Examinando por Autor "Pereira Santaella, M."

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Acceso Abierto
A CO molecular gas wind 340 pc away from the Seyfert 2 nucleus in ESO 420-G13 probes an elusive radio jet
(EDP Sciences, 2020-01-21) Fernández Ontiveros, J. A.; Dasyra, K. M.; Hatziminaoglou, Evanthia; Malkan, M. A.; Pereira Santaella, M.; Papachristou, M.; Spinoglio, L.; Combes, F.; Aalto, S.; Nagar, N.; Imanishi, M.; Andreani, P.; Ricci, C.; Slater, R.; Agenzia Spaziale Italiana (ASI); Comunidad de Madrid; Hellenic Foundation for Research and Innovation (HFRI); Comisión Nacional de Investigación Científica y Tecnológica (CONICYT); http://dx.doi.org/10.13039/501100002848; Fernández Ontiveros, J. A. [0000-0001-9490-899X]; Hatziminaoglou, E. [0000-0003-0917-9636]; Spignoglio, L. [0000-0001-8840-1551]; Combes, F. [0000-0003-2658-7893]; Nagar, N. [0000-0001-6920-662X]; Imanishi, M. [0000-0001-6186-8792]; Andreani, P. [0000-0001-9493-0169]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
A prominent jet-driven outflow of CO(2-1) molecular gas is found along the kinematic minor axis of the Seyfert 2 galaxy ESO 420-G13, at a distance of 340-600 pc from the nucleus. The wind morphology resembles the characteristic funnel shape, formed by a highly collimated filamentary emission at the base, and likely traces the jet propagation through a tenuous medium, until a bifurcation point at 440 pc. Here the jet hits a dense molecular core and shatters, dispersing the molecular gas into several clumps and filaments within the expansion cone. We also trace the jet in ionised gas within the inner less than or similar to 340 pc using the [NeII](12.8 mu m) line emission, where the molecular gas follows a circular rotation pattern. The wind outflow carries a mass of similar to 8 x 10(6) M-circle dot at an average wind projected speed of similar to 160 km s(-1), which implies a mass outflow rate of similar to 14 M-circle dot yr(-1). Based on the structure of the outflow and the budget of energy and momentum, we discard radiation pressure from the active nucleus, star formation, and supernovae as possible launching mechanisms. ESO 420-G13 is the second case after NGC 1377 where a previously unknown jet is revealed through its interaction with the interstellar medium, suggesting that unknown jets in feeble radio nuclei might be more common than expected. Two possible jet-cloud configurations are discussed to explain an outflow at this distance from the AGN. The outflowing gas will likely not escape, thus a delay in the star formation rather than quenching is expected from this interaction, while the feedback effect would be confined within the central few hundred parsecs of the galaxy.
