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 H 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.
Abstract
We present here the analysis performed using the
pyPipe3D
pipeline for the final MaNGA data set included in the Sloan Digital Sky Survey data release 17. This data set comprises more than ...10,000 individual data cubes, being the integral field spectroscopic (IFS) galaxy survey with the largest number of galaxies.
pyPipe3D
processes the IFS data cubes to extract spatially resolved spectroscopic properties of both the stellar population and the ionized gas emission lines. A brief summary of the properties of the sample and the characteristics of the analyzed data are included. The article provides details of: (i) the analysis performed; (ii) a description of the pipeline; (iii) the adopted stellar population library; (iv) the morphological and photometric analysis; (v) the adopted data model for the spatially resolved properties derived; and (vi) the individual integrated and characteristic galaxy properties included in the final catalog. Comparisons with the results from a previous version of the pipeline for earlier data releases and from other tools using this data set are included. A practical example of how to use the full data set and the final catalog illustrates how to handle the delivered product. Our full analysis can be accessed and downloaded from our web page.
ABSTRACT
Core-collapse supernova remnants are the gaseous nebulae of galactic interstellar media (ISM) formed after the explosive death of massive stars. Their morphology and emission properties ...depend both on the surrounding circumstellar structure shaped by the stellar wind–ISM interaction of the progenitor star and on the local conditions of the ambient medium. In the warm phase of the Galactic plane ($n\approx 1\, \rm cm^{-3}$, $T\approx 8000\, \rm K$), an organized magnetic field of strength $7\, \mu \rm G$ has profound consequences on the morphology of the wind bubble of massive stars at rest. In this paper, we show through 2.5D magnetohydrodynamical simulations, in the context of a Wolf–Rayet-evolving $35\, \rm M_{\odot }$ star, that it affects the development of its supernova remnant. When the supernova remnant reaches its middle age ($15\!-\!20\, \rm kyr$), it adopts a tubular shape that results from the interaction between the isotropic supernova ejecta and the anisotropic, magnetized, shocked stellar progenitor bubble into which the supernova blast wave expands. Our calculations for non-thermal emission, i.e. radio synchrotron and inverse-Compton radiation, reveal that such supernova remnants can, due to projection effects, appear as rectangular objects in certain cases. This mechanism for shaping a supernova remnant is similar to the bipolar and elliptical planetary nebula production by wind–wind interaction in the low-mass regime of stellar evolution. If such a rectangular core-collapse supernova remnant is created, the progenitor star must not have been a runaway star. We propose that such a mechanism is at work in the shaping of the asymmetric core-collapse supernova remnant Puppis A.
Context. Angeloni and collaborators have discovered a bipolar jet extending out to ~6 pc from “Sanduleak’s star” in the Large Magellanic Cloud (LMC). This is the first angularly resolved stellar jet ...system that has been observed outside our Galaxy. Aims. In this paper we use archival Hubble Space Telescope (HST) images of this jet in order to estimate the flow parameters, and use them to explore two possible theoretical scenarios for modelling this bipolar outflow. Methods. We have computed axisymmetric gasdynamic simulations of a conical outflow with an opening angle that increases with time and of a cylindrical jet interacting with a stratified circumstellar structure. The results of these models are then compared with the observed morphology of the jets from Sanduleak’s star. Results. From the observations, we obtain Ṁj ≈ 1.2 × 10−5M⊙ yr−1 and Lm ≈ 1000 L⊙ for the mass loss rate and the mechanical luminosity (respectively) of each of the outflow lobes. We also obtain a (deprojected) flow velocity vj ≈ 1000 km s−1 and a dynamical time tdyn ≈ 7300 yr. From the simulations that we have computed (with these flow parameters), we find that both the “opening out conical wind” and the “jet+stratified environment” scenarios have characteristics that resemble the observed morphologies. A more complete model for the jets from Sanduleak’s star might incorporate some of the features of these two scenarios.
