Gemini Multi-Object Spectrograph Integral Field Research Articles

AGN-driven outflows in the OH absorber galaxy IRAS 19154+2704

ABSTRACT We present a two-dimensional study of the gas distribution, excitation, and kinematics of the OH absorber galaxy IRAS 19154+2704 using Gemini Multi-Object Spectrograph integral field unit observations. Its continuum image shows a disturbed morphology indicative of a past or ongoing interaction. The ionized gas emission presents two kinematic components: a narrow (σ ≲ 300 km s−1) component that may be tracing the gas orbiting in the galaxy potential and a broad (σ ≳ 500 km s−1) component, which is produced by an active galactic nucleus (AGN)-driven outflow, with velocities reaching −500 km s−1, which may exceed the escape velocity of the galaxy. The emission-line ratios and Baldwin–Phillips–Terlevich diagrams confirm that the gas excitation in the inner ∼2 kpc is mainly due to the AGN, while in regions farther away, a contribution from star formation is observed. We estimate a mass-outflow rate of $\dot{M}_{\rm out}=4.0\pm 2.6$ M⊙ yr−1 at a distance of 850 pc from the nucleus. The corresponding outflow kinetic power, $\dot{E}_{\rm out} = (2.5\pm 1.6)\times 10^{42}$ erg s−1, is only 3 × 10−4 Lbol (the AGN luminosity), but the large mass-outflow rate, if kept for an ∼10 Myr AGN life cycle, will expel ≈108 M⊙ in ionized gas alone. This is the sixth of a series of papers in which we have investigated the kinematics of ultra-luminous infrared galaxies, most of which are interacting galaxies showing OH megamasers. IRAS 19154 shows the strongest signatures of an active AGN, supporting an evolutionary scenario: interactions trigger AGN that fully appears in the most advanced stages of the interaction.

Unraveling the Complex Structure of AGN-driven Outflows. VI. Strong Ionized Outflows in Type 1 AGNs and the Outflow Size–Luminosity Relation

We present spatially resolved gas kinematics, ionization, and energetics of 11 type 1 and 5 type 2 active galactic nuclei (AGNs) with strong ionized gas outflows at z <0.3 using Gemini Multi-Object Spectrograph Integral Field Unit data. We find a strongly blueshifted region in [O iii] velocity maps, representing an approaching cone in biconical outflows, and blueshifted and redshifted regions in Hα velocity maps, which show gravitationally rotating kinematics. AGN photoionization is dominant in the central region of most targets, and some of them also show ring-like structures of LINER or composite that surround the AGN-dominated center. Following our previous studies, we kinematically determine outflow sizes by the ratio between [O iii] and stellar velocity dispersion. Outflow sizes of type 1 AGNs follow the same kinematic outflow size–[O iii] luminosity relation obtained from the type 2 Integral Field Unit sample in Kang & Woo and Luo (updated slope 0.29 ± 0.04), while they are limited to the central kiloparsec scales, indicating the lack of global impact of outflows on the interstellar medium. Small mass outflow rates and large star formation rates of the combined sample support that there is no evidence of rapid star formation quenching by outflows, which is consistent with the delayed AGN feedback.

