arXiv subjects

T. C. Fischer

Publications and source records attributed to T. C. Fischer.

At least 19 recordsLinked to original sources

arXiv2025

Hot, Photoionized X-ray Gas in Two Luminous Type 2 Quasars: Chandra-HST Evidence for a Wind-Driven Sequence

We present new Chandra/ACIS-S imaging spectroscopy of two luminous type 2 quasars, FIRST J120041.4+314745 ($z$=0.116) and 2MASX J13003807+5454367 ($z$=0.088), and compare their X-ray emission with Hubble Space Telescope [O III]$\lambda$5007 morphologies and kinematics. Both systems show kiloparsec-scale soft X-ray emission. In FIRST J120041, the X-ray morphology is clumpy and closely follows the [O III] structures, with surface-brightness peaks co-spatial with the highest [O III] velocities (600-750 km s$^{-1}$) and broadest line widths ($\sim$1700 km s$^{-1}$). In 2MASX J130038, the X-ray emission is centrally concentrated and weakly correlated with rotational [O III] kinematics. Spectral modeling indicates that photoionization dominates the soft X-rays in both quasars. The inferred hot-gas reservoirs are substantial, $M_{\rm x-ray}\sim4.5\times10^{8}M_\odot$ (FIRST J120041) and $M_{\rm x-ray}\sim1.8\times10^{8}M_\odot$ (2MASX J130038), exceeding the outflowing [O III] masses by factors of $\sim$4 and $\sim$16. In 2MASX J130038, we identify a tentative blueshifted Fe XXVI Ly$\alpha$ line at $E_{\rm rest}=7.14\pm0.06$ keV ($v\sim7600$ km s$^{-1}$), consistent with a hot wind confined to the inner few hundred parsecs. Combining these results with a broader sample of twelve type 2 quasars, we argue that luminous quasars evolve along a continuous feedback sequence regulated by progressive clearing of circumnuclear gas. As AGN radiation and winds pierce the surrounding medium, systems transition from heavily enshrouded, compact configurations to phases where the X-ray and [O III] components strongly couple and, eventually, to energetically dominant outflows. FIRST J120041 and 2MASX J130038 represent two points along this sequence, tracing the emergence and growth of hot winds as primary drivers of quasar-scale feedback.

astro-ph.GA↗

arXiv2024

Hubble Space Telescope Observations of Nearby Type 1 Quasars. I. Characterisation of the Extended [O III] 5007Å Emission

We use the Hubble Space Telescope to analyse the extended [O III] 5007A emission in seven bright radio-quiet type 1 quasars (QSO1s), focusing on the morphology and physical conditions of their extended Narrow-Line Regions (NLRs). We find NLRs extending 3-9 kpc, with four quasars showing roughly symmetrical structures (b/a=1.2-1.5) and three displaying asymmetric NLRs (b/a=2.4-5.6). When included with type 1 and type 2 AGNs from previous studies, the sizes of the extended [O III] regions scale with luminosity as $R[O III] \sim L[O III]^{0.5}$, consistent with photoionisation. However, when analysed separately, type 1s exhibit a steeper slope ($γ=0.57\pm0.05$) compared to type 2 AGNs ($γ=0.48\pm0.02$). We use photoionisation modeling to estimate the maximum NLRs sizes, assuming a minimum ionisation parameter of $\log(U) = -3$, an ionising luminosity based on the $L[O III]$-derived bolometric luminosity, and a minimum gas number density $n_H \sim 100\,\text{cm}^{-3}$, assuming that molecular clouds provide a reservoir for the ionised gas. The derived sizes agree well with direct measurements for a sample of type 2 quasars, but are underestimated for the current sample of QSO1s. A better agreement is obtained for the QSO1s using bolometric luminosities derived from the 5100A continuum luminosity. Radial mass profiles for the QSO1s show significant extended mass in all cases, but with less [O III]-emitting gas near the central AGN compared to QSO2s. This may suggest that the QSO1s are in a later evolutionary stage than QSO2s, further past the blow-out stage.

