Proyecto de Investigación: LA PERSPECTIVA DE ALMA SOBRE EL CICLO DE GAS EN GALAXIAS ACTIVAS
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PID2019-106027GA-C44
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The multi-phase ISM in the nearby composite AGN-SB galaxy NGC 4945: large-scale (parsecs) mechanical heating
(EDP Sciences, 2020-10-15) Bellocchi, Enrica; Martín Pintado, J. ; Güsten, R.; Requena Torres, Miguel Angel; Harris, A.; Van der Werf, P. P.; Israel, F. P.; Weiss, A.; Kramer, C.; García-Burillo, Santiago; Stutzki, J.; European Space Agency (ESA); Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Bellocchi, E. [0000-0001-9791-4228]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Understanding the dominant heating mechanism in the nuclei of galaxies is crucial to understanding star formation in starbursts (SBs), active galactic nuclei (AGN) phenomena, and the relationship between star formation and AGN activity in galaxies. Analysis of the carbon monoxide (12CO) rotational ladder versus the infrared continuum emission (hereafter, 12CO/IR) in galaxies with different types of activity reveals important differences between them.
Aims. We aim to carry out a comprehensive study of the nearby composite AGN-SB galaxy, NGC 4945, using spectroscopic and photometric data from the Herschel satellite. In particular, we want to characterize the thermal structure in this galaxy using a multi-transition analysis of the spatial distribution of the 12CO emission at different spatial scales. We also want to establish the dominant heating mechanism at work in the inner region of this object at smaller spatial scales (≲200 pc).
Methods. We present far-infrared (FIR) and sub-millimeter (sub-mm) 12CO line maps and single spectra (from Jup = 3 to 20) using the Heterodyne Instrument for the Far Infrared (HIFI), the Photoconductor Array Camera and Spectrometer (PACS), and the Spectral and Photometric Imaging REceiver (SPIRE) onboard Herschel, and the Atacama Pathfinder EXperiment (APEX). We combined the 12CO/IR flux ratios and the local thermodynamic equilibrium (LTE) analysis of the 12CO images to derive the thermal structure of the interstellar medium (ISM) for spatial scales raging from ≲200 pc to 2 kpc. In addition, we also present single spectra of low- (12CO, 13CO and [CI]) and high-density (HCN, HNC, HCO+, CS and CH) molecular gas tracers obtained with APEX and HIFI applying LTE and non-LTE (NLTE) analyses. Furthermore, the spectral energy distribution of the continuum emission from the FIR to sub-mm wavelengths is also presented.
Results. From the NLTE analysis of the low- and high-density tracers, we derive gas volume densities (103–106 cm−3) for NGC 4945 that are similar to those found in other galaxies with different types of activity. From the 12CO analysis we find a clear trend in the distribution of the derived temperatures and the 12CO/IR ratios. It is remarkable that at intermediate scales (360 pc–1 kpc, or 19″–57″) we see large temperatures in the direction of the X-ray outflow while at smaller scales (≲200 pc–360 pc, or ∼9″–19″), the highest temperature, derived from the high-J lines, is not found toward the nucleus but toward the galaxy plane. The thermal structure derived from the 12CO multi-transition analysis suggests that mechanical heating, like shocks or turbulence, dominates the heating of the ISM in the nucleus of NGC4945 located beyond 100 pc (≳5″) from the center of the galaxy. This result is further supported by published models, which are able to reproduce the emission observed at high-J (PACS) 12CO transitions when mechanical heating mechanisms are included. Shocks and/or turbulence are likely produced by the barred potential and the outflow observed in X–rays.
A radio-jet driven outflow in the Seyfert 2 galaxy NGC 2110?