Gauging the effect of supermassive black holes feedback on quasar host galaxies

ABSTRACT In order to gauge the role that active galactic nuclei play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO 2’s (z ∼ 0.3), we observed eight such objects with bolometric luminosities $L_{bol} \sim 10^{46}\rm {erg\, s^{-1}}$ using Gemini Multi-Object Spectrograph-integral field units. 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 ∼1 to 8 kpc, being ${\sim }\, 0.5\, {\pm }\, 0.3$ times the extent of the [$\mathrm{O\,{\small III}}$] ionized gas region. Our ‘default’ assumptions for the gas density (obtained from the [$\mathrm{S\,{\small II}}$] doublet) and outflow velocities resulted in peak mass outflow rates of $\dot{M}_{\mathrm{ out}}^{{\tt def}}\sim$ 3–30 $\rm {M_{\odot }}\, yr^{-1}$ and outflow power of $\dot{E}_{\mathrm{ out}}^{{\tt \mathrm{ def}}}\sim \, 10^{41}$–$10^{43}\, \mathrm{erg\, s^{-1}}$. The corresponding kinetic coupling efficiencies are $\varepsilon _f^{{\tt def}}=\dot{E}_{\mathrm{ out}}^{{\tt def}}/L_{\mathrm{ bol}}\, \sim 7\times 10^{-4}$–0.5 per cent, with the average efficiency being only 0.06 per cent (0.01 per cent median), implying little feedback powers from ionized gas outflows in the host galaxies. We investigated the effects of varying assumptions and calculations on $\dot{M}_{\mathrm{ out}}$ and $\dot{E}_{\mathrm{ out}}$ regarding the ionized gas densities, velocities, masses, and inclinations of the outflow relative to the plane of the sky, resulting in average uncertainties of 1 dex. In particular, we found that better indicators of the [$\mathrm{O\,{\small III}}$] emitting gas density than the default [$\mathrm{S\,{\small II}}$] line ratio, such as the [$\mathrm{Ar\,{\small IV}}$] λλ4711,40 line ratio, result in almost an order of magnitude decrease in the εf.

Exploring the AGN-merger connection in Arp 245 I: Nuclear star formation and gas outflow in NGC 2992

ABSTRACT Galaxy mergers are central to our understanding of galaxy formation, especially within the context of hierarchical models. Besides having a large impact on the star formation history, mergers are also able to influence gas motions at the centre of galaxies and trigger an active galactic nucleus (AGN). In this paper, we present a case study of the Seyfert galaxy NGC 2992, which together with NGC 2993 forms the early-stage merger system Arp 245. Using Gemini Multi-Object Spectrograph integral field unit data from the inner 1.1 kpc of the galaxy, we were able to spatially resolve the stellar populations, the ionization mechanism, and kinematics of ionized gas. From full spectral synthesis, we found that the stellar population is primarily composed by old metal-rich stars (t ≥ 1.4 Gyr, Z ≥ 2.0 Z⊙), with a contribution of at most 30 per cent of the light from a young and metal-poor population (t ≤ 100 Myr, Z ≤ 1.0 Z⊙). We detect H α and H β emission from the broad-line region with a full width at half-maximum of ∼2000 $\rm km\, s^{-1}$. The narrow-line region kinematics presents two main components: one from gas orbiting the galaxy disc and a blueshifted (velocity ≈ −200 $\rm km\, s^{-1}$) outflow, possibly correlated with the radio emission, with mass outflow rate of ∼2 M⊙ yr−1 and a kinematic power of ∼2 × 1040 erg s−1 ($\dot{E}_{\mathrm{ out}}$/Lbol ≈ 0.2 per cent). We also show even though the main ionization mechanism is the AGN radiation, ionization by young stars and shocks may also contribute to the emission line ratios presented in the innermost region of the galaxy.

Chemical abundances in Seyfert galaxies – V. The discovery of shocked emission outside the AGN ionization axis

ABSTRACT We present maps for the electron temperature in the inner kpc of three luminous Seyfert galaxies: Mrk 79, Mrk 348, and Mrk 607 obtained from Gemini Multi-Object Spectrograph-integral field unit observations at spatial resolutions of ∼110–280 pc. We study the distributions of electron temperature in active galaxies and find temperatures varying in the range from ∼8000 to $\gtrsim 30\, 000\,$K. Shocks due to gas outflows play an important role in the observed temperature distributions of Mrk 79 and Mrk 348, while standard photoionization models reproduce the derived temperature values for Mrk 607. In Mrk 79 and Mrk 348, we find direct evidence for shock ionization with overall orientation orthogonal to the ionization axis, where shocks can be easily observed as the active galactic nuclei radiation field is shielded by the nuclear dusty torus. This also indicates that even when the ionization cones are narrow, the shocks can be much wider angle.