astro-ph.GA↗

arXiv2023

The AGNIFS survey: spatially resolved observations of hot molecular and ionised outflows in nearby active galaxies

We present the hot molecular and warm ionised gas kinematics for 33 nearby ($0.001\lesssim z\lesssim0.056$) X-ray selected active galaxies using the H$_2 2.1218 μ$m and Br$γ$ emission lines observed in the K-band with the Gemini Near-Infrared Field Spectrograph (NIFS). The observations cover the inner 0.04$-$2 kpc of each AGN at spatial resolutions of 4$-$250 pc with a velocity resolution of $σ_{\rm inst}\approx$20 ${\rm km s^{-1}}$. We find that 31 objects (94 per cent) present a kinematically disturbed region (KDR) seen in ionised gas, while such regions are observed in hot molecular gas for 25 galaxies (76 per cent). We interpret the KDR as being due to outflows with masses of 10$^2-$10$^7$ M$_\odot$ and 10$^0-$10$^4$ M$_\odot$ for the ionised and hot molecular gas, respectively. The ranges of mass-outflow rates ($\dot{M}_{\rm out}$) and kinetic power ($\dot{E}_{\rm K}$) of the outflows are 10$^{-3}-$10$^{1}$ M$_\odot$yr$^{-1}$ and $\sim$10$^{37}$$-$10$^{43}$ erg s$^{-1}$ for the ionised gas outflows, and 10$^{-5}$$-$10$^{-2}$ M$_\odot$ yr$^{-1}$ and 10$^{35}$$-$10$^{39}$ erg s$^{-1}$ for the hot molecular gas outflows. The median coupling efficiency in our sample is $\dot{E}_{K}/L_{\rm bol}\approx1.8\times10^{-3}$ and the estimated momentum fluxes of the outflows suggest they are produced by radiation-pressure in low-density environment, with possible contribution from shocks.

astro-ph.GA↗

arXiv2022

Tracking X-ray Outflows with Optical/IR Footprint Lines

We use Cloudy photoionisation models to predict the flux profiles for optical/IR emission lines that trace the footprint of X-ray gas, such as [Fe X] 6375A and [Si X] 1.43$μ$m. These are a subset of coronal lines, from ions with ionisation potential $\geq$ that of O VII, i.e., 138eV. The footprint lines are formed in gas over the same range in ionisation state as the H and He-like of O and Ne ions, which are also the source of X-ray emission lines. The footprint lines can be detected with optical and IR telescopes, such as the Hubble Space Telescope/STIS and James Webb Space Telescope/NIRSpec, and can potentially be used to measure the kinematics of the extended X-ray emission gas. As a test case, we use the footprints to quantify the properties of the X-ray outflow in the Seyfert 1 galaxy NGC 4151. To confirm the accuracy of our method, we compare our model predictions to the measured flux from archival STIS spectra and previous ground-based studies, and the results are in good agreement. We also use our X-ray footprint method to predict the mass profile for the X-ray emission-line gas in NGC 4151 and derive a total spatially-integrated X-ray mass of $7.8(\pm 2.1) \times 10^{5}~M_{\odot}$, in comparison to $5.4(\pm 1.1) \times 10^{5}~M_{\odot}$ measured from a Chandra X-ray analysis. Our results indicate that high-ionisation footprint emission lines in the optical and near-infrared can be used to accurately trace the kinematics and physical conditions of AGN ionised, X-ray emission-line gas.

astro-ph.GA↗

arXiv2021

Hubble Space Telescope [O III] Emission-Line Kinematics in Two Nearby QSO2s: A Case for X-ray Feedback

