arXiv subjects

Begoña García-Lorenzo

Publications and source records attributed to Begoña García-Lorenzo.

15 recordsLinked to original sources

arXiv2026

Breaking the Blend: A multi-tracer kinematic decomposition method for IFS data applied to disentangling the AGN outflow and circumnuclear ring in NGC 5728 with JWST

Integral field spectroscopy (IFS) of the central kiloparsecs of active galactic nuclei (AGN) reveals a mixture of spatially coincident emission from star-formation and AGN feedback exciting the interstellar medium. Disentangling these components remains a challenge, as most spectral tracers are affected by both processes, limiting robust interpretation of kinematics and energetics. We present a new framework for decomposing IFS data into distinct components on a spaxel-by-spaxel basis using a multi-tracer, stacked kinematics approach. This method combines kinematic modelling with imposed flux decomposition per spaxel, quantifying the contribution of each component across the field of view. We apply this method to JWST IFS observations of the Seyfert galaxy NGC 5728 from the Galaxy Activity, Torus, and Outflow Survey (GATOS), analysing twelve mid-infrared fine-structure lines (4.49 < $λ$ < 25.89 $μ$m, 7.9 < IP < 126.2 eV). We find that the circumnuclear emission can be decomposed into two dominant components: a star-forming ring and an AGN-driven biconical outflow. Our method separates these structures and recovers their detailed spatial morphology. This framework provides a general and scalable method for physically motivated component separation in IFS data, applicable across many wavelength ranges and targets, enabling reliable interpretation of complex emission line structures (or morphologies) in active galaxies and beyond.

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arXiv2026

Focal-Plane Diagnostics of Atmospheric and Dome-Induced Turbulence: Exploring techniques and applications

Atmospheric turbulence remains the dominant source of image degradation in ground-based astronomy. Its impact depends not only on the integrated turbulence strength but also on the wavefront spatial-coherence outer scale (\LO) and on turbulence generated within the telescope enclosure (dome seeing). While seeing, coherence time, and related parameters are routinely monitored at major observatories, measurements of \LO\ and dome-induced turbulence remain sparse, limiting our ability to predict image quality and to construct accurate point-spread function (PSF) models. Building on methodology recently developed for seeing-limited integral-field spectroscopic (IFS) data, we present a series of complementary studies showing how spatial information encoded in standard observations can be used to diagnose both atmospheric and dome turbulence. We investigate the feasibility of extending these techniques beyond IFS observations to other seeing-limited instruments through the analysis of wavelength-dependent spatial profiles. We also present the development of data-driven three-dimensional PSF models based on atmospheric statistics for the reconstruction of seeing-limited IFS observations. These results show that widely available seeing-limited scientific observations, both from archival data and routine observatory operations, can provide meaningful and operationally useful constraints on key turbulence parameters and on the spectral behavior of dome seeing, complementing dedicated site-testing instrumentation. The resulting turbulence diagnostics have direct applications to PSF modelling, image reconstruction, image-quality prediction, and the optimization of future ELT operations.

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arXiv2026

CNN-Based Reanalysis of Optical Turbulence at the Canary Islands Observatories (OCAN)

Atmospheric optical turbulence, caused by refractive-index fluctuations driven by wind and temperature inhomogeneities, is the primary source of image degradation in ground-based telescopes. Its vertical distribution, described by the refractive-index structure constant (Cn2(h)), determines essential parameters such as seeing, isoplanatic angle, and coherence time, which characterize astronomical sites and are also crucial for the design and performance of high-resolution instruments. The Observatorios de Canarias (OCAN), comprising the Observatorio del Roque de los Muchachos on La Palma and the Observatorio del Teide on Tenerife, have been extensively characterized through long-term Generalized SCIDAR campaigns. In total, the database comprises nearly 300 observing nights and hundreds of thousands of individual Cn2(h) profiles. We present a reanalysis of the OCAN database using deep-learning techniques. An end-to-end software framework was developed to ingest, preprocess, and transform the original turbulence measurements into standardized numerical representations suitable for machine-learning analysis. Temporal-vertical turbulence heatmaps are generated under multiple temporal configurations and enriched with seasonal information. These representations are processed by pre-trained convolutional neural networks (CNN) used as frozen feature extractors to obtain compact deep embeddings. Unsupervised clustering is subsequently applied to identify latent atmospheric regimes within the dataset. The resulting clusters reveal coherent turbulence structures and offer a complementary perspective on atmospheric conditions at the Canary Islands observatories. This methodology provides new insights into turbulence variability at the Canary Islands sites and represents a novel approach to large-scale turbulence characterization using modern deep-learning techniques.

