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The jiggling lemma of Thurston shows that any triangulation can be jiggled (read: subdivided and then perturbed) to be in general position with respect to a distribution. Our main result is a generalization of Thurston's lemma. It states that piecewise smooth solutions of a given open and fiberwise dense differential relation $\mathcal{R} \subset J^1(E)$ of first order can be constructed by jiggling arbitrary sections of $E$. Our statement also holds in parametric and relative form. We understand this as an h-principle without homotopical assumptions for piecewise smooth solutions of $\mathcal{R}$., Comment: 33 pages, 8 figures

Recent observations from JWST have revealed an abundant population of active galactic nuclei (AGN) and so-called ``Little Red Dots'' (LRDs) at $2\lesssim z \lesssim 11$, many of which are characterized by V-shaped UV-to-optical continua with turnovers around the Balmer limit. The physical nature of these LRDs is unclear, and it remains debated whether the peculiar spectral shape originates from AGN, compact galaxies, or both. We present the analysis of new NIRSpec-IFU data from the BlackTHUNDER JWST Large Programme and archival NIRSpec-MSA data of a lensed LRD at $z=7.04$. The spectra confirm the presence of a smooth Balmer break and a broad H$\beta$ tracing the Broad Line Region (BLR) of an AGN. The small velocity dispersion of the H$\beta$ narrow component indicates a small dynamical mass of the host galaxy of $M_{\rm dyn}<4 \times 10^8~M_{\odot}$, which implies that the stellar population cannot contribute more than 10% to the optical continuum. We show that the Balmer break can be well described by an AGN continuum absorbed by very dense ($n_{\rm H}\sim 10^{10}~{\rm cm^{-3}}$) and nearly dust-free gas along our line-of-sight (possibly gas in the BLR or its surrounding). The same gas is expected to produce H$\beta$ absorption, at a level consistent with a tentative detection ($3\sigma$) in the high-resolution spectrum. Such a non-stellar origin of the Balmer break may apply to other LRDs, and would alleviate the issue of extremely high stellar mass surface densities inferred in the case of a stellar interpretation of the Balmer break. We note that this is a rare case of a black hole that is overmassive relative to both the host galaxy stellar and dynamical masses. We finally report indications of variability and the first attempt of AGN reverberation mapping at such an early epoch., Comment: 34 pages, 24 figures, submitted to MNRAS

Objetive: In the care of renal patients, prioritising their quality of life and nursing care is essential. Research links patients' perceptions of care quality to improved outcomes such as safety, clinical efficacy, treatment adherence, and preventive practices. This study aimed to evaluate the quality of life and care perception in these patients and explore potential associations between these dimensions. Material and methods: A cross-sectional descriptive study was conducted with 43 patients attending an advanced CKD clinic. Quality of life was assessed using the KDQOL-36 questionnaire, while the IECPAX questionnaire measured perceived care quality. Sociodemographic and clinical data were collected from patient records. Participants completed the questionnaires during routine visits, with scores analysed to identify associations between variables. Results: The study included 60% men (n=28) and 32% women (n=15), with a mean age of 78 years . Among participants, 45% were diabetic, 79% hypertensive, and 58% took more than five medications daily. Mean scores were 78.76 for KDQOL-36 and 5.54 for IECPAX. Significant differences were found in the physical role domain between men and women (p=0.01) and for individuals over 65 years (p=0.04). Higher IECPAX scores were associated with taking more than five medications (p=0.05). However, no correlation was observed between KDQOL-36 and IECPAX scores. Conclusions: The findings suggest that quality of life and perceived care quality are independent in advanced CKD patients. While this study provides insights, larger multicentre studies are needed to validate these results. These findings highlight the importance of addressing both aspects separately to improve outcomes in this population., Comment: 21 pages, 2 figures, 7 tables

We present JWST/NIRSpec IFU observations of the z=7.152 galaxy system B14-65666, as part of the GA-NIFS survey. Line and continuum emission in this massive system (log10(M*/Msol)=9.8+/-0.2) is resolved into two strong cores, two weaker clumps, and a faint arc, as seen in recent JWST/NIRCam imaging. Our dataset contains detections of [OII]3727,3729, [NeIII]3869,3968, Balmer lines (HBeta, HGamma, HDelta, HEpsilon, HZeta), [OIII]5007, and weak [OIII]4363. Each spectrum is fit with a model that consistently incorporates interstellar medium conditions (i.e., electron temperature, T_e, electron density, n_e, and colour excess, E(B-V)). The resulting line fluxes are used to constrain the gas-phase metallicity (~0.3-0.4 solar) and HBeta-based SFR (310+/-40 Msol/yr) for each region. Common line ratio diagrams (O32-R23, R3-R2, Ne3O2-R23) reveal that each line-emitting region lies at the intersection of local and high-redshift galaxies, suggesting low ionisation and higher metallicity compared to the predominantly lower-mass galaxies studied with the JWST/NIRSpec IFU so far at z>5.5. Spaxel-by-spaxel fits reveal evidence for both narrow (FWHM<400 km/s) and broad (FWHM >500 km/s) line emission, the latter of which likely represents tidal interaction or outflows. Comparison to ALMA [CII]158um and [OIII]88um data shows a similar velocity structure, and optical-far infrared diagnostics suggest regions of high Lyman continuum escape fraction and n_e. This source lies on the mass-metallicity relation at z>4, suggesting an evolved nature. The two core galaxies show contrasting properties (e.g., SFR, M*, gas-phase metallicity), suggesting distinct evolutionary pathways. Combining the NIRSpec IFU and ALMA data sets, our analysis opens new windows into the merging system B14-65666., Comment: 23 pages, 15 figures. Submitted to MNRAS

The {\it Javalambre Photometric Local Universe Survey} (J-PLUS) is a {\it spectro-photometric} survey covering about 3,000~deg$^2$ in its third data release (DR3), and containing about 300,000 galaxies with high quality ({\it odds}$>0.8$) photometric redshifts (hereafter photo-$z$s). We use this galaxy sample to conduct a tomographic study of the counts and redshift angular fluctuations under Gaussian shells sampling the redshift range $z\in[0.05,0.25]$. We confront the angular power spectra of these observables measured under shells centered on 11 different redshifts with theoretical expectations derived from a linear Boltzmann code ({\tt ARFCAMB}). Overall we find that J-PLUS DR3 data are well reproduced by our linear, simplistic model. We obtain that counts (or density) angular fluctuations (hereafter ADF) are very sensitive to the linear galaxy bias $b_g(z)$, although weakly sensitive to radial peculiar velocities of the galaxy field, while suffering from systematics residuals for $z>0.15$. Angular redshift fluctuations (ARF), instead, show higher sensitivity to radial peculiar velocities and also higher sensitivity to the average uncertainty in photo-$z$s ($\sigma_{\rm Err}$), with no obvious impact from systematics. For $z<0.15$ both ADF and ARF agree on measuring a monotonically increasing linear bias varying from $b_g(z=0.05)\simeq 0.9\pm 0.06$ up to $b_g(z=0.15)\simeq 1.5\pm 0.05$, while, by first time, providing consistent measurements of $\sigma_{\rm Err}(z)\sim 0.014$ that are $\sim 40~\%$ higher than estimates from the photo-$z$ code {\tt LePhare}, ($\sigma_{\rm Err}^{\rm LePhare}=0.010$). As expected, this photo-$z$ uncertainty level prevents the detection of radial peculiar velocities in the modest volume sampled by J-PLUS DR3, although prospects for larger galaxy surveys of similar (and higher) photo-$z$ precision are promising., Comment: About 20 pages and 14 figures, to be submitted to the Open Journal for Astrophysics. Comments welcome!

