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

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 2 Gyr) is dominant. The [Fe ii] λ1.2570μm 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 galax

Feeding versus feedback in active galactic nuclei from near-infrared integral field spectroscopy : XII. NGC 5548

We map the gas excitation and kinematics, and the stellar population properties of the Seyfert 1 galaxy NGC 5548 using Gemini Near Infrared Integral Field Spectrograph in the J and K bands at a spatial and velocity resolution of 105 pc and 45 km s−1, respectively. Emission-line flux distributions in ionized and molecular gas extend up to ≈400 pc from the nucleus, where they are found to peak. The mass of HII is 4.8±0.6 × 106 M and the mass of warm H2 is 1.1±0.2 × 103 M , while the mass of cold H2 is estimated as 5.8±1.2 × 108 M . The Pa β emission shows two kinematic components: one in blueshift, with velocity reaching ≈−300 km s−1 and another showing a velocity field characteristic of rotation in the galaxy plane. The blueshifted component is also observed in the coronal line [S IX]λ1.2523 μm, while the rotational component is also observed in the molecular gas.We interpret this velocity field as due to gas rotating in the galaxy plane plus an outflow, and estimate a mass outflow rate of 6.8±0.75 M yr−1. Spectral synthesis of the continuum shows nuclear emission dominated by a featureless AGN continuum combined with hot dust emission attributed to a dusty torus. The stellar population is dominated by an old (2 Gyr < t ≤ 15 Gyr) component between 160 and 300 pc, while closer to the nucleus, an intermediate age (50 Myr < t ≤ 2 Gyr) component contributes at levels ranging from ≈40 per cent to ≈100 per cent to the flux at 2.12 μm

SDSS IV MaNGA : star-formation driven biconical outflows in face-on galaxies

We find 132 face-on and low inclination galaxies with central star formation driven biconical gas outflows (FSFB) in the SDSS MaNGA (Mapping Nearby Galaxies at APO) survey. The FSFB galaxies show either double peaked or broadened emission line profiles at their centres. The peak and maximum outflow velocities are 58 and 212 km s−1, respectively. The gas velocity dispersion reveals a mild dependence on the central star formation surface density compatible with models of gas dispersion powered by the Jeansinstability in gas clumps or by gasturbulence dissipation. We estimate the gas outflow rate and conclude that the central gas depletion time does not depend on galactic mass. In turn, the ratio of the gas outflow rate to the gas consumption rate by the star formation is low in massive galaxies and high in low mass objects, while the star formation is a more rapid process of the gas consumption. We compare properties of the FSFB galaxies with a control sample of 375 comparison galaxies and find that the FSFB objects have high central concentration of star formation and also younger central stellar population with respect to their periphery. We analysed the environment of the galaxies and identified nearby satellites and elements of low surface brightness structure. We see that many tidal-enhanced features that can be assigned to early and intermediate stages of galactic interaction are much more frequent in the FSFB galaxies with respect to the comparison sample. We conclude that the gas should be replenished via the accretion from small satellites

SDSS-IV MaNGA : star-formation-driven biconical outflows in the local universe

We present a sample of 48 nearby galaxies with central, biconical outflows identified by the Mapping Nearby Galaxies at APO survey. All considered galaxies have star-formation-driven biconical (SFB) central outflows, with no signs of an active galactic nucleus. We find that the SFB outflows require high central concentration of the star formation rate. This increases the gas velocity dispersion over the equilibrium limit and helps maintain the gas outflows. The central starbursts increase the metallicity, extinction, and the [α/Fe] ratio in the gas. A significant amount of young stellar population at the centers suggests that the SFBs are associated with the formation of young bulges in galaxies. More than 70% of SFB galaxies are group members or have companions with no prominent interaction, or show asymmetry of external isophotes. In 15% of SFB cases, stars and gas rotate in the opposite directions, which points at the gas infall from satellites as the primary reason for triggering the SFB phenomena

