arXiv subjects

M. Pereira-Santaella

Publications and source records attributed to M. Pereira-Santaella.

At least 19 recordsLinked to original sources

arXiv2026

Wild is the wind from low-luminosity AGN: A jet-driven gas bubble blowing out a massive CO-dark outflow in ESO 420-G13

We present JWST/MIRI mid-infrared integral field spectroscopy combined with ALMA CO(2-1) observations of the post-starburst galaxy ESO 420-G13, hosting a low-luminosity AGN. The unprecedented spatial and spectral resolution of MIRI enables a detailed study of the molecular and ionised gas kinematics, excitation, and energetics in the nuclear kiloparsec, revealing the impact of AGN feedback in a system with modest radiative output. Despite its faint radio and X-ray emission ($L_{2-10keV} \sim 10^{40}$ erg/s), ESO 420-G13 exhibits powerful kinetic feedback in the form of massive molecular and ionised gas outflows, with a total kinetic power of $\sim 1.4 \times 10^{41}$ erg/s. This corresponds to a jet-ISM coupling efficiency of ~3.8%, within the range observed in more powerful AGN. The feedback is driven by a previously undetected compact jet, traced by collimated coronal-line and extended X-ray emission to >870 pc from the nucleus. The interaction is strongest ~370 pc north of the nucleus, where a fast ionised gas stream emerges perpendicular to the jet axis, coinciding with a bend in the jet direction. Enhanced velocity dispersion in warm H$_2$ surrounds this gas stream, consistent with an expanding molecular bubble. Massive molecular outflows are detected at its edges; the blueshifted outflow is devoid of CO emission, likely due to CO destruction in shocks or by cosmic rays from the jet-ISM interaction. About 5% of the central molecular reservoir has already been expelled, and the remaining gas is turbulent and warm, suggesting an ongoing phase of AGN-driven feedback in this post-starburst galaxy. Our results highlight the enormous potential of mid-IR imaging spectroscopy to uncover jet-driven feedback in low-luminosity AGN. Without the spatially resolved MIRI diagnostics, the kinetic power of the AGN in ESO 420-G13 and its role in shaping the host galaxy ISM would have remained hidden.

astro-ph.GA↗

arXiv2026

Extended coronal line emission and new clues to a possible dual AGN in the merger J1356+1026

Merging luminous galaxies are ideal laboratories to study some of the most extreme astrophysical phenomena. The local (z=0.1232) obscured quasar J1356+1026 has two nuclei, North and South (J1356N and J1356S), but despite numerous efforts, J1356S had not yet been confirmed as an AGN. Thanks to the superb sensitivity and spatial resolution of the MIRI/MRS instrument on board the JWST, we present new evidence suggesting that J1356S may indeed host an AGN with log L$_{\rm bol}=43.4\pm^{0.6}_{0.5} erg s^{-1}$. This is supported by the detection of strong coronal line emission at this location and by a spectral shape that differs from that of J1356N and those of the narrow-line region (NLR). Aided by the spatially resolved information of MIRI/MRS and VLT/SINFONI, we also find that the high ionization gas, traced by the coronal lines [Ne V]$14.3~μ$m and [Si VI]$1.963 μ$m, has an extension of ~13-15.5 kpc. This is likely a lower limit of the true extension, as suggested by the comparison with optical imaging from HST. {The extended [Ne V] emission can be accounted for by photoionization from the quasar in J1356N in a relatively low density environment, ranging from $\rm n_e\leq 2000-3800 cm^{-3}$ in J1356N and $\rm n_e\leq 600-1200 cm^{-3}$ in J1356S and the NLR, as measured from the [Ne V]$14.3μ$m and $24.3~μ$m lines.

astro-ph.GA↗

arXiv2026

The Galaxy Activity, Torus, and Outflow Survey (GATOS): N. Unveiling physical processes in local active galaxies. Unsupervised hierarchical clustering of JWST MIRI/MRS observations

