arXiv subjects

Rogemar A. Riffel

Publications and source records attributed to Rogemar A. Riffel.

At least 127 records · Page 7Linked to original sources

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.

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arXiv2018

Circumnuclear star formation in Mrk 42 mapped with Gemini Near-infrared Integral Field Spectrograph

We present Gemini Near-infrared Integral Field Spectrograph (NIFS) observations of the inner $1.5\times1.5$ kpc$^2$ of the narrow-line Seyfert 1 galaxy Mrk 42 at a spatial resolution of 60 pc and spectral resolution of 40 km s$^{-1}$. The emission-line flux and equivalent width maps clearly show a ring of circumnuclear star formation regions (CNSFRs) surrounding the nucleus with radius of $\sim$500 pc. The spectra of some of these regions show molecular absorption features which are probably of CN, TiO or VO, indicating the presence of massive evolved stars in the thermally pulsing asymptotic giant branch (TP-AGB) phase. The gas kinematics of the ring is dominated by rotation in the plane of the galaxy, following the large scale disk geometry, while at the nucleus an additional outflowing component is detected blueshifted by 300-500 kms$^{-1}$, relative to the systemic velocity of the galaxy. Based on the equivalent width of Br$γ$, we find evidences of gradients in the age of HII regions along the ring of Mrk 42, favoring the pearls on a string scenario of star formation. The broad component of Pa$β$ emission line presents a Full Width at Half Maximum (FWHM) of $\sim$1480 kms$^{-1}$, implying in a mass of $\sim\,2.5\times10^{6}$~M$_{\odot}$ for the central supermassive black hole. Based on emission-line ratios we conclude that besides the active galactic nucleus, Mrk 42 presents nuclear Starburst activity.

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arXiv2018

SDSS-IV MaNGA: Star formation cessation in low-redshift galaxies I. Dependence on stellar mass and structural properties

We investigate radial gradients in the recent star formation history (SFH) using 1917 galaxies with $0.01<z<0.14$ and integral-field spectroscopy from the ongoing MaNGA survey. For each galaxy, we obtain two-dimensional maps and radial profiles for three spectroscopically-measured parameters that are sensitive to the recent SFH: D$_n$(4000) (the 4000Å break), EW(H$δ_A$) (equivalent width of the H$δ$ absorption line), and EW(H$α$) (equivalent width of the H$α$ emission line). We find the majority of the spaxels in these galaxies are consistent with models with continuously declining star formation rate, indicating that starbursts occur rarely in local galaxies. We classify the galaxies into three classes: fully star-forming (SF), partly quenched (PQ) and totally quenched (TQ), according to the fraction of quenched area within 1.5 times the effective radius, $f_Q(1.5R_e)$. We find that galaxies less massive than $10^{10}$M$_{\odot}$ present at most weak radial gradients in all the diagnostic parameters. In contrast, galaxies with stellar mass above $10^{10}$M$_{\odot}$ present significant gradients in all the three diagnostic parameters if classified as SF or PQ, but show weak gradients in D$_n$(4000) and EW(H$δ_A$) and no gradients in EW(H$α$) if in the TQ class. This implies the existence of a critical stellar mass, at $\sim10^{10}$M$_{\odot}$, above which the star formation in a galaxy gets shutdown from the inside out. Galaxies tend to evolve synchronously from inner to outer regions before their mass reaches the critical value. We have further divided the sample at fixed mass by both bulge-to-total luminosity ratio and morphological type, finding that our conclusions hold regardless of these factors: it appears that the presence of a central dense object is not a driving parameter, but rather a byproduct of the star formation cessation process.

