Emission-line Flux Distributions Research Articles

A panchromatic spatially resolved study of the inner 500 pc of NGC 1052 – II. Gas excitation and kinematics

ABSTRACT We map the optical and near-infrared (NIR) emission-line flux distributions and kinematics of the inner 320 × 535 pc2 of the elliptical galaxy NGC 1052. The integral field spectra were obtained with the Gemini Telescope using the GMOS-IFU and NIFS instruments, with angular resolutions of 0.88 and 0.1 arcsec in the optical and NIR, respectively. We detect five kinematic components: (1) and (2) two spatially unresolved components: a broad-line region visible in H α, with a full width at half-maximum (FWHM) of ∼3200 km s−1, and an intermediate broad component seen in the [O iii] λλ4959,5007 doublet; (3) an extended intermediate-width component with 280 km s−1 < FWHM < 450 km s−1 and centroid velocities up to 400 km s−1, which dominates the flux in our data, attributed either to a bipolar outflow related to the jets, rotation in an eccentric disc or to a combination of a disc and large-scale gas bubbles; (4) and (5) two narrow (FWHM < 150 km s−1) components, one visible in [O iii], and another visible in the other emission lines, extending beyond the field of view of our data, which is attributed to large-scale shocks. Our results suggest that the ionization within the observed field of view cannot be explained by a single mechanism, with photoionization being the dominant mechanism in the nucleus with a combination of shocks and photoionization responsible for the extended ionization.

Outflows, inflows, and young stars in the inner 200 pc of the Seyfert galaxy NGC 2110

ABSTRACT We present a 2D mapping of stellar population age components, emission-line fluxes, gas excitation, and kinematics within the inner ∼200 pc of the Seyfert 2 galaxy NGC 2110. We used the Gemini North Integral Field Spectrograph (NIFS) in the J and K bands at a spatial resolution of ∼22 pc. The unresolved nuclear continuum is originated in combined contributions of young stellar population (SP; age ≤ 100 Myr), a featureless AGN continuum and hot dust emission. The young-intermediate SP (100 < age ≤ 700 Myr) is distributed in a ring-shaped structure at ≈140 pc from the nucleus, which is roughly coincident with the lowest values of the stellar velocity dispersion. In the inner ≈115 pc the old SP (age > 2 Gyr) is dominant. The [Fe ii] $\lambda \, 1.2570\, \mu$m emission-line flux distribution is correlated with the radio emission and its kinematics comprise two components, one from gas rotating in the galaxy plane and another from gas in outflow within a bicone-oriented along north–south. These outflows seem to originate in the interaction of the radio jet with the ambient gas producing shocks that are the main excitation mechanism of the [Fe ii] emission. We estimate: (1) an ionized gas mass outflow rate of ∼0.5 M⊙ yr−1 at ∼70 pc from the nucleus; and (2) a kinetic power for the outflow of only 0.05 per cent of the AGN bolometric luminosity implying weak feedback effect on the galaxy.

A close look at the dwarf AGN of NGC 4395: optical and near-IR integral field spectroscopy

Intermediate mass black holes (10$^3$-10$^5$ M$_\odot$) in the center of dwarf galaxies are believed to be analogous to growing Active Galactic Nuclei (AGN) in the early Universe. Their characterization can provide insight about the early galaxies. We present optical and near-infrared integral field spectroscopy of the inner $\sim$50 pc of the dwarf galaxy NGC4395, known to harbor an AGN. NGC 4395 is an ideal candidate to investigate the nature of dwarf AGN, as it is nearby ($d\approx4.4$ Mpc) enough to allow a close look at its nucleus. The optical data were obtained with the Gemini GMOS-IFU covering the 4500 A to 7300 A spectral range at a spatial resolution of 10 pc. The J and K-band spectra were obtained with the Gemini NIFS at spatial resolutions of $\sim$5 pc. The gas kinematics show a compact, rotation disk component with a projected velocity amplitude of 25 km s$^{-1}$. We estimate a mass of $7.7\times10^5$ M$_\odot$ inside a radius of 10 pc. From the H$\alpha$ broad line component, we estimate the AGN bolometric luminosity as $L_{ bol}=(9.9\pm1.4)\times10^{40}$ erg s$^{-1}$ and a mass $M_{ BH}=(2.5^{+1.0}_{-0.8})\times10^5$ M$_\odot$ for the central black hole. The mean surface mass densities for the ionized and molecular gas are in the ranges (1-2) M$_{\odot} $pc$^{-2}$ and (1-4)$\times10^{-3}$ M${_\odot}$ pc$^{-2}$ and the average ratio between ionized and hot molecular gas masses is $\sim$500. The emission-line flux distributions reveal an elongated structure at 24 pc west of the nucleus, which is blueshifted relative to the systemic velocity of the galaxy by $\approx$30 km s$^{-1}$. We speculate that this structure is originated by the accretion of a gas-rich small satellite or by a low metallicity cosmic cloud.