(EDP Sciences, 2023-05-10) Peralta de Arriba, L.; Alonso-Herrero, Almudena; García-Burillo, Santiago; García Bernete, Ismael; Villar Martín, M.; García Lorenzo, Begoña; Davies, R. I.; Rosario, D.; Hönig, Sebastian; Levenson, Nancy A.; Packham, Christopher; Ramos Almeida, Cristina; Pereira Santaella, Miguel; Audibert, Anelise; Bellocchi, Enrica; Hicks, Erin K. S.; Labiano, Alvaro; Ricci, Claudio; Rigopoulou, Dimitra; European Commission (EC); Gobierno de Canarias; University of Oxford; Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Ministerio de Ciencia e Innovación (MICINN); Science and Technology Facilities Council (STFC); Centros de Excelencia Severo Ochoa, CENTRO NACIONAL DE BIOTECNOLOGIA (CNB), SEV-2017-0712
We present a spatially-resolved study of the ionised gas in the central 2 kpc of the Seyfert 2 galaxy NGC 2110 and investigate the role of its moderate luminosity radio jet (kinetic radio power of $P_\mathrm{jet} = 2.3 \times 10^{43}\mathrm{erg\ s^{-1}}$). We use new optical integral-field observations taken with the MEGARA spectrograph at GTC. We fit the emission lines with a maximum of two Gaussian components, except at the AGN position where we used three. Aided by existing stellar kinematics, we use the observed velocity and velocity dispersion of the emission lines to classify the different kinematic components. The disc component is characterised by lines with $\sigma \sim 60-200\ \mathrm{km\ s^{-1}}$. The outflow component has typical values of $\sigma \sim 700\ \mathrm{km\ s^{-1}}$ and is confined to the central 400 pc, which is coincident with linear part of the radio jet detected in NGC 2110. At the AGN position, the [O III]$\lambda$5007 line shows high velocity components reaching at least $1000\ \mathrm{km\ s^{-1}}$. This and the high velocity dispersions indicate the presence of outflowing gas outside the galaxy plane. Spatially-resolved diagnostic diagrams reveal mostly LI(N)ER-like excitation in the outflow and some regions in the disc, which could be due to the presence of shocks. However, there is also Seyfert-like excitation beyond the bending of the radio jet, probably tracing the edge of the ionisation cone that intercepts with the disc of the galaxy. NGC 2110 follows well the observational trends between the outflow properties and the jet radio power found for a few nearby Seyfert galaxies. All these pieces of information suggest that part of observed ionised outflow in NGC 2110 might be driven by the radio jet. However, the radio jet was bent at radial distances of 200 pc (in projection) from the AGN, and beyond there, most of the gas in the galaxy disc is rotating.
The Galaxy Activity, Torus, and Outflow Survey (GATOS): III. Revealing the inner icy structure in local active galactic nuclei
(EDP Sciences, 2024-01-01) García Bernete, Ismael; Alonso-Herrero, Almudena; Rigopoulou, Dimitra; Pereira Santaella, Miguel; Shimizu, Thomas Taro; Davies, Richard; Donnan, Fergus; Roche, P. F.; González Martín, Omaira; Ramos Almeida, Cristina; Bellocchi, Enrica; Boorman, Peter; Combes, Francoise; Efstathiou, A.; Esparza Arredondo, Donaji; García-Burillo, Santiago; González Alfonso, E. ; Hicks, Erin K. S.; Hönig, Sebastian; Labiano, Alvaro; Levenson, Nancy A.; Lopez-Rodriguez, Enrique; Ricci, Claudio; Packham, Christopher; Rouan, Daniel; Stalevski, Marko; Ward, M. J.; Ministerio de Ciencia e Innovación (MICINN); Science and Technology Facilities Council (STFC); Universidad Nacional Autónoma de México (UNAM); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
We use JWST/MIRI MRS spectroscopy of a sample of six local obscured type 1.9/2 active galactic nuclei (AGN) to compare their nuclear mid-IR absorption bands with the level of nuclear obscuration traced by X-rays. This study is the first to use subarcsecond angular resolution data of local obscured AGN to investigate the nuclear mid-IR absorption bands with a wide wavelength coverage (4.9–28.1 μm). All the nuclei show the 9.7 μm silicate band in absorption. We compare the strength of the 9.7 and 18 μm silicate features with torus model predictions. The observed silicate features are generally well explained by clumpy and smooth torus models. We report the detection of the 6 μm dirty water ice band (i.e., a mix of water and other molecules such as CO and CO2) at subarcsecond scales (∼0.26″ at 6 μm; inner ∼50 pc) in a sample of local AGN with different levels of nuclear obscuration in the range log NHX-Ray (cm−2)∼22 − 25. We find good correlation between the 6 μm water ice optical depths and NHX-Ray. This result indicates that the water ice absorption might be a reliable tracer of the nuclear intrinsic obscuration in AGN. The weak water ice absorption in less obscured AGN (log NHX-ray (cm−2)≲23.0 cm−2) might be related to the hotter dust temperature (> TsubH2O ∼ 110 K) expected to be reached in the outer layers of the torus due to their more inhomogeneous medium. Our results suggest it might be necessary to include the molecular content, such as H2O, aliphatic hydrocarbons (CH−), and more complex polycyclic aromatic hydrocarbon (PAH) molecules, in torus models to better constrain key parameters such as the torus covering factor (i.e., nuclear obscuration).