Acceso Abierto
A proto-pseudobulge in ESO 320-G030 fed by a massive molecular inflow driven by a nuclear bar
(EDP Sciences, 2021-01-07) González Alfonso, E.; Pereira Santaella, M.; Fischer, J.; García Burillo, S.; Yang, C.; Alonso Herrero, A.; Colina, L.; Ashby, M. L. N.; Smith, H. A.; Rico Villas, F.; Martín Pintado, J.; Cazzoli, S.; Stewart, F. P.; National Aeronautics and Space Administration (NASA); Agencia Estatal de Investigación (AEI); Comunidad de Madrid; European Commission (EC); 0000-0001-5285-8517; 0000-0001-6697-7808; 0000-0003-0444-6897; 0000-0002-8117-9991; 0000-0001-6794-2519; 0000-0002-7705-2525; 0000-0001-8266-8298; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Galaxies with nuclear bars are believed to efficiently drive gas inward, generating a nuclear starburst and possibly an active galactic nucleus. We confirm this scenario for the isolated, double-barred, luminous infrared galaxy ESO 320-G030 based on an analysis of Herschel and ALMA spectroscopic observations. Herschel/PACS and SPIRE observations of ESO 320-G030 show absorption or emission in 18 lines of H2O, which we combine with the ALMA H2O 4(23)-3(30) 448 GHz line (E-upper similar to 400 K) and continuum images to study the physical properties of the nuclear region. Radiative transfer models indicate that three nuclear components are required to account for the multi-transition H2O and continuum data. An envelope, with radius R similar to 130-150 pc, dust temperature T-dust approximate to 50 K, and N-H2 similar to 2x10(23) cm(-2), surrounds a nuclear disk with R similar to 40 pc that is optically thick in the far-infrared (tau (100 mu m)similar to 1.5-3, N-H2 similar to 2x10(24) cm(-2)). In addition, an extremely compact (R similar to 12 pc), warm (approximate to 100 K), and buried (tau (100 mu m)> 5, N-H2 greater than or similar to 5x10(24) cm(-2)) core component is required to account for the very high-lying H2O absorption lines. The three nuclear components account for 70% of the galaxy luminosity (SFR similar to 16-18 M-circle dot yr(-1)). The nucleus is fed by a molecular inflow observed in CO 2-1 with ALMA, which is associated with the nuclear bar. With decreasing radius (r=450-225 pc), the mass inflow rate increases up to M-inf similar to 20 M yr(-1), which is similar to the nuclear star formation rate (SFR), indicating that the starburst is sustained by the inflow. At lower r, similar to 100-150 pc, the inflow is best probed by the far-infrared OH ground-state doublets, with an estimated M-inf similar to 30 M yr(-1). The inferred short timescale of similar to 20 Myr for nuclear gas replenishment indicates quick secular evolution, and indicates that we are witnessing an intermediate stage (< 100 Myr) proto-pseudobulge fed by a massive inflow that is driven by a strong nuclear bar. We also apply the H2O model to the Herschel far-infrared spectroscopic observations of H218O, OH, 18OH, OH+, H2O+, H3O+, NH, NH2, NH3, CH, CH+, 13CH+, HF, SH, and C3, and we estimate their abundances.
Acceso Abierto
A radio-jet driven outflow in the Seyfert 2 galaxy NGC 2110?
(EDP Sciences, 2023-05-10) Peralta de Arriba, L.; Alonso Herrero, A.; García Burillo, S.; García Bernete, I.; Villar Martín, M.; García Lorenzo, B.; Davies, R. I.; Rosario, D.; Hönig, S. F.; Levenson, N. A.; Packham, C.; Ramos Almeida, C.; Pereira Santaella, M.; Audibert, A.; Bellocchi, E.; Hicks, E. K. S.; Labiano, Á.; Ricci, C.; Rigopoulou, D.; 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.
Acceso Abierto
Black Hole-Galaxy Scaling Relation Evolution From z~2.5: Simulated Observations With HARMONI on the ELT
(Extragalactic Astronomy, 2019-12-06) García Lorenzo, B.; Monreal Ibero, A.; Mediavilla, E.; Pereira Santaella, M.; Thatte, N.; Science and Technology Facilities Council (STFC); Comunidad de Madrid; Ministerio de Economía y Competitividad (MINECO); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We present preliminary results on the potential of HARMONI, the first light integral field spectrograph for the ELT, to explore the evolution of central super massive black holes (SMBH)—host galaxy relation in the range from z~0.7 to z~2.5. We simulated HARMONI observations of QSO+host galaxy at different redshifts, assuming different morphologies for the host galaxy. As input, we combined MUSE observations of nearby galaxies and a theoretical QSO spectrum. These were dimmed and redshifted to the desired cosmic epoch. We scaled the total host galaxy luminosity to three different values, sampling three orders of magnitude. Likewise, we assumed two different luminosities for the central QSO. Simulations were performed for the 30×60 mas2 HARMONI spatial scale and LTAO working at 0.67 arcsec seeing. The selected wavelength range (i.e., 4,700–5,300 Å at rest-frame) was sampled at the lowest HARMONI spectral resolving power (i.e., R~3,200). This configuration included all the ingredients to estimate the host galaxy parameters and the SMBH mass, as well as for assessing the morphological type of the host galaxy.