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arXiv2018

SDSS-IV MaNGA: Evidence of the importance of AGN feedback in low-mass galaxies

We present new evidence for AGN feedback in a subset of 69 quenched low-mass galaxies ($M_{\star} \lesssim 5\times10^{9}$ M$_{\odot}$, $M_{\rm{r}} > -19$) selected from the first two years of the SDSS-IV MaNGA survey. The majority (85 per cent) of these quenched galaxies appear to reside in a group environment. We find 6 galaxies in our sample that appear to have an active AGN that is preventing on-going star-formation; this is the first time such a feedback mechanism has been observed in this mass range. Interestingly, five of these six galaxies have an ionised gas component that is kinematically offset from their stellar component, suggesting the gas is either recently accreted or outflowing. We hypothesise these six galaxies are low-mass equivalents to the "red geysers" observed in more massive galaxies. Of the other 63 galaxies in the sample, we find 8 do appear for have some low-level, residual star formation, or emission from hot, evolved stars. The remaining galaxies in our sample have no detectable ionised gas emission throughout their structures, consistent with them being quenched. This work shows the potential for understanding the detailed physical properties of dwarf galaxies through spatially resolved spectroscopy.

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arXiv2017

Gemini IFU, VLA and HST observations of the OH Megamaser galaxy IRASF23199+0123: the hidden monster and its outflow

We present Gemini Multi-Object Spectrograph (GMOS) Integral field Unit (IFU), Very Large Array (VLA) and Hubble Space Telescope (HST) observations of the OH Megamaser (OHM) galaxy IRASF23199+0123. Our observations show that this system is an interacting pair, with two OHM sources associated to the eastern (IRAS23199E) member. The two members of the pair present somewhat extended radio emission at 3 and 20~cm, with flux peaks at each nucleus. The GMOS-IFU observations cover the inner $\sim$6kpc of IRAS23199E at a spatial resolution of 2.3~kpc. The GMOS-IFU flux distributions in H$α$ and [NII]$λ$6583 are similar to that of an HST [NII]+H$α$ narrow-band image, being more extended along the northeast-southwest direction, as also observed in the continuum HST F814W image. The GMOS-IFU H$α$ flux map of IRAS23199E shows three extranuclear knots attributed to star-forming complexes. We have discovered a Seyfert 1 nucleus in this galaxy, as its nuclear spectrum shows an unresolved broad (FWHM$\approx$2170 kms$^{-1}$) double-peaked H$α$ component, from which we derive a black hole mass of M$_{BH}$= 3.8$^{+0.3}_{-0.2}\times 10^{6}$M$_{\odot}$. The gas kinematics shows low velocity dispersions ($σ$) and low [NII]/H$α$ ratios for the star-forming complexes and higher $σ$ and [NII]/H$α$ surrounding the radio emission region, supporting interaction between the radio-plasma and ambient gas. The two OH masers detected in IRASF23199E are observed in the vicinity of these enhanced $σ$ regions, supporting their association with the active nucleus and its interaction with the surrounding gas. The gas velocity field can be partially reproduced by rotation in a disk, with residuals along the north-south direction being tentatively attributed to emission from the front walls of a bipolar outflow.

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arXiv2017

SDSS-IV MaNGA: Identification of active galactic nuclei in optical integral field unit surveys

In this paper, we investigate 2727 galaxies observed by MaNGA as of June 2016 to develop spatially resolved techniques for identifying signatures of active galactic nuclei (AGN). We identify 303 AGN candidates. The additional spatial dimension imposes challenges in identifying AGN due to contamination from diffuse ionized gas, extra-planar gas and photoionization by hot stars. We show that the combination of spatially-resolved line diagnostic diagrams and additional cuts on H$α$ surface brighness and H$α$ equivalent width can distinguish between AGN-like signatures and high-metallicity galaxies with LINER-like spectra. Low mass galaxies with high specific star formation rates are particularly difficult to diagnose and routinely show diagnostic line ratios outside of the standard star-formation locus. We develop a new diagnostic -- the distance from the standard diagnostic line in the line-ratios space -- to evaluate the significance of the deviation from the star-formation locus. We find 173 galaxies that would not have been selected as AGN candidates based on single-fibre spectral measurements but exhibit photoionization signatures suggestive of AGN activity in the MaNGA resolved observations, underscoring the power of large integral field unit (IFU) surveys. A complete census of these new AGN candidates is necessary to understand their nature and probe the complex co-evolution of supermassive black holes and their hosts.