We present a dynamical study of the narrow-line regions in two nearby QSO2s. We construct dynamical models based on detailed photoionization models of the emission-line gas, including the effects of internal dust, to apply to observations of large-scale outflows from these AGNs. We use Mrk 477 and Mrk 34 in order to test our models against recent HST STIS observations of [O III] emission-line kinematics since these AGNs possess more energetic outflows than found in Seyfert galaxies. We find that the outflows within 500 pc are consistent with radiative acceleration of dusty gas, however, the outflows in Mrk 34 are significantly more extended and may not be directly accelerated by radiation. We characterize the properties of X-ray winds found from the expansion of [O III]-emitting gas close to the black hole. We show that such winds possess the kinetic energy density to disturb [O III] gas at 1.8 kpc, and have sufficient energy to entrain the [O III] clouds at 1.2 kpc. Assuming that the X-ray wind possesses the same radial mass distribution as the [O III] gas, we find that the peak kinetic luminosity for this wind is 2% of Mrk 34's bolometric luminosity, which is in the 0.5% - 5% range required by some models for efficient feedback. Our work shows that, although the kinetic luminosity as measured from [O III]-emitting gas is frequently low, X-ray winds may provide more than one order of magnitude higher kinetic power.

astro-ph.GA↗

arXiv2021

Gauging the effect of Supermassive Black Holes feedback on Quasar host galaxies

In order to gauge the role that active galactic nuclei (AGN) play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO$\,$2's ($z\sim0.3$), we observed eight such objects with bolometric luminosities $L_{bol} \sim 10^{46}\rm{erg\,s^{-1}}$ using Gemini GMOS-IFU's. The emission lines were fitted with at least two Gaussian curves, the broadest of which we attributed to gas kinetically disturbed by an outflow. We found that the maximum extent of the outflow ranges from $\sim$1 to 8 kpc, being ${\sim}\,0.5\,{\pm}\,0.3$ times the extent of the [O$\,$III] ionized gas region. Our `${\tt default}$' assumptions for the gas density (obtained from the {[S$\,$II] doublet) and outflow velocities resulted in peak mass outflow rates of $\dot{M}_{out}^{\tt defa}{\sim}\,3\,{-}\,30\,\rm{M_{\odot}}\,yr^{-1}$ and outflow power of $\dot{E}_{out}^{\tt defa}\sim\,10^{41}\,{-}\,10^{43}\,\mathrm{erg\,s^{-1}}$. The corresponding kinetic coupling efficiencies are $\varepsilon_f^{\tt defa}=\dot{E}_{out}^{\tt defa}/L_{bol}\,\sim7\times10^{-4}\,{-}\,0.5\,\%$, with the average efficiency being only $0.06\,\%$ ($0.01\,\%$ median), implying little feedback powers from ionized gas outflows in the host galaxies. We investigated the effects of varying assumptions and calculations on $\dot{M}_{out}$ and $\dot{E}_{out}$ regarding the ionized gas densities, velocities, masses and inclinations of the outflow relative to the plane of the sky, resulting in average uncertainties of one dex. In particular, we found that better indicators of the [O$\,$III] emitting gas density than the default [S$\,$II] line ratio, such as the [Ar$\,$IV]$λλ$4711,40 line ratio, result in almost an order of magnitude decrease in the $\varepsilon_f$.

astro-ph.GA↗

arXiv2021

The AGNIFS survey: distribution and excitation of the hot molecular and ionised gas in the inner kpc of nearby AGN hosts