A large, faint nebula was unexpectedly discovered near M31 using narrowband [O III] images. Its apparent size and the lack of a clear counterpart at other wavelengths make it unique and challenging to explain. We aim to determine whether the nebula is extragalactic or located within the Milky Way. This will enable us to constrain its physical properties and assess its nature. To do so, we obtained deep narrowband [O II]3727 and H$\alpha$+[NII] observations with the JAST80 telescope at the Observatorio Astrof\'isico de Javalambre, as well as high-spectral-resolution spectroscopy at four locations within the region of interest using MEGARA at the Gran Telescopio Canarias. We found extended [O II] emission along two near-parallel strands to the [O III], offset by six arcmin. The nebular spectra reveals up to 6 emission lines from [O III]4959,5007, H$\beta$, [N II]6583, and [S II]6716,6731. Their receding velocities are above $-$40 km s$^{-1}$, far from the systemic velocity of M31 ($-$300 km s$^{-1}$). The fluxes and velocities are consistent for the same lines across different regions of the nebula. The nebular properties suggest a location within the Milky Way rather than being physically associated with M31. The most likely scenario is a resolved ionization structure in a Galactic nebula with a separation between [O II] and [O III] of a few parsecs. The observed receding velocities would be unprecedented for an object physically linked to M31 but are common for nearby gas filaments. Their consistency across the nebula would also be unusual if it were larger than a kiloparsec. The analysis of the emission-line ratios, line widths, and morphology suggests the possibility of it being an interstellar gas filament with an additional source of ionization to explain the [O III] emission. However, the complex properties of this object call for further observations to confirm its nature., Comment: 13 pages, 6 figures. Submitted to Astronomy & Astrophysics

Distant quasars (QSOs) in galaxy overdensities are considered key actors in the evolution of the early Universe. In this work, we studied the kinematic and physical properties of the BR1202-0725 system at z=4.7, one of the most overdense fields known in the early Universe, consisting of a QSO, a submillimeter galaxy (SMG), and three Lyman-$\alpha$ emitters. We used data from the JWST/NIRSpec Integral Field Unit (IFU) to analyze the rest-frame optical emission of each source in the system. We estimated a bolometric luminosity of log($L_{\rm bol}/$[erg/s]) = 47.2 $\pm$ 0.4 and a black hole mass of log($M_{\rm BH}/M_\odot$) = 10.1 $\pm$ 0.5 for the QSO, which are consistent with previous measurements obtained with ground-based observations. The NIRSpec spectra of the SMG revealed instead unexpected [OIII] and H$\alpha$+[NII] profiles. The overall [OIII] line profile is blue-shifted by more than 700 km/s relative to the systemic velocity of the galaxy. Additionally, both the [OIII] and H$\alpha$+[NII] lines show prominent broad (1300 km/s), blueshifted wings associated with outflowing ionized gas. The analysis of NIRSpec and X-ray observations indicates that the SMG likely hosts an accreting supermassive black hole as supported by the following results: (i) the excitation diagnostic diagram is consistent with ionization from an active galactic nucleus (AGN); (ii) the X-ray luminosity is higher than $10^{44}$ erg/s; and (iii) it hosts a fast outflow ($v_{\rm out}$ = 5000 km/s), comparable to those observed in luminous QSOs. Therefore, the QSO-SMG pair represents one of the highest-redshift double AGN to date, with a projected separation of 24 kpc. Finally, we investigated the environment of this system and found four new galaxies at the same redshift of the QSO and within a projected distance of 5 kpc from it. This overdense system includes at least ten galaxies in only 980 kpc$^2$., Comment: 21 pages, 19 figures, Submitted to Astronomy & Astrophysics

Studying the distribution and properties of ionised gas in outflows driven by AGN is crucial for understanding the feedback mechanisms at play in extragalactic environments. In this study, we explore the connection between ionised outflows traced by rest-frame UV absorption and optical emission lines in GS133, a Compton thick AGN at z = 3.47. We combine observations from the JWST NIRSpec Integral Field Spectrograph (IFS) with archival VLT VIMOS long-slit spectroscopic data, as part of the GA-NIFS project. We perform a multi-component kinematic decomposition of the UV and optical line profiles to derive the physical properties of the absorbing and emitting gas in GS133. Our kinematic decomposition reveals two distinct components in the optical lines. The first component likely traces a rotating disk with a dynamical mass of 2e10 Msun. The second component corresponds to a galaxy-wide, bi-conical outflow, with a velocity of 1000 km/s and an extension of 3 kpc. The UV absorption lines show two outflow components, with bulk velocities v_out = -900 km/s and -1900 km/s, respectively. This characterises GS133 as a mini-BAL system. Balmer absorption lines with similar velocities are tentatively detected in the NIRSpec spectrum. Both photoionisation models and outflow energetics suggest that the ejected absorbing gas is located at 1-10 kpc from the AGN. We use 3D gas kinematic modelling to infer the orientation of the [O III] bi-conical outflow, and find that a portion of the emitting gas resides along our line of sight, suggesting that [O III] and absorbing gas clouds are partially mixed in the outflow. The derived mass-loading factor (i.e. the mass outflow rate divided by the SFR) of 1-10, and the kinetic coupling efficiency (i.e. the kinetic power divided by LAGN) of 0.1-1% per cent suggest that the outflow in GS133 provides significant feedback on galactic scales., Comment: 18 pages, 13 figures, submitted to Astronomy & Astrophysics. Comments are welcome

Inferring the coupling of different atmospheric layers requires observing spectral lines sensitive to the atmospheric parameters, particularly the magnetic field vector, at various heights. The best way to tackle this goal is to perform multi-line observations simultaneously. For instance, the new version of the Gregor Infrared Spectrograph instrument offers the possibility to observe the spectral lines at 8542 and 10830 A simultaneously for the first time. The first spectral window contains the Ca II 8542 A spectral line, while the Si I 10827 A transition and He I 10830 A triplet infrared lines can be found in the second spectral window. As the sensitivity to the atmospheric parameters and the height of formation of those transitions is different, combining them can help understand the properties of the solar photosphere and chromosphere and how they are magnetically coupled. Traditionally, the analysis of the Si I 10827 A transition assumes local thermodynamic equilibrium (LTE), which is not the best approximation to model this transition. Hence, in this work, we examine the potential of performing non-LTE (NLTE) inversions of the full Stokes vector of the Si I 10827 A spectral line. The results indicate that we properly infer the atmospheric parameters through an extended range of atmospheric layers in comparison with the LTE case (only valid for the spectral line wings, i.e., the low photosphere), with no impact on the robustness of the solution and just a minor increase in computational time. Thus, the NLTE assumption will help to accurately constrain the photospheric physical parameters when performing combined inversions with, e.g., the Ca II 8542 A spectral line., Comment: 7 pages, 8 figures, regular paper