Outflow signatures in Gemini GMOS-IFU observations of 5 nearby Seyfert 2 galaxies

AbstractWe use Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU) observations of a sample of 5 bright nearby Seyfert galaxies to map their emission-line flux distributions and kinematics at a spatial resolution ranging from 110 to 280 pc. For all galaxies, the gas kinematics show two components: a rotation and an outflow component.

Star formation and gas inflows in the OH megamaser galaxy IRAS03056+2034

We have obtained observations of the OH Megamaser galaxy IRAS03056+0234 using Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Very Large Array (VLA) and Hubble Space Telescope (HST). The HST data reveals spiral arms containing knots of emission associated to star forming regions. The GMOS-IFU data cover the spectral range of 4500 to 7500 \AA\ at a velocity resolution of 90 km s$^{-1}$ and spatial resolution of 506 pc. The emission-line flux distributions reveal a ring of star forming regions with radius of 786 pc centred at the nucleus of the galaxy, with an ionized gas mass of 1.2$\times$ 10$^{8}$M$_{\odot}$, an ionizing photon luminosity of log Q[H$^{+}$]=53.8 and a star formation rate of 4.9 M$_{\odot}$ yr$^{-1}$. The emission-line ratios and radio emission suggest that the gas at the nuclear region is excited by both starburst activity and an active galactic nucleus. The gas velocity fields are partially reproduced by rotation in the galactic plane, but show, in addition, excess redshifts to the east of the nucleus, consistent with gas inflows towards the nucleus, with velocity of $\sim$45 km s$^{-1}$ and a mass inflow rate of $\sim$7.7$\times$10$^{-3}$ M$_{\odot}$ yr$^{-1}$.

Outflows in the Seyfert 2 galaxy NGC 5643 traced by the [S iii] emission

AbstractWe use Gemini Multi-Object Spectrograph integral Field Unit observations of the inner 285 × 400 pc2 region of the Seyfert 2 galaxy NGC 5643 to map the [S iii]λ9069 emission line flux distribution and kinematics, as well as the stellar kinematics, derived by fitting the Ca iiλλλ8498,8542,8662 triplet, at a spatial resolution of 45 pc. The stellar velocity field shows regular rotation, with a projected velocity of 100 km s−1 and kinematic major axis along a position angle of –36°. A ring of low stellar velocity dispersion values (∼70 km s−1), attributed to young/intermediate age stellar populations, is seen surrounding the nucleus with a radius of 50 pc. We found that the [S iii] flux distribution shows an elongated structure along the east–west direction and its kinematics is dominated by outflows within a bi-cone at an ionised gas outflow rate of 0.3 M⊙ yr−1. In addition, velocity slices across the [S iii]λ9069 emission line reveal a kinematic component attributed to rotation of gas in the plane of the galaxy.