Gemini Multi-Object Spectrograph Integral Field Unit Spectroscopy of the Double-peaked Broad Emission Line of a Red Active Galactic Nucleus

Abstract Galaxy mergers are expected to produce multiple supermassive black holes (SMBHs) in close-separation, but the detection of such SMBHs has been difficult. 2MASS J165939.7 + 183436 is a red active galactic nucleus (AGN) that is a prospective merging SMBH candidate owing to its merging features in Hubble Space Telescope imaging and double-peaked broad emission lines (BELs). Herein, we report a Gemini Multi-Object Spectrograph Integral Field Unit observation of a double-peaked broad Hα line of 2MASS J165939.7+183436. Furthermore, we confirm the existence of two BEL peaks that are kinematically separated by 3000 km s−1, with the SMBH of each BEL component weighing at and , if they arise from independent BELs near the two SMBHs. The BEL components were not separated at &gt;0.″1; however, under several plausible assumptions regarding the fitting of each spaxel, the two components are found to be spatially separated at 0.″085 (∼250 pc). Different assumptions for the fitting can lead to a null (&lt;0.″05) or a larger spatial separation (∼0.″15). Given the uncertainty regarding the spatial separation, various models, such as the disk emitter and multiple SMBH models, are viable solutions to explain the double BEL components. These results will promote future research for finding more multiple SMBH systems in red AGNs, and higher-resolution imaging validates these different models.

Mapping the inner kpc of the interacting Seyfert galaxy NGC 2992: Stellar populations and gas kinematics

AbstractWe present Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) observations of the inner 1.1 kpc of the interacting Seyfert galaxy NGC 2992. From full spectral synthesis we found that the stellar population is mainly (up to 80 per cent of the total light) composed by an old (t ≥ 1.4 Gyr) metal-rich (Z ≥ 2.0) populations with a smaller but considerable contribution (up to 30 per cent) from young (t ≤ 100 Myr) metal-poor (Z ≥ 1.0) populations. The gas kinematics presents two main components: one from gas in orbit in the galaxy disk and an outflow with mass outflow rate of ˜2 Mʘ yr–1 and a kinematic power of ˜ 2 × 1040 erg s–1.

The DIVING3D Project: Analysis of the nuclear region of Early-type Galaxies

AbstractIn this work, we present preliminary results regarding the nuclear emission lines of a statistically complete sample of 56 early-type galaxies that are part of the Deep Integral Field Spectroscopy View of Nuclei of Galaxies (DIVING3D) Project. All early type galaxies (ETGs) were observed with the Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) installed on the Gemini South Telescope. We detected emission lines in 93% of the sample, mostly low-ionization nuclear emission-line region galaxies (LINERs). We did not find Transition Objects nor H II regions in the sample. Type 1 objects are seen in ∼23% of the galaxies.

Feedback from ionised gas outflows in the central kpc of nearby active galaxies

AbstractWe use integral-field spectroscopy obtained with the Gemini instrument GMOS-IFU (Gemini Multi-Object Spectrograph Integral Field Unit) to map the gas distribution, excitation and kinematics in the central kpc of 11 nearby active galaxies. We use channel maps to quantify the ionised gas masses, mass outflow rates and powers of the outflows in order to gauge the feedback effect of these outflows on the host galaxies. We compare this method with others previously used to calculate the feedback power of such outflows.

Gemini IFU, VLA, and HST observations of the OH Megamaser Galaxy IRAS17526 + 3253★

AbstractWe present a multiwavelength study of the OH megamaser galaxy IRAS17526 + 3253, based on new Gemini multi-object spectrograph integral field unit (GMOS/IFU) observations, Hubble Space Telescope F814W, and H α + [N ii] images, and archival 2MASS and 1.49 GHz VLA data. The Hubble Space Telescope(HST) images clearly reveal a mid-to-advanced stage major merger whose northwestern and southeastern nuclei have a projected separation of ∼8.5 kpc. Our HST/H α + [N ii] image shows regions of ongoing star formation across the envelope on ∼10 kpc scales, which are aligned with radio features, supporting the interpretation that the radio emission originates from star-forming regions. The measured H α luminosities imply that the unobscured star formation rate (SFR) is ∼10–30 M⊙ yr−1. The GMOS/IFU data reveal two structures in northwestern separated by 850 pc and by a discontinuity in the velocity field of ∼ 200 km s−1. We associate the blueshifted and redshifted components with, respectively, the distorted disc of northwestern and tidal debris, possibly a tail originating in southeastern. Star formation is the main ionization source in both components, which have SFRs of ∼2.6–7.9 M⊙ yr−1 and ∼1.5–4.5 M⊙ yr−1, respectively. Fainter line emission bordering these main components is consistent with shock ionization at a velocity ∼200 km s−1 and may be the result of an interaction between the tidal tail and the northwestern galaxy’s disc. IRAS17526 + 3253 is one of only a few systems known to host both luminous OH and H2O masers. The velocities of the OH and H2O maser lines suggest that they are associated with the northwestern and southeastern galaxies, respectively (Martin et al.; Wagner).