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arXiv2017

The first 62 AGN observed with SDSS-IV MaNGA - I: their characterization and definition of a control sample

We report the characterization of the first $62$ MaNGA Active Galactic Nuclei (AGN) hosts in the Fifth Product Launch (MPL-5) and the definition of a control sample of non-active galaxies. This control sample - comprising two galaxies for each AGN - was selected in order to match the AGN hosts in terms of stellar mass, redshift, visual morphology and inclination. The stellar masses are in the range $9.4<\log(M/M_\odot)<11.5$, and most objects have redshifts $\leq 0.08$. The AGN sample is mostly comprised of low-luminosity AGN, with only 17 nuclei with $L([OIII]λ5007)\geq 3.8\times 10^{40}$ erg s$^{-1}$ (that we call "strong AGN"). The stellar population of the control sample galaxies within the inner $1$-$3$ kpc is dominated by the old ($\sim$ $4$ - $13$ Gyr) age component, with a small contribution of intermediate age ($\sim 640$-$940$ Myr) and young stars ($\leq 40$ Myr) to the total light at $5700Å$. While the weaker AGN show a similar age distribution to that of the control galaxies, the strong AGN show an increased contribution of younger stars and a decreased contribution of older stars. Examining the relationship between the AGN stellar population properties and $L([OIII])$, we find that with increasing $L([OIII])$, the AGN exhibit a decreasing contribution from the oldest ($>4$ Gyr) stellar population relative to control galaxies, but have an increasing contribution from the younger components with ages $\sim 40$ Myr. We also find a correlation of the mean age differences (AGN - control) with $L([OIII])$, in the sense that more luminous AGN are younger than the control objects, while the low-luminosity AGN seem to be older. These results support a connection between the growth of the galaxy bulge via formation of new stars and the growth of the Supermassive Black Hole via matter accretion in the AGN phase.

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arXiv2017

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$α$ 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$α$ 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-$σ$ 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.

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arXiv2017

Gemini NIFS survey of feeding and feedback processes in nearby Active Galaxies: I - Stellar kinematics

We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral resolution of 40 km/s. We find that the line-of-sight (LOS) velocity fields for most galaxies are well reproduced by rotating disk models. The kinematic position angle (PA) derived for the LOS velocity field is consistent with the large scale photometric PA. The residual velocities are correlated with the hard X-ray luminosity, suggesting that more luminous AGN have a larger impact in the surrounding stellar dynamics. The central velocity dispersion values are usually higher than the rotation velocity amplitude, what we attribute to the strong contribution of bulge kinematics in these inner regions. For 50% of the galaxies, we find an inverse correlation between the velocities and the $h_3$ Gauss-Hermitte moment, implying red wings in the blueshifted side and blue wings in the redshifted side of the velocity field, attributed to the movement of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational potential of a nuclear bar. Velocity dispersion maps show rings of low-$σ$ values (50-80 km/s) for 4 objects and "patches" of low-sigma for 6 galaxies at 150-250 pc from the nucleus, attributed to young/ intermediate age stellar populations.

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arXiv2017

Dusty spirals versus gas kinematics in the inner kiloparsec of Four Low-Luminosity Active Galactic Nuclei

We used the Gemini Multi-Object Spectrograph Integral Field Unit to map the gas distribution, excitation and kinematics within the inner kiloparsec of four nearby low-luminosity active galaxies: NGC3982, NGC4501, NGC2787 and NGC4450. The observations cover the spectral range 5600-7000Å at a velocity resolution of 120km/s and spatial resolution ranging from 50 to 70pc at the galaxies. Extended emission in Hα, [NII]λλ6548,6583, [SII]λλ6716,6730 over most of the field-of-view is observed for all galaxies, while only NGC3982 shows [OI]λ6300 extended emission. The Hα equivalent widths combined with the [NII]/Hα line ratios reveal that NGC3982 and NGC4450 harbor Seyfert nuclei surrounded by regions with LINER excitation, while NGC2787 and NGC4501 harbor LINER nuclei. NGC3982 shows a partial ring of recent star-formation at 500pc from the nucleus, while in NGC4501 a region at 500pc west of the nucleus shows LINER excitation but has been interpreted as an aging HII region with the gas excitation dominated by shocks from supernovae. The line-of-sight velocity field of the gas shows a rotation pattern for all galaxies, with deviations from pure disk rotation observed in NGC3982, NGC4501 and NGC4450. For NGC4501 and NGC4450, many of these deviations are spatially coincident with dust structures seen in optical continuum images, leading to the interpretation that the deviations are due to shocks in the gas traced by the dust. A speculation is that these shocks lead to loss of angular momentum, allowing the gas to be transferred inwards to feed the AGN. In the case of NGC2787, instead of deviations in the rotation field, we see a misalignment of 40{^\circ} between the orientation of the line of nodes of the gas rotation and the photometric major axis of the galaxy. Evidence of compact nuclear outflows are seen in NGC4501 and NGC4450.