Integral field spectroscopy of the inner kpc of the elliptical galaxy NGC 5044

We used Gemini Multi-Object Spectrograph (GMOS) in the Integral Field Unit mode to map the stellar population, emission line flux distributions and gas kinematics in the inner kpc of NGC 5044. From the stellar populations synthesis we found that the continuum emission is dominated by old high metallicity stars ($\sim$13 Gyr, 2.5Z$\odot$). Also, its nuclear emission is diluted by a non thermal emission, which we attribute to the presence of a weak active galactic nuclei (AGN). In addition, we report for the first time a broad component (FWHM$\sim$ 3000km$s^{-1}$) in the H$\alpha$ emission line in the nuclear region of NGC 5044. By using emission line ratio diagnostic diagrams we found that two dominant ionization processes coexist, while the nuclear region (inner 200 pc) is ionized by a low luminosity AGN, the filamentary structures are consistent with being excited by shocks. The H$\alpha$ velocity field shows evidence of a rotating disk, which has a velocity amplitude of $\sim$240kms$^{-1}$ at $\sim$ 136 pc from the nucleus. Assuming a Keplerian approach we estimated that the mass inside this radius is $1.9\times10^9$ $M_{\odot}$, which is in agreement with the value obtained through the M-$\sigma$ relation, $ M_{SMBH}=1.8\pm1.6\times10^{9}M_{\odot}$. Modelling the ionized gas velocity field by a rotating disk component plus inflows towards the nucleus along filamentary structures, we obtain a mass inflow rate of $\sim$0.4 M$_\odot$. This inflow rate is enough to power the central AGN in NGC 5044.

A SINFONI view of the nuclear activity and circumnuclear star formation in NGC 4303

We present new maps of emission-line flux distributions and kinematics in both ionized (traced by HI and [FeII] lines) and molecular (H2) gas of the inner 0.7x0.7kpc2 of the galaxy NGC4303, with a spatial resolution 40-80pc and velocity resolution 90-150 km/s obtained from near-IR integral field specroscopy using the VLT instrument SINFONI. The most promiment feature is a 200-250pc ring of circum-nuclear star-forming regions. The emission from ionized and molecular gas shows distinct flux distributions: while the strongest HI and [FeII] emission comes from regions in the west side of the ring (ages~4Myr), the H2 emission is strongest at the nucleus and in the east side of the ring (ages>10Myr). We find that regions of enhanced hot H2 emission are anti-correlated with those of enhanced [FeII] and HI emission, which can be attributed to post starburst regions that do not have ionizing photons anymore but still are hot enough (~2000K) to excite the H2 molecule. The line ratios are consistent with the presence of an AGN at the nucleus. The youngest regions have stellar masses in the range 0.3-1.5E5 MSun and ionized and hot molecular gas masses of ~0.25-1.2E4 Msun and 2.5-5 Msun, respectively. The stellar and gas velocity fields show a rotation pattern, with the gas presenting larger velocity amplitudes than the stars, with a deviation observed for the H2 along the nuclear bar, where increased velocity dispersion is also observed, possibly associated with non circular motions along the bar. The stars in the ring show smaller velocity dispersion than the surroundings, that can be attributed to a cooler dynamics due to their recent formation from cool gas.

The origin of the near-IR line emission from molecular, low and high ionization gas in the inner kiloparsec of NGC 6240

The understating of the origin of the H2 line emission from the central regions of galaxies represent an important key to improve our knowledge about the excitation and ionization conditions of the gas in these locations. Usually these lines can be produced by Starburts, shocks and/or radiation from an active galactic nucleus (AGN). Luminous Infrared Galaxies (LIRG) represent ideal and challenging objects to investigate the origin of the H2 emission, as all processes above can be observed in a single object. In this work, we use K-band integral field spectroscopy to map the emission line flux distributions and kinematics and investigate the origin of the molecular and ionized gas line emission from inner 1.4x2.4 kpc2 of the LIRG NGC6240, known to be the galaxy with strongest H2 line emission. The emission lines show complex profiles at locations between both nuclei and surrounding the northern nucleus, while at locations near the southern nucleus and at 1" west of the northern nucleus, they can be reproduced by a single gaussian component. We found that the H2 emission is originated mainly by thermal processes, possible being dominated by heating of the gas by X-rays from the AGN at locations near both nuclei. For the region between the northern and southern nuclei shocks due to the interacting process may be the main excitation mechanism, as indicated by the high values of the H2l2.12um/Brg line ratio. A contribution of fluorescent excitation may also be important at locations near 1" west of the northern nucleus, which show the lowest line ratios. The [FeII]l2.072um/Brg ratio show a similar trend as observed for H2l2.12um/Brg, suggesting that [FeII] and H2 line emission have similar origins. Finally, the [CaVIII]l2.32um coronal line emission is observed mainly in regions next to the nuclei, suggesting it is originated gas ionized by the radiation from the AGN.