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arXiv2026

JWST reveals the diversity of nuclear obscuring dust in nearby AGN: nuclear isolation of MIRI/MRS datacubes and continuum spectral fitting

We investigate the capabilities of the mid-infrared instrument (MIRI) of James Webb Space Telescope (JWST) to advance our knowledge of AGN dust using the spectral fitting technique on an AGN collection of 21 nearby (z<0.05) AGN (7 type-1 and 14 type-2) observations obtained with the medium resolution spectroscopy (MRS) mode. This collection includes publicly available AGN and data from the collaboration of Galactic Activity, Torus, and Outflow Survey (GATOS). We developed a tool named MRSPSFisol that decomposes MRS cubes into point-like and extended contributions. We found statistically good fits for 12 targets with current AGN dust models. The model that provides good fits (chi2/dof<2) for {these 12 targets} assumes a combination of clumpy and smooth distribution of dust in a flare-disk geometry where the dust grain size is a free parameter. Still, two and one AGN statistically prefer the disk+wind and the classical clumpy torus model, respectively. However, the currently available models fail to reproduce 40% of the targets, likely due to the extreme silicate features not well reproduced by the models and signatures of water-ice and aliphatic hydrocarbon absorption features in most targets. New models exploring, for instance, new chemistry, are needed to explain the complexity of AGN dust continuum emission observed by JWST.

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arXiv2025

Impact of AGN and nuclear star formation on the ISM turbulence of galaxies: Insights from JWST/MIRI spectroscopy

Active galactic nuclei (AGN), star formation (SF), and galaxy interactions can drive turbulence in the gas of the ISM, which in turn plays a role in the SF within galaxies. The impact on molecular gas is of particular importance, as it serves as the primary fuel for SF. Our goal is to investigate the origin of turbulence and the emission of molecular gas, as well as low- and intermediate-ionization gas, in the inner few kpc of both AGN hosts and SF galaxies. We use JWST MIRI/MRS observations of a sample consisting of 54 galaxies at z<0.1. We present fluxes of the H2 S(5)6.9091, [Ar II]6.9853, [FeII]5.3403, and [Ar III]8.9914 lines, along with velocity dispersion from W80. For galaxies with coronal emission, [Mg V]5.6098 is also included. Line ratios are compared to photoionization and shock models to explore the origin of the gas emission. AGNs exhibit broader emission lines than SFGs, with the largest velocity dispersions observed in radio-strong (RS) AGNs. H2 gas is less turbulent compared to ionized gas, while coronal gas presents higher velocity dispersions. The W80 values for the ionized gas exhibits a decrease from the nucleus out to radii of approximately 0.5--1 kpc, followed by an outward increase up to 2-3 kpc. In contrast, the H2 line widths generally display increasing profiles with distance from the center. Correlations W80 and line ratios such as H2 S(5)/[ArII] and [FeII]/[ArII] indicate that the most turbulent gas is associated with shocks, enhancing H2 and [FeII] emissions. We speculate that these shocked gas regions are produced by AGN outflows and jet-cloud interactions in AGN-dominated sources, while in SFGs, they may be created by stellar winds and mergers. This shock-induced gas heating may be an important mechanism of AGN (or stellar) feedback, preventing the gas from cooling and forming new stars.