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arXiv2017

Zooming into local active galactic nuclei: The power of combining SDSS-IV MaNGA with higher resolution integral field unit observations

Ionised gas outflows driven by active galactic nuclei (AGN) are ubiquitous in high luminosity AGN with outflow speeds apparently correlated with the total bolometric luminosity of the AGN. This empirical relation and theoretical work suggest that in the range L_bol ~ 10^43-45 erg/s there must exist a threshold luminosity above which the AGN becomes powerful enough to launch winds that will be able to escape the galaxy potential. In this paper, we present pilot observations of two AGN in this transitional range that were taken with the Gemini North Multi-Object Spectrograph Integral Field Unit (IFU). Both sources have also previously been observed within the Sloan Digital Sky Survey-IV (SDSS) Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. While the MaNGA IFU maps probe the gas fields on galaxy-wide scales and show that some regions are dominated by AGN ionization, the new Gemini IFU data zoom into the centre with four times better spatial resolution. In the object with the lower L_bol we find evidence of a young or stalled biconical AGN-driven outflow where none was obvious at the MaNGA resolution. In the object with the higher L_bol we trace the large-scale biconical outflow into the nuclear region and connect the outflow from small to large scales. These observations suggest that AGN luminosity and galaxy potential are crucial in shaping wind launching and propagation in low-luminosity AGN. The transition from small and young outflows to galaxy-wide feedback can only be understood by combining large-scale IFU data that trace the galaxy velocity field with higher resolution, small scale IFU maps.

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arXiv2016

The growth of the central region by acquisition of counter-rotating gas in star-forming galaxies

Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations and more intense, ongoing star formation than their outer parts, indicating ongoing growth of the central regions. The result offers observational evidence that the acquisition of external gas in blue galaxies is possible; the interaction with pre-existing gas funnels the gas into nuclear regions (< 1 kpc) to form new stars.

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arXiv2016

SDSS-IV MaNGA: A serendipitous observation of a potential gas accretion event

The nature of warm, ionized gas outside of galaxies may illuminate several key galaxy evolutionary processes. A serendipitous observation by the MaNGA survey has revealed a large, asymmetric H$α$ complex with no optical counterpart that extends $\approx8"$ ($\approx6.3$ kpc) beyond the effective radius of a dusty, starbursting galaxy. This H$α$ extension is approximately three times the effective radius of the host galaxy and displays a tail-like morphology. We analyze its gas-phase metallicities, gaseous kinematics, and emission-line ratios, and discuss whether this H$α$ extension could be diffuse ionized gas, a gas accretion event, or something else. We find that this warm, ionized gas structure is most consistent with gas accretion through recycled wind material, which could be an important process that regulates the low-mass end of the galaxy stellar mass function.

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arXiv2016

Gemini Near Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy Mrk 573: In Situ Acceleration of Ionized and Molecular Gas Off Fueling Flows

We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph (DIS) at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in a 700 x 2100 pc^2 circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region (NLR) are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges.

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arXiv2016

A SINFONI view of the nuclear activity and circum-nuclear 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.

