arXiv subjects

Thaisa Storchi-Bergmann

Publications and source records attributed to Thaisa Storchi-Bergmann.

At least 19 recordsLinked to original sources

arXiv2026

Blowing star formation away in AGN hosts (BAH) -- V: The Feeding-Feedback Cycle in local AGNs as revealed by their stellar populations

We present a spatially resolved analysis of the stellar populations in the inner kiloparsec of NGC 3884, 3C 293, and CGCG 012-070. Using near-infrared spectroscopy, we reconstruct their star formation histories (SFHs) by comparing the M13, XSL, and FSPS stellar population synthesis models. The stellar light is dominated by intermediate-age to old populations (t >= 1 Gyr) with super-solar metallicities (Z >= 1 Z_sun). All models clearly indicate recent star formation (rejuvenation) in these AGN hosts, with young to intermediate-age populations contributing significantly in the nuclear regions. The SFHs from M13 and XSL broadly agree in showing coexisting old and young components, whereas FSPS favours a larger fraction of very young (t < 50 Myr) stars. Moreover, XSL- and FSPS-based SFHs are generally more irregular and "bumpy," while M13 yields smoother, more continuous SFHs. In NGC 3884 and 3C 293, stars with 0.2 < t <= 0.7 Gyr form a ring-like structure around the nucleus. The nuclear spectra further require non-stellar components: a featureless power-law continuum (FC) and hot dust emission (HD). In 3C 293, the FC component appears in two spatially separated regions, possibly indicating a dual active galactic nucleus, though a heavily reddened starburst origin for the secondary component cannot be excluded. Nearly all fits show a central drop in stellar metallicity, consistent with inflow of metal-poor gas that fuels recent accretion and AGN activity. Radial profiles show that HD and FC contributions decrease with radius, while younger stellar populations become more prominent outward. Together, these results support a feeding-feedback scenario in which gas inflows trigger circumnuclear star formation and, via stellar mass loss, help sustain ongoing AGN activity. .

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arXiv2026

Jet-driven shocks and turbulence in radio-loud Active Galactic Nuclei observed with JWST MIRI/MRS

Jet-cloud interactions are a key manifestation of Active Galactic Nucleus (AGN) feedback on nuclear scales, distinct from the large-scale radio-mode feedback that suppresses gas cooling in galaxy halos. On these smaller scales, radio jets can inject energy and momentum into the interstellar medium (ISM), shaping the physical and kinematic properties of the nuclear and circumnuclear regions of galaxies. Using JWST MIRI/MRS observations of seven nearby radio-loud AGN (3C293, 3C305, Centaurus A, Cygnus A, IC5063, NGC1052, and M87), we investigate jet-driven turbulence in both the warm molecular and ionized gas phases. By combining spatially resolved H$_2$/PAH flux ratios with diagnostic line ratios of the ionized gas, we constrain the dominant H$_2$ excitation processes and assess the impact of radio jet--ISM interactions on the multiphase gas. We find that radio jets drive enhanced turbulence in both molecular and ionized (traced by [FeII], [NeII] and [NeIII] lines) gas, not only along but also perpendicular to the jet axis, indicating that jet--ISM interactions extend beyond the collimated jet channel and affect the nuclear environment. Strong correlations between the H$_2$/PAH ratio, the H$_2$ excitation temperature, and shock-sensitive ionized-gas tracers indicate that jet-driven shocks dominate the excitation of the H$_2$ rotational lines in most sources. These results indicate that radio jets are a key driver of multiphase ISM kinematics and excitation in nearby radio-loud galaxies.

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arXiv2026

AGN Variability with Rubin Observatory in the 2030s

AGN variability offers a direct probe of accretion physics, disk structure, and black hole growth, but progress has been limited by sample size, cadence heterogeneity, and photometric systematics. The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will deliver multi-band light curves for millions of AGN, enabling variability studies at a true population scale. We synthesize recent results from the Zwicky Transient Facility (ZTF), which demonstrate that optical variability amplitudes and timescales are primarily regulated by accretion state, with secondary dependence on black hole mass and redshift, and establish the feasibility of survey-driven continuum reverberation mapping. ZTF measurements reveal optical continuum-emitting region sizes that often exceed standard thin disk predictions, implicating diffuse continuum emission from the broad line region as a significant contributor to observed inter-band lags. We evaluate the implications of LSST cadence and survey strategy, particularly the deep drilling fields, for continuum and emission line reverberation mapping, changing-look AGN, extreme variability quasars, and periodic variability searches. Key limitations of broadband photometric variability are identified, including variable emission line contamination, diffuse BLR continuum emission, and cadence-dependent lag recoverability. We argue that realizing LSST's full scientific potential requires community-scale, standardized variability metric pipelines, probabilistic classification integrated with alert brokers for follow-up triggering, and complementary medium-band photometric observations to isolate the accretion disk continuum. Together, these elements will enable LSST to convert photometric variability into quantitative constraints on accretion disks, BLR structure, and supermassive black hole growth across cosmic time.