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arXiv2025

GATOS. VIII. On the physical origin of the extended MIR emission in AGN

The polar mid-infrared (MIR) emission detected within 10-100s pcs in some active galactic nuclei (AGN) has been associated with dusty winds driven away by radiation pressure. The physical characterization of this extended polar emission remains uncertain. Here we combine 10-21 $μ$m JWST/MIRI imaging observations with 7-25 $μ$m JWST/MRS integral field spectroscopic observations of 6 nearby, $\bar{D}=35.4\pm4.6$ Mpc, AGN from the GATOS Survey to quantify the nature of the extended MIR emission at ~75 pc resolution at 21 $μ$m. These AGN have similar bolometric luminosities, $\log_{10}(\bar{L}_{bol}\,[erg\,s^{-1}])=44.0\pm0.3$, span a wide range of optical outflow rates, $\dot{M}=0.003-0.21$ M$_{\odot}$ yr$^{-1}$, column densities, $\log_{10}(N_{H}^{X-ray}[cm^{-2}])=22.2-24.3$, and Eddington ratios, $λ_{Edd}=0.005-0.06$. We cross-correlate the line-only and continuum-only images and find a poor correlation, which indicates that the extended MIR continuum emission is spatially uncorrelated with the warm outflows associated with narrow emission lines within 10-15 $μ$m. Line emission is resolved along the jet axis, while dust emission is perpendicular to it. The 75-450 pc continuum emission has a fairly constant dust temperature, $T_{d}=132^{+7}_{-7}$ K, and mass, $M_{d}=728^{+29}_{-27}$ M$_{\odot}$. Using the conditions of energy balance between radiation-pressure and gravity ($λ_{Edd}$ vs. N$_{H}$), we find that our AGN sample is in the gravitationally bounded regime consistent with no detection of dusty winds. At 10 $μ$m, the level of extended line emission contribution is correlated with the outflow kinetic energy and mass outflow rates. We find no correlation with the AGN properties. These results indicate that the radio jet may be triggering the gas outflow and line emission, while the extended dust emission is distributed in molecular clouds and/or shocked regions.

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arXiv2025

The properties of the obscuring material of an AGNs sample from mid-IR and X-ray simultaneous fitting

Over ten mid-infrared (mid-IR) and X-ray models are currently attempting to describe the nuclear obscuring material of active galactic nuclei (AGNs), but many questions remain unresolved. This study aims to determine the physical parameters of the obscuring material in nearby AGNs and explore their relationship with nuclear activity. We selected 24 nearby Seyfert AGNs with X-ray luminosities ranging from $10^{41}$ to $10^{44}$ erg/s, using NuSTAR and Spitzer spectra. Our team fitted the spectra using a simultaneous fitting technique. Then, we compared the resulting parameters with AGN properties, such as bolometric luminosity, accretion rate, and black hole mass. Our analysis shows that dust and gas share a similar structure in most AGNs. Approximately 70% of the sample favors a combination of the X-ray UXclumpy model with the Clumpy and two-phases models at IR wavelengths. We found that linking the half-opening angle and torus angular width parameters from X-ray and mid-IR models helps constrain other parameters and break degeneracies. The study reveals that Sy1 galaxies are characterized by low covering factors, half-opening angles, and column densities but high Eddington rates. In contrast, Sy2 galaxies display higher covering factors and column densities, with a broader range of half-opening angles. We also observed that the distribution of obscuring material is closer to the nucleus in intermediate-luminosity sources, while it is more extended in more luminous AGNs. Our findings reinforce the connection between the properties of gas-dust material within 10 pc and AGN activity. Applying this methodology to a larger sample and incorporating data from facilities such as JWST and XRISM will be crucial in further refining these results.

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arXiv2024

The Galaxy Activity, Torus, and Outflow Survey (GATOS). (IV): Exploring Ionized Gas Outflows in Central Kiloparsec Regions of GATOS Seyferts

Utilizing JWST MIRI/MRS IFU observations of the kiloparsec scale central regions, we showcase the diversity of ionized gas distributions and kinematics in six nearby Seyfert galaxies included in the GATOS survey. Specifically, we present spatially resolved flux distribution and velocity field maps of six ionized emission lines covering a large range of ionization potentials ($15.8-97.1$ eV). Based on these maps, we showcase the evidence of ionized gas outflows in the six targets, and find some highly disturbed regions in NGC\,5728, NGC\,5506, and ESO137-G034. We propose AGN-driven radio jets plausibly play an important role in triggering these highly disturbed regions. With the outflow rates estimated based on [Ne~{\footnotesize V}] emission, we find the six targets tend to have ionized outflow rates converged to a narrower range than previous finding. These results have important implication for the outflow properties in AGN of comparable luminosity.