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.

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 5600-7000{\AA} at a velocity resolution of 120km/s and spatial resolution ranging from 50 to 70pc at the galaxies. Extended emission in H{\alpha}, [NII]{\lambda}{\lambda}6548,6583, [SII]{\lambda}{\lambda}6716,6730 over most of the field-of-view is observed for all galaxies, while only NGC3982 shows [OI]{\lambda}6300 extended emission. The H{\alpha} equivalent widths combined with the [NII]/H{\alpha} 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.

UNRAVELLING THE COMPLEX STRUCTURE OF AGN-DRIVEN OUTFLOWS. II. PHOTOIONIZATION AND ENERGETICS

ABSTRACT Outflows have been shown to be prevalent in galaxies hosting luminous active galactic nuclei (AGNs); they present a physically plausible way to couple the AGN energy output with the interstellar medium of their hosts. Despite their prevalence, accurate characterization of these outflows has been challenging. In the second of a series of papers, we use Gemini Multi-Object Spectrograph integral field unit (IFU) data of six local (z &lt; 0.1) and moderate-luminosity Type 2 AGNs to study the ionization properties and energetics of AGN-driven outflows. We find strong evidence connecting the extreme kinematics of the ionized gas to the AGN photoionization. The kinematic component related to the AGN-driven outflow is clearly separated from other kinematic components, such as virial motions or rotation, on the velocity and velocity dispersion diagram. Our spatially resolved kinematic analysis reveals that 30 to 90% of the total mass and kinetic energy of the outflow is contained within the central kpc of the galaxy. The spatially integrated mass and kinetic energy of the gas entrained in the outflow correlate well with the AGN bolometric luminosity and results in energy conversion efficiencies between 0.01% and 1%. Intriguingly, we detect ubiquitous signs of ongoing circumnuclear star formation. Their small size, the centrally contained mass and energy, and the universally detected circumnuclear star formation cast doubts on the potency of these AGN-driven outflows as agents of galaxy-scale negative feedback.

UNRAVELING THE COMPLEX STRUCTURE OF AGN-DRIVEN OUTFLOWS. I. KINEMATICS AND SIZES

ABSTRACT Outflows driven by active galactic nuclei (AGNs) are often invoked as agents of the long-sought AGN feedback. Yet, characterizing and quantifying the impact on their host galaxies has been challenging. We present Gemini Multi-Object Spectrograph integral field unit data of six local (z &lt; 0.1 ?> ) and luminous (L [ O III ] &gt; 10 42 ?> erg s−1) type 2 AGNs. In the first of a series of papers, we investigate the kinematics and constrain the size of the outflows. The ionized gas kinematics can be described as a superposition of a gravitational component that follows the stellar motion and an outflow-driven component that shows large velocity (up to 600 km s−1) and large velocity dispersion (up to 800 km s−1). Using the spatially resolved measurements of the gas, we kinematically measure the size of the outflow, which is found to be between 1.3 and 2.1 kpc. Owing to the lack of a detailed kinematic analysis, previous outflow studies likely overestimate their size by up to more than a factor of two, depending on how the size is estimated and whether the [O iii] or Hα emission line is used. The relatively small size of the outflows for all six of our objects casts doubts on their potency as a mechanism for negative AGN feedback.

