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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. Here, 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. Counter-rotating gases demonstrate external gas acquisition in galaxies, but their presence in blue, star-forming galaxies has not been studied systematically. Here, the authors analyse the MaNGA survey data to find a fraction of counter-rotators among blue galaxies whose central regions show ongoing growth.

I briefly describe a simple routine for emission-line profile fitting by Gaussian curves or Gauss–Hermite series. The profit (line- pro file fit ting) routine represent a new alternative for use in fits data cubes, as the ones from Integral Field Spectroscopy or Fabry–Pérot 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 ] λ =1.257 μm emission-line profiles for about 1800 spectra of the inner 350 pc of the Seyfert galaxy Mrk 1066 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 to be in regions close to the edge of the radio structure. These high values may be originating with 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.

We present 1.3 and 3.6 cm radio continuum images and a HCO+ spectrum of the massive star forming region G75.78+0.34 obtained with the Very Large Array (VLA) and with the Berkley Illinois Maryland Association (BIMA) interferometer. Three structures were detected in the continuum emission: one associated with the well-known cometary H ɪɪ region, plus two more compact structures located at 6′′ east and at 2′′ south of cometary H ɪɪ region. Using the total flux and intensity peak we estimated an electron density of ≈1.5 × 104 cm−3, an emission measure of ≈6 × 107 cm−6 pc, a mass of ionized gas of ≈3 M⊙, and a diameter of 0.05 pc for the cometary H ɪɪ region, being typical values for an ultracompact H ɪɪ region. The HCO+ emission probably originates from the molecular outflows previously observed in HCN and CO.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The understating of the origin of the ... line emission from the central regions of galaxies represents 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 Starburst, 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 ... 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 ... of the LIRG NGC6240, known to be the galaxy with strongest ... 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 ... west of the northern nucleus, they can be reproduced by a single Gaussian component. We found that the ... 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 ... line ratio. A contribution of fluorescent excitation may also be important at locations near ... west of the northern nucleus, which show the lowest line ratios. The [Feii]... ratio show a similar trend as observed for ..., suggesting that [Feii] and ... line emission have similar origins. Finally, the [Caviii]... coronal line emission is observed mainly in regions next to the nuclei, suggesting it is originated gas ionized by the radiation from the AGN.

We 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.

Frequent accretion of external cold gas is thought to play an important role in galaxy assembly. However, almost all known kinematically misaligned galaxies identify only one gas disk that is misaligned with the stellar disk, implying a single gas acquisition event. Here we report a new configuration in two galaxies where both contain two gas disks misaligned with each other and also with the stellar disk. Such systems are not expected to be stable or long-lasting, challenging the traditional picture of gas accretion of galaxies and their angular momentum build-up. The differences in kinematic position angles are larger than 120° between the two gas disks, and 40° between each gas disk and the stellar component. The star formation activity is enhanced at the interface of the two gas disks compared with the other regions within the same galaxy. Such systems illustrate that low-redshift galaxies can still experience multiple gas acquisition events, and provide a new view into the origins of galactic gas. Multiple gas disks, both misaligned with the stellar disk, are reported in two galaxies, providing evidence for multiple gas acquisition events, challenging the traditional picture of galaxy accretion and suggesting a new trigger mechanism for star formation.

We used Gemini NIFS integral field spectroscopy to analyse the molecular and ionised gas kinematics of six nearby (z ⩽ 0.015) Seyfert galaxies with a spatial coverage of 0.1 – 0.6 kpc2. By fitting the emission-line profiles using multiple Gaussian components we determined that the ionised and hot molecular gas kinematics are dominated by gas outflows and rotation, respectively, even though three objects also present molecular outflows.

We investigate the ionized gas excitation and kinematics in the inner 4.3 × 6.2 kpc2 of the merger radio galaxy 4C +29.30. Using optical integral field spectroscopy with the Gemini North Telescope, we find signatures of gas outflows, including high blueshifts of up to ∼−650 km s−1 observed in a region ∼1″ south of the nucleus, which also presents high velocity dispersion (∼250 km s−1). A possible redshifted counterpart is observed north from the nucleus. We propose that these regions correspond to a bipolar outflow possibly due to the interaction of the radio jet with the ambient gas. We estimate a total ionized gas mass outflow rate of $\\[{\\dot M_{out}} = 18.1\\begin{array}{c} + 8.2\\\ - 5.3\\end{array}{\\kern 1pt} {\\kern 1pt} \\]$ with a kinetic power of $\\[\\dot E = 5.8\\begin{array}{c} + 7.6\\\ - 2.9\\end{array} \\times {10^{42}}{\\kern 1pt} {\\kern 1pt} \\]$ , which represents $\\[3.9\\begin{array}{c} + 5.1\\\ - 1.5\\end{array}\\% \\]$ of the AGN bolometric luminosity. These values are higher than usually observed in nearby active galaxies and could imply a significant impact of the outflows on the evolution of the host galaxy.

The understating of the origin of the H 2 line emission from the central regions of galaxies represents 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 Starburst, 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 H 2 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 1.4 × 2.4 kpc 2 of the LIRG NGC 6240, known to be the galaxy with strongest H 2 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 H 2 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 H 2 λ 2.12 μm / Br γ 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 [Fe  ii ] λ 2.072 μm / Br γ ratio show a similar trend as observed for H 2 λ 2.12 μm / Br γ , suggesting that [Fe  ii ] and H 2 line emission have similar origins. Finally, the [Ca  viii ] λ 2.32 μm coronal line emission is observed mainly in regions next to the nuclei, suggesting it is originated gas ionized by the radiation from the AGN.

We present Gemini Near-Infrared Integral-Field Spectrograph (NIFS) observations of the inner 660 × 660 pc2 of the Seyfert 2 galaxy NGC 1125, which reveals that the emission-line profiles present two kinematic components: a narrow one (σ < 150 km s−1) due to emission of the gas in the disk and a broad component (σ > 150 km s−1) produced by a bipolar outflow, perpendicular to the galaxy’s disk.