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arXiv2024

AGN feedback in the Local Universe: multiphase outflow of the Seyfert galaxy NGC 5506

We present new optical GTC/MEGARA seeing-limited (0.9") integral-field observations of NGC 5506, together with ALMA observations of the CO(3-2) transition at a 0.2" (25 pc) resolution. NGC 5506 is a luminous (bolometric luminosity of $\sim 10^{44}$ erg/s) nearby (26 Mpc) Seyfert galaxy, part of the Galaxy Activity, Torus, and Outflow Survey (GATOS). We modelled the CO(3-2) kinematics with 3D-Barolo, revealing a rotating and outflowing cold gas ring within the central 1.2 kpc. We derived an integrated cold molecular gas mass outflow rate for the ring of 8 M$_{\odot}$/yr. We fitted the optical emission lines with a maximum of two Gaussian components to separate rotation from non-circular motions. We detected high [OIII]$λ$5007 projected velocities (up to 1000 km/s) at the active galactic nucleus (AGN) position, decreasing with radius to an average 330 km/s around 350 pc. We also modelled the [OIII] gas kinematics with a non-parametric method, estimating the ionisation parameter and electron density in every spaxel, from which we derived an ionised mass outflow rate of 0.076 M$_{\odot}$/yr within the central 1.2 kpc. Regions of high CO(3-2) velocity dispersion, extending to projected distances of 350 pc from the AGN, appear to be the result from the interaction of the AGN wind with molecular gas in the galaxy's disc. Additionally, we find the ionised outflow to spatially correlate with radio and soft X-ray emission in the central kiloparsec. We conclude that the effects of AGN feedback in NGC 5506 manifest as a large-scale ionised wind interacting with the molecular disc, resulting in outflows extending to radial distances of 610 pc

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arXiv2024

Integral field spectroscopy supports atmospheric optics to reveal the finite outer scale of the turbulence

The spatial coherence wavefront outer scale (L_0) characterizes the size of the largest turbulence eddies in Earth's atmosphere, determining low spatial frequency perturbations in the wavefront of the light captured by ground-based telescopes. The motivation of this work is to introduce a novel technique for estimating L_0 from seeing-limited integral field spectroscopic (IFS) data. This approach is based on the impact of a finite L_0 on the light collected by the pupil entrance of a ground-based telescope. We take advantage of the homogeneity of IFS to generate band filter images spanning a wide wavelength range, enabling the assessment of image quality (IQ) at the telescope's focal plane. Comparing the measured wavelength-dependent IQ variation with predictions from Tokovinin (2002) analytical approach offers valuable insights into the prevailing L_0 parameter during the observations. We applied the proposed technique to observations from MUSE in the Wide Field Mode obtained at the Paranal Observatory. Our analysis successfully validates Tokovinin's analytical expression, which combines the seeing (E_0) and the L_0 parameters, to predict the IQ variations with the wavelength in ground-based astronomical data. However, we observed some discrepancies between the measured and predictions of the IQ that are analyzed in terms of uncertainties in the estimated E_0 and dome-induced turbulence contributions. This work constitutes the empirical validation of the analytical expression for estimating IQ at the focal plane of ground-based telescopes under specific E_0 and finite L_0 conditions. Additionally, we provide a simple methodology to characterize the L_0 and dome-seeing (E_d) as by-products of IFS observations routinely conducted at major ground-based astronomical observatories.

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arXiv2023

The ESO's Extremely Large Telescope Working Groups

Since 2005 ESO has been working with its community and industry to develop an extremely large optical/infrared telescope. ESO's Extremely Large Telescope, or ELT for short, is a revolutionary ground-based telescope that will have a 39-metre main mirror and will be the largest visible and infrared light telescope in the world. To address specific topics that are needed for the science operations and calibrations of the telescope, thirteen specific working groups were created to coordinate the effort between ESO, the instrument consortia, and the wider community. We describe here the goals of these working groups as well as their achievements so far.

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arXiv2018

Precision determination of corotation radii in galaxy disks: Tremaine-Weinberg v. Font-Beckman for NGC 3433

Density waves in galaxy disks have been proposed over the years, in a variety of specific models, to explain spiral arm structure and its relation to the mass distribution, notably in barred galaxies. An important parameter in dynamical density wave theories is the corotation radius, the galactocentric distance at which the stars and gas rotate at the same speed as the quasi-static propagating density wave. Determining corotation, and the pattern speed of a bar have become relevant to tests of cosmologically based theories of galaxy evolution involving the dynamical braking of bars by interaction with dark matter haloes. Here comparing two methods, one of which measures the pattern speed and the other the radius of corotation, using two instruments (an integral field spectrometer and a Fabry-Perot interferometer) and using both the stellar and interstellar velocity fields, we have determined the bar corotation radius, and three further radii of corotation for the SAB(s)b galaxy NGC3433. The results of both methods, with both instruments, and with both disk components give excellent agreement. This strengthens our confidence in the value of the two methods, and offers good perspectives for quantitative tests of different theoretical models.