Acceso Abierto
Cold molecular gas and PAH emission in the nuclear and circumnuclear regions of Seyfert galaxies
(EDP Sciences, 2020-07-07) Alonso Herrero, A.; Pereira Santaella, M.; Rigopoulou, D.; García Bernete, I.; García Burillo, S.; Domínguez Fernández, A. J.; Combes, F.; Davies, R. I.; Díaz Santos, T.; Esparza Borges, E.; González Martín, O.; Hernán Caballero, A.; Hicks, E. K. S.; Hönig, S. F.; Levenson, N. A.; Ramos Almeida, C.; Roche, P. F.; Rosario, D.; Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Science and Technology Facilities Council (STFC); Universidad Nacional Autónoma de México (UNAM); European Research Council (ERC); National Aeronautics and Space Administration (NASA); 0000-0001-8353-649X; 0000-0003-0699-6083; 0000-0002-0001-3587; 0000-0002-8524-8413; 0000-0003-4949-7217; 0000-0002-6353-1111
We investigate the relation between the detection of the 11.3 mu m polycyclic aromatic hydrocarbon (PAH) feature in the nuclear (similar to 24-230 pc) regions of 22 nearby Seyfert galaxies and the properties of the cold molecular gas. For the former we use ground-based (0.3-0.6 '' resolution) mid-infrared (mid-IR) spectroscopy. The cold molecular gas is traced by ALMA and NOEMA high (0.2-1.1 '') angular resolution observations of the CO(2-1) transition. Galaxies with a nuclear detection of the 11.3 mu m PAH feature contain more cold molecular gas (median 1.6x10(7) M-circle dot) and have higher column densities (N(H-2) = 2x10(23) cm(-2)) over the regions sampled by the mid-IR slits than those without a detection. This suggests that molecular gas plays a role in shielding the PAH molecules in the harsh environments of Seyfert nuclei. Choosing the PAH molecule naphthalene as an illustration, we compute its half-life in the nuclear regions of our sample when exposed to 2.5 keV hard X-ray photons. We estimate shorter half-lives for naphthalene in nuclei without a 11.3 mu m PAH detection than in those with a detection. The Spitzer/IRS PAH ratios on circumnuclear scales (similar to 4 ''similar to 0.25-1.3 kpc) are in between model predictions for neutral and partly ionized PAHs. However, Seyfert galaxies in our sample with the highest nuclear H-2 column densities are not generally closer to the neutral PAH tracks. This is because in the majority of our sample galaxies, the CO(2-1) emission in the inner similar to 4 '' is not centrally peaked and in some galaxies traces circumnuclear sites of strong star formation activity. Spatially resolved observations with the MIRI medium-resolution spectrograph on the James Webb Space Telescope will be able to distinguish the effects of an active galactic nucleus (AGN) and star formation on the PAH emission in nearby AGN.
