We have studied the nuclear region of the previously detected dual AGN system in the galaxy pair IRAS 05589 + 2828 and 2MASX J06021107 + 2828382, through new optical spectroscopy observations, along with radio and X-ray archival data. Our multiwavelength data strongly suggest that the Sy 1 IRAS 05589+2828 (z = 0.0330 +/- 0.0002) conforms to a dual AGN system with the Sy2 2MASX J06021107 + 2828382 (z = 0.0334 +/- 0.0001), with a projected separation obtained from the radio data of 20.08 arcsec (similar to 13.3 kpc). Analysis of the optical spectra reveals a faint narrow extended emission from H alpha and [O III) amidst the two AGN, supporting evidence for an ongoing merger. IRAS 05589 + 2828 is a double component narrow emission-line AGN, with complex broad Balmer emission line profiles that clearly show a strong red-peaklet with a velocity shift of similar to 3500 km s(-1). The black hole mass estimates of IRAS 05589 +/- 2828 and 2MASX J06021107 + 2828382 are log M-BH = 8.59 +/- 0.14 (M-circle dot) and log M-BH = 8.21 +/- 0.2 (M-circle dot), respectively. In the X-ray bands, IRAS 05589 + 2828 is compatible with a Type 1 object, showing both spectral and flux variability. Chandra data of 2MASX J06021107 + 2828382 allowed us to measure a high hardness ratio in this source, providing evidence for a Type 2 AGN. The 22 GHz image obtained with the Karl G. Jansky Very Large Array has revealed that both AGN are compact radio objects with spectral indices -0.26 +/- 0.03 and -0.70 +/- 0.11, confirming for the first time its dual AGN nature in the radio bands.

ABSTRACT A detailed multiwavelength study of the properties of the triple-peaked active galactic nucleus (AGN) Mrk 622 showing different aspects of the nuclear emission region is presented. Radio, near- and mid-infrared, optical, and X-ray data have been considered for the analysis. In the optical, the WHAN diagnostic diagrams show that the three nuclear peaks are strong active galactic nuclei since the equivalent width of H α is > 6 Å and log [N ii] λ6584/H α ratio is > −0.4. Optical variability of both the continuum flux and intensity of the narrow emission lines is detected in a time span of 13 yr. The size of the narrow-line region is found to be 2.7 pc, with a light-crossing time of 8.7 yr. Analysis done to an archival Hubble Space Telescope image at 1055.2 nm shows that the host galaxy has a 3.6 kpc inner bar with PA = 74°, faint spiral arms, and a pseudobulge, evolving through secular processes. High-resolution mid-infrared images obtained with the Gran Telescopio Canarias (GTC) and the instrument CanariCam show that the nuclear emission at 11.6 $\rm{\mu m}$ is not spatially resolved. Very Large Array archival observations at 10 GHz reveal a core source with a total flux density of 1.47 ± 0.03 mJy. The spectral index of the core between 8 and 12 GHz is −0.5 ± 0.2, characteristic of AGN. The core deconvolves into a source with dimensions of 82 ± 13 mas $\, \times \,$ 41 ± 20 mas, and a PA = 70 ± 18 deg, which suggests that the core is elongated or that it is constituted by multiple components distributed along a ∼65° axis.

We use our state-of-the-art semi-analytic model for GAlaxy Evolution and Assembly (GAEA), and observational measurements of nearby galaxies to study the influence of the environment on the gas content and gaseous/stellar disc sizes of star-forming galaxies. We analyse the origin of differences between physical properties of satellites and those of their central counterparts, identified by matching the V-max of their host haloes at the accretion time of the satellites. Our model nicely reproduces the differences between centrals and satellites measured for the HI mass, size of the star-forming region, and stellar radii. In contrast, our model predicts larger differences with respect to data for the molecular gas mass and star formation rate. By analysing the progenitors of central and satellite model galaxies, we find that differences in the gas content arise after accretion, and can be entirely ascribed to the instantaneous stripping of the hot gas reservoir. The suppression of cold gas replenishment via cooling and star formation leads to a reduction of the cold gas and of its density. Therefore, more molecular gas is lost than lower density HI gas, and model satellites have less molecular gas and lower star formation rates than observed satellites. We argue that these disagreements could be largely resolved with the inclusion of a proper treatment for ram-pressure stripping of cold gas and a more gradual stripping of the hot gas reservoir. A more sophisticated treatment of angular momentum exchanges, accounting for the multi-phase nature of the gaseous disc, is also required.