Our understanding of the structure, composition and evolution of galaxies hasstrongly improved in the last decades, mostly due to new results based on large spectro-scopic and imaging surveys. In ...particular, the nature of ionized gas, its ionization mech-anisms, its relation with the stellar properties and chemical composition, the existence ofscaling relations that describe the cycle between stars and gas, and the corresponding evo-lution patterns have been widely explored and described. More recently, the introduction ofadditional techniques, in particular integral field spectroscopy, and their use in large galaxysurveys, have forced us to re-interpret most of those recent results from a spatially resolvedperspective. This review is aimed to complement recent efforts to compile and summarizethis change of paradigm in the interpretation of galaxy evolution. To this end we replicatepublished results, and present novel ones, based on the largest compilation of IFS data ofgalaxies in the nearby universe to date.
Abstract
One way the active galactic nuclei (AGN) are expected to influence the evolution of their host galaxies is by removing metal content via outflows. In this article we present results that ...show that AGN can have an effect on the chemical enrichment of their host galaxies using the fossil record technique on CALIFA galaxies. We classified the chemical enrichment histories of all galaxies in our sample regarding whether they show a drop in the value of their metallicity. We find that galaxies currently hosting an AGN are more likely to show this drop in their metal content compared to the quiescent sample. Once we separate the sample by their star-forming status we find that star-forming galaxies are less likely to have a drop in metallicity but have deeper decreases when these appear. This behavior could be evidence for the influence of either pristine gas inflows or galactic outflows triggered by starbursts, both of which can produce a drop in metallicity.
Abstract
Mass outflow generated by the dynamical feedback from massive stars is currently a topic of great interest. Using a purpose-developed analysis technique, and taking full advantage of the ...high kinematic and angular resolution of our instrument, we have detected a number of expanding superbubbles in the interacting pair of galaxies Arp 244 (NGC 4038/9), commonly known as the Antennae. We used a Fabry–Pérot interferometer GHαFaS to measure the profile of H α in emission over the full extent of the object, except for the extended H i tails. The superbubbles are found to be centred on most of the brightest H ii regions, especially in the overlap area of the two merging galaxies. We use measured sizes, expansion velocities and luminosities of the shells to estimate most of the physical parameters of the bubbles, including the kinetic energy of the expansion. In order to assess the validity of our results and approximations, we perform a hydrodynamic simulation and manage to reproduce well our best measured superbubble with reasonable physical input assumptions. We also study the sources of ionization of the shells, finding that at the current, quite late stage of expansion, radiation from the remaining stars dominates, although the effect of supernova shocks can still be observed.
Using a specialized technique sensitive to the presence of expanding ionized gas, we have detected a set of three concentric expanding shells in an H ii region in the nearby spiral galaxy M33. After ...mapping the kinematics in Hα with Fabry–Perot spectroscopy, we used slit spectra to measure the intensities of the S ii doublet at λλ671.9, 673.1 nm and the N ii doublet at λλ645.8, 658.3 nm to corroborate the kinematics and apply diagnostic tests using line ratios. These showed that the expanding shells are shock dominated as would be the case if they had originated with supernova explosions. Estimating their kinetic energies, we find fairly low values, indicating a fairly advanced stage of evolution. We obtain density, mass and parent star mass estimates, which, along with the kinetic energies, are inconsistent with the simplest models of shock–interstellar medium interaction. We propose that the presence and properties of an inhomogeneous medium offer a scenario which can account for these observations, and discuss the implications. Comparing our results with data from the literature supports the combined presence of an H ii region and supernova remnant material at the observed position.
ABSTRACT
We apply fossil record techniques to the CALIFA sample to study how galaxies in the Local Universe have evolved in terms of their chemical content. We show how the stellar metallicity and ...the mass–metallicity relation (MZR) evolve through time for the galaxies in our sample and how this evolution varies when we divide them based on their mass, morphology, and star-forming status. We also check the impact of measuring the metallicity at the centre or the outskirts. We find the expected results that the most massive galaxies were enriched more quickly, and that the MZR was steeper at higher redshifts. However, once we separate the galaxies into morphology bins this behaviour is less clear, which suggests that morphology is a primary factor in determining how quickly a galaxy becomes enriched, but with mass determining the final enrichment. We also find that star-forming galaxies (SFGs) appear to be asymptotic in their chemical evolution; that is, the metallicity of SFGs of any mass is very similar at recent times unlike several Gyr ago.
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