Acceso Abierto
Herschel/PACS OH Spectroscopy of Seyfert, LINER, and Starburst Galaxies
(The Institute of Physics (IOP), 2020-12-11) Runco, J. N.; Malkan, M. A.; Fernández Ontiveros, J. A.; Spinoglio, L.; Pereira Santaella, M.; Agenzia Spaziale Italiana (ASI); Science and Technology Facilities Council (STFC); Comunidad de Madrid; National Aeronautics and Space Administration (NASA); 0000-0003-4852-8958; 0000-0001-6919-1237; 0000-0001-9490-899X; 0000-0001-8840-1551; 0000-0002-4005-9619; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We investigated the 65, 71, 79, 84, 119, and 163 μm OH doublets of 178 local (0 < z < 0.35) galaxies. They were observed using the Herschel/Photoconductor Array Camera and Spectrometer, including Seyfert galaxies, low-ionization nuclear emission-line regions, and star-forming galaxies. We observe these doublets exclusively in absorption (OH71), primarily in absorption (OH65, OH84), mostly in emission (OH79), only in emission (OH163), and an approximately even mix of the both (OH119). In 19 galaxies we find P Cygni or reverse P Cygni line profiles in the OH doublets. We use several galaxy observables to probe spectral classification, brightness of a central active galactic nucleus (AGN)/starburst component, and radiation field strength. We find that OH79, OH119, and OH163 are more likely to display strong emission for bright, unobscured AGNs. For less luminous, obscured AGNs and nonactive galaxies, we find populations of strong absorption (OH119), weaker emission (OH163), and a mix of weak emission and weak absorption (OH79). For OH65, OH71, and OH84, we do not find significant correlations with the observables listed above. For OH79 and OH119, we find relationships with both the 9.7 μm silicate feature and Balmer decrement dust extinction tracers in which more dust leads to weaker emission/stronger absorption. The origin of emission for the observed OH doublets, whether from collisional excitation or from radiative pumping by infrared photons, is discussed.
Acceso Abierto
Integral field spectroscopy of luminous infrared main-sequence galaxies at cosmic noon
(Oxford Academics: Oxford University Press, 2021-02-26) Hogan, L.; Rigopoulou, D.; Magdis, Georgios E.; Pereira Santaella, M.; García Bernete, I.; Thatte, N.; Grisdale, K.; Huang, J. S.; Science and Technology Facilities Council (STFC); Villum Fonden; Comunidad de Madrid; Magdis, G. E. [0000-0002-4872-2294]; Pereira Santaella, M. [0000-0002-4005-9619]; Grisdale, K. [0000-0003-0375-5997]
We present the results of an integral field spectroscopy survey of a sample of dusty (ultra) luminous infrared galaxies (U/LIRGs) at 2 < z < 2.5 using KMOS on the Very Large Telescope. The sample has been drawn from Herschel deep field surveys and benefits from ancillary multiwavelength data. Our goal is to investigate the physical characteristics, kinematics, and the drivers of star formation in the galaxies whose contribution dominates the peak of the cosmic star formation density. Two-thirds of the sample are main-sequence galaxies in contrast to the starburst nature of local U/LIRGs. Our kinematic study, unique in its focus on z ∼ 2 dusty star-forming galaxies, uses the H α emission line to find that ∼40 per cent appear to be isolated discs based on the ratio of rotational velocity to the velocity dispersion, suggesting steady-state mechanisms are sufficient to power the large star formation rates (SFRs). The ratio of obscured to unobscured star formation indicates the sample of galaxies experiences less dust obscuration compared to intermediate and local counterparts, while also hosting cooler dust than local U/LIRGs. In addition to H α we detect [N II] 6583 Å in our targets and show the gas-phase metallicities do not exhibit the metal deficiency of local U/LIRGs. These results indicate that, despite their extreme IR luminosity, the underlying mechanisms driving the massive SFRs found at cosmic noon are due to scaled up disc galaxies as opposed to mergers.