Mrk 622 is a Compton thick active galactic nuclei (AGN) and a double-peaked narrow emission line galaxy, thus a dual AGN candidate. In this work, new optical long-slit spectroscopic observations clearly show that this object is rather a triple peaked narrow emission line galaxy, with both blue and red shifted narrow emission lines, as well as a much narrower emission line centred at the host galaxy systemic velocity. The average velocity offset between the blue and red shifted components is similar to 500 km s(-1), which is producing the apparent double-peaked emission lines. These two components are in the loci of AGN in the Baldwin, Phillips & Terlevich diagrams and are found to be spatially separated by similar to 76 pc. Analysis of the optical spatially resolved spectroscopic observations presented in this work favours that Mrk 622 is a system consisting of a composite AGN amidst a binary AGN candidate, likely the result of a recent merger. This notwithstanding, outflows from a starburst, or single AGN could also explain the triple nature of the emission lines.

We have used Spitzer images of a sample of 68 barred spiral galaxies in the local universe to make systematic measurements of bar length and bar strength. We combine these with precise determinations of the corotation radii associated with the bars, taken from our previous study, which used the phase change from radial inflow to radial outflow of gas at corotation, based on high-resolution two-dimensional velocity fields in Hα taken with a Fabry–Pérot spectrometer. After presenting the histograms of the derived bar parameters, we study their dependence on the galaxy morphological type and on the total stellar mass of the host galaxy, and then produce a set of parametric plots. These include the bar pattern speed versus bar length, the pattern speed normalized with the characteristic pattern speed of the outer disk versus the bar strength, and the normalized pattern speed versus , the ratio of corotation radius to bar length. To provide guidelines for our interpretation, we used recently published simulations, including disk and dark matter halo components. Our most striking conclusion is that bars with values of < 1.4, previously considered dynamically fast rotators, can be among the slowest rotators both in absolute terms and when their pattern speeds are normalized. The simulations confirm that this is because as the bars are braked, they can grow longer more quickly than the outward drift of the corotation radius. We conclude that dark matter halos have indeed slowed down the rotation of bars on Gyr timescales.

We present results derived from the first multi-chord stellar occultation by the trans-Neptunian object (229762) 2007 UK126, observed on 2014 November 15. The event was observed by the Research and Education Collaborative Occultation Network project and International Occultation Timing Association collaborators throughout the United States. Use of two different data analysis methods obtain a satisfactory fit to seven chords, yielding an elliptical fit to the chords with an equatorial radius of = R 338(-10)(+15) km and equivalent radius of = Req 319(-7)(+14) km. A circular fit also gives a radius of = R 324(-23)(+30) km. Assuming that the object is a Maclaurin spheroid with indeterminate aspect angle, and using two published absolute magnitudes for the body, we derive possible ranges for geometric albedo between p(V) = 0.159(-0.013) (+ 0.007) and p(R) = 0.189(-0.015)(+0.009), and for the body oblateness between is an element of= 0.105 (-0.040) (+0.050) and is an element of= 0.118 (-0.048) (+0.055). For a nominal rotational period of 11.05 hr, an upper limit for density of rho = 1740 kg m(-3) is estimated for the body.