We use the Gemini NIFS instrument to map the H$_2 2.1218μ$m and Br$γ$ flux distributions in the inner 0.04-2 kpc of a sample of 36 nearby active galaxies ($0.001\lesssim z\lesssim0.056$) at spatial resolutions from 4 to 250 pc. We find extended emission in 34 galaxies. In $\sim$55% of them, the emission in both lines is most extended along the galaxy major axis, while in the other 45% the extent follows a distinct orientation. The emission of H$_2$ is less concentrated than that of Br$γ$, presenting a radius that contains half of the flux 60% greater, on average. The H$_2$ emission is driven by thermal processes - X-ray heating and shocks - at most locations for all galaxies, where $0.4 6$ (seen in 40% of the galaxies), shocks are the main H$_2$ excitation mechanism, while in regions with H$_2$/Br$γ<0.4$ (25% of the sample) the H$_2$ emission is produced by fluorescence. The only difference we found between type 1 and type 2 AGN was in the nuclear emission-line equivalent widths, that are smaller in type 1 than in type 2 due to a larger contribution to the continuum from the hot dusty torus in the former. The gas masses in the inner 125 pc radius are in the range $10^1-10^4$ M$_\odot$ for the hot H$_2$ and $10^3-10^6$ M$_\odot$ for the ionised gas and would be enough to power the AGN in our sample for $10^5-10^8$ yr at their current accretion rates.

astro-ph.GA↗

arXiv2020

Hubble Space Telescope Observations of [O~III] Emission in Nearby QSO2s: Physical Properties of the Ionised Outflows

We use Hubble Space Telescope (HST)/ Space Telescope Imaging Spectrograph (STIS) long-slit G430M and G750M spectra to analyse the extended [O~III] 5007A emission in a sample of twelve nearby (z < 0.12) luminous (L_bol > 1.6 x 10^45 erg s^-1) QSO2s. The purpose of the study is to determine the properties of the mass outflows of ionised gas and their role in AGN feedback. We measure fluxes and velocities as functions of radial distances. Using Cloudy models and ionising luminosities derived from [O~III] 5007A, we are able to estimate the densities for the emission-line gas. From these results, we derive masses of [O~III]-emitting gas, mass outflow rates, kinetic energies, kinetic luminosities, momenta and momentum flow rates as a function of radial distance for each of the targets. For the sample, masses are several times 10^3 - 10^7 solar masses and peak outflow rates are 9.3 x 10^-3 Msun/yr to 10.3 Msun/yr. The peak kinetic luminosities are 3.4 x 10^-8 to 4.9 x 10^-4 of the bolometric luminosity, which does not approach the 5.0 x 10^-3 - 5.0 x 10^-2 range required by some models for efficient feedback. For Mrk 34, which has the largest kinetic luminosity of our sample, in order to produce efficient feedback there would have to be 10 times more [O~III]-emitting gas than we detected at its position of maximum kinetic luminosity. Three targets show extended [O~III] emission, but compact outflow regions. This may be due to different mass profiles or different evolutionary histories.

astro-ph.GA↗

arXiv2020

Gemini Near-Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy Mrk 3: Feeding and Feedback on Galactic and Nuclear Scales

We explore the kinematics of the stars, ionized gas, and warm molecular gas in the Seyfert 2 galaxy Mrk~3 (UGC~3426) on nuclear and galactic scales with {\it Gemini} Near-Infrared Field Spectrograph (NIFS) observations, previous {\it Hubble Space Telescope} data, and new long-slit spectra from the {\it Apache Point Observatory} ({\it APO}) 3.5 m telescope. The {\it APO} spectra are consistent with our previous suggestion that a galactic-scale gas/dust disk at PA $=$ 129\arcdeg, offset from the major axis of the host S0 galaxy at PA $=$ 28\arcdeg, is responsible for the orientation of the extended narrow-line region (ENLR). The disk is fed by an H~I tidal stream from a gas-rich spiral galaxy (UGC~3422) $\sim$100 kpc to the NW of Mrk 3, and is ionized by the AGN to a distance of at least $\sim$20\arcsec\ ($\sim$5.4 kpc) from the central supermassive black hole (SMBH). The kinematics within at least 320 pc of the SMBH are dominated by outflows with radial (line of sight) velocities up to 1500 km s$^{-1}$ in the ionized gas and 500 km s$^{-1}$ in the warm molecular gas, consistent with in situ heating, ionization, and acceleration of ambient gas to produce the narrow-line region (NLR) outflows. There is a disk of ionized and warm molecular gas within $\sim$400 pc of the SMBH that has re-oriented close to the stellar major axis but is counter-rotating, consistent with claims of external fueling of AGN in S0 galaxies.