With the rise of the integral field spectroscopy, we are currently dealing with large amounts of spatially resolved data, whose analysis has become challenging, especially when observing complex objects such as nearby galaxies. We aim to develop a method to automatically separate different physical regions within the central parts (1"~160 pc, on average) of galaxies. This can allow us to better understand the systems, and provide an initial characterisation of the main ionisation sources affecting its evolution. We have developed an unsupervised hierarchical clustering algorithm to analyse data cubes based on spectral similarity. It clusters together spaxels with similar spectra, which is useful to disentangle between different physical processes. We have applied this method to a sample of 15 nearby (distances <100 Mpc) galaxies, 7 from the Galaxy Activity, Torus, and Outflow Survey (GATOS) and 8 archival sources, all observed with the medium resolution spectrometer (MRS) of the Mid-Infrared Instrument (MIRI) on board of the JWST. From the clusters, we computed their median spectrum and measured the line and continuum properties. We used these measurements to train random forest models and create several empirical mid-IR diagnostic diagrams for the MRS channel 3 wavelength range, including among others the bright [Ne II], [Ne III], and [Ne V] lines, several H2 transitions, and PAH features. The clustering technique allows to differentiate emission coming from an AGN, the disc, and star forming regions in galaxies, and other composite regions, potentially ionised by several sources simultaneously. This is supported by the results from the empirical diagnostic diagrams, that are indeed able to separate physically distinct regions. This innovative method serves as a tool to identify regions of interest in any data cube prior to an in-depth analysis of the sources. [abridged]

astro-ph.GA↗

arXiv2026

Abundant hydrocarbons in a buried galactic nucleus with signs of carbonaceous grain and polycyclic aromatic hydrocarbon processing

Hydrocarbons play a key role in shaping the chemistry of the interstellar medium (ISM), but their enrichment and relationship with carbonaceous grains and polycyclic aromatic hydrocarbons (PAHs) still lack clear observational constraints. We report JWST NIRSpec+MIRI/MRS infrared (IR; 3-28 micron) observations of the local ultra-luminous IR galaxy (ULIRG) IRAS 07251-0248, revealing the extragalactic detection of small gas-phase hydrocarbons such as benzene (C$_6$H$_6$), triacetylene (C$_6$H$_2$), diacetylene (C$_4$H$_2$), acetylene (C$_2$H$_2$), methane (CH$_4$), and methyl radical (CH$_3$) as well as deep amorphous C-H absorptions in the solid phase. The unexpectedly high abundance of these molecules indicates an extremely rich hydrocarbon chemistry, not explained by high-temperature gas-phase chemistry, ice desorption or oxygen depletion. Instead, the most plausible explanation is the erosion and fragmentation of carbonaceous grains and PAHs. This scenario is supported by the correlation between the abundance of one of their main fragmentation products, C$_2$H$_2$, and cosmic ray (CR) ionization rate for a sample of local ULIRGs. These hydrocarbons are outflowing at $\sim$160 km/s, which may represent a potential formation pathway for hydrogenated amorphous grains. Our results suggest that IRAS 07251-0248 might not be unique but represents an extreme example of the commonly rich hydrocarbon chemistry prevalent in deeply obscured galactic nuclei.

astro-ph.GA↗

arXiv2026

Spatially Resolved Star Formation relations in local LIRGs along the complete merger sequence

We investigate the properties of the interstellar medium (ISM) at ~100 pc scales in a sample of 27 nearby luminous infrared galaxies (LIRGs) spanning the entire merger sequence. In particular, we study the relations between star-formation (SF) and molecular gas surface density as a function of the interaction stage using two complementary approaches: beam-sized (unresolved, line-of-sight) regions and physically identified molecular gas clumps. To map the distribution of molecular gas we use ALMA CO(2-1) observations, while SF is traced using HST Pa-alpha or Pa-beta images. We derive spatially resolved Kennicutt-Schmidt (KS) relations for each galaxy. When using beam-sized regions, we find that 67% of galaxies follow a single relation between Sigma_SFR and Sigma_H2. However, in the remaining galaxies, the relation splits into two branches, indicating the presence of a duality in this relation. In contrast, when using physical gas clumps, the duality disappears and all galaxies show a single trend. We also study other ISM/clump properties as a function of the merger stage. We find that isolated galaxies and systems in early stages of interaction exhibit lower amounts of gas and SF. As the merger progresses, however, the amount of gas in the central kpc of the galaxy undergoing the merger increases, along with the SFR, and the slope of the KS relation becomes steeper, indicating an increase in SF efficiency of the gas clumps. Clumps in late-stage mergers are predominantly located at small distances from the nucleus, confirming that most of the activity is concentrated in the central regions. Finally, the relation between the SF efficiency and the boundedness parameter evolves from being roughly flat in the early stages of the merger to becoming positive in the final phases, indicating that clump self-gravity only starts to regulate the SF process between the early- and mid-merger stages.