Feeding versus feedback in AGN from near-infrared IFU observations: the case of Mrk 766

We have mapped the emission-line flux distributions and ratios as well as the gaseous kinematics of the inner 450 pc radius of the type 1 Seyfert galaxy Mrk 766 using integral field near-infrared J- and Kl-band spectra obtained with the Gemini Near Infrared Integral Field Spectrograph at a spatial resolution of 60 pc and velocity resolution of 40 km s−1. Emission-line flux distributions in ionized and molecular gas extend up to ≈ 300 pc from the nucleus. Coronal [S ix] λ1.2523 μm line emission is resolved, being extended up to 150 pc from the nucleus. At the highest flux levels, the [Fe ii] λ1.257 μm line emission is most extended to the south-east, where a radio jet has been observed. The emission-line ratios [Fe ii] λ1.2570 μm/Paβ and H2λ2.1218 μm/Brγ show a mixture of Starburst and Seyfert excitation; the Seyfert excitation dominates at the nucleus, to the north-west and in an arc-shaped region between 0.2 and 0.6 arcsec to the south-east at the location of the radio jet. A contribution from shocks at this location is supported by enhanced [Fe ii]/[P ii] line ratios and increased [Fe ii] velocity dispersion. The gas velocity field is dominated by rotation that is more compact for H2 than for Paβ, indicating that the molecular gas has a colder kinematics and is located in the galaxy plane. There is about 103 M⊙ of hot H2, implying ≈109 M⊙ of cold molecular gas. At the location of the radio jet, we observe an increase in the [Fe ii] velocity dispersion (150 km s−1), as well as both blueshift and redshifts in the channel maps, supporting the presence of an outflow there. The ionized gas mass outflow rate is estimated to be ≈10 M⊙ yr−1, and the power of the outflow ≈0.08 Lbol.

Near-IR Integral Field Spectroscopy of the central region of NGC 5929

AbstractWe present two-dimensional (2D) near-infrared spectra of the inner 300×300 pc2 of the Seyfert 2 galaxy NGC 5929 at a spatial resolution of ~20 pc obtained with the Gemini Near infrared Integral Field Spectrograph (NIFS). We present 2D maps for the emission line flux distributions and kinematics and report the discovery of a linear structure ~300 pc in extent and of ~50 pc in width oriented perpendicular to the radio jet, showing broadened emission-line profiles.While over most of the field the emission-line profiles have full-widths-at-half-maximum (FWHM) of ~210 km/s, at a linear structure perpendicular do the radio jet the emission-line FWHMs are twice this value, and are due to two velocity components, one blueshifted and the other redshifted relative to the systemic velocity. We attribute these velocities to an outflow from the nucleus which is launched perpendicular to the radio jet. We reported the detection of this peculiar outflow in Riffel, Storchi-Bergmann & Riffel (2014a), where more details of the analysis can be found. Since, NGC 5929 has a Type 2 nucleus, this detection implies that: (1) both ionizing radiation and relativistic particles are escaping through holes in the torus perpendicular to the radio jet; and/or (2) the torus is also outflowing, as proposed by recent models of tori as winds from the outer parts of an accretion flow; or (3) the torus is absent in NGC 5929.At other locations the gas kinematics is dominated by rotation in a disk, although some evidences of interaction of the radio jet with the emitting gas are seen as a broadening of the line profiles at the locations of the radio structures.The flux distributions for the [P ii], [Fe ii], H i and H2 emission lines show that the line emission is more extended along the PA = 60/240^, extending to up to 1.5” to both sides of the nucleus, while to the perpendicular direction (PA = -30/150^) the emission is extended to 0.7” from the nucleus. The flux distributions of all emission lines show a good correlation with radio the radio structures, with the two peak of emission associated to the soutwestern and northeastern radio knots. Some differences are observed among distinct emission lines. While the [Fe ii] and H2 emission peak at the location of the soutwestern radio structure at 0.6” from the nucleus, the H i recombination lines present the their highest fluxes at the location of the northeastern radio hotspot at 0.5” from the nucleus. Another difference is that the H2 emission is less collimated than that for other lines, being more extended perpendicularly to the radio jet. A detailed analysis of the line emission and kinematics will be presented in Riffel, Storchi-Bergmann & Riffel (2014b).