astro-ph.GA↗

arXiv2020

Mass Outflow of the X-ray Emission Line Gas in NGC 4151

We have analysed Chandra/High Energy Transmission Gratings spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth order spectral images show extended H- and He-like O and Ne, up to a distance $r \sim$ 200 pc from the nucleus. Using the 1st order spectra, we measure an average line velocity $\sim -230$ km s$^{-1}$, suggesting significant outflow of X-ray gas. We generated Cloudy photoionisation models to fit the 1st order spectra. We required three emission-line components, with column density, log$N_{H}$, and ionisation parameter, log$U$, of 22.5/1.0, 22.5/0.19, and 23.0/-0.50, respectively. To estimate the total mass of ionised gas and the mass outflow rates, we applied the model parameters to fit the zeroth order emission-line profiles of Ne~IX and Ne~X. We determined the total mass of $\approx 5.4 \times$ 10$^{5}$ M_sun. Assuming the same kinematic profile as that for the [O~III] gas, the peak X-ray mass outflow rate was $\approx 1.8$ M_sun yr$^{-1}$, at $r \sim 150$ pc. The total mass and mass outflow rates are similar to those determined using [O~III], implying that the X-ray gas is a major outflow component. However, unlike the optical outflows, the X-ray outflow rate does not drop off at $r >$ 100 pc, which suggests that it may have a greater impact on the host galaxy.

astro-ph.GA↗

arXiv2019

Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. II. Spatially Resolved Mass Outflow Rates for the QSO2 Markarian 34

We present spatially resolved mass outflow rate measurements ($\dot M_{out}$) for the narrow line region of Markarian 34, the nearest Compton-thick type 2 quasar (QSO2). Spectra obtained with the Hubble Space Telescope and at Apache Point Observatory reveal complex kinematics, with distinct signatures of outflow and rotation within 2 kpc of the nucleus. Using multi-component photoionization models, we find that the outflow contains a total ionized gas mass of $M \approx 1.6 \times 10^6 M_{\odot}$. Combining this with the kinematics yields a peak outflow rate of $\dot M_{out} \approx 2.0 \pm 0.4~M_{\odot}$ yr$^{-1}$ at a distance of 470 pc from the nucleus, with a spatially integrated kinetic energy of $E \approx 1.4 \times 10^{55}$ erg. These outflows are more energetic than those observed in Mrk 573 and NGC 4151, supporting a correlation between luminosity and outflow strength even though they have similar peak outflow rates. The mix of rotational and outflowing components suggests that spatially resolved observations are required to determine accurate outflow parameters in systems with complex kinematics. (See appended erratum for updated values.)

astro-ph.GA↗

arXiv2018

Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. I. Spatially Resolved Mass Outflow Rates for the Seyfert 2 Galaxy Markarian 573

We present the first spatially resolved mass outflow rate measurements ($\dot M_{out}$) of the optical emission line gas in the narrow line region (NLR) of a Seyfert 2 galaxy, Markarian 573. Using long slit spectra and [O III] imaging from the Hubble Space Telescope and Apache Point Observatory in conjunction with emission line diagnostics and Cloudy photoionization models, we find a peak outflow rate of $\dot M_{out} \approx$ 3.4 $\pm$ 0.5 $M_{\odot}$ yr$^{-1}$ at a distance of 210 pc from the central supermassive black hole (SMBH). The outflow extends to distances of 600 pc from the nucleus with a total mass and kinetic energy of $M \approx 2.2 \times 10^6 M_{\odot}$ and $E \approx 5.1 \times 10^{54}$ erg, revealing the outflows to be more energetic than those in the lower luminosity Seyfert 1 galaxy NGC 4151 (Crenshaw et al. 2015). The peak outflow rate is an order of magnitude larger than the mass accretion and nuclear outflow rates, indicating local in-situ acceleration of the circumnuclear NLR gas. We compare these results to global techniques that quantify an average outflow rate across the NLR, and find the latter are subject to larger uncertainties. These results indicate that spatially resolved observations are critical for probing AGN feedback on scales where circumnuclear star formation occurs.