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arXiv2025

Blowing star formation away in AGN Hosts (BAH) -- IV: Feeding and feedback in 3C 293 observed with JWST NIRSpec

We use JWST/NIRSpec observations of the radio galaxy 3C 293 to map the emission, extinction, and kinematics of hot molecular and ionized gas, as well as stellar kinematics, within the inner ~ 2 kpc. The stellar velocity field is well described by a rotating disk model, with its kinematical center offset by ~ 0.5 arcsec from the continuum peak. The hot molecular gas is traced by the H$_2$2.12$μ$m emission line, and the ionized gas by [Fe II]1.64$μ$m and Pa$α$. The gas presents three main kinematic components: a rotating disk seen as a narrow component ($σ$ ~ 100 kms$^{-1}$); a blueshifted broad outflow ($σ$ ~ 250 kms$^{-1}$); and a fast ionized outflow as a very broad component ($σ$ ~ 640 kms$^{-1}$). Extinction maps reveal high A$_V$ values, up to ~ 35, spatially coincident with dust lanes seen in optical images. In addition to the disk and outflows components, inflows along the dust lanes are detected in H$_2$ gas, with a mass inflow rate of $\dot{M}_{in}$ ~ 4 x 10$^{-4}$ M$_{\odot}$ yr$^{-1}$, which is lower than the AGN accretion rate. For the outflows, we derive peak mass-outflow rates of 0.08 $\pm$ 0.02 M$_{\odot}$yr$^{-1}$ (molecular) and 6.5 $\pm$ 1.7 M$_{\odot}$yr$^{-1}$ (ionized). The outflow, driven by the radio jet, has a kinetic power of 5.7% of the jet power - enough to suppress star formation. Our results highlight 3C 293's turbulent post-merger history and JWST's unique capability to probe dust-obscured AGN.

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arXiv2025

NGC 6860, Mrk 915, and MCG -01-24-012. II. Inflowing and outflowing cold molecular gas and the connection with ionized gas in Seyfert galaxies

We present a study of the cold molecular gas kinematics in the inner ~ 4-7 kpc (projected sizes) of three nearby Seyfert galaxies, with AGN luminosities of ~ 10$^{44}$ erg/s, using observations of the CO(2-1) emission line, obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) at ~ 0.5-0.8$^{\prime\prime}$ (~ 150-400 pc) spatial resolutions. After modeling the CO profiles with multiple Gaussian components, we detected regions with double-peak profiles that exhibit kinematics distinct from the dominant rotational motion. In NGC 6860, a molecular outflow surrounding the bipolar emission of the [O III] ionized gas is observed extending up to $R_{out}$ ~ 560 pc from the nucleus. There is evidence of molecular inflows along the stellar bar, although an alternative scenario, involving a decoupled rotation in a circumnuclear disk (CND) can also explain the observed kinematics. Mrk 915 shows double-peak CO profiles along one of its spiral arms. Due to its ambiguous disk orientation, part of the CO emission can be interpreted as a molecular gas inflow or an outflow reaching $R_{out}$ ~ 2.8 kpc. MCG -01-24-012 has double-peak profiles associated with a CND, perpendicular to the [O III] bipolar emission. The CO in the CND is rotating while outflowing within $R_{out}$ ~ 3 kpc, with the disturbances possibly being caused by the passage of the ionized gas outflow. Overall, the mass inflow rates are larger than the accretion rate needed to produce the observed luminosities, suggesting that only a fraction of the inflowing gas ends up feeding the central black holes. Although we found signatures of AGN feedback on the cold molecular phase, the mass outflow rates of ~ 0.09-3 M$_\odot$/yr indicate an overall weak impact at these AGN luminosities. Nonetheless, we may be witnessing the start of the depletion and ejection of the molecular gas reservoir that has accumulated over time.