We present JWST/NIRSpec integral field spectroscopic (IFS) observations of the \Lyalpha emitter CR7 at z ~ 6.6, observed as part of the GA-NIFS program. Using low-resolution PRISM (R ~ 100) data, we confirm a bright \Lyalpha emitter, and a diffuse \Lyalpha halo extending up to 3 kpc from the peak of ionized emission, both of them associated to the most massive, UV bright galaxy in the system (CR7-A). We confirm the presence of two additional UV-bright satellites (CR7-B and CR7-C) detected at projected distances of 6.4 and 5.2 kpc from the primary source. We perform SED fitting of the low-resolution data and revealed an inverted star formation history between two satellites at early epochs and a spatially resolved anti-correlation of the gas-phase metallicity and the star formation rate density, likely driven by the gas exchange among the satellites, favouring the merger scenario for CR7. From the high-resolution G395H (R ~ 2700) data, we discover at least three additional companions mainly traced by the \OIIIL emission line, although they are not detected in continuum. We disentangle the kinematics of the system and reveal extended ionised emission linking the main galaxy and the satellites. We spatially resolve the \OIIIL, \OIII[4363], and \Hgamma emission lines and use a diagnostic diagram tailored to high-z systems to reveal tentative evidence of AGN ionisation across the main galaxy (CR7-A) and the N-E companion (CR7-B). Moreover, we detect an unresolved blue-shifted outflow from one of the satellites and present first evidence for a redshifted outflow from the main galaxy. Finally, we compute resolved electron temperature (T$_e \sim 1.6 \times 10^4$ K) and metallicity maps (log(Z/\zsun) from --0.8 to --0.5), and provide insights on how the physical properties of the system evolved at earlier epochs., Comment: 17 pages, 16 figures, submitted to A&A

We present deep JWST/NIRSpec integral-field spectroscopy (IFS) and ALMA [CII]$\lambda$158$\mu$m observations of COS-3018, a star-forming galaxy at z$\sim$6.85, as part of the GA-NIFS programme. Both G395H (R$\sim$ 2700) and PRISM (R$\sim$ 100) NIRSpec observations revealed that COS-3018 is comprised of three separate components detected in [OIII]$\lambda$5008, which we dub as Main, North and East, with stellar masses of 10$^{9.4 \pm 0.1}$, 10$^{9.2 \pm 0.07}$, 10$^{7.7 \pm 0.15}$ M$_{\odot}$. We detect [OIII]$\lambda$5008, [OIII]$\lambda\lambda$3727,29 and multiple Balmer lines in all three components together with [OIII]$\lambda$4363 in the Main and North components. This allows us to measure an ISM temperature of T$_{e}$= 1.27$\pm0.07\times 10^4$ and T$_{e}$= 1.6$\pm0.14\times 10^4$ K with densities of $n_{e}$ = 1250$\pm$250 and $n_{e}$ = 700$\pm$200 cm$^{-3}$, respectively. These deep observations allow us to measure an average metallicity of 12+log(O/H)=7.9--8.2 for the three components with the T$_{e}$-method. We do not find any significant evidence of metallicity gradients between the components. Furthermore, we also detect [NII]$\lambda$6585, one of the highest redshift detections of this emission line. We find that in a small, metal-poor clump 0.2 arcsec west of the North component, N/O is elevated compared to other regions, indicating that nitrogen enrichment originates from smaller substructures, possibly proto-globular clusters. [OIII]$\lambda$5008 kinematics show that this system is merging, which is probably driving the ongoing, luminous starburst., Comment: Submitted to MNRAS

This paper addresses the long-time dynamics of solutions to the 2D incompressible Euler equations. We construct solutions with continuous vorticity $\omega_{\varepsilon}(x,t)$ concentrated around points $\xi_{j}(t)$ that converge to a sum of Dirac delta masses as $\varepsilon\to0$. These solutions are associated with the Kirchhoff-Routh point-vortex system, and the points $\xi_{j}(t)$ follow an expanding self similar trajectory of spirals, with the support of the vorticities contained in balls of radius $3\varepsilon$ around each $\xi_{j}$.

We consider the Ginzburg-Landau equation in the plane linearized around the standard degree-one vortex solution $W(x)=w(r)e^{i\theta}$. Using explicit representation formulae for the Fourier modes in $\theta$, we obtain sharp estimates for the inverse of the linearized operator which hold for a large class of right-hand sides. This theory can be applied, for example, to estimate the inverse after dropping the usual orthogonality conditions., Comment: 21 pages

The James Webb Space Telescope is revolutionising our ability to understand the host galaxies and local environments of high-z quasars. Here we obtain a comprehensive understanding of the host galaxy of the z=7.08 quasar J1120+0641 by combining NIRSpec integral field spectroscopy with NIRCam photometry of the host continuum emission. Our emission line maps reveal that this quasar host is undergoing a merger with a bright companion galaxy. The quasar host and the companion have similar dynamical masses of $\sim10^{10}M_\odot$, suggesting that this is a major galaxy interaction. Through detailed quasar subtraction and SED fitting using the NIRCam data, we obtain an estimate of the host stellar mass of $M_{\ast}\simeq2.6\times10^9M_\odot$, with $M_{*}\simeq5.0\times10^9M_\odot$ for the companion galaxy. Using the H$\beta$ Balmer line we estimate a virial black hole mass of $M_{\rm{BH}}\simeq1.4\times10^9 M_\odot$. Thus, J1120+0641 has an extreme black hole - stellar mass ratio of $M_{\rm{BH}}/M_\ast\simeq0.54$, which is ~3 dex larger than expected by the local scaling relations between black hole and stellar mass. J1120+0641 is powered by an overmassive black hole with the highest reported black hole - stellar mass ratio, in a quasar host that is currently undergoing a major merger -- these new insights highlight the power of JWST for measuring and understanding these extreme first quasars., Comment: Submitted to A&A, comments welcome

In this paper we study the solvability of the magnetohydrostatic equations with Grad-Rubin boundary conditions in general domains. Earlier results for this problem were obtained in the recent years by D. Alonso-Or\'an and J. L. L. Vel\'azquez, where particularly simple geometries were considered. In this article we develop a theory that allows to solve these boundary value problems for a larger class of domains. We will give precise applications to more physically relevant situations, like the case of the space between two circumferences or spheres and domains close to them., Comment: 60 pages, 1 figure

We explore self-induced parametric coupling, also called internal resonances (IRs), in a membrane nanoelectromechanical system. Specifically, we focus on the formation of a limit cycle manifesting as a phononic frequency comb. Utilizing a pump-noisy-probe technique and theoretical modeling, we reveal the behavior of mechanical excitations revealing themselves as sidebands of the stationary IR response. We find that when the energy-absorbing excitation of a lower mode is parametrically-upconverted to hybridize with a higher mode, significant squeezing and bimodality in the upper mode occurs. Instead, when the upconverted absorbing excitation hybridizes with an emitting sideband of the higher mode, a Hopf bifurcation occurs and a limit cycle forms, manifesting as a frequency comb. We thus reveal a unique mechanism to obtain frequency combs in parametrically-coupled modes. We furthermore demonstrate a rich variety of IR effects, the origin of which significantly extends beyond standard linear parametric coupling phenomena. Our findings enhance the understanding of energy transfer mechanisms with implications for advanced sensing technologies and novel phononic metamaterials.