Acceso Abierto
MUSE view of Arp220: Kpc-scale multi-phase outflow and evidence for positive feedback
(EDP Sciences, 2020-11-17) Perna, M.; Arribas, S.; Catalán Torrecilla, C.; Colina, L.; Bellocchi, E.; Fluetsch, A.; Maiolino, R.; Cazzoli, S.; Hernán Caballero, A.; Pereira Santaella, M.; Piqueras López, J.; Rodríguez del Pino, B.; Ministerio de Economía y Competitividad (MINECO); ESO Multi Unit Spectroscopic Explorer (MUSE); Comunidad de Madrid; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Perna, M. [0000-0002-0362-5941]; Arribas, S. [0000-0001-7997-1640]; Colina, L. [0000-0002-9090-4227]; Bellocchi, E. [0000-0001-9791-4228]; Cazzoli, S. [0000-0002-7705-2525]; Pereira Santaella, M. [0000-0002-4005-9619]; Piqueras López, J. [0000-0003-1580-1188]; Rodríguez del Pino, B. [0000-0001-5171-3930]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709
Context. Arp220 is the nearest and prototypical ultra-luminous infrared galaxy; it shows evidence of pc-scale molecular outflows in its nuclear regions and strongly perturbed ionised gas kinematics on kpc scales. It is therefore an ideal system for investigating outflow mechanisms and feedback phenomena in detail. Aims. We investigate the feedback effects on the Arp220 interstellar medium (ISM), deriving a detailed picture of the atomic gas in terms of physical and kinematic properties, with a spatial resolution that had never before been obtained (0.56″, i.e. ∼210 pc). Methods. We use optical integral-field spectroscopic observations from VLT/MUSE-AO to obtain spatially resolved stellar and gas kinematics, for both ionised ([N II]λ6583) and neutral (Na IDλλ5891, 96) components; we also derive dust attenuation, electron density, ionisation conditions, and hydrogen column density maps to characterise the ISM properties. Results. Arp220 kinematics reveal the presence of a disturbed kpc-scale disc in the innermost nuclear regions as well as highly perturbed multi-phase (neutral and ionised) gas along the minor axis of the disc, which we interpret as a galactic-scale outflow emerging from the Arp220 eastern nucleus. This outflow involves velocities up to ∼1000 km s−1 at galactocentric distances of ≈5 kpc; it has a mass rate of ∼50 M⊙ yr−1 and kinetic and momentum power of ∼1043 erg s−1 and ∼1035 dyne, respectively. The inferred energetics do not allow us to distinguish the origin of the outflows, namely whether they are active galactic nucleus- or starburst-driven. We also present evidence for enhanced star formation at the edges of – and within – the outflow, with a star-formation rate SFR ∼ 5 M⊙ yr−1 (i.e. ∼2% of the total SFR). Conclusions. Our findings suggest the presence of powerful winds in Arp220: They might be capable of heating or removing large amounts of gas from the host (“negative feedback”) but could also be responsible for triggering star formation (“positive feedback”).
Acceso Abierto
Physics of ULIRGs with MUSE and ALMA: The PUMA project I. Properties of the survey and first MUSE data results
(EDP Sciences, 2021-02-16) Perna, M.; Arribas, S.; Pereira Santaella, M.; Colina, L.; Bellocchi, E.; Catalán Torrecilla, C.; Cazzoli, S.; Crespo Gómez, A.; Maiolino, R.; Piqueras López, J.; Rodríguez del Pino, B.; Comunidad de Madrid; Agencia Estatal de Investigación (AEI); European Research Council (ERC); Science and Technology Facilities Council (STFC); Perna, M. [0000-0002-0362-5941]; Arribas, S. [0000-0001-7997-1640]; Colina, L. [0000-0002-9090-4227]; Bellocchi, E. [0000-0001-9791-4228]; Catalán Torrecilla, C. [0000-0002-8067-0164]; Cazzoli, S. [0000-0002-7705-2525]; Maiolino, R. [0000-0002-4985-3819]; Piqueras López, J. [0000-0003-1580-1188]; Rodríguez del Pino, B. [0000-0001-5171-3930]; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709
Context. Ultraluminous infrared galaxies (ULIRGs) are characterised by extreme starburst (SB) and active galactic nucleus (AGN) activity, and are therefore ideal laboratories for studying the outflow phenomena and their feedback effects. We have recently started a project called Physics of ULIRGs with MUSE and ALMA (PUMA), which is a survey of 25 nearby (z < 0.165) ULIRGs observed with the integral field spectrograph MUSE and the interferometer ALMA. This sample includes systems with both AGN and SB nuclear activity in the pre- and post-coalescence phases of major mergers. Aims. The main goals of the project are (i) to study the prevalence of (ionised, neutral, and molecular) outflows as a function of the galaxy