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arXiv2025

AGN STORM 2. XI. Spectroscopic reverberation mapping of the hot dust in Mrk 817

The AGN Space Telescope and Optical Reverberation Mapping 2 (STORM 2) campaign targeted Mrk 817 with intensive multi-wavelength monitoring and found its soft X-ray emission to be strongly absorbed. We present results from 157 near-IR spectra with an average cadence of a few days. Whereas the hot dust reverberation signal as tracked by the continuum flux does not have a clear response, we recover a dust reverberation radius of $\sim 90$ light-days from the blackbody dust temperature light-curve. This radius is consistent with previous photometric reverberation mapping results when Mrk 817 was in an unobscured state. The heating/cooling process we observe indicates that the inner limit of the dusty torus is set by a process other than sublimation, rendering it a luminosity-invariant `dusty wall' of a carbonaceous composition. Assuming thermal equilibrium for dust optically thick to the incident radiation, we derive a luminosity of $\sim 6 \times 10^{44}$ erg s$^{-1}$ for the source heating it. This luminosity is similar to that of the obscured spectral energy distribution, assuming a disk with an Eddington accretion rate of $\dot{m} \sim 0.2$. Alternatively, the dust is illuminated by an unobscured lower luminosity disk with $\dot{m} \sim 0.1$, which permits the UV/optical continuum lags in the high-obscuration state to be dominated by diffuse emission from the broad-line region. Finally, we find hot dust extended on scales $> 140-350$ pc, associated with the rotating disk of ionised gas we observe in spatially-resolved [SIII] $λ9531$ images. Its likely origin is in the compact bulge of the barred spiral host galaxy, where it is heated by a nuclear starburst.

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arXiv2025

Feeding frenzy in the mighty black holes: what we could learn from them?

Eddington ratio is a paramount parameter governing the accretion history and life cycles of Active Galactic Nuclei (AGNs). This short review presents a multi-faceted view of the importance of the Eddington ratio spanning varied AGN studies. We find that the Eddington ratio is crucial for standardizing the Radius-Luminosity (R-L) relation - a necessary step for employing quasars (QSOs) as standardizable cosmological probes to help clarify the standing of the Hubble tension. In this data-driven era, we consolidated disparate aspects by developing novel relations borne out of large datasets, such as the robust, nearly universal anti-correlation between fractional variability and Eddington ratio derived from Zwicky Transient Facility (ZTF) data, which is vital for interpreting forthcoming high-cadence surveys like Rubin Observatory's LSST. Addressing the conundrum where JWST results suggest an overabundance of massive high-redshift black holes, we demonstrate that local AGNs offer clarification: Changing-Look AGNs (CLAGNs), driven by rapid Eddington ratio shifts, cluster in the low-accretion regime, a rate independently confirmed by our integral field spectroscopy and photoionization modeling of a well-known Seyfert 2 galaxy, rich in high-ionization, forbidden, coronal lines. Conversely, for the high-redshift, high-luminosity population where traditional reverberation mapping (RM) is highly impractical, photometric reverberation mapping (PRM) offers a rapid alternative to constrain accretion disk sizes, enabling efficient estimates of black hole masses and Eddington ratios. Finally, we developed tailored semi-empirical spectral energy distributions (SEDs) for extremely high-accretion quasars, successfully validating their characteristic extreme physical conditions.

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arXiv2025

Blowing Star Formation Away in AGN Hosts (BAH) -- III. Serendipitous discovery of a $z\sim2.9$ star-forming galaxy lensed by the galactic bulge of CGCG 012-070 using JWST NIRSpec

We report the detection of a gravitationally lensed galaxy by the nearby spiral galaxy CGCG 012-070 ($z = 0.048$) using Integral Field Unit (IFU) observations with the Near-Infrared Spectrograph (NIRSpec) instrument on board the James Webb Space Telescope (JWST). The lensed galaxy is identified through the flux distributions of emission lines in the rest-frame optical, consistent with a source located at a redshift of $z\sim2.89$. The system is detected in [O III]$λ\lambda4959,5007$, H$β$, and H$α$ emission lines, exhibiting line ratios typical of a star-forming galaxy. The emission-line flux distributions reveal three distinct components, which are modeled using an elliptical power-law (EPL) mass profile for the lens galaxy. This model provides a good characterization of the source and reveals a disturbed star-forming morphology consistent with those of galaxies at cosmic noon. This serendipitous discovery of a rare low-redshift strong lens highlights the critical role of IFU observations in expanding the lens census and advancing our understanding of galaxy mass profiles and evolution.