astro-ph.GA↗

arXiv2018

An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU Observations

We present two-dimensional stellar and gaseous kinematics of the inner 0.7 $\times$ 1.2 kpc$^{2}$ of the Seyfert galaxy ESO 362-G18, derived from optical spectra obtained with the GMOS/IFU on the Gemini South telescope at a spatial resolution of $\approx$170 pc and spectral resolution of 36 km s$^{-1}$. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [OIII] emission shows a fan-shaped extension of $\approx$ 10\arcsec\ to the SE. We detect the [OIII] doublet, [NII] and H$α$ emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of $\approx$137$^{\circ}$. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122$^{\circ}$ to 139$^{\circ}$. A double-Gaussian fit to the [OIII]$λ$5007 and H$α$ lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100-250 km s$^{-1}$ higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 $\times$ 10$^{-2}$ M$_{\odot}$ yr$^{-1}$ in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 $\times$ 10$^{-2}$ M$_{\odot}$ yr$^{-1}$. The total ionized gas mass within $\sim$84 pc of the nucleus is 3.3 $\times$ 10$^{5}$ M$_{\odot}$; infall velocities of $\sim$34 km s$^{-1}$ in this gas would be required to feed both the outflow and SMBH accretion.

astro-ph.GA↗

arXiv2018

The [OIII] profiles of infrared-selected active galactic nuclei: More powerful outflows in the obscured population

We explore the kinematics of ionized gas via the [O III] $λ$5007 emission lines in active galactic nuclei (AGN) selected on the basis of their mid-infrared (IR) emission, and split into obscured and unobscured populations based on their optical-IR colors. After correcting for differences in redshift distributions, we provide composite spectra of spectroscopically and photometrically defined obscured/Type 2 and unobscured/Type 1 AGN from 3500 to 7000 Å. The IR-selected obscured sources contain a mixture of narrow-lined Type 2 AGN and intermediate sources that have broad H$α$ emission and significantly narrower H$β$. Using both [OIII] luminosities and AGN luminosities derived from optical-IR spectral energy distribution fitting, we find evidence for enhanced large-scale obscuration in the obscured sources. In matched bins of luminosity we find that the obscured population typically has broader, more blueshifted \OIII\ emission than in the unobscured sample, suggestive of more powerful AGN-driven outflows. This trend is not seen in spectroscopically classified samples, and is unlikely to be entirely explained by orientation effects. In addition, outflow velocities increase from small to moderate AGN $E(B-V)$ values, before flattening out (as traced by FWHM) and even decreasing (as traced by blueshift). While difficult to fully interpret in a single physical model, due to both the averaging over populations and the spatially-averaged spectra, these results agree with previous findings that simple geometric unification models are insufficient for the IR-selected AGN population, and may fit into an evolutionary model for obscured and unobscured AGN.

astro-ph.GA↗

arXiv2017

Gemini NIFS survey of feeding and feedback processes in nearby Active Galaxies: II -The sample and surface mass density profiles