We have combined observations of the Antennae galaxies from the radio interferometer ALMA (Atacama Large Millimeter/submillimeter Array) and from the optical interferometer GH$\alpha$FaS (Galaxy H$\alpha$ Fabry-Perot System). The two sets of observations have comparable angular and spectral resolutions, enabling us to identify 142 giant molecular clouds (GMCs) and 303 HII regions. We have measured, and compared, their basic physical properties (radius, velocity dispersion, luminosity). For the HII regions, we find two physical regimes, one for masses $>10^{5.4} \mathrm{M_{\odot}}$ of ionized gas, where the gas density increases with gas mass, the other for masses $<10^{5.4} \mathrm{M_{\odot}}$ of ionized gas, where the gas density decreases with gas mass. For the GMCs, we find, in contrast to previous studies in other galaxies over a generally lower mass range of clouds, that the gas surface density increases with the radius, hinting at two regimes for these clouds if we consider both sources of data. We also find that the GMC mass function has a break at $10^{6.7}\mathrm{M_{\odot}}$. Using the velocity dispersion measurements, we claim that the difference between the regimes is the nature of the dominant binding force. For the regions in the lower mass range, the dominant force is the external pressure, while in the higher mass range it is the internal gravity of the clouds. In the regime where gravity is dominant, the star formation rate, derived from the dust-corrected H$\alpha$ luminosity, increases super-linearly with the velocity dispersion, and the gas density increases with the gas mass.

A growing body of evidence indicates that the star formation rate per unit stellar mass (sSFR) decreases with increasing mass in normal main-sequence star-forming galaxies. Many processes have been advocated as being responsible for this trend (also known as mass quenching), e.g., feedback from active galactic nuclei (AGNs), and the formation of classical bulges. In order to improve our insight into the mechanisms regulating the star formation in normal star-forming galaxies across cosmic epochs, we determine a refined star formation versus stellar mass relation in the local Universe. To this end we use the Hα narrow-band imaging followup survey (Hα3) of field galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Coma and Local superclusters. By complementing this local determination with high-redshift measurements from the literature, we reconstruct the star formation history of main-sequence galaxies as a function of stellar mass from the present epoch up to z = 3. In agreement with previous studies, our analysis shows that quenching mechanisms occur above a threshold stellar mass Mknee that evolves with redshift as ∝(1 + z) 2 . Moreover, visual morphological classification of individual objects in our local sample reveals a sharp increase in the fraction of visually classified strong bars with mass, hinting that strong bars may contribute to the observed downturn in the sSFR above Mknee. We test this hypothesis using a simple but physically motivated numerical model for bar formation, finding that strong bars can rapidly quench star formation in the central few kpc of field galaxies. We conclude that strong bars contribute significantly to the red colors observed in the inner parts of massive galaxies, although additional mechanisms are likely required to quench the star formation in the outer regions of massive spiral galaxies. Intriguingly, when we extrapolate our model to higher redshifts, we successfully recover the observed redshift evolution for Mknee. Our study highlights how the formation of strong bars in massive galaxies is an important mechanism in regulating the redshift evolution of the sSFR for field main-sequence galaxies.

Context. It has been recently found that the characteristic photometric parameters of anti-truncated discs in SO galaxies follow tight scaling relations.Aims. We investigate whether similar scaling relations are satisfied by galaxies of other morphological types.Methods. We have analysed the trends in several photometric planes relating the characteristic surface brightness and scalelengths of the breaks and the inner and miter discs of local anti-truncated S0-Scd galaxies, using published data and fits performed to the surface brightness profiles of two samples of Type-III galaxies in the R and Spitzer 3.6 pm bands. We have performed linear his to the correlations followed by different galaxy types in each plane, as well as several statistical tests to determine their significance.Results. We have found that 1) the anti-truncated discs of all galaxy types from Sa to Scd obey tight scaling relations both in R and 3.6 mu m, as observed in S0s, 2) the majority of these correlations are significant accounting for the numbers of the available data samples; 3) the trends are clearly linear when the characteristic scalelengths are plotted on a logarithmic scale; and 4) the correlations relating the characteristic surface brightnesses of the inner and outer discs and the breaks with the various characteristic scalelengths significantly improve when the scalelengths are normalized to the optical radius of the galaxy. The observational uncertainties prevent us from discerning robustly whether the trends differ between the different types and bands, but we do not find statistical evidence of significant differences between the distributions of S0s and spirals or of barred and unbarred galaxies. These results suggest that the scaling relations of Type-III discs are independent of the morphological type and the presence (or absence) of bars within the observational uncertainties of the available datasets. However, larger and deeper samples are required to confirm this.Conclusions. The tight structural coupling implied by these scaling relations imposes strong constraints on the mechanisms proposed to explain the formation of anti-truncated stellar discs in the galaxies across the whole Hubble sequence.

