What are we learning from the relative orientation between density structures and the magnetic field in molecular clouds?

We investigate the conditions of ideal magnetohydrodynamic (MHD) turbulence responsible for the relative orientation between density structures, characterized by their gradient, $\vec{\nabla}\rho$, and the magnetic field, $\vec{B}$, in molecular clouds (MCs). For that purpose, we construct an expression for the time evolution of the angle, $\phi$, between $\vec{\nabla}\rho$ and $\vec{B}$ based on the transport equations of MHD turbulence. Using this expression, we find that the configuration where $\vec{\nabla}\rho$ and $\vec{B}$ are mostly parallel, $\cos\phi=1$, and where $\vec{\nabla}\rho$ and $\vec{B}$ are mostly perpendicular, $\cos\phi=0$, constitute attractors, that is, the system tends to evolve towards either of these configurations and they are more represented than others. This fact would explain the predominant alignment or anti-alignment between column density, $N_H$, structures and the projected magnetic field orientation, $\hat{B}_\perp$, reported in observations. Additionally, we find that departures from the $\cos\phi=0$ configurations are related to convergent flows, quantified by the divergence of the velocity field, $\vec{\nabla}\cdot\vec{v}$, in the presence of a relatively strong magnetic field. This would explain the observed change in relative orientation between $N_H$-structures and $\hat{B}_\perp$ towards MCs, from mostly parallel at low $N_H$ to mostly perpendicular at the highest $N_H$, as the result of the gravitational collapse and/or convergence of flows. Finally, we show that the density threshold that marks the observed change in relative orientation towards MCs, from $N_H$ and $\hat{B}_\perp$ being mostly parallel at low $N_H$ to mostly perpendicular at the highest $N_H$, is related to the magnetic field strength and constitutes a crucial piece of information for determining the role of the magnetic field in the dynamics of MCs.Comment: 10 pages, 8 figures. Submitted to A&

The Orion-Taurus ridge: a synchrotron radio loop at the edge of the Orion-Eridanus superbubble

Large-scale synchrotron loops are recognized as the main source of diffuse radio-continuum emission in the Galaxy at intermediate and high Galactic latitudes. Their origin, however, remains rather unexplained. Using a combination of multi-frequency data in the radio band of total and polarized intensities, for the first time in this letter, we associate one arc -- hereafter, the Orion-Taurus ridge -- with the wall of the most prominent stellar-feedback blown shell in the Solar neighborhood, namely the Orion-Eridanus superbubble. We traced the Orion-Taurus ridge using 3D maps of interstellar dust extinction and column-density maps of molecular gas, $N_{\rm H_2}$. We found the Orion-Taurus ridge at a distance of 400\,pc, with a plane-of-the-sky extent of $180$\,pc. Its median $N_{\rm H_2}$ value is $(1.4^{+2.6}_{-0.6})\times 10^{21}$ cm$^{-2}$. Thanks to the broadband observations below 100 MHz of the Long Wavelength Array, we also computed the low-frequency spectral-index map of synchrotron emissivity, $\beta$, in the Orion-Taurus ridge. We found a flat distribution of $\beta$ with a median value of $-2.24^{+0.03}_{-0.02}$ that we interpreted in terms of depletion of low-energy ($<$ GeV) cosmic-ray electrons in recent supernova remnants ($10^5$ - $10^6$ yrs). Our results are consistent with plane-of-the-sky magnetic-field strengths in the Orion-Taurus ridge larger than a few tens of $\mu$G ($> 30 - 40 \,\mu$G). We report the first detection of diffuse synchrotron emission from cold-neutral, partly molecular, gas in the surroundings of the Orion-Eridanus superbubble. This observation opens a new perspective to study the multiphase and magnetized interstellar medium with the advent of future high-sensitivity radio facilities, such as the C-Band All-Sky Survey and the Square Kilometre Array.Comment: Accepted for publication in Astronomy & Astrophysic

Detailed 3D structure of OrionA in dust with Gaia DR2

The unprecedented astrometry from Gaia DR2 provides us with an opportunity to study in detail molecular clouds in the solar neighbourhood. Extracting the wealth of information in these data remains a challenge, however. We have further improved our Gaussian Processes-based, three-dimensional dust mapping technique to allow us to study molecular clouds in more detail. These improvements include a significantly better scaling of the computational cost with the number of stars, and taking into account distance uncertainties to individual stars. Using Gaia DR2 astrometry together with 2MASS and WISE photometry for 30 000 stars, we infer the distribution of dust out to 600 pc in the direction of the Orion A molecular cloud. We identify a bubble-like structure in front of Orion A, centred at a distance of about 350 pc from the Sun. The main Orion A structure is visible at slightly larger distances, and we clearly see a tail extending over 100 pc that is curved and slightly inclined to the line-of-sight. The location of our foreground structure coincides with 5-10 Myr old stellar populations, suggesting a star formation episode that predates that of the Orion Nebula Cluster itself. We identify also the main structure of the Orion B molecular cloud, and in addition discover a background component to this at a distance of about 460 pc from the Sun. Finally, we associate our dust components at different distances with the plane-of-the-sky magnetic field orientation as mapped by Planck. This provides valuable information for modelling the magnetic field in 3D around star forming regions.Comment: Accepted for publication in Astronomy and Astrophysics. 9 pages, 12 figure

