The absence of star formation in the bar region that has been reported for some galaxies can theoretically be explained by shear. However, it is not clear how star-forming (SF) bars fit into this picture and how the dynamical state of the bar is related to other properties of the host galaxy. We used integral-field spectroscopy from VLT/MUSE to investigate how star formation within bars is connected to structural properties of the bar and the host galaxy. We derived spatially resolved Hα fluxes from MUSE observations from the CARS survey to estimate star formation rates in the bars of 16 nearby (0.01 < z < 0.06) disc galaxies with stellar masses between 10 10 M and 10 11 M . We further performed a detailed multicomponent photometric decomposition on images derived from the data cubes. We find that bars clearly divide into SF and non-star-forming (non-SF) types, of which eight are SF and eight are non-SF. Whatever the responsible quenching mechanism is, it is a quick process compared to the lifetime of the bar. The star formation of the bar appears to be linked to the flatness of the surface brightness profile in the sense that only the flattest bars (n bar ≤ 0.4) are actively SF SFR b > 0.5 M yr −1 . Both parameters are uncorrelated with Hubble type. We find that star formation is 1.75 times stronger on the leading than on the trailing edge and is radially decreasing. The conditions to host non-SF bars might be connected to the presence of inner rings. Additionally, from testing an AGN feeding scenario, we report that the star formation rate of the bar is uncorrelated with AGN bolometric luminosity. The results of this study may only apply to type-1 AGN hosts and need to be confirmed for the full population of barred galaxies.
We present near-infrared (NIR) H + K-band long-slit spectra of eleven galaxies that were obtained with SOFI at the NTT (ESO). The galaxies are chosen from the low-luminosity type-1 quasi-stellar object (LLQSO) sample, which comprises the 99 closest (z ≤ 0.06) QSOs from the Hamburg/ESO survey for bright UV-excess QSOs. These objects are ideal targets to study the gap between local Seyfert galaxies and high-redshift quasars because they show much stronger AGN activity than local objects, but are still close enough for a detailed structural analysis. We fit hydrogen recombination, molecular hydrogen, and [Fe ii] lines after carefully subtracting the continuum emission. From the broad Paα components, we estimated black hole masses and enlarged the sample of LLQSOs that deviate from the M BH −L bulge relations of inactive galaxies from 12 to 16 objects. All objects show emission from hot dust (T ∼ 1200 K) as well as stellar contribution. However, the respective fractions vary strongly among the objects. More than half of the objects show H 2 emission lines, which indicate a large reservoir of molecular gas that is needed to feed the AGN and star formation. In the NIR diagnostic diagram all objects lie in the location of AGN-dominated objects. However, most of the objects show indications of star formation activity, suggesting that their offset location with respect to M BH -L bulge relations of inactive galaxies may be a consequence of overluminous bulges.
NGC 3718 is a low-ionization nuclear emission line region (LINER) L1.9 galaxy, lying at a distance of about ∼17.4 Mpc from the Earth; its similarities with NGC 5128 often award it the name northern Centaurus A. The presence of a compact radio source with a candidate jet structure, a prominent dust lane, and a strongly warped molecular and atomic gas disk are indications that NGC 3718 has undergone some sort of a large-scale gravitational interaction sometime in the recent past, which channeled gas towards the center, feeding the black hole and igniting the central engine. One proposed scenario involves an encounter with the close neighboring galaxy NGC 3729, while other authors favor a merging event with mass ratio ≥(3−4):1 as the origin of NGC3718. We use high angular resolution (∼100 mas) e-Merlin radio and Subaru near-IR (NIR) (∼170 mas) data to take a detailed view of the processes taking place in its central region. In order to preserve some objectivity in our interpretation, we combine our results with literature values and findings from previous studies. Our NIR maps suggest, on the one hand, that towards the stellar bulge there are no largescale absorption phenomena caused by the apparent dust lane and, on the other, that there is a significant (local) contribution from hot (∼1000 K) dust to the nuclear NIR emission. The position where this takes place appears to be closer to the offset compact radio emission from our e-Merlin 6 cm map and is offset by ∼4.25 pc from the center of the underlying stellar bulge. The shape of the radio map suggests the presence of one (or possibly two, forming an X-shape) bipolar structure(s) ∼1 (∼0.6) arcsec across, which combined with the balance between the gas and the stellar velocity dispersions and the presence of hard X-ray emission, point towards effects expected by AGN feedback. We also argue that NGC 3718 has a core in its surface brightness profile, although it is a gas-rich galaxy and we discuss its mixed photometric and spectroscopic characteristics. These characteristics combined with the observed spatial NIR and radio emission offsets, the relative redshift between the broad and the narrow Hα line, the limited star formation activity, and AGN feedback strongly imply the existence of a supermassive black hole recoil. Finally, we discuss a possible interpretation that could naturally incorporate all these findings into one physically consistent picture.
Purpose – The purpose of this paper is to describe the design and implementation of policies, digital infrastructures and hands-on support for eResearch at the University of Göttingen. Core elements of this activity are to provide support for research data management to researchers of all disciplines and to coordinate on-campus activities. These activities are actively aligned with disciplinary, national and international policies and e-infrastructures. Design/methodology/approach – The process of setting up and implementing an institutional data policy and its necessary communications and workflows are described and analysed. A first assessment of service development and uptake is provided in the area of embedded research data support. Findings – A coordination unit for eResearch brings together knowledge about methods and tools that are otherwise scattered across disciplinary units. This provides a framework for policy implementation and improves the quality of institutional research environments. Practical implications – The study provides information about an institutional implementation strategy for infrastructure and services related to research data. The lessons learned allow insights into current challenges and work ahead. Originality/value – With a cross-cutting, “horizontal” approach, in the Göttingen eResearch Alliance, two research-orientated infrastructure providers, a library and an IT service, combine their services and expertise to develop an eResearch service and support portfolio for the Göttingen Campus.
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