Feeding versus feedback in NGC 1068 probed with Gemini NIFS – I. Excitation

We present emission-line flux distributions and ratios for the inner 200pc of the narrow-line region of the Seyfert2 galaxy NGC1068, using observations obtained with the Gemini Near-infrared Integral Field Spectrograph (NIFS) in the J, H and K bands at a spatial resolution of 10pc and spectral resolution of 5300. The molecular gas emission - traced by the K-band H_2 emission lines - outlines an off-centered circumnuclear ring with a radius of 100pc showing thermal excitation. The ionized gas emission lines show flux distributions mostly outlining the previously known [OIII]5007 ionization bicone. But while the flux distributions in the HI and HeII emission lines are very similar to that observed in [OIII], the flux distribution in the [FeII] emission lines is more extended and broader than a cone close to the nucleus, showing a "double bowl" or `hourglass" structure". This difference is attributed to the fact that the [FeII] emission, besides coming from the fully ionized region, comes also from the more extended partially ionized regions, in gas excited mainly by X-rays from the active galactic nucleus. A contribution to the [FeII] emission from shocks along the bicone axis to NE and SW of the nucleus is also supported by the enhancement of the [FeII](1.2570)/[PII](1.1885) and [FeII](1.2570)/Pabeta emission-line ratios at these locations and is attributed to the interaction of the radio jet with the NLR. The mass of ionized gas in the inner 200pc of NGC1068 is MHII~2.2E4 M_Sun, while the mass of the H2 emitting gas is only M_{H2}~29M_Sun. Taking into account the dominant contribution of the cold molecular gas, we obtain an estimate of the total molecular gas mass of Mcold~2E7 M_Sun.

Feeding versus feedback in AGNs from near-infrared IFU observations: the case of Mrk 79

We have mapped the gaseous kinematics and the emission-line flux distributions and ratios from the inner ~680pc radius of the Seyfert 1 galaxy Mrk79, using two-dimensional (2D) near-IR J- and Kl-band spectra obtained with the Gemini instrument NIFS at a spatial resolution of ~100pc and velocity resolution of ~40km/s. The molecular hydrogen flux distribution presents two spiral arms extending by ~700pc, one to the north and another to the south of the nucleus, with an excitation indicating heating by X-rays from the central source. The low velocity dispersion (sigma~50km/s) and rotation pattern supports a location of the H2 gas in the disk of the galaxy. Blueshifts observed along the spiral arm in the far side of the galaxy and redshifts in the spiral arm in the near side, suggest that the spiral arms are feeding channels of H2 to the inner 200pc. From channel maps along the H2 l2.1218um emission-line profile we estimate a mass inflow rate of ~4E-3 M_Sun/year, which is one order of magnitude smaller than the mass accretion rate necessary to power the AGN of Mrk79. The emission from the ionized gas (traced by Pabeta and [FeII]l1.2570um emission lines) is correlated with the radio jet and with the narrow-band [OIII] flux distribution. Its kinematics shows both rotation and outflows to the north and south of the nucleus. The ionized gas mass outflow rate through a cross section with radius ~320pc located at a distance of ~455pc from the nucleus is 3.5 MSun/year, which is much larger than the AGN mass accretion rate, indicating that most of the outflowing gas originates in the interstellar medium surrounding the galaxy nucleus, which is pushed away by a nuclear jet.

Feeding and feedback in the active nucleus of Mrk 1157 probed with the Gemini Near-Infrared Integral-Field Spectrograph