We present and characterize a sample of 20 nearby Seyfert galaxies selected for having BAT 14--195keV luminosities $L_X \ge 10^{41.5}$ erg s$^{-1}$, redshift $z\le$0.015, being accessible for observations with the Gemini Near-Infrared Field Spectrograph (NIFS) and showing extended [OIII]$λ$5007 emission. Our goal is to study Active Galactic Nuclei (AGN) feeding and feedback processes from near-infrared integral-field spectra, that include both ionized (HII) and hot molecular (H$_2$) emission. This sample is complemented by other 9 Seyfert galaxies previously observed with NIFS. We show that the host galaxy properties (absolute magnitudes $M_B$, $M_H$, central stellar velocity dispersion and axial ratio) show a similar distribution to those of the 69 BAT AGN. For the 20 galaxies already observed, we present surface mass density ($Σ$) profiles for HII and H$_2$ in their inner $\sim$500 pc, showing that HII emission presents a steeper radial gradient than H$_2$. This can be attributed to the different excitation mechanisms: ionization by AGN radiation for HII and heating by X-rays for H$_2$. The mean surface mass densities are in the range ($0.2\le Σ_{HII} \le 35.9$)M$_\odot$pc$^{-2}$, and ($0.2\le Σ_{H2} \le 13.9$)$\times10^{-3}$M$_\odot$pc$^{-2}$, while the ratios between the HII and H$_2$ masses range between $\sim$200 to 8000. The sample presented here will be used in future papers to map AGN gas excitation and kinematics, providing a census of the mass inflow and outflow rates and power as well as their relation with the AGN luminosity.

astro-ph.GA↗

arXiv2014

A Minor Merger Caught In The Act Of Fueling The AGN In Mrk 509

In recent observations by the Hubble Space Telescope (HST) as part of a campaign to discover locations and kinematics of AGN outflows, we found that Mrk 509 contains a 3$''$ ($\sim$2100 {\it pc}) linear filament in its central region. Visible in both optical continuum and [OIII] imaging, this feature resembles a `check mark' of several knots of emission that travel northwest to southeast before jutting towards the nucleus from the southwest. Space Telescope Imaging Spectrograph (STIS/HST) observations along the inner portion of the filament reveal redshifted velocities, indicating that the filament is inflowing. We present further observations of the nucleus in Mrk 509 using the Gemini Near-Infrared Integral Field Spectrograph (NIFS), from which we conclude that this structure cannot be related to previously studied, typical NLR outflows and instead embodies the remains of an ongoing minor merger with a gas-rich dwarf galaxy, therefore providing a great opportunity to study the fueling of an AGN by a minor merger in progress.

astro-ph.GA↗

arXiv2014

Feedback from Mass Outflows in Nearby Active Galactic Nuclei. II. Outflows in the Narrow-Line Region of NGC 4151

We present a detailed study of AGN feedback in the narrow-line region (NLR) of the Seyfert 1 galaxy NGC 4151. We illustrate the data and techniques needed to determine the mass outflow rate and kinetic luminosity of the outflowing ionized gas as a function of position in the NLR. We find that the mass outflow rate peaks at a value of 3 solar masses per year at a distance of 70 pc from the central supermassive black hole (SMBH), which is about 10 times the outflow rate coming from inside 13 pc, and 230 times the mass accretion rate inferred from the bolometric luminosity of NGC 4151. Thus, most of the outflow must arise from "in situ" acceleration of ambient gas throughout the NLR. The kinetic luminosity peaks at 90 pc and drops rapidly thereafter, indicating that most of the kinetic energy is deposited within about 100 pc from the SMBH. Both values exceed the mass outflow rate and kinetic luminosity determined for the UV/X-ray absorber outflows in NGC 4151, indicating the importance of NLR outflows in providing feedback on scales where circumnuclear star formation and bulge growth occur.

astro-ph.GA↗

arXiv2014

Spatially-Resolved Spectra of the "Teacup" AGN: Tracing the History of a Dying Quasar

The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing Extended Emission-Line Regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup Active Galactic Nucleus (AGN), nicknamed for its EELR, which has a handle like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze physical conditions of this galaxy with long-slit ground based spectroscopy from Lowell, Lick, and KPNO observatories. With the Lowell 1.8m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] 6716/6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by this amount in a continuous fashion over 46,000 years, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long time scale variability.

astro-ph.GA↗