properties, (ii) to constrain the driving mechanisms of the outflows (e.g. distinguish between SB and AGN winds), and (iii) to identify and characterise feedback effects on the host galaxy. In this first paper, we present details on the sample selection, MUSE observations, and data reduction, and derive first high-level data products. Methods. MUSE data cubes were analysed to study the dynamical status of each of the 21 ULIRGs observed so far, taking the stellar kinematics and the morphological properties inferred from MUSE narrow-band images into account. We also located the ULIRG nuclei, taking advantage of near-infrared (HST) and millimeter (ALMA) data, and studied their optical spectra to infer (i) the ionisation state through standard optical line ratio diagnostics, and (ii) outflows in both atomic ionised ([O III], Hα) and neutral (Na ID) gas. Results. We show that the morphological and stellar kinematic classifications are consistent: post-coalescence systems are more likely associated with ordered motions, while interacting (binary) systems are dominated by non-ordered and streaming motions. We also find broad and asymmetric [O III] and Na ID profiles in almost all nuclear spectra, with line widths in the range [300 − 2000] km s−1, possibly associated with AGN- and SB-driven winds. This result reinforces previous findings that indicated that outflows are ubiquitous during the pre- and post-coalescence phases of major mergers.
Acceso Abierto
Physics of ULIRGs with MUSE and ALMA: The PUMA project II. Are local ULIRGs powered by AGN? The subkiloparsec view of the 220 GHz continuum
(EDP Sciences, 2021-07-12) Pereira Santaella, M.; Colina, L.; García Burillo, S.; Lamperti, I.; González Alfonso, E.; Perna, M.; Arribas, S.; Alonso Herrero, A.; Aalto, S.; Combes, F.; Labiano, Á.; Piqueras López, J.; Rigopoulou, D.; Van der Werf, P. P.; Comunidad de Madrid; Agencia Estatal de Investigación (AEI); Science and Technology Facilities Council (STFC); Pereira Santaella, M. [0000-0002-4005-9619]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We analyze new high-resolution (400 pc) ∼220 GHz continuum and CO(2–1) Atacama Large Millimeter Array (ALMA) observations of a representative sample of 23 local (z < 0.165) ultra-luminous infrared systems (ULIRGs; 34 individual nuclei) as part of the “Physics of ULIRGs with MUSE and ALMA” (PUMA) project. The deconvolved half-light radii of the ∼220 GHz continuum sources, rcont, are between < 60 pc and 350 pc (median 80–100 pc). We associate these regions with the regions emitting the bulk of the infrared luminosity (LIR). The good agreement, within a factor of 2, between the observed ∼220 GHz fluxes and the extrapolation of the infrared gray-body as well as the small contributions from synchrotron and free–free emission support this assumption. The cold molecular gas emission sizes, rCO, are between 60 and 700 pc and are similar in advanced mergers and early interacting systems. On average, rCO are ∼2.5 times larger than rcont. Using these measurements, we derived the nuclear LIR and cold molecular gas surface densities (ΣLIR = 1011.5 − 1014.3 L⊙ kpc−2 and ΣH2 = 102.9 − 104.2 M⊙ pc−2, respectively). Assuming that the LIR is produced by star formation, the median ΣLIR corresponds to ΣSFR = 2500 M⊙ yr−1 kpc−2. This ΣSFR implies extremely short depletion times, ΣH2/ΣSFR < 1–15 Myr, and unphysical star formation efficiencies > 1 for 70% of the sample. Therefore, this favors the presence of an obscured active galactic nucleus (AGN) in these objects that could dominate the LIR. We also classify the ULIRG nuclei in two groups: (a) compact nuclei (rcont < 120 pc) with high mid-infrared excess emission (ΔL6−20 μm/LIR) found in optically classified AGN; and (b) nuclei following a relation with decreasing ΔL6−20 μm/LIR for decreasing rcont. The majority, 60%, of the nuclei in interacting systems lie in the low-rcont end (<120 pc) of this relation, while this is the case for only 30% of the mergers. This suggests that in the early stages of the interaction, the activity occurs in a very compact and dust-obscured region while, in more advanced merger stages, the activity is more extended, unless an optically detected AGN is present. Approximately two-thirds of the nuclei have nuclear radiation pressures above the Eddington limit. This is consistent with the ubiquitous detection of massive outflows in local ULIRGs and supports the importance of the radiation pressure in the outflow launching process.