The liquid drop model was introduced by Gamow in 1928 and Bohr-Wheeler in 1938 to model atomic nuclei. The model describes the competition between the surface tension, which keeps the nuclei together, and the Coulomb force, corresponding to repulsion among protons. More precisely, the problem consists of finding a surface $\Sigma =\partial \Omega$ in $\mathbb{R}^3$ that is critical for the energy $$ E(\Omega) = {\rm Per\,} (\Omega ) + \frac 12 \int_\Omega\int_\Omega \frac {dxdy}{|x-y|} $$ under the volume constraint $|\Omega| = m$. The term ${\rm Per\,} (\Omega ) $ corresponds to the surface area of $\Sigma$. The associated Euler-Lagrange equation is $$ H_\Sigma (x) + \int_{\Omega } \frac {dy}{|x-y|} = \lambda \quad \hbox{ for all } x\in \Sigma, \quad $$ where $H_\Sigma$ stands for the mean curvature of the surface, and where $\lambda\in\mathbb{R}$ is the Lagrange multiplier associated to the constraint $|\Omega|=m$. Round spheres enclosing balls of volume $m$ are always solutions. They are minimizers for sufficiently small $m$. Since the two terms in the energy compete, finding non-minimizing solutions can be challenging. We find a new class of compact, embedded solutions with large volumes, whose geometry resembles a "pearl necklace" with an axis located on a large circle, with a shape close to a Delaunay's unduloid surface of constant mean curvature. The existence of such equilibria is not at all obvious, since for the closely related constant mean curvature problem $H_\Sigma = \lambda$, the only compact embedded solutions are spheres, as stated by the classical Alexandrov result.

The polarization of the Mg II h & k resonance lines is the result of the joint action of scattering processes and the magnetic field induced Hanle, Zeeman, and magneto-optical effects, thus holding significant potential for the diagnostic of the magnetic field in the solar chromosphere. The Chromospheric LAyer Spectro-Polarimeter sounding rocket experiment, carried out in 2019, successfully measured at each position along the 196 arcsec spectrograph slit the wavelength variation of the four Stokes parameters in the spectral region of this doublet around 280 nm, both in an active region plage and in a quiet region close to the limb. We consider some of these CLASP2 Stokes profiles and apply to them the recently-developed HanleRT Tenerife Inversion Code, which assumes a one-dimensional model atmosphere for each spatial pixel under consideration (i.e., it neglects the effects of horizontal radiative transfer). We find that the non-magnetic causes of symmetry breaking, due to the horizontal inhomogeneities and the gradients of the horizontal components of the macroscopic velocity in the solar atmosphere, have a significant impact on the linear polarization profiles. By introducing such non-magnetic causes of symmetry breaking as parameters in our inversion code, we can successfully fit the Stokes profiles and provide an estimation of the magnetic field vector. For example, in the quiet region pixels, where no circular polarization signal is detected, we find that the magnetic field strength in the upper chromosphere varies between 1 and 20 gauss., Comment: Accepted for publication in the Astrophysical Journal

We provide the first construction of overhanging gravity water waves having the approximate form of a disk joined to a strip by a thin neck. The waves are solitary with constant vorticity, and exist when an appropriate dimensionless gravitational constant $g>0$ is sufficiently small. Our construction involves combining three explicit solutions to related problems: a disk of fluid in rigid rotation, a linear shear flow in a strip, and a rescaled version of an exceptional domain discovered by Hauswirth, H\'elein, and Pacard \cite{hauswirth-helein-pacard}. The method developed here is related to the construction of constant mean curvature surfaces through gluing., Comment: 93 pages

The combination of a strong pump and a weak probe has been widely applied to investigate both optical and nanomechanical devices. Such pump-probe measurements allows for the exploration of nonlinear dynamics, driven by the large pump tone, by measuring the system response to a probe tone. In contrast, here we report on the dynamics of a mechanical Duffing resonator driven with a combination of two large tones at different frequencies. Our results indicate the presence of various distinct regimes with very different dynamics. We systematically investigate the impact of the relative strength and detuning between the two drives on the dynamical response. This provides an illustrative example of dynamical phase transitions in out-of-equilibrium systems., Comment: 9 pages, 6 figures

The BCJ duality between color and kinematics brings two advantages to calculating multi-loop scattering amplitudes. First the number of ordered cuts that need to be performed to fix the integrand to a gauge theory is minimal -- reducing the factorially-growing number of diagrams to a single-digit basis in all known cases. Second is the trivial generation of related gravitational amplitudes from gauge theory amplitudes via double-copy. Mounting evidence suggests there are some cases where no local color-dual representations exist, even when the semi-classical theory is color-dual. Can we still simplify the calculations without making the duality manifest at the level of the integrand? Here we take a non-trivial step in this direction by showing that the satisfaction of tree-level BCJ relations is sufficient to dramatically reduce the number of explicit cuts that must be performed, even when the loop-level relations are not explicitly satisfied. We introduce an agglomerative algorithm, color-dual cut tiling, that identifies and builds the entire integrand from the simplest on-shell conditions applied to a seed of off-shell integrand information. Specifically, we demonstrate that for two-to-two scattering at three loops in the maximally supersymmetric gauge theory there is sufficient information contained in planar cuts -- completely determined by positivity constraints -- to generate all of the non-planar sector. Additionally, we make use of the generalized double copy to generate a representation of maximally supersymmetric gravity as a functional of the planar SYM input. We discuss how the process might generalize, and then close by commenting on the applicability of this method for additional cases of interest where performing explicit unitarity cuts is expensive., Comment: 8 pages, 5 figures

We apply the HanleRT Tenerife Inversion Code to the spectro-polarimetric observations obtained by the Chromospheric LAyer SpectroPolarimeter. This suborbital space experiment measured the variation with wavelength of the four Stokes parameters in the near-ultraviolet spectral region of the Mg II h & k lines over a solar disk area containing part of an active region plage and the edge of a sunspot penumbra. We infer the stratification of the temperature, the electron density, the line of-sight velocity, the micro-turbulent velocity, and the longitudinal component of the magnetic field from the observed intensity and circular polarization profiles. The inferred model atmosphere shows larger temperature and electron density in the plage and the superpenumbra regions than in the quiet regions. The shape of the plage region in terms of its brightness is similar to the pattern of the inferred longitudinal component of the magnetic field in the chromosphere, as well as to that of the overlying moss observed by AIA in the 171 A band, which suggests a similar magnetic origin for the heating in both the plage and the moss region. Moreover, this heating is particularly significant in the regions with larger inferred magnetic flux. In contrast, in the superpenumbra, the regions with larger electron density and temperature are usually found in between these regions with larger magnetic flux, suggesting that the details of the heating mechanism in the chromosphere of the superpenumbra may be different to those in the plage, but with the magnetic field still playing a key role., Comment: Accepted for publication in the Astrophysical Journal

The Mg II k resonance line is commonly used for diagnosing the solar chromosphere. We theoretically investigated its intensity and polarization in solar prominences, taking 3D radiative transfer and Hanle and Zeeman effects into account. We used an optically thick 3D model representative of a solar prominence and applied several inversion methods to the synthetic Stokes profiles, clarifying their pros and cons for inferring prominence magnetic fields. We conclude that the self-consistent 3D inversion with radiative transfer is necessary to determine the magnetic field vector, although its geometry cannot be inferred with full fidelity. We also demonstrate that more traditional methods, such as those based on the weak field approximation or the constant-property slab assumption, can offer useful information under certain conditions., Comment: 9 pages, 9 figures, accepted for publication in A&A