Neutral hydrogen represents the major observable baryonic constituent of galaxies that fuels the formation of stars through the transformation in molecular hydrogen. The emission of the hydrogen recombination line Halpha is the most direct tracer of the process that transforms gas (fuel) into stars. We continue to present Halpha3 (acronym for Halpha-alpha-alpha), an extensive Halpha+[NII] narrow-band imaging campaign of galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA), using the instrumentation available at the San Pedro Martir observatory (Mexico). In only four years since 2011 we were able to complete in 48 nights the Halpha imaging observations of 724 galaxies in the region of the Coma supercluster 10^h < R.A. <16^h; 24^o < Dec. <28^o and 3900<cz<9000 kms^{-1}. Of these, 603 are selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) and constitute a 97% complete sample. They provide for the first time a complete census of the massive star formation properties of local gas-rich galaxies belonging to different environments (cluster vs filaments), morphological type (spirals vs dwarf Irr), over a wide range of stellar mass (10^{8}-10^{11.5} Modot) in the Coma Supercluster. The present Paper V provides the Halpha data and the derived star formation rates for the observed galaxies.

Neutral hydrogen represents the major observable baryonic constituent of galaxies that fuels the formation of stars through the transformation in molecular hydrogen. The emission of the hydrogen recombination line Halpha is the most direct tracer of the process that transforms gas (fuel) into stars. We continue to present Halpha3 (acronym for Halpha-alpha-alpha), an extensive Halpha+[NII] narrow-band imaging campaign of galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA), using the instrumentation available at the San Pedro Martir observatory (Mexico). In only four years since 2011 we were able to complete in 48 nights the Halpha imaging observations of 724 galaxies in the region of the Coma supercluster 10^h < R.A. <16^h; 24^o < Dec. <28^o and 3900

We present measurements of internal proper motions at more than 500 positions of NGC 2392, the Eskimo Nebula, based on images acquired with WFPC2 on board the Hubble Space Telescope at two epochs separated by 7.695 yr. Comparisons of the two observations clearly show the expansion of the nebula. We measured the amplitude and direction of the motion of local structures in the nebula by determining their relative shift during that interval. In order to assess the potential uncertainties in the determination of proper motions in this object, in general, the measurements were performed using two different methods, used previously in the literature. We compare the results from the two methods, and to perform the scientific analysis of the results we choose one, the cross-correlation method, because it is more reliable. We go on to perform a "criss-cross" mapping analysis on the proper motion vectors, which helps in the interpretation of the velocity pattern. By combining our results of the proper motions with radial velocity measurements obtained from high resolution spectroscopic observations, and employing an existing 3D model, we estimate the distance to the nebula to be 1.3 kpc.

We present the first results from the Ha Galaxy Groups Imaging Survey (HAGGIS), a narrow-band imaging survey of SDSS groups at z < 0.05 conducted using the Wide Field Imager (WFI) on the ESO/MPG 2.2-meter telescope and the Wide Field Camera (WFC) on the Issac Newton Telescope (INT). In total, we observed 100 galaxy groups with a wide range of halo mass (10(12)-10(14)M(circle dot)) in pairs of narrow-band filters selected to get continuum subtracted rest-frame Ha images for each galaxy. The excellent data allows us to detect Ha down to the 10(-18) ergs/s/cm(2)/arcsec(2) level. Here, we examine the role played by halo mass and galaxy stellar mass in deciding the overall star formation activity in star forming disks by comparing stacked Ha profiles of galaxies in different halo mass and stellar mass bins. With this preliminary study, we have found that the star-formation activity in star-forming galaxies decreases in larger halos compared to the field galaxies. Using median equivalent width profiles, we can infer how environmental processes affect star-forming galaxies differently at different radii.