Restringido
Predicting the observability of population III stars with ELT-HARMONI via the helium 1640 Å emission line
(Oxford Academics: Oxford University Press, 2021-01-08) Grisdale, K.; Thatte, N.; Devriendt, J.; Pereira Santaella, M.; Slyz, A.; Kimm, T.; Dubois, Y.; Yi, S. K.; Science and Technology Facilities Council (STFC); National Research Foundation of Korea (NRF); 0000-0003-0375-5997
Population III (Pop. III) stars, as of yet, have not been detected, however as we move into the era of extremely large telescopes this is likely to change. One likely tracer for Pop. III stars is the He IIλ1640 emission line, which will be detectable by the HARMONI spectrograph on the European Extremely Large Telescope (ELT) over a broad range of redshifts (2 ≤ z ≤ 14). By post-processing galaxies from the cosmological, AMR-hydrodynamical simulation NEWHORIZON with theoretical spectral energy distributions (SED) for Pop. III stars and radiative transfer (i.e. the Yggdrasil Models and CLOUDY look-up tables, respectively) we are able to compute the flux of He IIλ1640 for individual galaxies. From mock 10 h observations of these galaxies we show that HARMONI will be able to detect Pop. III stars in galaxies up to z ∼ 10 provided Pop. III stars have a top heavy initial mass function (IMF). Furthermore, we find that should Pop. III stars instead have an IMF similar to those of the Pop. I stars, the He IIλ1640 line would only be observable for galaxies with Pop. III stellar masses in excess of 107M⊙⁠, average stellar age <1Myr at z = 4. Finally, we are able to determine the minimal intrinsic flux required for HARMONI to detect Pop. III stars in a galaxy up to z = 10.
Acceso Abierto
Searching for molecular gas inflows and outflows in the nuclear regions of five Seyfert galaxies.
(EDP Sciences, 2020-11-13) Domínguez Fernández, A. J.; Alonso Herrero, A.; García Burillo, S.; Davies, R. I.; Usero, A.; Labiano, Á.; Levenson, N. A.; Pereira Santaella, M.; Imanishi, M.; Ramos Almeida, C.; Rigopoulou, D.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Comunidad de Madrid; Science and Technology Facilities Council (STFC); Ramos Almeida, C. [https://orcid.org/0000-0001-8353-649X]; Davies, R. [https://orcid.org/0000-0003-4949-7217]; Alonso Herrero, A. [https://orcid.org/0000-0001-6794-2519]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Active galactic nucleus (AGN) driven outflows are believed to play an important role in regulating the growth of galaxies, mostly via negative feedback. However, their effects on their hosts are far from clear, especially for low- and moderate-luminosity Seyferts. To investigate this issue, we obtained cold molecular gas observations, traced by the CO(2-1) transition, using the NOEMA interferometer of five nearby (distances between 19 and 58 Mpc) Seyfert galaxies. The resolution of ∼0.3–0.8 (∼30–100 pc) and field of view of NOEMA allowed us to study the CO(2-1) morphology and kinematics in the nuclear regions (∼100 pc) and up to radial distances of ∼900 pc. We detected CO(2-1) emission in all five galaxies with disky or circumnuclear ring-like morphologies. We derived cold molecular gas masses on nuclear (∼100 pc) and circumnuclear (∼650 pc) scales in the range from 106 to 107 M⊙ and from 107 to 108 M⊙, respectively. In all of our galaxies, the bulk of this gas is rotating in the plane of the galaxy. However, noncircular motions are also present. In NGC 4253, NGC 4388, and NGC 7465, we can ascribe the streaming motions to the presence of a large-scale bar. In Mrk 1066 and NGC 4388, the noncircular motions in the nuclear regions are explained as outflowing material due to the interaction of the AGN wind with molecular gas in the galaxy disk. We conclude that for an unambiguous and precise interpretation of the kinematics of the cold molecular gas, we need detailed knowledge of the host galaxy (i.e., presence of bars, interactions, etc.), and also of the ionized gas kinematics and ionization cone geometry.