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arXiv2016

Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy NGC 1365

We observed the nuclear region of the galaxy NGC 1365 with the integral field unit of the Gemini Multi Object Spectrograph mounted on the GEMINI-South telescope. The field of view covers $13^{\prime\prime} \times 6^{\prime\prime}$ ($1173 \times 541$ pc$^{2}$) centered on the nucleus, at a spatial resolution of $52$ pc. The spectral coverage extends from $5600$ Å to $7000$ Å, at a spectral resolution $R=1918$. NGC 1365 hosts a Seyfert 1.8 nucleus, and exhibits a prominent bar extending out to $100^{\prime\prime}$ (9 kpc) from the nucleus. The field of view lies within the inner Lindblad resonance. Within this region, we found that the kinematics of the ionized gas (as traced by [OI], [NII], H$α$, and [SII]) is consistent with rotation in the large-scale plane of the galaxy. While rotation dominates the kinematics, there is also evidence for a fan-shaped outflow, as found in other studies based on the [OIII] emission lines. Although evidence for gas inflowing along nuclear spirals has been found in a few barred galaxies, we find no obvious signs of such features in the inner kiloparsec of NGC 1365. However, the emission lines exhibit a puzzling asymmetry that could originate from gas which is slower than the gas responsible for the bulk of the narrow-line emission. We speculate that it could be tracing gas which lost angular momentum, and is slowly migrating from the inner Lindblad resonance towards the nucleus of the galaxy.

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arXiv2016

Integral Field Spectroscopy of the circumnuclear region of the Radio Galaxy Pictor A

We present optical integral field spectroscopy of the inner $2.5 \times 3.4$ kpc$^2$ of the broad-line radio galaxy Pictor A, at a spatial resolution of $\approx 400$ pc. Line emission is observed over the whole field-of-view, being strongest at the nucleus and in an elongated linear feature (ELF) crossing the nucleus from the south-west to the north-east along PA $\sim 70^\circ$. Although the broad double-peaked H$α$ line and the [OI]6300/H$α$ and [SII]6717+31/H$α$ ratios are typical of AGNs, the [NII]6584/H$α$ ratio (0.15 - 0.25) is unusually low. We suggest that this is due to the unusually low metallicity of the gas. Centroid velocity maps show mostly blueshifts to the south and redshifts to the north of the nucleus, but the velocity field is not well fitted by a rotation model. Velocity dispersions are low (< 100 km s$^{-1}$) along the ELF, ruling out a jet-cloud interaction as the origin of this structure. The ELF shows both blueshifts and redshifts in channel maps, suggesting that it is close to the plane of the sky. The ELF is evidently photoionized by the AGN, but its kinematics and inferred low metallicity suggest that this structure may have originated in a past merger event with another galaxy. We suggest that the gas acquired in this interaction may be feeding the ELF.

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arXiv2015

Feeding Versus Feedback in AGN from Near-Infrared IFU Observations XI: NGC 2110

We present a two-dimensional mapping of the gas flux distributions, as well as of the gas and stellar kinematics in the inner 220 pc of the Seyfert galaxy NGC 2110, using K-band integral field spectroscopy obtained with the Gemini NIFS at a spatial resolution of ~24pc and spectral resolution of ~40 km/s. The H2 emission extends over the whole field-of-view and is attributed to heating by X-rays from the AGN and/or by shocks, while the Brgamma emission is restricted to a bi-polar region extending along the South-East-North-West direction. The masses of the warm molecular gas and of the ionized gas are ~1.4x10^3 Msun and ~1.8x10^6 Msun, respectively. The stellar kinematics present velocity dispersions reaching 250km/s and a rotation pattern reaching an amplitude of 200 km/s. The gas velocity fields present a similar rotation pattern but also additional components that we attribute to inflows and outflows most clearly observed in the molecular gas emission. The inflows are observed beyond the inner 70 pc and are associated to a spiral arm seen in blueshift to the North-East and another in redshift to the South-West. We have estimated a mass inflow rate in warm molecular gas of ~4.6x10^-4 Msun/year. Within the inner 70 pc, another kinematic component is observed in the H2 emission that can be interpreted as due to a bipolar nuclear outflow oriented along the East-West direction, with a mass-outflow rate of ~4.3x10^-4 Msun/year in warm H2.

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