We have mapped the stellar and gaseous kinematics, as well as the emission-line flux distributions and ratios, from the inner 450pc radius of Mrk1157, using 2D near-IR spectra obtained with the Gemini NIFS at a spatial resolution of 35pc. The stellar velocity field shows a rotation pattern, with a discrete S-shaped zero velocity curve. The presence of a bar is also supported by the residual map between the observed rotation field and a model of circular orbits in a Plummer potential. The stellar velocity dispersion map presents a partial ring of low-sigma values (50-60km/s) at 250pc from the nucleus surrounded by higher sigma values from the galaxy bulge, originated in kinematically colder regions with recent star formation. The velocity dispersion of the bulge (100km/s) implies in a black hole mass of 8.3x10^6M_Sun. Emission-line flux distributions are most extended along PA=27/153deg, reaching at least 450pc from the nucleus and following the orientation observed in previous optical emission-line [OIII] imaging and radio jet. The molecular H_2 emission is dominated by thermal processes, mainly due to X-ray heating by the active nucleus. The [FeII] excitation has a larger contribution from shocks produced by the radio jet, as evidenced by the line-ratio maps and velocity dispersion map, which show spatial correlation with the radio structures. The gaseous kinematics shows two components, one due to gas located in the galaxy plane and another in outflow, which is oriented close to the plane of the sky, thus extending to high latitudes, as the galaxy plane is inclined by 45deg relative to the plane of the sky. The gas rotating in the plane dominates the H_2 and Pa-beta emission, while the gas in outflow is observed predominantly in [FeII] emission. From the outflow velocities and implied geometry, we estimate an outflow mass rate of 6M_sun/yr for the ionised gas.

Profit: a new alternative for emission-line profile fitting

I briefly describe a simple routine for emission-line profiles fitting by Gaussian curves or Gauss-Hermite series. The PROFIT (line-PROfile FITting) routine represent a new alternative for use in fits data cubes, as those from Integral Field Spectroscopy or Fabry-Perot Interferometry, and may be useful to better study the emission-line flux distributions and gas kinematics in distinct astrophysical objects, such as the central regions of galaxies and star forming regions. The PROFIT routine is written in IDL language and is available at http://www.ufsm.br/rogemar/software.html. The PROFIT routine was used to fit the [Fe II]1.257um emission-line profiles for about 1800 spectra of the inner 350 pc of the Seyfert galaxy Mrk1066 obtained with Gemini NIFS and shows that the line profiles are better reproduced by Gauss-Hermite series than by the commonly used Gaussian curves. The two-dimensional map of the h_3 Gauss-Hermite moment shows its highest absolute values in regions close to the edge of the radio structure. These high values may be originated in an biconical outflowing gas associated with the radio jet - previously observed in the optical [O III] emission. The analysis of this kinematic component indicates that the radio jet leaves the center of the galaxy with the north-west side slightly oriented towards us and the south-east side away from us, being partially hidden by the disc of the galaxy.

Near-infrared dust and line emission from the central region of Mrk 1066: constraints from Gemini NIFS

We present integral field spectroscopy of the inner 350 pc of the Mrk1066 obtained with Gemini NIFS at a spatial resolution of 35 pc. This high spatial resolution allowed us to observe, for the first time in this galaxy, an unresolved dust concentration with mass 0.014 M_Sun, which may be part of the dusty torus. The emission-line fluxes are elongated in PA=135/315deg in agreement with the [OIII] and radio images and, except for the H lines, are brighter to the north-west than to the south-east. The H emission is stronger to the south-east, where we find a large region of star-formation. The strong correlation between the radio emission and the highest emission-line fluxes indicates that the radio jet plays a fundamental role at these intensity levels. The H2 flux is more uniformly distributed and has an excitation temperature of 2100 K. Its origin appears to be circumnuclear gas heated by X-rays from the AGN. The [FeII] emission also is consistent with X-ray heating, but with additional emission due to excitation by shocks in the radio jet. The coronal-line emission of [CaVIII] and [SIX] are unresolved by our observations indicating a distribution within 18pc from the nucleus. The reddening ranges from E(B-V) ~ 0 to E(B-V) ~ 1.7 with the highest values defining a S-shaped structure along PA ~ 135/315deg. The emission-line ratios are Seyfert-like within the ionization cone indicating that the line emission is powered by the central active nucleus in these locations. Low ionization regions are observed away from the ionization cone, and may be powered by the diffuse radiation field which filters through the ionization cone walls. Two regions at 0.5 arcsec south-east and at 1 arcsec north-west of the nucleus show starburst-like line ratios, attributed to additional emission from star forming regions.

