Examinando por Autor "Shimizu, Thomas Taro"

Mostrando 1 - 5 de 5

Acceso Abierto
AGN feedback in the Local Universe: Multiphase outflow of the Seyfert galaxy NGC 5506
(EDP Sciences, 2024-06-01) Esposito, Federico; Alonso-Herrero, Almudena; García-Burillo, Santiago; Casasola, Viviana; Combes, Francoise; Dallacasa, Daniele; Davies, Richard; García Bernete, Ismael; García-Lorenzo, Begoña; Hermosa Muñoz, Laura; Peralta de Arriba, L.; Pereira Santaella, Miguel; Pozzi, Francesca; Ramos Almeida, Cristina; Shimizu, Thomas Taro; Vallini, Livia; Bellocchi, Enrica ; González Martín, Omaira; Hicks, Erin K. S.; Hönig, Sebastian; Labiano, Alvaro; Levenson, Nancy A.; Ricci, Claudio; Rosario, David J.; Ministerio de Ciencia e Innovación (MICINN); Universidad Nacional Autónoma de México (UNAM); Science and Technology Facilities Council (STFC); Ministero dell\u2019Istruzione, dell\u2019Università e della Ricerca (MIUR); European Commission (EC); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Istituto Nazionale di Astrofisica (INAF); National Aeronautics and Space Administration (NASA)
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 ~1044 erg s-1) nearby (26 Mpc) Seyfert galaxy, part of the Galaxy Activity, Torus, and Outflow Survey (GATOS). We modelled the CO(3 - 2) kinematics with 3DBAROLO, 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⊙ yr-1. We fitted the optical emission lines with a maximum of two Gaussian components to separate rotation from non-circular motions. We detected high [OIII]λ5007 projected velocities (up to ~1000 km s-1) at the active galactic nucleus (AGN) position, decreasing with radius to an average ~330 km s-1 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⊙ yr-1 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.
Acceso Abierto
Molecular gas stratification and disturbed kinematics in the Seyfert galaxy MCG-05-23-16 revealed by JWST and ALMA
(EDP Sciences, 2025-01-15) Esparza Arredondo, Donaji; Ramos Almeida, Cristina; Audibert, A.; Pereira Santaella, Miguel; García Bernete, Ismael; García-Burillo, Santiago; Shimizu, Thomas Taro; Davies, Richard; Hermosa Muñoz, Laura; Alonso-Herrero, Almudena; Combes, Francoise; Speranza, G.; Zhang, Lulu; Campbell, Stephanie; Bellocchi, Enrica; Bunker, Andrew J.; Díaz Santos, T.; García Lorenzo, B. ; González Martín, Omaira; Hicks, Erin K. S.; Labiano, Alvaro; Levenson, Nancy A.; Ricci, Claudio; Rosario, D.; Hönig, Sebastian; Packham, Christopher; Stalevski, Marko ; Fuller, L.; Izumi, T.; López Rodríguez, Enrique, E.; Rigopoulou, Dimitra; Rouan, Daniel; Ward, Martin; European Research Council (ERC); Comunidad de Madrid; Agencia Estatal de Investigación (España); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Space Telescope Science Institute (US); Hellenic Foundation for Research and Innovation; Agencia Nacional de Investigación y Desarrollo (Chile)
Understanding the processes that drive the morphology and kinematics of molecular gas in galaxies is crucial for comprehending star formation and, ultimately, galaxy evolution. Using data from the Galactic Activity, Torus and Outflow Survey (GATOS) obtained with the James Webb Space Telescope (JWST) and the archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), we study the behavior of the warm molecular gas at temperatures of hundreds of Kelvin and the cold molecular gas at tens of Kelvin in the galaxy MCG−05−23−16, which hosts an active galactic nucleus (AGN). Hubble Space Telescope (HST) images of this spheroidal galaxy, classified in the optical as S0, show a dust lane resembling a nuclear spiral and a surrounding ring. These features are also detected in CO(2−1) and H2, and their morphologies and kinematics are consistent with rotation plus local inward gas motions along the kinematic minor axis in the presence of a nuclear bar. The H2 transitions 0-0 S(3), 0-0 S(4), and 0-0 S(5), which trace warmer and more excited gas, show more disrupted kinematics than 0-0 S(1) and 0-0 S(2), including clumps of high velocity dispersion (of up to ∼160 km s−1), in regions devoid of CO(2−1). The kinematics of one of these clumps, located ∼350 pc westward of the nucleus, are consistent with outflowing gas, possibly driven by localized star formation traced by polycyclic aromatic hydrocarbon emission at 11.3 μm. Overall, we observe a stratification of the molecular gas, with the colder gas located in the nuclear spiral, ring, and connecting arms, and most of the warmer gas with a higher velocity dispersion filling the inter-arm space. The compact jet, approximately 200 pc in size, detected with Very Large Array (VLA) observations, does not appear to significantly affect the distribution and kinematics of the molecular gas, possibly due to its limited intersection with the molecular gas disk.