We present JWST/NIRSpec integral-field spectroscopy observations of the z ~ 9.11 lensed galaxy MACS1149-JD1, as part of the GA-NIFS programme. The data was obtained with both the G395H grating (R~ 2700) and the prism (R~ 100). This target shows a main elongated UV-bright clump and a secondary component detected in continuum emission at a projected distance of 2 kpc. The R2700 data trace the ionised-gas morpho-kinematics in between the two components, showing an elongated emission mainly traced by [O III]5007. We spatially resolve [O II]3726,3729, [O III]4959,5007, and [O III]4363, which enable us to map the electron density (ne ~ 1.0 x 103 cm-3), temperature (Te ~ 1.6 x 104 K), and direct-method gas-phase metallicity (-1.2 to -0.7 dex solar). A spatially resolved full-spectrum modelling of the prism indicates a north-south gas metallicity and stellar age gradient between the two components. We found 3-sigma evidence of a spatially resolved anti-correlation of the gas-phase metallicity and the star formation rate density, which is likely driven by gas inflows, enhancing the star formation in JD1. We employ high-z sensitive diagnostic diagrams to rule out the presence of a strong AGN in the main component. These findings show the unambiguous presence of two distinct stellar populations, with the majority of the mass ascribed to an old star formation burst, as suggested by previous works. We disfavour the possibility of a rotating-disc nature for MACS1149-JD1; we favour a merger event that has led to a recent burst of star formation in two separate regions, as supported by high values of [O III]5007/Hbeta, ionised gas velocity dispersion, and gas-phase metallicity., Comment: 14 pages, 16 figures

The study of starburst and active galactic nuclei (AGN) feedback is crucial for understanding the regulation of star formation and the evolution of galaxies across cosmic time. Arp 220, the closest ultraluminous infrared galaxy (ULIRG), is in an advanced phase of a major merger with two distinct nuclei, and it shows evidence of multiphase and multiscale (from < 0.1 to > 5 kpc) outflows. Therefore, it represents an ideal system for investigating outflow mechanisms and feedback phenomena in detail. Using new JWST NIRSpec IFU observations, we investigated the spatially resolved gaseous (in both ionized and hot molecular phases) and stellar kinematics in the innermost 1 kpc. We decoupled the different gas kinematic components through multi-Gaussian fitting, identifying two multiphase outflows, each associated with one nucleus, with velocities up to $\sim 1000$km/s. We also resolved two counter-rotating discs around each nucleus embedded in a larger-scale rotational disk. We compute the total outflow mass ($\approx 10^7$M$_\odot$), the mass rate ($\sim 15$M$_{\odot}$yr$^{-1}$), and the energetics ($\dot E_{out}\approx 10^{42}$erg/s) for each nucleus, and we found that the ionized and hot molecular outflowing gas contribute around 2-30% of the total mass and the energy of the outflows, as inferred from the combination of multiwavelength information. We discuss the possible origin of the outflows, finding no compelling evidence to prefer a starburst- or AGN-driven scenario. Regardless of their nature, outflows in Arp~220 propagate in multiple directions from parsec to kiloparsec scales, potentially impacting a significant portion of the host galaxy. This contrasts with isolated systems where outflows typically follow a more collimated path or are limited to the central region of the galaxy and hence do not affect the interstellar medium throughout the entire galaxy., Comment: In press to A&A, 24 figures, aa51442-24

We analyze four epochs of HST imaging over 18 years for the Draco dwarf spheroidal galaxy. We measure precise proper motions (PMs) for hundreds of stars and combine these with existing line-of-sight (LOS) velocities. This provides the first radially-resolved 3D velocity dispersion profiles for any dwarf galaxy. These constrain the intrinsic velocity anisotropy and resolve the mass-anisotropy degeneracy. We solve the Jeans equations in oblate axisymmetric geometry to infer the mass profile. We find the velocity dispersion to be radially anisotropic along the symmetry axis and tangentially anisotropic in the equatorial plane, with a globally-averaged value $\overline{\beta_{\mathrm B}}=-0.20^{+ 0.28}_{- 0.53}$, (where $1 - \beta_{\mathrm B} \equiv \langle v_{\mathrm{ tan}}^2 \rangle / \langle v_{\mathrm{ rad}}^2 \rangle$ in 3D). The logarithmic dark matter (DM) density slope over the observed radial range, $\Gamma_{\mathrm{ dark}}$, is $-0.83^{+ 0.32}_{- 0.37}$, consistent with the inner cusp predicted in $\Lambda$CDM cosmology. As expected given Draco's low mass and ancient star formation history, it does not appear to have been dissolved by baryonic processes. We rule out cores larger than 487, 717, 942 pc at respective 1-, 2-, 3-$\sigma$ confidence, thus imposing important constraints on the self-interacting DM cross-section. Spherical models yield biased estimates for both the velocity anisotropy and the inferred slope. The circular velocity at our outermost data point (900 pc) is $24.19^{+ 6.31}_{- 2.97} \ \mathrm{km~s^{-1}}s$. We infer a dynamical distance of $75.37^{+ 4.73}_{- 4.00}$ kpc, and show that Draco has a modest LOS rotation, with $\left = 0.22 \pm 0.09$. Our results provide a new stringent test of the so-called `cusp-core' problem that can be readily extended to other dwarfs., Comment: 35 pages, 18 figures, 3 Tables. Accepted for publication in ApJ. Journal version has better readability. Data is available at Zenodo: https://zenodo.org/records/11111113

In topology, one averages over local geometrical details to reveal robust global features. This approach proves crucial for understanding quantized bulk transport and exotic boundary effects of linear wave propagation in (meta-)materials. Moving beyond linear Hamiltonian systems, the study of topology in physics strives to characterize open (non-Hermitian) and interacting systems. Here, we establish a framework for the topological classification of driven-dissipative nonlinear systems. Specifically, we define a graph index for the Floquet semiclassical equations of motion describing such systems. The graph index builds upon topological vector analysis theory and combines knowledge of the particle-hole nature of fluctuations around each out-of-equilibrium stationary state. To test this approach, we divulge the topological invariants arising in a micro-electromechanical nonlinear resonator subject to forcing and a time-modulated potential. Our framework classifies the complete phase diagram of the system and reveals the topological origin of driven-dissipative phase transitions, as well as that of under- to over-damped responses. Furthermore, we predict topological phase transitions between symmetry-broken phases that pertain to population inversion transitions. This rich manifesting phenomenology reveals the pervasive link between topology and nonlinear dynamics, with broad implications for all fields of science., Comment: 8 pages, 4 figures (G.V. and J.d.P. contributed equally to this work)