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 × 1.5 kpc2 of the narrow-line Seyfert 1 galaxy Mrk 42 at a spatial resolution of 60 pc and spectral resolution of 40 kms−1. The emission-line flux and equivalent width maps clearly show a ring of circumnuclear star formation regions surrounding the nucleus with radius of ∼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 phase. The gas kinematics of the ring is dominated by rotation in the plane of the galaxy, following the large-scale disc geometry, while at the nucleus an additional outflowing component is detected blueshifted by 300–500 km s−1, relative to the systemic velocity of the galaxy. Based on the equivalent width of Br γ we find pieces of evidence of gradients in the age of HII regions along the ring of Mrk 42, favouring the pearls on a string scenario of star formation. The broad component of Pa β emission line presents a FullWidth at Half Maximum of ∼1480 km s−1, implying in a mass of ∼2.5 × 106 M 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

Host galaxy properties of changing-look AGNs revealed in the MaNGA survey

Changing-look active galactic nuclei (CL-AGNs) are a subset of AGNs in which the broad Balmer emission lines appear or disappear within a few years. We use the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to identify five CL-AGNs. The 2D photometric and kinematic maps reveal common features as well as some unusual properties of CL-AGN hosts as compared to the AGN hosts in general. All MaNGA CL-AGNs reside in the star-forming main sequence, similar to MaNGA non-changing-look AGNs (NCL-AGNs). The 80 ± 16 per cent of our CL-AGNs do possess pseudo-bulge features, and follow the overall NCL-AGN MBH–σ∗ relationship. The kinematic measurements indicate that they have similar distributions in the plane of angular momentum versus galaxy ellipticity. MaNGA CL-AGNs, however, show a higher, but not statistically significant (20 ± 16 per cent) fraction of counter-rotating features compared to that (1.84 ± 0.61 per cent) in general star formation population. In addition, MaNGA CL-AGNs favour more face-on (axial ratio > 0.7) than that of type I NCL-AGNs. These results suggest that host galaxies could play a role in the CL-AGN phenomenon

The metal-poor dwarf irregular galaxy candidate next to Mrk 1172

In this work, we characterize the properties of the object SDSS J020536.84−081424.7, an extended nebular region with projected extension of 14 × 14 kpc2 in the line of sight of the ETG Mrk 1172, using unprecedented spectroscopic data from MUSE. We perform a spatially resolved stellar population synthesis and estimate the stellar mass for both Mrk 1172 (1 × 1011 M ) and our object of study (3 × 109 M ). While the stellar content of Mrk 1172 is dominated by an old (∼10 Gyr) stellar population, the extended nebular emission has its light dominated by young to intermediate age populations (from ∼100 Myr to ∼1 Gyr) and presents strong emission lines such as H β; [O III] λλ4959, 5007 Å; H α; [N II] λλ6549, 6585 Å; and [S II] λλ6717, 6732 Å. Using these emission lines, we find that it is metal poor (with Z ∼ 1/3 Z , comparable to the LMC) and is actively forming stars (0.70 M yr−1), especially in a few bright clumpy knots that are readily visible in H α. The object has an ionized gas mass ≥3.8 × 105 M . Moreover, the motion of the gas is well described by a gas in circular orbit in the plane of a disc and is being affected by interaction wtih Mrk 1172. We conclude that SDSS J020536.84−081424.7 is most likely a dwarf irregular galaxy (the dIGal)

Gemini NIFS survey of feeding and feedback in nearby active galaxies III. Ionized versus warm molecular gas masses and distributions