Se realizo un estudio cinematico del remanente de supernova galactico G206.9+2.3 (PKS 0646+06) en las lineas [SII]λ6717 y 6731 A. Este es uno de los primeros pasos de un proyecto a largo plazo de determinacion de distancias cinematicas a RSN galacticos con contraparte optica. Se obtuvo la distancia cinematica a esta nebulosa, mostrando primero que los filamentos detectados son realmente la contraparte optica del RSN en radio. La distancia estimada en este trabajo es ligeramente mayor que la distancia de Monoceros. Se estimo que G206.9+2.3 esta localizada a 2.2 kpc del Sol, en una region del cielo donde se observan varias nebulosas superpuestas a diferentes velocidades. Se midio una velocidad de choque de 86 kms-1 y un diametro lineal de 18 pe. Finalmente se calculo que la energia depositada al medio interestelar por la explosion de supernova es de 1.7 x 1049 ergs por lo que se concluyo que G206.9+2.3 esta en la fase radiativa de su evolucion, con una edad de 6.4 x 104 anos

We have observed the Arp 270 system (NGC 3395 and NGC 3396) in H alpha emission using the Galaxy H alpha Fabry-Perot spectrometer on the 4.2 m William Herschel Telescope (La Palma). In NGC 3396, which is edge-on to us, we detect gas inflow towards the centre, and also axially confined opposed outflows, characteristic of galactic superwinds, and we go on to examine the possibility that there is a shrouded AGN in the nucleus. The combination of surface brightness, velocity and velocity dispersion information enabled us to measure the radii, FWHM, and the masses of 108 H ii regions in both galaxies. We find two distinct modes of physical behaviour, for high and lower luminosity regions. We note that the most luminous regions show especially high values for their velocity dispersions and hypothesize that these occur because the higher luminosity regions form from higher mass, gravitationally bound clouds while those at lower luminosity H ii regions form within molecular clouds of lower mass, which are pressure confined.

Galaxy mergers were more common, and important for galaxy evolution, in the earlier denser universe, but the physical processes involved are best studied in the local universe, where we can observe them in sufficient detail. Here we present 2-dimensional mapping of the interacting galaxy pair Arp 271 (NGC 5426+NGC 5427) in surface brightness and velocity using H alpha emission with the GH alpha FaS Fabry-Perot spectrometer. We detected emission within the velocity range of NGC 5426 superposed on the disk of NGC 5427, strongest between the arms and just outside the disk. From this ionization image of the latter in hydrogen captured from the former we could derive the gas infall rate, and relate it to the enhanced SFR across the disk of NGC 5427.

We present the analysis of Halpha3, an Halpha imaging survey of galaxies selected from the HI ALFALFA Survey in the Coma Supercluster. By using the Halpha line as a tracer of the "instantaneous" star formation, complemented with optical colors from SDSS we explore the hypothesis that a morphological sequence of galaxies of progressively earlier type, lower gas-content exists in the neighborhood of the Coma cluster, with specific star formation activity decreasing with increasing local galaxy density and velocity dispersion. In the dwarf regime (8.5<log(M*)< 9.5) we identify a 4-step sequence of galaxies with progressively redder colors, i.e. of decreasing specific star formation, from (1) HI-rich Late-Type Galaxies belonging to the blue-cloud exhibiting extended plus nuclear star formation, (2) HI-poor LTGs with nuclear star formation only, (3) HI-poor galaxies with no star formation either extended or nuclear, but with nuclear Post-Star-Burst signature,(4) Early-type Galaxies in the red-sequence, with no gas or star formation on all scales. Along this sequence the quenching of the star formation proceeds radially outside-in. The progression toward redder colors found along this "morphological" (gas content) sequence is comparable to the one obtained increasing the local galaxy density, from the cosmic filaments (1,2), to the rich clusters (2,3,4). In the dwarf regime we find evidence for evolution of HI-rich LTGs into ETGs, passing through HI-poor and PSB galaxies, driven by the environment. We identify ram-pressure as the mechanism most likely responsible for this transformation. We conclude that infall of low-mass galaxies has proceeded for the last 7.5 Gyr building up the Coma cluster at a rate of approximately 100 galaxies per Gyr.