We used the Javalambre Photometric Local Universe Survey (J-PLUS) DR2 photometry in twelve optical bands over 2176 deg2 to estimate the fraction of white dwarfs with presence of CaII H+K absorption along the cooling sequence. We compared the J-PLUS photometry against metal-free theoretical models to estimate the equivalent width in the J0395 passband of 10 nm centered at 395 nm (EW_J0395), a proxy to detect calcium absorption. A total of 4399 white dwarfs within 30000 > Teff > 5500 K and mass M > 0.45 Msun were analyzed. Their EW_J0395 distribution was modeled using two populations, corresponding to polluted and non-polluted systems, to estimate the fraction of calcium white dwarfs (f_Ca) as a function of Teff. The probability for each individual white dwarf of presenting calcium absorption, pca, was also computed. The comparison with both the measured Ca/He abundance and the metal pollution from spectroscopy shows that EW_J0395 correlates with the presence of calcium. The fraction of calcium white dwarfs increases from f_Ca = 0 at Teff = 13500 K to f_Ca = 0.15 at Teff = 5500 K. We compare our results with the fractions derived from the 40 pc spectroscopic sample and from SDSS spectra. The trend found in J-PLUS observations is also present in the 40 pc sample, however SDSS shows a deficit of metal-polluted objects at Teff < 12000 K. Finally, we found 39 white dwarfs with pca > 0.99. Twenty of them have spectra presented in previous studies, whereas we observed six additional targets. These 26 objects were all confirmed as metal-polluted systems. The J-PLUS optical data provide a robust statistical measurement for the presence of CaII H+K absorption in white dwarfs. We find a 15 +- 3 % increase in the fraction of calcium white dwarfs from Teff = 13500 K to 5500 K, which reflects their selection function in the optical from the total population of metal-polluted systems., Comment: Submitted to Astronomy and Astrophysics. Comments are welcome

We present JWST NIRSpec observations in IFS mode of the galaxy GS5001 at redshift z=3.47, the brightest member of a candidate protocluster in the GOODS-S field. The data cover a field of view (FoV) of 4''$\times$4'' (~$30\times30$~kpc$^2$) and were obtained as part of the GA-NIFS GTO program. The observations include both high (R~2700) and low (R~100) spectral resolution data, spanning the rest-frame wavelength ranges 3700-6780A and 1300-11850A, respectively. We analyse the spatially resolved ionised gas kinematics and interstellar medium properties, including obscuration, gas metallicity, excitation, ionisation parameter, and electron density. In addition to the central galaxy, the NIRSpec FoV covers three components in the south, with velocities blue-shifted by -150 km/s with respect to the main galaxy, and another source in the north redshifted by ~200 km/s. The emission line ratios in the BPT diagram are consistent with star formation for all the sources in the FoV. We measure electron densities of ~500 cm$^{-3}$ in the different sources. The gas-phase metallicity in the main galaxy is 12+log(O/H) $= 8.45\pm0.04$, and slightly lower in the companions (12+log(O/H)$ = 8.34-8.42$), consistent with the mass-metallicity relation at $z\sim3$. We find peculiar line ratios (high log [NII]/H$\alpha$, low log [OIII]/H$\beta$) in the northern part of the main galaxy (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, with an extension of about 3 kpc. We find maximum outflow velocities of ~400 km/s, an outflow mass of $(1.7\pm0.4)\times 10^8$ M$_{\odot}$, a mass outflow rate of $23\pm5$ M$_{\odot}$ yr$^{-1}$ and a mass loading factor of 0.23. These properties are compatible with star formation being the driver of the outflow., Comment: Submitted to A&A

JWST is discovering increasing numbers of quiescent galaxies 1--2 billion years after the Big Bang, whose redshift, high mass, and old stellar ages indicate that their formation and quenching were surprisingly rapid. This fast-paced evolution seems to require that feedback from AGN (active galactic nuclei) be faster and/or more efficient than previously expected \citep{Xie24}. We present deep ALMA observations of cold molecular gas (the fuel for star formation) in a massive, fast-rotating, post-starburst galaxy at $z=3.064$. This galaxy hosts an AGN, driving neutral-gas outflows with a mass-outflow rate of $60\pm20$ M$_{\odot}$ yr$^{-1}$, and has a star-formation rate of $<5.6$ M$_{\odot}$ yr$^{-1}$. Our data reveal this system to be the most distant gas-poor galaxy confirmed with direct CO observations (molecular-gas mass $< 10^{9.1}$ M$_{\odot}$; <0.8 % of its stellar mass). Combining ALMA and JWST observations, we estimate the gas-consumption history of this galaxy, showing that it evolved with net zero gas inflow, i.e., gas consumption by star formation matches the amount of gas this galaxy is missing relative to star-forming galaxies. This could arise both from preventive feedback stopping further gas inflow, which would otherwise refuel star formation or, alternatively, from fine-tuned ejective feedback matching precisely gas inflows. Our methods, applied to a larger sample, promise to disentangle ejective vs preventive feedback., Comment: 14 pages, 4 figures

The first observations of JWST have revolutionized our understanding of the Universe by identifying for the first time galaxies at $z\sim13$. In addition, the discovery of many luminous galaxies at Cosmic Dawn ($z>10$) has suggested that galaxies developed rapidly, in apparent tension with many standard models. However, most of these galaxies lack spectroscopic confirmation, so their distances and properties are uncertain. We present JADES JWST/NIRSpec spectroscopic confirmation of two luminous galaxies at redshifts of $z=14.32^{+0.08}_{-0.20}$ and $z=13.90\pm0.17$. The spectra reveal ultraviolet continua with prominent Lyman-$\alpha$ breaks but no detected emission lines. This discovery proves that luminous galaxies were already in place 300~million years after the Big Bang and are more common than what was expected before JWST. The most distant of the two galaxies is unexpectedly luminous and is spatially resolved with a radius of 260 parsecs. Considering also the very steep ultraviolet slope of the second galaxy, we conclude that both are dominated by stellar continuum emission, showing that the excess of luminous galaxies in the early Universe cannot be entirely explained by accretion onto black holes. Galaxy formation models will need to address the existence of such large and luminous galaxies so early in cosmic history., Comment: 15 figures, 3 tables, published in Nature

We present observations of the $z\sim5.7$ Lyman-break galaxy HZ10 with the JWST/NIRSpec IFU in high and low spectral resolution (G395H, $R\sim2700$ and PRISM, $R\sim100$, respectively), as part of the GA-NIFS program. By spatially resolving the source, we find evidence for three spatially and spectrally distinct regions of line emission along with one region of strong continuum emission, all within a projected distance of $<10$kpc. The R2700 data features strong detections in H$\beta$, [OIII]$\lambda\lambda4959{,}5007$, [NII]$\lambda\lambda6548{,}6584$, H$\alpha$, and [SII]$\lambda\lambda6716{,}6731$. The R100 data additionally contains a strong detection of the Ly$\alpha$ break, rest-UV continuum, and [OII]$\lambda\lambda3726{,}3729$. None of the detected lines present strong evidence for AGN excitation from line diagnostic diagrams, and no high-ionisation lines are detected. Using the detected lines, we constrain the electron density $\left( \rm \log_{10}\left( n_e / cm^{-3}\right)\sim2.5-3.3\right)$ and metallicity ($\sim0.5-0.7$ solar) in each component. Spaxel-by-spaxel fits of each cube reveal a strong east-west velocity gradient and significant line asymmetries (indicating tidal features or outflows). The western component features a very red UV slope ($\beta_{UV}\sim-1$) and significant H$\alpha$ emission, suggesting an evolved population and active star formation. From a comparison to high resolution [CII]$158\mu$m imaging obtained with the Atacama Large Millimetre/submillimetre Array (ALMA), we find that the continuum emitter is associated with a gas-poor stellar population. Altogether, these data suggest that HZ10 represents an ongoing merger, with a complex distribution of stars, gas, and dust $<1$Gyr after the Big Bang., Comment: 16 pages, 11 figures. Submitted to MNRAS