Confirmation Of Two Galactic Supernova Remnant Candidates Discovered By THOR

Anderson et al. (2017) identified seventy six candidate supernova remnants (SNRs) using data from The HI, OH, Recombination line survey of the Milky Way (THOR). The spectral index and polarization properties can help distinguish between SNRs and H II regions, which are often confused. We confirm two SNR candidates using spectral index data and morphology. However, we observe that the fractional linear polarization cannot distinguish between SNRs and H II regions, likely due to contamination by diffuse Galactic synchrotron emission. We also comment on the association of SNR candidates with pulsars through geometric and age considerations.Comment: 12 pages, 4 figures; Accepted for publication in Ap

“Skills for pills”: The dialectical-behavioural therapy skills training reduces polypharmacy in borderline personality disorder

Objective: Polypharmacy and overprescription of off-label medications are common in patients with borderline personality disorder (BPD). The aim of the present naturalistic study was to explore whether the skills training module of dialectical-behavioural therapy (DBT) can reduce polypharmacy in these patients in routine clinical practice. Methods: Retrospective, observational study of 377 patients with a primary diagnosis of BPD consecutively admitted to the BPD outpatient unit from 2010 through 2020. All patients were invited to participate in the DBT skills training module (DBT-ST). DBT-ST participants (n = 182) were compared with a control group who did not participate in DBT-ST (n = 195). Pre-post intervention changes in medication load and use of antidepressants, benzodiazepines, mood stabilizers, and antipsychotics were evaluated. Results: At baseline, most patients (84.4%) were taking at least one medication and 46.9% were on polypharmacy. Compared to controls, patients in the DBT-ST group presented a significant reduction in the number of medications (2.67–1.95 vs. 2.16–2.19; p < 0.001), medication load (4.25–3.05 vs. 3.45–3.48; p < 0.001), use of benzodiazepines (54.4%–27.5% vs. 40%–40.5%; p < 0.001), mood stabilizers (43.4%–33% vs. 36.4%–39.5%; p < 0.001), and antipsychotics (36.3%–29.1% vs. 34.4%–36.9%; p < 0.001). Conclusions: These findings suggest that patients with BPD can benefit from the DBT-ST module, which may reduce the medication load, particularly of sedatives. The results suggest that DBT-ST may be useful to treat overmedication in patients with BPD and could help to promote “deprescription” in clinical practice.This study was supported by Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM). The authors would like to thank Bradley Londres for professional English language editing

Seguimiento Grado en Matemáticas. Curso 13-14

El objetivo principal de esta red ha sido la coordinación y seguimiento de los cursos correspondientes al Grado en Matemáticas que se ha implantado en su totalidad en el presente curso académico en la Facultad de Ciencias de la Universidad de Alicante y se engloba dentro del proceso general del seguimiento de todos los títulos de la Facultad de Ciencias. La red está coordinada por la coordinadora del Grado en Matemáticas y formada por los coordinadores de cada uno de los semestres. Se pretende evidenciar los progresos del título en el desarrollo del Sistema de Garantía Interno de Calidad (SGIC), con el fin de detectar las posibles deficiencias en el proceso de implantación del grado y contribuir a sus posibles mejoras elaborando propuestas de acciones para mejorar su diseño y desarrollo

Evidence for Spatial Separation of Galactic Dust Components

We present an implementation of a Bayesian mixture model using Hamiltonian Monte Carlo (HMC) techniques to search for spatial separation of Galactic dust components. Utilizing intensity measurements from \Planck High Frequency Instrument (HFI), we apply this model to high-latitude Galactic dust emission. Our analysis reveals a strong preference for a spatially-varying two-population dust model in intensity, with each population being well characterized by a single-component dust spectral-energy distribution (SED). While no spatial information is built into the likelihood, our investigation unveils spatially coherent structures with high significance, pointing to a physical origin for the observed spatial separation. These results are robust to our choice of likelihood and of input data. Furthermore, they are favored over a single-component dust model by Bayesian evidence calculations. Incorporating \IRAS 100\,$\mu m$ to constrain the Wein-side of the blackbody function, we find the dust populations differ at the $2.5\sigma$ level on the spectral index ($\beta_d$) vs. temperature $(T_d)$ plane. The presence of a multi-population dust has implications for component separation techniques frequently employed in the recovery of the Cosmic Microwave Background.Comment: 16 pages, 8 figures. Submitted to Ap