Acceso Abierto
Polycyclic aromatic hydrocarbon emission in galaxies as seen with JWST
(Royal Astronomical Society, 2024-08-01) Rigopoulou, Dimitra; Donnan, Fergus; García Bernete, Ismael; Pereira Santaella, Miguel; Alonso-Herrero, Almudena; Davies, Richard; Hunt, L. K.; Roche, P. F.; Shimizu, Thomas Taro; Ministerio de Ciencia e Innovación (MICINN); Science and Technology Facilities Council (STFC)
We present a systematic study of mid-infrared spectra of galaxies including star-forming galaxies and active galactic nuclei observed with JWST MIRI-MRS and NIRSpec-IFU. We focus on the relative variations of the 3.3, 6.2, 7.7, 11.3, 12.7, and 17 m polycyclic aromatic hydrocarbon (PAH) features within spatially resolved regions of galaxies including NGC 3256, NGC 7469, VV 114, II Zw96, and NGC 5728. Using theoretical PAH models and extending our earlier work, we introduce a new PAH diagnostic involving the 17 m PAH feature. To determine the drivers of PAH band variations in galaxies, we compare observed PAH spectral bands to predictions from theoretical PAH models. We consider extinction, dehydrogenation, and PAH size and charge as possible drivers of PAH band variations. We find a surprising uniformity in PAH size distribution among the spatially resolved regions of the galaxies studied here, with no evidence for preferential destruction of the smallest grains, contrary to earlier findings. Neither extinction nor dehydrogenation play a crucial role in setting the observed PAH bands. Instead, we find that PAH charge plays a significant role in PAH inter-band variations. We find a tight relation between PAH charge and the intensity of the radiation field as traced by the [Ne iii][Ne ii] maps. In agreement with recent JWST results, we find a predominance of neutral PAH molecules in the nuclei of active galaxies and their outflows. Ionized PAHs are the dominant population in star-forming galaxies. We discuss the implications of our findings for the use of PAHs as ISM tracers in high redshift galaxies.
Acceso Abierto
The Galaxy Activity, Torus, and Outflow Survey (GATOS) V. Unveiling PAH survival and resilience in the circumnuclear regions of AGNs with JWST
(EDP Sciences, 2024-09-09) García Bernete, Ismael; Rigopoulou, Dimitra; Donnan, Fergus; Alonso-Herrero, Almudena; Pereira Santaella, Miguel; Shimizu, Thomas Taro; Davies, Richard; Roche, P. F.; García-Burillo, Santiago; Labiano, Alvaro; Hermosa Muñoz, Laura; Zhang, Lulu; Audibert, A.; Bellocchi, Enrica; Bunker, Andrew J.; Combes, Francoise; Delaney, D.; Esparza Arredondo, Donaji; Gandhi, P.; González Martín, Omaira; Hönig, Sebastian; Imanishi, Masatoshi; Hicks, Erin K. S.; Fuller, L.; Leist, Mason Tanner; Levenson, Nancy A.; López Rodríguez, Enrique; Packham, Christopher; Ramos Almeida, Cristina; Ricci, Claudio; Stalevski, Marko; Villar Martín, M.; Ward, M. J.; Science and Technology Facilities Council (STFC); Comunidad de Madrid; European Commission (EC); European Space Agency (ESA); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Ministerio de Ciencia e Innovación (MICINN); National Aeronautics and Space Administration (NASA); Space Telescope Science Institute (STScI); Universidad Nacional Autónoma de México (UNAM)
This study analyses JWST MIRI/MRS observations of the infrared (IR) polycyclic aromatic hydrocarbon (PAH) bands in the nuclear (∼0.4″ at 11 μm; ∼75 pc) and circumnuclear regions (inner ∼kpc) of local active galactic nuclei (AGNs) from the Galactic Activity, Torus, and Outflow Survey (GATOS). We examine the PAH properties in the circumnuclear regions of AGNs and the projected direction of AGN-outflows and compare them to those in star-forming regions and the innermost regions of AGNs. This study employs 4.9–28.1 μm sub-arcsecond angular resolution data to investigate the properties of PAHs in three nearby sources (DL ∼ 30 − 40 Mpc). Our findings are aligned with previous JWST studies, demonstrating that the central regions of AGNs display a larger fraction of neutral PAH molecules (i.e. elevated 11.3/6.2 and 11.3/7.7 μm PAH ratios) in comparison to star-forming galaxies. We find that AGNs might affect not only the PAH population in the innermost region, but also in the extended regions up to ∼kpc scales. By comparing our observations to PAH diagnostic diagrams, we find that, in general, regions located in the projected direction of the AGN-outflow occupy similar positions on the PAH diagnostic diagrams as those of the innermost regions of AGNs. Star-forming regions that are not affected by the AGNs in these galaxies share the same part of the diagram as star-forming galaxies. We also examined the potential of the PAH-H2 diagram to disentangle AGN-versus-star-forming activity. Our results suggest that in Seyfert-like AGNs, the illumination and feedback from the AGN might affect the PAH population at nuclear and kpc scales, particularly with respect to the ionisation state of the PAH grains. However, PAH molecular sizes are rather similar. The carriers of the ionised PAH bands (6.2 and 7.7 μm) are less resilient than those of neutral PAH bands (11.3 μm), which might be particularly important for strongly AGN-host coupled systems. Therefore, caution must be applied when using PAH bands as star-formation rate indicators in these systems even at kpc scales, with the effects of the AGN being more important for ionised ones.
Acceso Abierto
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).