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arXiv2025

Ionized Gas Outflows and Shock-Heated Emission in the Highly Inclined Active Galaxy CGCG 012-070

Active Galactic Nuclei (AGNs) exhibit excess mid-infrared H$_2$ emission compared to star-forming galaxies, likely driven by outflows and shocks inferred from integrated spectra. We present optical IFU observations of the central 2\,kpc of the AGN host CGCG 012-070, selected for its pronounced H$_2$ emission excess, to map stellar and gas kinematics. The stellar velocity field is well described by a rotating disc with a line of nodes at $103^\circ \pm 4^\circ$, with the northwest side approaching and the southeast side receding. Gas kinematics, traced by strong emission lines, show two components: a narrow one ($σ\lesssim 200\,{\rm km\,s^{-1}}$) in the disc plane following stellar motions, and a broad ($σ\gtrsim 300\,{\rm km\,s^{-1}}$) associated with outflows within the inner $\sim$1\,kpc. Disc gas emission is mainly driven by AGN photoionization, while the outflow also includes shock-heated gas, as indicated by flux ratio diagnostics. The outflows are radiatively driven, with a mass-outflow rate of $(0.067 \pm 0.026)\,M_{\odot}\,{\rm yr^{-1}}$ and a kinetic coupling efficiency of 0.07%, potentially redistributing gas and contributing to maintenance-mode feedback in CGCG 012-070. Our results provide further evidence that the warm H$_2$ emission excess in nearby AGN is associated with shocks produced by outflows. Observations of other gas phases, such as cold molecular gas, are necessary to gain a more comprehensive understanding of the impact of the outflows on the host galaxy.

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arXiv2025

The differences in the Narrow Line Region of nearby QSOs 1 and 2 -- I: higher excitation and contribution of shocks in type 1's

We compare the excitation of the Narrow-Line Region (NLR) of type 1 and type 2 QSOs for redshifts $0.4 \le z \le 0.5$ via the analysis of their emission line properties in Sloan Digital Sky Survey (SDSS) near-UV/optical spectra. We fit the continuum and emission lines, using two kinematic components for \oiii$λ$5007 and \hb\ (narrow and broad) and a single component for the weaker lines. We find two main differences in the NLR excitation of type 1 and 2 QSOs: (i) QSOs 2 have higher \oiii/\hb\ than QSOs 1 in both narrow and broad components; (ii) QSOs 1 present higher \nev, \neiii\ and \oiii$\lambda4363$ luminosities, higher \nev/\neiii\ and \neiii/\oii\ ratios and higher temperatures than QSOs 2. These differences support more highly excited regions, higher temperature gas and prevalence of shocks in type 1 relative to type 2 QSOs. We suggest two possible scenarios: (i) type 1 QSOs are seen more pole-on, allowing the observation of more highly excited gas closer to the nucleus, supporting the Unified Model scenario; (ii) evolution from type 2 to type 1 QSOs, with highest excitation regions obscured in type 2's and cleared up in a ``blow-out phase". Support for the evolutionary scenario is given by the usually higher L\oiii\ in QSOs 2, in the sense that these sources host a more powerful AGN that, in its evolution, clears up the excess dust and gas to reveal a lower-luminosity but more highly excited type 1 AGN.

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arXiv2025

NGC 6860, Mrk 915 and MCG -01-24-012. I. Spatial anti-correlation between cold molecular and ionized gas distributions in Seyfert galaxies

We present a study of the cold molecular versus the ionized gas distribution in three nearby Seyfert galaxies: NGC 6860, Mrk 915 and MCG -01-24-012. To constrain the cold molecular flux distribution at $\sim$ 0.5 - 0.8$^{\prime\prime}$ ($\sim$ 150 - 400 pc) scales, we used data from the CO(2-1) emission line, obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). For the ionized gas, we used Hubble Space Telescope (HST) narrow-band images, centered on the [O III]$λλ$4959,5007 emission lines. Within the inner kiloparsec of the three galaxies, we observe gaps in the CO emission in regions co-spatial with the [O III] flux distribution, similarly to what has been recently observed in other active galaxies. From our original sample of 13 nearby AGN sources, 12 objects present the same trend. This indicates that CO molecules might be partially dissociated by AGN radiation or that there is a deficit of cold molecular gas on nuclear scales driven by ionized gas outflows/jets. If so, this represents a form of AGN feedback that is not captured when only outflow kinematics properties, such as mass outflow rates, are considered. We also discuss that part of the molecular gas might still be present in hotter H$_2$ phases, as observed already in other objects.