astro-ph.GA↗

arXiv2025

Silicate emission in a type-2 quasar: JWST/MIRI constraints on torus geometry and radiative feedback

Type-2 quasars (QSO2s) are AGN seen through a significant amount of dust and gas that obscures the central supermassive black hole and the broad line region. Despite this, recent mid-infrared spectra of the central 0.5-1.1 kpc of five QSO2s at z~0.1, obtained with the MRS module of JWST/MIRI, revealed 9.7, 18, and 23 micron silicate features in emission in two of them. This indicates that the high angular resolution of JWST/MIRI now allows us to peer into their nuclear region, exposing some of the directly illuminated dusty clouds that produce silicate emission. To test this, we fitted the nuclear mid-infrared spectrum of the QSO2 with the strongest silicate features, J1010, with two different sets of torus models implemented in an updated version of the Bayesian tool {\tt BayesClumpy}. These are the CLUMPY and the CAT3D-WIND models. The CAT3D-WIND model is preferred by the observations based on the marginal likelihood and fit residuals, although the two torus models successfully reproduce the spectrum by means of intermediate covering factors ($\rm C_T=0.45\pm^{0.26}_{0.18}$ and $\rm C_T=0.66\pm^{0.16}_{0.17}$ for the CLUMPY and CAT3D-WIND models) and low inclinations ($\rm i=50^\circ\pm^{8^\circ}_{9^\circ}$ and $\rm i=13^\circ\pm^{7^\circ}_{6^\circ}$). Indeed, four of the five QSO2s with JWST/MIRI observations, including J1010, are in the blowout or ''forbidden'' region of the Eddington ratio-column density diagram, indicating that they are actively clearing gas and dust from their nuclear regions, leading to reduced covering factors. This is in contrast with Seyfert 2 galaxies observed with JWST, which are in the ''permitted'' regions of the diagram and show 9.7 micron silicate features in absorption. This supports a scenario where the more luminous the AGN and the higher their Eddington ratio, the lower the torus covering factor, driven by radiation pressure on dusty gas.

astro-ph.GA↗

arXiv2025

The PAH 3.4 micron feature as a tracer of shielding in the Orion Bar and NGC 6240

We have carried out a detailed analysis of the 3.4 micron spectral feature arising from Polycyclic Aromatic Hydrocarbons (PAH), using JWST archival data. For the first time in an external galaxy (NGC 6240), we have identified two distinct spectral components of the PAH 3.4 micron feature: a shorter wavelength component at 3.395 micron, which we attribute to short aliphatic chains tightly attached to the aromatic rings of the PAH molecules; and a longer wavelength feature at 3.405 microns that arises from longer, more fragile, aliphatic chains that are weakly attached to the parent PAH molecule. These longer chains are more easily destroyed by far-ultraviolet photons (>5eV) and PAH thermal emission only occurs where PAH molecules are shielded from more energetic photons by dense molecular gas. We see a very strong correlation in the morphology of the PAH 3.395 micron feature with the PAH 3.3 micron emission, the latter arising from robust aromatic PAH molecules. We also see an equally strong correlation between the PAH 3.405 micron morphology and the warm molecular gas, as traced by H2 vibrational lines. We show that the flux ratio PAH_3.395/PAH_3.405 < 0.3 corresponds strongly to regions where the PAH molecules are shielded by dense molecular gas, so that only modestly energetic UV photons penetrate to excite the PAHs. Our work shows that PAH 3.405 micron and PAH 3.395 micron emission features can provide robust diagnostics of the physical conditions of the interstellar medium in external galaxies, and can be used to quantify the energies of the photon field penetrating molecular clouds.