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arXiv2015

Comparative internal kinematics of the HII regions in interacting and isolated galaxies: implications for massive star formation modes

We have observed 10 interacting galaxy pairs using the Fabry-Perot interferometer GH$α$FaS (Galaxy H$α$ Fabry-Perot system) on the $4.2\rm{m}$ William Herschel Telescope (WHT) at the Observatorio del Roque de los Muchachos, La Palma. We present here the H$α$ surface brightness, velocity and velocity dispersion maps for the 10 systems we have not previously observed using this technique, as well as the physical properties (sizes, H$α$ luminosities and velocity dispersion) of 1259 HII regions from the full sample. We also derive the physical properties of 1054 HII regions in a sample of 28 isolated galaxies observed with the same instrument in order to compare the two populations of HII regions. We find a population of the brightest HII regions for which the scaling relations, for example the relation between the H$α$ luminosity and the radius, are clearly distinct from the relations for the regions of lower luminosity. The regions in this bright population are more frequent in the interacting galaxies. We find that the turbulence, and also the star formation rate, are enhanced in the HII regions in the interacting galaxies. We have also extracted the H$α$ equivalent widths for the HII regions of both samples, and we have found that the distribution of HII region ages coincides for the two samples of galaxies. We suggest that the SFR enhancement is brought about by gas flows induced by the interactions, which give rise to gravitationally bound gas clouds which grow further by accretion from the flowing gas, producing conditions favourable to star formation.

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arXiv2014

BUBBLY: A method for detecting and characterizing interstellar bubbles using Fabry-Perot spectroscopy

We present a new method for the detection and characterization of expansion in galaxy discs based on Hα Fabry-Perot spectroscopy, taking advantage of the high spatial and velocity resolution of our instrument (GHαFaS). The method analyses multi-peaked emission line profiles to find expansion along the line of sight on a point-by-point basis. At this stage we have centred our attention on the large scale structures of expanding gas associated with HII regions which show a characteristic pattern of expansion velocities, of order 100 km/s, as a result of both bubble shape and projection effects. We show an example of the expansion map obtained with our method from a superbubble detected in the Antennae galaxies. We use the information obtained from the method to measure the relevant physical parameters of the superbubbles, including their ages which can be used to date young star clusters.

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arXiv2014

Two physical regimes for the Giant HII Regions and Giant Molecular Clouds in the Antennae Galaxies

We have combined observations of the Antennae galaxies from the radio interferometer ALMA (Atacama Large Millimeter/submillimeter Array) and from the optical interferometer GH$α$FaS (Galaxy H$α$ Fabry-Perot System). The two sets of observations have comparable angular and spectral resolutions, enabling us to identify 142 giant molecular clouds (GMCs) and 303 HII regions. We have measured, and compared, their basic physical properties (radius, velocity dispersion, luminosity). For the HII regions, we find two physical regimes, one for masses $>10^{5.4} \mathrm{M_{\odot}}$ of ionized gas, where the gas density increases with gas mass, the other for masses $<10^{5.4} \mathrm{M_{\odot}}$ of ionized gas, where the gas density decreases with gas mass. For the GMCs, we find, in contrast to previous studies in other galaxies over a generally lower mass range of clouds, that the gas surface density increases with the radius, hinting at two regimes for these clouds if we consider both sources of data. We also find that the GMC mass function has a break at $10^{6.7}\mathrm{M_{\odot}}$. Using the velocity dispersion measurements, we claim that the difference between the regimes is the nature of the dominant binding force. For the regions in the lower mass range, the dominant force is the external pressure, while in the higher mass range it is the internal gravity of the clouds. In the regime where gravity is dominant, the star formation rate, derived from the dust-corrected H$α$ luminosity, increases super-linearly with the velocity dispersion, and the gas density increases with the gas mass.

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