We report the detection of continuum excess in the rest-frame UV between 3000 {\AA} and 3550 {\AA} in the JWST/NIRSpec spectrum of GN-z11, a galaxy hosting an active galactic nucleus (AGN) at z = 10.603. The shape of the continuum excess resembles a Balmer continuum but has a break around 3546 {\AA} in the rest frame, which is 100 {\AA} bluewards to the Balmer limit at 3646 {\AA}. A Balmer continuum model alone cannot fit the spectrum, implying a different origin for the continuum excess. The absence of the Balmer jump indicates an electron temperature of $\sim 3\times 10^4$ K, which is significantly higher than the temperature of $T_{e}({\rm O^{2+}}) \approx 1.3\times 10^{4}$ K inferred from [OIII]$\lambda 4363$. The temperature difference must result from mixing of different ionized regions: the Balmer emission mainly arises from dense and hot clouds in the Broad Line Region, close to the accreting black hole, whereas the forbidden lines originate from less dense and colder gas in the host galaxy (although these ionized regions are kinematically similar in GN-z11 due to its small BH mass). We propose a potential explanation for the observed continuum excess to come from a complex of FeII emission, which shows a characteristic jump bluewards to the Balmer limit as previously seen in the spectra of many lower-redshift quasars. Through comparisons with Cloudy models, we show an Fe abundance or an overall metallicity above $\sim 1/3$ solar is likely needed. Besides the FeII emission, part of the small blue bump might also be associated with an OIII Bowen fluorescent line, a line often enhanced in dense AGN-ionized gas. Finally, the spectrum provides further evidence against Wolf-Rayet or massive stars dominating the nebular emission in GN-z11., Comment: 22 pages (including appendix), 18 figures, submitted to MNRAS

Feedback is the key physical mechanism regulating galaxy formation. Stars in galaxies form when baryons radiatively cool down and fall into gravitational wells. Eventually, star formation quenches as gas is depleted and/or perturbed by feedback processes, no longer being able to collapse and condense. For massive galaxies, astronomers identify feedback from accreting supermassive black holes (active galactic nuclei, AGN) as the main agent responsible for quenching. We report the first spatially resolved spectroscopic observations of a massive, completely quiescent galaxy at $z=3.714$ (Jekyll) and its neighborhood. Jekyll is part of a galaxy pair with a compact, dusty, massive star-forming companion (Hyde). We find large amounts of ionized and neutral gas in the intergalactic medium around the pair, yet Jekyll has remained quiescent for more than 500~Myr. The emitting gas is consistent with AGN photoionization, but no AGN is observed in Jekyll. We find that, in contrast to standard scenarios, AGN in satellite galaxies can be critical contributors for keeping massive galaxies quiescent in the early Universe. After the accelerated formation and quenching of the massive central galaxy, tidally induced gas stripping additionally contributes to the star-formation regulation on subsequent satellite galaxy generations., Comment: Submitted. Comments welcome

With its 12 optical filters, the Javalambre-Photometric Local Universe Survey (J-PLUS) provides an unprecedented multicolor view of the local Universe. The third data release (DR3) covers 3,192 deg$^2$ and contains 47.4 million objects. However, the classification algorithms currently implemented in its pipeline are deterministic and based solely on the sources morphology. Our goal is classify the sources identified in the J-PLUS DR3 images into stars, quasi-stellar objects (QSOs), and galaxies. For this task, we present BANNJOS, a machine learning pipeline that uses Bayesian neural networks to provide the probability distribution function (PDF) of the classification. BANNJOS is trained on photometric, astrometric, and morphological data from J-PLUS DR3, Gaia DR3, and CatWISE2020, using over 1.2 million objects with spectroscopic classification from SDSS DR18, LAMOST DR9, DESI EDR, and Gaia DR3. Results are validated using $1.4 10^5$ objects and cross-checked against theoretical model predictions. BANNJOS outperforms all previous classifiers in terms of accuracy, precision, and completeness across the entire magnitude range. It delivers over 95% accuracy for objects brighter than $r = 21.5$ mag, and ~90% accuracy for those up to $r = 22$ mag, where J-PLUS completeness is < 25%. BANNJOS is also the first object classifier to provide the full probability distribution function (PDF) of the classification, enabling precise object selection for high purity or completeness, and for identifying objects with complex features, like active galactic nuclei with resolved host galaxies. BANNJOS has effectively classified J-PLUS sources into around 20 million galaxies, 1 million QSOs, and 26 million stars, with full PDFs for each, which allow for later refinement of the sample. The upcoming J-PAS survey, with its 56 color bands, will further enhance BANNJOS's ability to detail each source's nature., Comment: Submitted to Astronomy and Astrophysics. 29 pages, 23 figures, 4 tables

We present the third data release of JADES, the JWST Advanced Deep Extragalactic Survey, providing both imaging and spectroscopy in the two GOODS fields. Spectroscopy consists of medium-depth and deep NIRSpec/MSA spectra of 4,000 targets, covering the spectral range 0.6-5.3 $\mu$m and observed with both the low-dispersion prism (R=30-300) and all three medium-resolution gratings (R=500-1,500). We describe the observations, data reduction, sample selection, and target allocation. We measured 2,375 redshifts (2,053 from multiple emission lines); our targets span the range from z=0.5 up to z=13, including 404 at z>5. The data release includes 2-d and 1-d fully reduced spectra, with slit-loss corrections and background subtraction optimized for point sources. We also provide redshifts and S/N>5 emission-line flux catalogs for the prism and grating spectra, and concise guidelines on how to use these data products. Alongside spectroscopy, we are also publishing fully calibrated NIRCam imaging, which enables studying the JADES sample with the combined power of imaging and spectroscopy. Together, these data provide the largest statistical sample to date to characterize the properties of galaxy populations in the first billion years after the Big Bang., Comment: 41 pages, 26 figures, 10 tables. Submitted to ApJS

We report the chemical abundance pattern of GS\_3073, a galaxy at $z=5.55$ which was previously confirmed to host an overmassive active black hole, by leveraging the detection of about 40 emission lines, combining JWST/NIRSpec observations and ground-based (VLT/VIMOS) data. Based on the rest-frame UV emission lines, which trace high-density ($\sim 10^5~{\rm cm}^{-3}$) and highly ionized gas, we derived an abundance ratio of $\rm log(N/O) = 0.42^{+0.13}_{-0.10}$. At an estimated metallicity of $0.2~Z_{\odot}$, this is the most extreme nitrogen-rich object found by JWST thus far. In comparison, the relative carbon abundance derived from the rest-frame UV emission lines is $\rm log(C/O) = -0.38^{+0.13}_{-0.11}$, which is not significantly higher than those in local galaxies and stars with similar metallicities. We also found potential detection of coronal lines including [FeVII]$\lambda 6087$ and [FeXIV]$\lambda 5303$, both blended with [CaV]. We inferred a range of Fe abundances compatible with those in local stars and galaxies. Overall, the chemical abundance pattern of GS\_3073 is compatible with enrichment by super-massive stars with $M_* \gtrsim 1000~M_\odot$, asymptotic giant branch (AGB) stars, or Wolf-Rayet (WR) stars. Interestingly, when using optical emission lines which trace lower density ($\sim 10^3~{\rm cm}^{-3}$) and lower ionization gas, we found a sub-solar N/O ratio. We interpret the difference in N/O derived from UV lines and optical lines as evidence for a stratified system, where the inner and denser region is both more chemically enriched and more ionized. Taking this luminous, well-studied system as a benchmark, our results suggest that nitrogen loudness in high-$z$ galaxies is confined to the central, dense, and highly ionized region of the galaxies, while the bulk of the galaxies evolves more normally., Comment: 28 pages, 15 figures, accepted for publication in MNRAS