Restringido
Simulating gas kinematic studies of high-redshift galaxies with the HARMONI integral field spectrograph.
(Oxford Academics: Oxford University Press, 2020-09-07) Richardson, M. L. A.; Routledge, L.; Thatte, N.; Tecza, M.; Houghton, R. C. W.; Pereira Santaella, M.; Rigopoulou, D.; Science and Technology Facilities Council (STFC); Comunidad de Madrid
We present simulated observations of gas kinematics in a galaxy formed in a 10 pc resolution cosmological simulation with the hydrodynamical + N-body code RAMSES, using the new RAMSES2HSIM pipeline with the simulated observing pipeline (HSIM) for the Extremely Large Telescope High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI IFS). We post-process the galaxy's gas kinematics and Hα line emission for each simulation cell, and integrate the emission to produce an extinction-corrected input cube. We then simulate observations of the input cube with HARMONI, for a range of exposure times, spatial sampling, and spectral resolution. We analyse the mock observations to recover galaxy properties such as its kinematics and compare with the known simulation values. We investigate the cause of biases between the ‘real’ and ‘observed’ kinematic values, demonstrating the sensitivity of the inferred rotation curve to knowledge of the instrument’s point spread function.
Restringido
The properties of polycyclic aromatic hydrocarbons in galaxies: constraints on PAH sizes, charge and radiation fields
(Oxford Academics: Oxford University Press, 2021-04-12) Rigopoulou, D.; Barale, M.; Clary, D. C.; Shan, X.; Alonso Herrero, A.; García Bernete, I.; Hunt, L.; Berkeni, B.; Pereira Santaella, M.; Roche, P. F.; Science and Technology Facilities Council (STFC); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Based on theoretical spectra computed using Density Functional Theory we study the properties of polycyclic aromatic hydrocarbons (PAH). In particular using bin-average spectra of PAH molecules with varying number of carbons we investigate how the intensity of the mid-infrared emission bands, 3.3, 6.2, 7.7, and 11.3 μm, respond to changes in the number of carbons, charge of the molecule, and the hardness of the radiation field that impinges the molecule. We confirm that the 6.2/7.7 band ratio is a good predictor for the size of the PAH molecule (based on the number of carbons present). We also investigate the efficacy of the 11.3/3.3 ratio to trace the size of PAH molecules and note the dependence of this ratio on the hardness of the radiation field. While the ratio can potentially also be used to trace PAH molecular size, a better understanding of the impact of the underlying radiation field on the 3.3 μm feature and the effect of the extinction on the ratio should be evaluated. The newly developed diagnostics are compared to band ratios measured in a variety of galaxies observed with the Infrared Spectrograph on board the Spitzer Space Telescope. We demonstrate that the band ratios can be used to probe the conditions of the interstellar medium in galaxies and differentiate between environments encountered in normal star forming galaxies and active galactic nuclei. Our work highlights the immense potential that PAH observations with the James Webb Space Telescope will have on our understanding of the PAH emission itself and of the physical conditions in galaxies near and far.