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arXiv2025

A Comprehensive Multiwavelength Study of the OH Megamaser galaxy IRAS 09320+6134

We present a multiwavelength study of the gas distribution, kinematics and excitation of the OH megamaser galaxy IRAS 09320+6134 (UGC 5101) using Gemini Multi-Object Spectrograph Integral Field Unit, Hubble Space Telescope, and Very Large Array observations. The HST ACS F814W i-band and H$α$ + [N II] $λλ$ 6548,84 narrow-band images indicate that this galaxy is a late-stage merger. The ionized gas emission in the inner $\sim$ 2 kpc radius, traced by the GMOS data, is consistent with two kinematic components: (i) a rotating disk, observed as a narrow component in the emission-line profiles, with velocity dispersion of $σ$ $\leq$ 200 km s$^{-1}$, and (ii) an outflow, traced by a broad component in the emission-line profiles, with $σ\geq$ 500 km s$^{-1}$. The disk component is well reproduced by a model of rotation in a plane with similar orientation to that of the large-scale galaxy disk. The outflow component presents bulk velocities of up to -500 km s$^{-1}$ and corresponds to a mass outflow rate of $\dot{M}_o = 0.122 \pm 0.026 M_{\odot}$ yr$^{-1}$. Emission-line ratio diagrams indicate that the gas excitation is mainly due to an active galactic nucleus, likely the driver of the outflow. The VLA radio image reveals a dominant radio core with two-sided emission along the NE-SW direction. The radio core's spectral index and brightness temperature indicate AGN emission, with the extended emission resembling both in morphology and spectral index the emission observed in radio-quiet quasars. Combined with previous similar studies of other OHM galaxies, the present work supports that this phase is linked to the triggering of an AGN, that seems to occur in the final stages of a merger.

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arXiv2025

Kinematic misalignment as a driver of black hole activity in galaxies with external interactions

The process of Active Galactic Nuclei (AGN) fuelling relies on the transport of gas across several orders of magnitude in physical scale until the gas reaches the supermassive black hole at the centre of a galaxy. This work explores the role of kinematically misaligned gas in the fuelling of AGN in a sample of 4769 local galaxies from the MaNGA survey. We investigate for the first time the relative role of external interactions and the presence of kinematic misalignment as mechanisms to explain the observed increase in AGN fraction in galaxies with large stellar to gas kinematic misalignment ($>$45 degrees). Using a sample of galaxies with evidence of recent external interactions we find that there is a significantly higher fraction of AGN in those where a large stellar to gas kinematic misalignment is observed (20$^{+6}_{-4}\%$) compared with 6.2$^{+0.6}_{-0.5}\%$ in galaxies where no kinematic misalignment is observed. We determine that gas to stellar misalignment has an important role in the fraction of AGN observed, increasing the AGN fraction beyond the potential effect of external interactions. This result demonstrates the importance of misaligned structures to the fuelling of supermassive black holes.

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arXiv2025

Blowing star formation away in AGN Hosts (BAH) -- II. Investigating the origin of the H2 emission excess in nearby galaxies with JWST MIRI

We use James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) medium-resolution spectrometer (MRS) observations of 3C 293 (UGC 8782), CGCG 012-070 and NGC 3884 to investigate the origin of the H$_2$ emission. These three nearby Active Galactic Nucleus (AGN) hosts are known to present H$_2$ emission excess relative to star-forming galaxies, as traced by the H$_2$ S(3)/PAH$_{\rm 11.3μm}$ line ratio. We define the kinematically disturbed region (KDR) by the AGN and the virially dominated region (VDR) based on the H$_2$ line widths, using the $W{\rm 80}$ parameter. From the correlations between $W{\rm 80}$ and H$_2$ S(3)/PAH${\rm 11.3μm}$, as well as the higher H$2$ S(5)/H$2$ S(3) and [Fe II]${\rm 5.34 μm}$/PAH${\rm 11.3μm}$ ratios and flatter power-law temperature distributions observed in the KDR, we conclude that the H$_2$ emission in the KDR is primarily driven by shock-heated gas. For 3C 293, the KDR is co-spatial with the radio core, indicating that the origin of the shocks is the interaction of the radio jet with the interstellar medium, which is also responsible for the observed molecular and ionized gas outflows in this source. The other galaxies are weak radio sources; however, due to the lack of high-resolution radio images, we cannot rule out low-power jets as the origin of the shock-heated H$_2$. Our results indicate that the excess H$_2$ emission excess is associated to shock heating of the gas, generated by outflows or by the interaction of the radio jet with the ambient gas.

