. Such a kinematics structure of disk-driven collimated rotating molecular outflow with gas supplies from a falling rotating disk indicates that the feedback of the compact obscured nucleus is likely regulated by the momentum transfer of the molecular gas that connects to both the feeding of the nuclear starburst and supermassive black hole.

Structure of the accretion flow of IX Velorum as revealed by high-resolution spectroscopy

Context. Several high mass-transfer cataclysmic variables show evidence of outflow from the system, which could play an important role in their evolution. We investigate the system IX Vel, which was proposed to show similar characteristics. Aims. We study the structure of the IX Vel system, particularly the structure of its accretion flow and accretion disc. Methods. We used high-resolution time-resolved spectroscopy to construct radial velocity curves of the components in IX Vel. We computed Doppler maps of the system, which we used to estimate the temperature distribution maps. Results. We have improved the spectroscopic ephemeris of the system and its orbital period Porb = 0.19392793(3) d. We constructed Doppler maps of the system based on hydrogen and helium emission lines and the Bowen blend. The maps show features corresponding to the irradiated face of the secondary star, the outer rim of the accretion disc, and low-velocity components located outside the accretion disc and reaching towards L3. We constructed a temperature distribution map of the system using the Doppler maps of Balmer lines. Apart from the features found in the Doppler maps, the temperature distribution map shows a region of high temperature in the accretion disc connecting the expected position of a bright spot and the inner parts of the disc. Conclusions. We interpret the low-velocity emission found in the Doppler map as emission originating in the accretion disc wind and in an outflow region located in the vicinity of the third Lagrangian point L3. This makes IX Vel a member of the RW Sex class of cataclysmic variables.

Optical Forbidden Emission Line Spectro-astrometry of T CrA: Evidence for a Multiple System and Multiple Jets* * Based on data collected by UVES 089.C-0299(A) observations at the VLT on Cerro Paranal (Chile), which is operated by the European Southern Observatory (ESO).

Spectro-astrometry is applied to echelle spectra of the young intermediate-mass star T CrA. The aim is to better understand the origin of the [O i] and [S ii] emission from T CrA and further explore the usefulness of spectro-astrometry in the search for a reliable tracer of MHD disk winds. The analysis reveals a small-scale curved jet in an east–west direction and inclined parallel to the plane of the sky. It is the inclination of this jet that led to the classification of the forbidden emission lines as a low-velocity component. Thus, spectro-astrometry highlights here that for close to edge-on disks spatial information is necessary. The position angle of the jet is not perpendicular to the position angle of the accretion disk nor does it agree with older observations of outflows likely driven by T CrA. The mass outflow rate of 5–10 × 10−8 M ⊙ yr−1 is within the range for intermediate-mass stars. We conclude that more than one outflow is driven by the T CrA system and that the curvature seen in the first detection of an outflow from T CrA and in the data presented here is likely due to the multiplicity of the system.

The influence of free stream turbulence on the development of a wind turbine wake

The wake of an isolated model-scale wind turbine is analysed in a set of inflow conditions having free stream turbulence intensity between 3 % and 12 %, and integral time scales in the range of 0.1–10 times the convective time scale based on the turbine diameter. It is observed that the wake generated by the turbine evolves more rapidly, with the onset of the wake evolution being closer to the turbine, for high turbulence intensity and low integral time scale flows, in accordance with literature, while flows at higher integral time scales result in a slow wake evolution, akin to that generated by low-turbulence inflow conditions despite the highly turbulent ambient condition. The delayed onset of the wake evolution is connected to the stability of the shear layer enveloping the near-wake, which is favoured for low-turbulence or high-integral time scale flows, and to the stability of the helical vortex set surrounding the wake, as this favours interaction events and prevents momentum exchange at the wake boundary which hinder wake evolution. The rate at which the velocity in the wake recovers to undisturbed conditions is instead analytically shown to be a function of the Reynolds shear stress at the wake centreline, an observation that is confirmed by measurements. The rate of production of Reynolds shear stress in the wake is then connected to the power harvested by the turbine to explain the differences between flows at equivalent turbulence intensity and different integral time scales. The wake recovery rate, and by extension the behaviour of the turbine wake in high-integral time scale flows, is seen to be a linear function of the free stream turbulence intensity for flows with Kolmogorov-like turbulence spectrum, in accordance with literature. This relation is seen not to hold for flows with different free stream turbulence spectral distribution; however, this trend is recovered if the contributions of low frequency velocity components to the turbulence intensity are ignored or filtered out from the computation.