astro-ph.GA↗

arXiv2025

JWST reveals cosmic ray dominated chemistry in the local ULIRG IRAS 07251$-$0248

We analyse the ro-vibrational absorption bands of various molecular cations (HCO$^+$, HCNH$^+$, and N$_2$H$^+$) and neutral species (HCN, HNC, and HC$_3$N) detected in the \textit{James Webb Space Telescope}/Mid-Infrared Instrument Medium Resolution Spectrometer spectrum (4.9--27.9\,$\upmu$m) of the local ultra luminous infrared galaxy IRAS~07251$-$0248. We find that the molecular absorptions are blueshifted by 160\,km\,s$^{-1}$ relative to the systemic velocity of the target. Using local thermal equilibrium (LTE) excitation models, we derive rotational temperatures ($T_{\rm rot}$) from 42 to 185\,K for these absorption bands. This range of measured $T_{\rm rot}$ can be explained by infrared (IR) radiative pumping as a by--product of the strength, effective critical density, and opacity of each molecular band. Thus, these results suggest that these absorptions originate in a warm expanding gas shell ($\dot{M}$$\sim$90--330\,$M_\odot$\,yr$^{-1}$), which might be the base of the larger scale cold molecular outflow detected in this source. Finally, the elevated abundance of molecular cations can be explained by a high cosmic ray ionization rate, with log($ζ_{\text{H}_2}$/n$_{\rm H}\, [\text{cm}^3\, \text{s}^{-1}])$ in the range of $-$18.2 (from H$_3^+$) to $-$19.1 (inferred from HCO$^+$ and N$_2$H$^+$, which are likely tracing denser gas), consistent with a cosmic ray dominated chemistry as predicted by chemical models.

astro-ph.GA↗

arXiv2025

Low D/H ratio for benzonitrile in TMC-1: Implication for the origin of polycyclic aromatic hydrocarbons in cold dark clouds

Radioastronomical observations have recently discovered PAHs of moderate size (up to 24 carbon atoms) in cold dark clouds, although it is currently unknown whether they are formed in situ through a bottom-up mechanism or from larger PAHs (20-100 carbon atoms) inherited from a previous diffuse stage in a top-down scenario. Infrared observations have recently shown that large PAHs present in UV-illuminated regions are strongly enriched in deuterium. In order to shed light on the origin of PAHs in cold clouds, we have searched for deuterated benzonitrile in the cold dark cloud TMC-1. To that purpose we have synthesized the three isomers (ortho, meta, and para) of monodeuterated benzonitrile, measured their rotational spectra across the 2-18 GHz and 75-110 GHz frequency ranges in the laboratory, and searched for them in TMC-1 using data from the QUIJOTE line survey. We did not detect any of the three species and have derived a 3sigma upper limit on the column density of each of them of 3.0e10 cm-2, meaning a fractional abundance relative to H2 of <3e-12. We derived a D/H ratio (which we define as the total number of D atoms with respect to the total number of H atoms present in benzonitrile) of <1.2 %. This value is in line with the range of D/H ratios observed for other molecules in TMC-1 (0.06-3.3 %), where deuterium enrichment is explained in terms of isotopic fractionation at low temperature. It is however below the range of D/H ratios derived for large unspecific PAHs from JWST observations of the galactic PDRs Orion Bar and M17 and the galaxies M51 and NGC3256-S (between 1% and <17%). Although it is not straightforward to compare the deuteration of PAHs in dark and UV-irradiated clouds, our results suggest that the population of PAHs detected in cold dark clouds does not result from the fragmentation of larger PAHs inherited from the previous diffuse stage in a top-down scenario.

astro-ph.GA↗

arXiv2025

Millimeter emission from supermassive black hole coronae

Active Galactic Nuclei (AGN) host accreting supermassive black holes (SMBHs). The accretion can lead to the formation of a hot, X-ray emitting corona close to the SMBH capable of accelerating relativistic electrons. Observations in the millimetre (mm) band can probe its synchrotron emission. We provide a framework to derive physical information of SMBH coronae by modelling their spectral energy distribution (SED) from radio to far infrared frequencies. We also explore the possibilities of deriving additional information from mm observations, such as the SMBH mass, and studying high-redshift lensed sources. We introduce a corona emission model based on a one-zone spherical region with a hybrid thermal and non-thermal plasma. We investigate in detail how the corona SED depends on different parameters such as size, opacity, and magnetic field strength. Other galactic emission components from dust, ionised gas and diffuse relativistic electrons are also included in the SED fitting scheme. We apply our code consistently to a sample of radio-quiet AGN with strong indications of a coronal component in the mm. The detected mm emission from SMBH coronae is consistent with having a non-thermal relativistic particle population with an energy density that is ~0.5-10% of that in the thermal plasma. This requires magnetic energy densities close to equipartition with the thermal gas, and corona sizes of 60-250 gravitational radii. The model can also reproduce the observed correlation between mm emission and SMBH mass when accounting for uncertainties in the corona size. The mm band offers a unique window into the physics of SMBH coronae, enabling the study of highly dust-obscured sources and high-redshift lensed quasars. Gaining a deeper understanding of the relativistic particle population in SMBH coronae can provide key insights into their potential multiwavelength and neutrino emission.