Circumnuclear Gas in Seyfert 1 Galaxies: Morphology, Kinematics, and Direct Measurement of Black Hole Masses

(Abridged) The two-dimensional distribution and kinematics of the molecular, ionized, and highly ionized gas in the nuclear regions of Seyfert 1 galaxies have been measured using high spatial resolution (~0''.09) near-infrared spectroscopy from NIRSPEC with adaptive optics on the Keck telescope. Molecular hydrogen, H2, is detected in all nine Seyfert 1 galaxies and, in the majority of galaxies, has a spatially resolved flux distribution. In contrast, the narrow component of the BrG emission has a distribution consistent with that of the K-band continuum. In general, the kinematics of H2 are consistent with thin disk rotation, with a velocity gradient of over 100 km/s measured across the central 0''.5 in three galaxies, and across the central 1''.5 in two galaxies. The kinematics of BrG are in agreement with the H2 rotation, except in all four cases the central 0''.5 is either blue- or redshifted by more than 75 km/s. The highly ionized gas, measured with the [Ca VIII] and [Si VII] coronal lines, is spatially and kinematically consistent with BrG in the central 0''.5. Dynamical models have been fitted to the two-dimensional H2 kinematics, taking into account the stellar mass distribution, the emission line flux distribution, and the point spread function. For NGC 3227 the modeling indicates a black hole mass of Mbh = 2.0{+1.0/-0.4} x 10^7 Msun, and for NGC 4151 Mbh = 3.0{+0.75/-2.2} x 10^7 Msun. In NGC 7469 the best fit model gives Mbh < 5.0 x 10^7 Msun. In all three galaxies, modeling suggests a near face-on disk inclination angle, which is consistent with the unification theory of active galaxies. The direct black hole mass estimates verify that masses determined from the technique of reverberation mapping are accurate to within a factor of three with no additional systematic errors.

Gemini near-infrared integral field spectroscopy of the narrow-line region of ESO 428-G14: kinematics, excitation and the role of the radio jet

We present two-dimensional (2D) gas kinematics and excitation of the inner 300 pc of the Seyfert galaxy ES0428-G14 at a sampling of 14 pc 2 , from near-infrared spectroscopic observations at R ≈ 6000 obtained with the Integral Field Unit (IFU) of the Gemini Near-Infrared Spectrograph. From measurements of fluxes and profiles of the emission lines [Fe II]λ 1.257 μm, Paβ, H 2 λ 2.121 μm and Bry, we construct 2D maps of line intensities and ratios, radial velocities and velocity dispersions. Emission line 'tomography' is provided by velocity slices obtained across the line profiles, a unique capability of IFUs, which allows the mapping of not only the peak velocities but including also the wings. We compare these maps with a previously published high spatial resolution radio map and find a tight relation between the radio structure and the emission-line flux distributions and kinematics, revealing that the radio jet plays a fundamental role not only in shaping the narrow-line region but also in the imprint of its kinematics. Blueshifts of up to 400 km s -1 and velocity dispersions of up to 150 km s -1 are observed in association with the radio jet at a position angle (PA) = 129°, which is also the PA of the photometric major axis of the galaxy. We conclude that the radio jet is launched at a small angle relative to the galactic plane, with the north-western side slightly oriented towards us. This angle is small enough for the radio jet to shock and compress the gas in the plane of the galaxy, and for the nuclear continuum to ionize and heat it. The distinct kinematics and flux distributions observed for the different emission lines suggest different origins for their emission. The [Fe ΙΙ] shows the largest blueshifts and velocity dispersions and its flux distribution is concentrated along the jet, while the H 2 shows the lowest velocity dispersions and has additional flux contribution from regions beyond the jet. Both X-rays emitted by the active galactic nucleus and shocks produced by the radio jet can excite the H 2 and [Fe II] emission lines. We use the 2D velocity dispersion maps to estimate upper limits to the contribution of the radio jet to the excitation of [Fe n] and H 2 which may reach 90 per cent for [Fe II] and 80 per cent for H 2 in the jet region. The [Fe II]/Paβ emission-line ratios and the association of the [Fe ΙΙ] flux distribution and kinematics with the radio structure support a stronger contribution of the radio jet to the [Fe ΙΙ] excitation than that of H 2 . In the regions beyond the jet, the observations favour X-ray excitation.