Integral Field Spectroscopy of the Extended Emission‐Line Region of 3C 249.1

We present Gemini Multiobject Spectrograph integral field spectroscopy of the extended emission-line region associated with quasar 3C 249.1. The kinematics of the ionized gas measured from the [O III] λ5007 line is rather complex and cannot be explained globally by a simple dynamical model, but some clouds can be modeled individually as having locally linear velocity gradients. The temperatures of the ionized gas appear uniform (varying from ~12,000 to 15,000 K), while the densities vary from a few tens to a few hundred per cubic centimeter. The emission mechanism of all of the emission clouds, as indicated by the line-ratio diagnostics, is consistent with both "shock + precursor" and pure photoionization models. The total mass of the ionized gas is on the order of 109 M☉. We estimate a bulk kinetic energy and momentum of the extended emission-line region of 2.5 × 1057 ergs and 1050 dyn s, and a dynamical timescale of ~10 Myr. By comparing the injection rates of kinetic energy and momentum of different galactic wind models with the observation, we argue that the emission-line clouds are most likely a direct result of the feedback of the quasar. We also discuss the nature of the extended X-ray emission surrounding the quasar.

Gemini Multi-Object Spectrograph Integral Field Unit Spectroscopy of the 167-317 (LV2) Proplyd in Orion

We present high spatial resolution spectroscopic observations of the proplyd 167-317 (LV2) near the Trapezium cluster in the Orion Nebula, obtained during the system verification run of the Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU) at the Gemini South Observatory. We have detected 38 forbidden and permitted emission lines associated with the proplyd and its redshifted jet. We have been able to detect three velocity components in the profiles of some of these lines: a peak with a 28–33 km s-1 systemic velocity that is associated with the photoevaporated proplyd flow, a highly redshifted component associated with a previously reported jet (which has receding velocities of about 80–120 km s-1 with respect to the systemic velocity and which is spatially distributed to the southeast of the proplyd), and a less obvious, approaching structure that may possibly be associated with a faint counterjet with a systemic velocity of -75 ± 15 km s-1. We find evidence that the redshifted jet has a variable velocity, with slow fluctuations as a function of the distance from the proplyd. We present several background-subtracted, spatially distributed emission-line maps, and we use this information to obtain the dynamical characteristics over the observed field. Using a simple model and extinction-corrected Hα fluxes, we estimate the mass-loss rate for both the proplyd photoevaporated flow and the redshifted microjet, obtaining proplyd = (6.2 ± 0.6) × 10-7 M⊙ yr-1 and jet = (2.0 ± 0.7) × 10-8 M⊙ yr-1, respectively.

Gemini Multi-Object Spectrograph Integral Field Spectroscopy of a Merging System with Enhanced Balmer Absorption

In this paper we present the three-dimensional dynamics of the galaxy SDSS J101345.39+011613.66, selected for its unusually strong Balmer absorption lines [W0(Hδ) = 7.5 A]. Using the Gemini Multi-Object Spectrograph-South integral field unit (IFU) in nod+shuffle mode, we have mapped the continuum and optical absorption lines of this z = 0.1055 field galaxy. This galaxy has a disturbed morphology, with a halo of diffuse material distributed asymmetrically toward the north. Using the [O II] emission line (W0[O ] = 4.1 A), we find that the gas and hot OB stars are offset from the older stars in the system. The gas also has a spatially extended and elongated morphology with a velocity gradient of 100 ± 20 km s-1 across 6 kpc in projection. Using the strong Hγ and Hδ absorption lines, we find that the A stars are widely distributed across the system and are not centrally concentrated, arguing that the A star population has formed in molecular clouds outside the nucleus. By cross-correlating the spectra from the data cube with an A star template, we find evidence that the A star population has a 40 km s-1 shear in the same direction as the gas. The disturbed morphology, strong color gradients, and strong Hδ and Hγ absorption lines in SDSS J101345.39 argue that this is a recent tidal interaction/merger between a passive elliptical and a star-forming galaxy. Although based on a single object, these results show that we can spatially resolve and constrain the dynamics of this short-lived (yet important) phase of galaxy formation in which the evolutionary process takes galaxies from star-forming to their quiescent end products.