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arXiv2024

Determining star formation rates in AGN hosts from strong optical emission lines

The influence of Active Galactic Nuclei (AGN) on star formation within their host galaxies remains a topic of intense debate. One of the primary challenges in quantifying the star formation rate (SFR) within AGN hosts arises from the prevalent assumption in most methodologies, which attribute gas excitation to young stars alone. However, this assumption does not consider the contribution of the AGN to the ionization of the gas in their environment. To address this issue, we evaluate the use of strong optical emission lines to obtain the SFR surface density ($Σ{\rm SFR_{AGN}}$) in regions predominantly ionized by an AGN, using a sample of 293 AGN hosts from the MaNGA survey, with SFR measurements available through stellar population fitting. We propose calibrations involving the H$α$ and [O\,{\sc iii}]$λ$5007 emission lines, which can be used to determine $Σ{\rm SFR_{AGN}}$, resulting in values consistent with those estimated through stellar population fitting.

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arXiv2024

AGN STORM 2: X. The origin of the interband continuum delays in Mrk 817

The local (z=0.0315) AGN Mrk 817, was monitored over more than 500 days with space-borne and ground-based instruments as part of a large international campaign AGN STORM 2. Here, we present a comprehensive analysis of the broad-band continuum variations using detailed modeling of the broad line region (BLR), several types of disk winds classified by their optical depth, and new numerical simulations. We find that diffuse continuum (DC) emission, with additional contributions from strong and broad emission lines, can explain the continuum lags observed in this source during high and low luminosity phases. Disk illumination by the variable X-ray corona contributes only a small fraction of the observed continuum lags. Our BLR models assume radiation pressure-confined clouds distributed over a distance of 2-122 light days. We present calculated mean-emissivity radii of many emission lines, and DC emission, and suggest a simple, transfer-function-dependent method that ties them to cross-correlation lag determinations. We do not find clear indications for large optical depth winds but identify the signature of lower column density winds. In particular, we associate the shortest observed continuum lags with a combination of tau(1 Ryd) approx. 2 wind and a partly shielded BLR. Even smaller optical depth winds may be associated with X-ray absorption features and with noticeable variations in the width and lags of several high ionization lines like HeII and CIV. Finally, we demonstrate the effect of torus dust emission on the observed lags in the i and z bands.

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arXiv2024

Blowing star formation away in AGN Hosts (BAH) -- I. Observation of Warm Molecular Outflows with JWST MIRI

We use the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) medium-resolution spectrometer (MRS) observations of the radio loud AGN host UGC 8782 to map the warm molecular and ionized gas kinematics. The data reveal spatially resolved outflows in the inner 2 kpc, seen in low ionization (traced by the [Ar ii] 6.99um emission) and in warm molecular gas (traced by the H2 rotational transitions). We find a maximum mass-outflow rate of 4.90 (2.04) M/yr at ~900 pc from the nucleus for the warm outflow (198 K< T< 1000 K) and estimate and outflow rate of up to 1.22 (0.51) M/yr for the hotter gas phase (T > 1000 K). These outflows can clear the entire nuclear reservoir of warm molecular gas in about 1 Myr. The derived kinetic power of the molecular outflows lead to coupling efficiencies of 2-5 percent of the AGN luminosity, way above the minimum expected to the AGN feedback be effective quenching the star formation.

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arXiv2024

AGN STORM 2: VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations

We observed the Seyfert 1 galaxy Mrk817 during an intensive multi-wavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in HST/COS spectra, both during the campaign and in other epochs extending over 14 years. We conclude that while the narrow absorption outflow system (at -3750 km/s with FWHM=177 km/s) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (logNH =19.5 cm-2) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the Hydrogen ionizing continuum flux) is log UH =-1.0. The outflow is located at a distance smaller than 38 parsecs from the central source, which implies a hydrogen density of nH > 3000 cm-3. The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 1e16 cm), with potential cloud geometries ranging from spherical to elongated along the line of sight.

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