astro-ph.HE↗

arXiv2025

Molecular gas excitation and outflow properties of obscured quasars at z$\sim$0.1

To investigate the impact of winds and low-to-moderate power jets on the cold molecular gas reservoirs of AGN, we present high angular resolution ALMA CO(2-1) and CO(3-2) observations of a sample of six type-2 quasars (QSO2s) at z$\sim$0.1 from the Quasar Feedback (QSOFEED) sample. Spatially resolved molecular line ratio maps, defined as $R_{32}=L'_{CO(3-2)}/L'_{CO(2-1)}$, and kinematic modelling were used to constrain changes in gas excitation and to identify gas outflows, respectively. We find that the molecular outflows are co-spatial with regions with $R_{32}$>1, indicating enhanced temperature relative to the discs and the presence of optically thin gas in the outflows. We find mass outflow rates of 5$<\dot{M}_{out}<$150$M_\odot$/yr, much lower than those expected from their AGN luminosities of $10^{45.5-46}$erg/s. The outflow kinetic energies might be driven by the combined action of jets and winds/radiation pressure, with radiative coupling efficiencies ($ε_{AGN}=\dot{E}_{out}/L_{bol}$) ranging from $10^{-6}<ε_{AGN}<10^{-4}$ and jet coupling efficiencies ($ε_{jet}=\dot{E}_{out}/P_{jet}$) from $10^{-3}<ε_{AGN}<10^{-2}$. A linear regression including the six QSO2s follows the locus of $ε_{jet}\sim$0.1\%. Our results provide evidence that AGN-driven jets/winds disturb the molecular gas kinematics and excitation within the central kpc of the galaxies. The coupling between compact jets and the ISM might be relevant to AGN feedback, even in the case of radio-quiet galaxies, which are more representative of the AGN population. Finally, we find that the warm and cold molecular gas phases seem to be tracing the same outflow, with the main distinction between them being the mass they carry, while the warm ionized outflows do not seem to be another face of the same outflow, as they show different orientation, velocity, and radius.

astro-ph.GA↗

arXiv2025

JWST MIRI reveals the diversity of nuclear mid-infrared spectra of nearby type-2 quasars

Type-2 quasars (QSO2s) are active galactic nuclei (AGN) seen through a significant amount of dust and gas that obscures the central supermassive black hole and the broad line region. Here we present new mid-infrared spectra of the central kiloparsec of five optically-selected QSO2s at redshift z~0.1 obtained with JWST/MIRI/MRS. These QSO2s belong to the QSOFEED sample and they have log Lbol=45.5-46.0 erg/s, global SFRs that place them above the main sequence, and practically identical optical spectral shape and [OIII] luminosity, but their nuclear mid-infrared spectra exhibit an unexpected diversity of both continua and features. They show: 1) 9.7 micron silicate features going from emission (strength of S9.7=0.5) to relatively strong absorption (S9.7=-1.0) and 18 and 23 micron silicates either in emission or flat. In addition, two of the QSO2s show absorption bands of CO, H2O, and aliphatic grains, indicating different levels of nuclear obscuration across the sample. 2) [NeV]/[NeII] ratios ranging from 0.1 to 2.1 and [NeIII]/[NeII] from 1.0 to 3.5, indicating different coronal line and ionizing continuum strengths. 3) Warm molecular gas masses of 1-4x10^7 Msun and warm-to-cold gas mass ratios of 1-2%, with molecular gas excitation likely due to jet-induced shocks in J1430+1339, and to UV heating and/or turbulence in J1509+0434. 4) PAH emission features with equivalent widths ranging from <0.002 to 0.075 micron, from which we measure a larger contribution from neutral molecules (PAH 11.3/6.2=1.3-3.4) and SFRs<3-7 Msun/yr. This unprecedented dataset allowed us to start exploring the role of various AGN and galaxy properties including ionizing continuum, obscuration, electron density, and jet-ISM interactions on some of the spectral differences listed above, but larger samples are now required to fully understand the diversity of QSO2s' nuclear mid-infrared spectra.