We have used the Gemini Near-Infrared Integral Field Spectrograph in the J and K bands to map the distribution, excitation, and kinematics of the ionized H ii and warm molecular gas H2, in the inner few 100 pc of six nearby active galaxies: NGC 788, Mrk 607, NGC 3227, NGC 3516, NGC 5506, NGC 5899. For most galaxies, this is the first time that such maps have been obtained. The ionized and H2 gas show distinct kinematics: while the H2 gas is mostly rotating in the galaxy plane with low velocity dispersion (σ), the ionized gas usually shows signatures of outflows associated with higher σ values, most clearly seen in the [Fe ii] emission line. These two gas species also present distinct flux distributions: the H2 is more uniformly spread over the whole galaxy plane, while the ionized gas is more concentrated around the nucleus and/or collimated along the ionization axis of its active galactic nucleus (AGN), presenting a steeper gradient in the average surface mass density profile than the H2 gas. The total H ii masses cover the range 2×105--2×107 M⊙, with surface mass densities in the range 3–150 M⊙ pc−2, while for the warm H2 the values are 103–4 times lower. We estimate that the available gas reservoir is at least ≈ 100 times more massive than needed to power the AGN. If this gas forms new stars the star formation rates, obtained from the Kennicutt–Schmidt scaling relation, are in the range 1–260 × 10−3 M⊙ yr−1. But the gas will also – at least in part – be ejected as the observed outflow

Oxygen abundances in the narrow line regions of Seyfert galaxies and the metallicity–luminosity relation

We present oxygen abundances relative to hydrogen (O/H) in the narrow line regions (NLRs) gas phases of Seyferts 1 (Sy 1s) and Seyferts 2 (Sy 2s) active galactic nuclei (AGNs). We used fluxes of the optical narrow emission line intensities [3 500 < λ(Å) < 7 000] of 561 Seyfert nuclei in the local Universe ( z 0.31) from the second catalogue and data release (DR2) of the BAT AGN Spectroscopic Survey, which focuses on the Swift-BAT hard X-ray ( 10 keV) detected AGNs. We derived O/H from relative intensities of the emission lines via the strong-line methods. We find that the AGN O/H abundances are related to their hosts stellar masses and that they follow a downward redshift evolution. The derived O/H together with the hard X-ray luminosity (LX) were used to study the X-ray luminosity–metallicity (LX–ZNLR) relation for the first time in Seyfert galaxies. In contrast to the broad-line focused (LX–ZBLR) studies, we find that the LX–ZNLR exhibit significant anticorrelations with the Eddington ratio (λEdd) and these correlations vary with redshifts. This result indicates that the low-luminous AGNs are more actively undergoing interstellar medium enrichment through star formation in comparison with the more luminous X-ray sources. Our results suggest that the AGN is somehow driving the galaxy chemical enrichment, as a result of the inflow of pristine gas that is diluting the metal rich gas, together with a recent cessation on the circumnuclear star-formation

Gemini NIFS survey of feeding and feedback in nearby active galaxies : IV. Excitation

The near-infrared spectra of active galactic nuclei (AGN) present emission lines of different atomic and molecular species. The mechanisms involved in the origin of these emission lines in AGN are still not fully understood. We use J- and K-band integral field spectra of six luminous (43.1 < logLbol/(erg s−1) < 44.4) Seyfert galaxies (NGC 788, Mrk 607, NGC 3227, NGC 3516, NGC 5506, and NGC 5899) in the local Universe (0.0039 <z< 0.0136) to investigate the gas excitation within the inner 100–300 pc radius of the galaxies at spatial resolutions of a few tens of parsecs. In all galaxies, the H2 emission originates from thermal processes with excitation temperatures in the range 2400–5200 K. In the high-line ratio (HLR) region of the H2/Brγ versus [Fe II]/Paβ diagnostic diagram, which includes 29 per cent of the spaxels, shocks are the main excitation mechanism, as indicated by the correlation between the line widths and line ratios. In the AGN region of the diagram (64 per cent of the spaxels) the H2 emission is due to the AGN radiation. The [Fe II] emission is produced by a combination of photoionization by the AGN radiation and shocks in five galaxies and is dominated by photoionization in NGC 788. The [S IX]1.2523 μm coronal emission line is present in all galaxies, and its flux distributions are extended from 80 to 185 pc from the galaxy nuclei, except for NGC 5899, in which this line is detected only in the integrated spectrum