A High-resolution Optical Survey of Upper Sco: Evidence for Coevolution of Accretion and Disk Winds

Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. Here, we analyze high-resolution (Δv ∼ 7 km s−1) optical spectra from a sample of 115 T Tauri stars in the ∼5–10 Myr Upper Sco association and focus on the [O i] λ6300 and Hα lines to trace disk winds and accretion, respectively. Our sample covers a large range of spectral types and we divide it into warm (G0-M3) and cool (later than M3) to facilitate comparison with younger regions. We detect the [O i] λ6300 line in 45 out of 87 Upper Sco sources with protoplanetary disks and 32 out of 45 are accreting based on Hα profiles and equivalent widths. All [O i] λ6300 Upper Sco profiles have low-velocity (centroid < −30 km s−1; low-velocity component (LVC)) emission and most (36/45) can be fit by a single Gaussian (SC). The single-component (SC) distribution of centroid velocities and FWHMs is consistent with MHD disk winds. We also find that the Upper Sco sample follows the same accretion luminosity−LVC [O i] λ6300 relation and the same anticorrelation between SC FWHM and Wide-field Infrared Survey Explorer W3-W4 spectral indices as the younger samples. These results indicate that accretion and disk winds coevolve and that, as inner disks clear out, wind emission arises further away from the star. Finally, our large spectral range coverage reveals that cool stars have larger FWHMs normalized by stellar mass than warm stars indicating that [O i] λ6300 emission arises closer in toward lower-mass/lower luminosity stars.

A Unified Model for Bipolar Outflows from Young Stars: Kinematic Signatures of Jets, Winds, and Their Magnetic Interplay with the Ambient Toroids

Kinematic signatures of the jet, winds, multicavities, and episodic shells arising in the unified model of bipolar outflows developed in Shang et al. (Paper I), in which an outflow forms by radially directed, wide-angle toroidally magnetized winds interacting with magnetized isothermal toroids, are extracted in the form of position–velocity diagrams. Elongated outflow lobes, driven by magnetized winds and their interplay with the environment, are dominated by extended bubble structures with mixing layers beyond the conventional thin-shell models. The axial cylindrically stratified density jet carries a broad profile near the base, across the projected velocity of the wide-angle wind, and narrows down along the axis with the collimated flow. The reverse shock encloses the magnetized free wind, forms an innermost cavity, and deflects the flow pattern. Shear, Kelvin–Helmholtz instabilities, and pseudopulses add fine and distinctive features between the jet–shell components, and the fluctuating jet velocities. The broad webbed velocity features connect the extremely high and the low velocities across the multicavities, mimicking nested outflowing slower-wind components. Rings and ovals in the perpendicular cuts trace multicavities at different heights, and the compressed ambient gap regions enrich the low-velocity features with protruding spikes. Our kinematic signatures capture the observed systematics of the high-, intermediate-, and low-velocity components from Class 0 to II jet–outflow systems in molecular and atomic lines. The nested shells observed in HH 212, HH 30, and DG Tau B are naturally explained. Outflows as bubbles are ubiquitous and form an inevitable integrative outcome of the interaction between wind and ambient media.

Forbidden emission lines in protostellar outflows and jets with MUSE

Context. Forbidden emission lines in protoplanetary disks are a key diagnostic in studies of the evolution of the disk and the host star. They signal potential disk accretion or wind, outflow, or jet ejection processes of the material that affects the angular momentum transport of the disk as a result. Aims. We report spatially resolved emission lines, namely, [O I] λλ6300, 6363, [N II] λλ6548, 6583, Hα, and [S II] λλ6716, 6730 that are believed to be associated with jets and magnetically driven winds in the inner disks, due to the proximity to the star, as suggested in previous works from the literature. With a resolution of 0.025 × 0.025 arcsec2, we aim to derive the position angle of the outflow/jet (PAoutflow/jet) that is connected with the inner disk. We then compare it with the position angle of the dust (PAdust) obtained from previous constraints for the outer disk. We also carry out a simple analysis of the kinematics and width of the lines and we estimate the mass-loss rate based on the [O I] λ6300 line for five T Tauri stars. Methods. Observations were carried out with the optical integral field spectrograph of the Multi Unit Spectroscopic Explorer (MUSE), at the Very Large Telescope (VLT). The instrument spatially resolves the forbidden lines, providing a unique capability to access the spatial extension of the outflows/jets that make the estimate of the PAoutflow/jet possible from a geometrical point of view. Results. The forbidden emission lines analyzed here have their origin at the inner parts of the protoplanetary disk. From the maximum intensity emission along the outflow/jet in DL Tau, CI Tau, DS Tau, IP Tau, and IM Lup, we were able to reliably measure the PAoutflow/jet for most of the identified lines. We found that our estimates agree with PAdust for most of the disks. These estimates depend on the signal-to-noise level and the collimation of the outflow (jet). The outflows/jets in CIDA 9, GO Tau, and GW Lup are too compact for a PAoutflow/jet to be estimated. Based on our kinematics analysis, we confirm that DL Tau and CI Tau host a strong outflow/jet with line-of-sight velocities much greater than 100 km s−1, whereas DS Tau, IP Tau, and IM Lup velocities are lower and their structures encompass low-velocity components to be more associated with winds. Our estimates for the mass-loss rate, Ṁloss, range between (1.1–6.5) × 10−7–10−8 M⊙ yr−1 for the disk-outflow/jet systems analyzed here. Conclusions. The outflow/jet systems analyzed here are aligned within around 1° between the inner and outer disk. Further observations are needed to confirm a potential misalignment in IM Lup.