astro-ph.GA↗

arXiv2025

On unveiling Buried Nuclei with JWST: a technique for hunting the most obscured galaxy nuclei from local to high redshift

We analyze JWST NIRSpec+MIRI/MRS observations of the infrared (IR) Polycyclic Aromatic Hydrocarbon (PAH) features in the central regions ($\sim$0.26'' at 6 micron; $\sim$50-440 pc depending on the source) of local luminous IR galaxies. In this work, we examine the effect of nuclear obscuration on the PAH features of deeply obscured nuclei, predominantly found in local luminous IR galaxies, and we compare these nuclei with ``normal'' star-forming regions. We extend previous work to include shorter wavelength PAH ratios now available with the NIRSpec+MIRI/MRS spectral range. We introduce a new diagnostic diagram for selecting deeply obscured nuclei based on the 3.3 and 6.2 micron PAH features and/or mid-IR continuum ratios at $\sim$3 and 5 micron. We find that the PAH equivalent width (EW) ratio of the brightest PAH features at shorter wavelengths (at 3.3 and 6.2 micron) is impacted by nuclear obscuration. Although the sample of luminous IR galaxies used in this analysis is relatively small, we find that sources exhibiting a high silicate absorption feature cluster tightly in a specific region of the diagram, whereas star-forming regions experiencing lower extinction levels occupy a different area in the diagram. This demonstrates the potential of this technique to identify buried nuclei. To leverage the excellent sensitivity of the MIRI imager onboard JWST, we extend our method of identifying deeply obscured nuclei at higher redshifts using a selection of MIRI filters. Specifically, the combination of various MIRI JWST filters enables the identification of buried sources beyond the local Universe and up to z$\sim$3, where other commonly used obscuration tracers such as the 9.7 micron silicate band, are out of the spectral range of MRS. Our results pave the way for identifying distant deeply obscured nuclei with JWST.

astro-ph.GA↗

arXiv2024

The Galaxy Activity, Torus, and Outflow Survey (GATOS). Black hole mass estimation using machine learning

The detailed feeding and feedback mechanisms of Active Galactic Nuclei (AGN) are not yet well known. For low-luminosity and obscured AGN, as well as late-type galaxies, determining the central black hole (BH) masses is challenging. Our goal with the GATOS sample is to study circum-nuclear regions and better estimate BH masses with more precision than scaling relations offer. Using ALMA's high spatial resolution, we resolve CO(3-2) emissions within ~100 pc around the supermassive black hole (SMBH) in seven GATOS galaxies to estimate their BH masses when sufficient gas is present. We study seven bright ($L_{AGN}(14-150\mathrm{keV}) \geq 10^{42}\mathrm{erg/s}$), nearby (<28 Mpc) galaxies from the GATOS core sample. For comparison, we searched the literature for previous BH mass estimates and made additional calculations using the \mbh~ - $σ$ relation and the fundamental plane of BH activity. We developed a supervised machine learning method to estimate BH masses from position-velocity diagrams or first-moment maps using ALMA CO(3-2) observations. Numerical simulations with a wide range of parameters created the training, validation, and test sets. Seven galaxies provided enough gas for BH mass estimations: NGC4388, NGC5506, NGC5643, NGC6300, NGC7314, NGC7465, and NGC~7582. Our BH masses, ranging from 6.39 to 7.18 log$(M_{BH}/M_\odot)$, align with previous estimates. Additionally, our machine learning method provides robust error estimations with confidence intervals and offers greater potential than scaling relations. This work is a first step toward an automated \mbh estimation method using machine learning.

astro-ph.GA↗

arXiv2024

JWST/NIRSpec insights into the circumnuclear region of Arp 220: A detailed kinematic study

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.

astro-ph.GA↗

arXiv2024

Molecular gas stratification and disturbed kinematics in the Seyfert galaxy MCG-05-23-16 revealed by JWST and ALMA