Measurable linear scattering polarization signals have been predicted and detected at the solar disk center in the core of chromospheric lines. These forward-scattering polarization signals, which are of high interest for magnetic field diagnostics, have always been modeled either under the assumption of complete frequency redistribution (CRD), or taking partial frequency redistribution (PRD) effects into account under the angle-averaged (AA) approximation. This work aims at assessing the suitability of the CRD and PRD-AA approximations for modeling the forward-scattering polarization signals produced by the presence of an inclined magnetic field, the so-called forward-scattering Hanle effect, in the chromospheric CaI 4227 A line. Radiative transfer calculations are performed in semi-empirical 1D solar atmospheres, out of local thermodynamic equilibrium (LTE). A two-step solution strategy is applied: the non-LTE RT problem is first solved considering a multilevel atom and neglecting polarization phenomena. The same problem is then solved including polarization, considering a two-level atom and keeping fixed the lower-level population calculated at the previous step. The emergent linear polarization signals calculated under the CRD and PRD-AA approximations are analyzed and compared to those obtained by modeling PRD effects in their general angle-dependent (AD) formulation. With respect to the PRD-AD case, the CRD and PRD-AA calculations significantly underestimate the amplitude of the line-center polarization signals produced by the forward-scattering Hanle effect. The results of this work suggest that a PRD-AD modeling is required in order to develop reliable diagnostic techniques exploiting the forward-scattering polarization signals observed in the CaI 4227 A line. These results need to be confirmed by full 3D calculations including non-magnetic symmetry-breaking effects.

Arp 220 is the nearest ULIRG; it shows evidence of 100 pc-scale molecular outflows likely connected with galaxy-scale outflows traced by ionised and neutral gas. The two highly obscured nuclei of Arp 220 are the site of intense star formation, with extreme star-formation rate surface densities (~ 10^3 Msun/yr/kpc2). Despite extensive investigations searching for AGN activity in the Arp 220 nuclei, direct evidence remains elusive. We present JWST/NIRSpec IFS observations covering the 0.9 - 5.1 um wavelength range of the innermost (5''x4'', i.e. 1.8x1.5 kpc) regions of Arp 220. The primary goal is to investigate the potential presence of AGN signatures in the nuclear regions by analysing the spectra extracted from circular apertures of radius 55 pc (0.15'') around each of the two nuclei. We identify ~ 70 ionised and ~ 50 molecular emission lines in the nuclear spectra of Arp 220; we use recombination line ratios to measure optical extinctions in the range AV ~ 11 - 14 mag. High ionisation lines are not detected, except the [Mg IV] line at 4.49 um which we interpret as due to shocks rather than to AGN ionisation. We identify broadening and multiple kinematic components in the HI and H2 lines caused by outflows and shocks, with velocities up to ~ 550 km/s. Significantly higher velocities (up to ~ 900 km/s) are detected in the off-nuclear regions; however, they do not conclusively represent evidence for AGN activity. Even with the unprecedented sensitivity of JWST/NIRSpec IFS, achieving an unambiguous identification or exclusion of the presence of an AGN in the Arp 220 system remains challenging, because of its extreme dust obscuration., Comment: submitted to A&A, comments welcome

We present rest-frame optical data of the z~4 sub-millimeter galaxy GN20 obtained with JWST/NIRSpec in integral field spectroscopy (IFS) mode. The H$\alpha$ emission is asymmetric and clumpy and extends over a projected distance of more than 15 kpc. To first order, the large-scale ionised gas kinematics are consistent with a turbulent ($\sigma\sim90$ km/s), rotating disc ($v_{\rm rot}\sim500$ km/s), congruent with previous studies of its molecular and ionised gas kinematics. However, we also find clear evidence for non-circular motions in the H$\alpha$ kinematics. We discuss their possible connection with various scenarios, such as external perturbations, accretion or radial flows. In the centre of GN20, we find broad line emission (FWHM $\sim1000-2000$ km/s) in the H$\alpha$+[N II] complex, suggestive of fast, AGN-driven winds or, alternatively, of the broad-line region of an active black hole. Elevated values of [N II]$\lambda6583$/H$\alpha>0.4$ and EW(H$\alpha)>6$ \r{A}, throughout large parts of GN20 suggest that feedback from the active black hole is able to photo-ionise the interstellar medium. Our data corroborates that GN20 offers a unique opportunity to observe key processes in the evolution of the most massive present-day galaxies acting in concert, over 12 billion years ago., Comment: 12 pages, 8 figures; accepted for publication in MNRAS; doi:10.1093/mnras/stae1993

We study the circular polarization of the magnetic field induced transition (MIT) between the $3d^5(^6S)4d\ ^7D_2$ and $3d^5(^6S)4p\ ^7P_4^\circ$ states of \ion{Cr}{1} at 533.03~nm (wavelength in air). The fractional circular polarization $V/I$ of this spectral line resulting from the solution of the radiation transfer problem in a sunspot model permeated by a homogeneous magnetic field of 3~kG shows amplitudes of about $2\%$. Spectro-polarimetric observations of two sunspots were obtained with the Zurich Imaging Polarimeter-3 at the Istituto ricerche solari Aldo e Cele Dacc\`o (IRSOL) observatory observatory in Locarno, Switzerland. The observed $V/I$ profiles show approximately anti-symmetrical shapes with an amplitude of around $0.1\%$ and $0.2\%$ for the two sunspots. The center of this profile coincides with the wavelengths predicted for the above-mentioned MIT. We apply an inversion code to the spectro-polarimetric data of the \ion{Cr}{1} permitted lines at 532.91 and 532.98~nm, as well as to the MIT line at 533.03~nm, to infer a stratification of the emitting atmosphere. We compare the $V/I$ profiles synthesized in the inferred atmosphere models with the observations, showing that the observed signal likely corresponds to the MIT line., Comment: Accepted for publication in the Astrophysical Journal

Solar magnetic fields alter scattering polarization in spectral lines like Sr I at 4607 {\AA} via the Hanle effect, making it a potential diagnostic for small-scale mixed-polarity photospheric magnetic fields. Recently, observational evidence for scattering polarization in the Sr I 4607 {\AA} at the solar disk center was found. Here, we investigate the reliability of the reconstruction method making possible this detection. To this end, we apply it to linear polarization profiles of the Sr I 4607 {\AA} line radiation emerging at the disk center obtained from a detailed 3D radiative transfer calculation in a magneto-hydrodynamic simulation snapshot with a small-scale dynamo contribution. The reconstruction method systematically reduces the scattering amplitudes by up to a factor of two, depending on the noise level. We demonstrate that the decrease can be attributed to two systematic errors: first, the physical constraint that underlies our assumptions regarding the dependence of scattering polarization on the quadrupolar moment of the radiation field, and second, the limitations of our method in accurately determining the sign of the radiation field tensor from the observed intensity image. However, consistently applying the reconstruction process and after taking into account image degradation effects due to the temporally variable image quality, such as imposed by seeing, observed and synthesized polarization signals show remarkable agreement. We thus conclude that the observed scattering polarization at solar disk center is consistent with that emerging from magneto-hydrodynamic model of the solar photosphere with an average magnetic field of 170 G at the visible surface., Comment: Accepted for publication in ApJ