Interpreting molecular hydrogen and atomic oxygen line emission of T Tauri disks with photoevaporative disk-wind models

Context. Winds in protoplanetary disks play an important role in their evolution and dispersal. However, the physical process that is actually driving the winds is still unclear (i.e. magnetically versus thermally driven), and can only be understood by directly confronting theoretical models with observational data. Aims. We aim to interpret observational data for molecular hydrogen and atomic oxygen lines that show kinematic disk-wind signatures in order to investigate whether or not purely thermally driven winds are consistent with the data. Methods. We use hydrodynamic photoevaporative disk-wind models and post-process them with a thermochemical model to produce synthetic observables for the spectral lines o–H2 1–0 S(1) at 2.12 µm and [OI] 1D2–3P2 at 0.63 µm and directly compare the results to a sample of observations. Results. We find that our photoevaporative disk-wind model is consistent with the observed signatures of the blueshifted narrow low-velocity component (NLVC) – which is usually associated with slow disk winds – for both tracers. Only for one out of seven targets that show blueshifted NLVCs does the photoevaporative model fail to explain the observed line kinematics. Our results also indicate that interpreting spectral line profiles using simple methods, such as the thin-disk approximation, to determine the line emitting region is not appropriate for the majority of cases and can yield misleading conclusions. This is due to the complexity of the line excitation, wind dynamics, and the impact of the actual physical location of the line-emitting regions on the line profiles. Conclusions. The photoevaporative disk-wind models are largely consistent with the studied observational data set, but it is not possible to clearly discriminate between different wind-driving mechanisms. Further improvements to the models are necessary, such as consistent modelling of the dynamics and chemistry, and detailed modelling of individual targets (i.e. disk structure) would be beneficial. Furthermore, a direct comparison of magnetically driven disk-wind models to the observational data set is necessary in order to determine whether or not spatially unresolved observations of multiple wind tracers are sufficient to discriminate between theoretical models.

GIARPS High-resolution Observations of T Tauri stars (GHOsT)

Aims. In the framework of the GIARPS High-resolution Observations of T Tauri stars (GHOsT) project, we study the accretion properties of 37 classical T Tauri stars of the Taurus-Auriga star-forming region (SFR) with the aim of characterizing their relation with the properties of the central star, with jets and disk winds, and with the global disk structure, in synergy with complementary ALMA millimeter observations. Methods. We derive the stellar parameters, optical veiling, the accretion luminosity (Lacc), and the mass accretion rate (Ṁacc) in a homogeneous and self-consistent way using high-resolution spectra acquired at the Telescopio Nazionale Galileo with the HARPS-N and GIANO spectrographs that are flux-calibrated based on contemporaneous low-resolution spectroscopic and photometric ancillary observations. Results. The Lacc–L*, Ṁacc–M* and Ṁacc–Mdisk relations of the Taurus sample are provided and compared with those of the coeval SFRs of Lupus and Chamaeleon I. We analyzed possible causes for the observed large spreads in the relations. We find that (i) a proper modeling in deriving the stellar properties in highly spotted stars can reduce the spread of the Ṁacc–M* relation, (ii) transitional disks tend to have lower Ṁacc at a given M*, (iii) stars in multiple systems have higher Ṁacc at the same Mdisk, (iv) the Ṁacc versus disk surface density has a smaller spread than the Ṁacc–Mdisk, indicating that opacity effects might be important in the derivation of Mdisk. Finally, the luminosities of the [O i] 630 nm narrow low-velocity component and high-velocity component (HVC) and the deprojected HVC peak velocity were found to correlate with the accretion luminosity. We discuss these correlations in the framework of the currently accepted models of jets and winds. Conclusions. Our results demonstrate the potential of contemporaneous optical and near-infrared high-resolution spectroscopy to simultaneously provide precise measurements of the stellar wind and accretion wind properties of young stars.

UV Counterpart of an X-Ray Ultrafast Outflow in IRAS 17020+4544

We report on the discovery of a UV absorption counterpart of a low-ionization X-ray ultrafast outflow (UFO) in the narrow-line Seyfert 1 galaxy IRAS 17020+4544. This UV signature of the UFO is seen as a narrow and blueshifted Lyα absorption feature in the far-UV spectrum, taken with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST). The Lyα feature is found to be outflowing with a velocity of −23,430 km s−1 (0.078 c). We carry out high-resolution UV spectroscopy and photoionization modeling to study the UFO that is seen in the HTS/COS spectrum. The results of our modeling show that the UV UFO corresponds to a low-ionization, low-velocity component of the X-ray UFO found previously with XMM-Newton’s Reflection Grating Spectrometer. The other higher-velocity and higher-ionization components of the X-ray UFOs are not significantly detected in the HST/COS spectrum, consistent with predictions of our photoionization calculations. The multiple ionization and velocity components of the UFOs in IRAS 17020+4544 suggest a scenario where a powerful primary UFO entrains and shocks the ambient medium, resulting in formation of weaker secondary UFO components, such as the one found in the UV band.