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 obtained with the James Webb Space Telescope (JWST) and 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 $\sim$ 160 km/s), in regions devoid of CO(2$-$1). The kinematics of one of these clumps, located at $\sim$ 350 pc westward from the nucleus, are consistent with outflowing gas, possibly driven by localized star formation traced by Polycyclic Aromatic Hydrocarbon (PAH) emission at 11.3 $μ$m. Overall, we observe a stratification of the molecular gas, with the colder gas located in the nuclear spiral, ring, and connecting arms, while most warmer gas with higher velocity-dispersion fills 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 disc.

astro-ph.GA↗

arXiv2024

AGN feeding along a one-armed spiral in NGC 4593: A study using ALMA CO(2-1) observations

We investigate active galactic nuclei (AGN) feeding through the molecular gas (CO(2-1) emission) properties of the local Seyfert 1 galaxy NGC 4593, using Atacama Large Millimeter Array (ALMA) observations and other multi-wavelength data. Our study aims to understand the interplay between the AGN and the interstellar medium (ISM) in this galaxy, examining the role of the AGN in steering gas dynamics within its host galaxy, evaluating the energy injected into the ISM, and determining whether gas is inflowing or outflowing from the galaxy. After reducing the ALMA CO(2-1) images, we employed two models, 3D-Barolo and DISCFIT, to construct a disc model and fit its emission to the ALMA data. Additionally, we used photometric data to build a spectral energy distribution (SED) and applied the CIGALE code to derive key physical properties of the AGN and its host. Our analysis reveals a complex interplay within NGC 4593, including a clear rotational pattern, the influence of a non-axisymmetric bar potential, and a central molecular zone (CMZ)-like ring. We observe an outflow of CO(2-1) gas along the minor axis, at a distance of approximately 220 pc from the nucleus. The total molecular gas mass is estimated to be between $1 - 5 \times 10^8 \, M_{\odot}$, with non-circular motions contributing about 10\%. Our SED analysis indicates an AGN fraction of 0.88 and a star formation rate (SFR) of 0.42 $M_{\odot} \, \text{yr}^{-1}$. These findings highlight the complex dynamics in the centre of NGC 4593, which are significantly influenced by the presence of the AGN. The overall physical properties of this system suggest that the AGN has a substantial impact on the evolution of NGC 4593.

astro-ph.GA↗

arXiv2024

A biconical ionised gas outflow and evidence for positive feedback in NGC 7172 uncovered by MIRI/JWST

We present observations of the type-2 Seyfert NGC7172 obtained with the medium-resolution spectrometer (MRS) of the Mid-Infrared Instrument (MIRI) on board of the JWST. This galaxy hosts one of the lowest ionised gas mass outflow rates (Mout~0.005 M/yr) in a sample of six AGN with similar bolometric luminosities (log Lbol~44erg/s) within the Galactic Activity, Torus and Outflow Survey (GATOS). We aim to understand the properties of the ionised gas outflow, mainly using the emission lines from the neon transitions, that cover a broad range of ionisation potentials (IP) from ~20 eV to ~130 eV. We applied parametric and non-parametric methods to characterise the line emission and kinematics. The low excitation lines (IP<25eV, e.g.[NeII]) trace the rotating disc emission. The high excitation lines (IP>90eV, e.g.[NeV]), which are likely photoionised exclusively by the AGN, are expanding in the direction nearly perpendicular to the disc of the galaxy, with maximum projected velocities of ~350-500 km/s. In particular, [NeV] and [NeVI] lines reveal a biconical ionised gas outflow emerging N-S from the nuclear region, extending at least ~2.5"N and 3.8"S (projected distance of ~450 and 680 pc). Most of the emission arising in the northern part of the cone was not previously detected due to obscuration. Given the almost face-on orientation of the outflow and the almost edge-on orientation of the galaxy, NGC7172 may be a case of weak coupling. Nevertheless, we found evidence for positive feedback in two distinct outflowing clumps at projected distances of 3.1" and 4.3" (i.e. ~560 and 780 pc) SW from the AGN. We estimated a star formation rate in these regions using the [NeII] and [NeIII] luminosities of 0.08 M/yr, that is ~10% of that found in the circumnuclear ring. The star formation activity might have been triggered by the interaction between the ionised gas outflow and the ISM of the galaxy.

astro-ph.GA↗