Double nucleus in M83

M 83 is one of the nearest galaxies with an enhanced nuclear star formation and it presents one of the best opportunities to study the kinematics and physical properties of a circumnuclear starburst. Our three-dimensional spectroscopy data in R band confirm the presence of a secondary nucleus or mass concentration (previously suggested by Thatte and coworkers). We determine the position of this hidden nucleus, which would be more massive than the visible one, and was not detected in the optical HST images due, probably, to the strong dust extinction. The optical nucleus has a mass of 5 x 10^6 M_Sun / sin i (r < 1''.5), and the hidden nucleus, located 3''.9 +/- 0''.5 at the NW (PA 271 +/- 15 deg) of the optical nucleus, would have a mass of 1 x 10^7 M_Sun / sin i (r < 1''.5). The emission line ratio map also unveils the presence of a second circumnuclear ring structure, previously discovered by IR imaging (Elmegreen and coworkers). The data allow us to resolve the behavior of the interstellar medium inside the circumnuclear ring and around the binary mass concentration.Comment: 28 pages, 11 figures. Discussion updated. Published versio

Outer-disk reddening and gas-phase metallicities: The CALIFA connection

Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC ).CALIFA Team: et al.We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. Sloan Digital Sky Survey (SDSS) g′- and r′-band surface brightness, (g′ - r′) color, and ionized-gas oxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (CALIFA) survey are used for this purpose. We perform a detailed light-profile classification, finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively), while the remaining 16% are well fitted by one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g′ - r′) color of ∼ 0.5mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses ≤10 M′ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.R. A. Marino is funded by the Spanish program of International Campus of Excellence Moncloa (CEI).We acknowledge support from the Plan Nacional de Investigación y Desarrollo funding programs, AyA2010-15081, AyA2012-30717 and AyA2013-46724P, of Spanish Ministerio de Economía y Competitividad (MINECO). A.G.d.P. acknowledges the support from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement PITNGA-2011-289313. C.C.-T. thanks the support of the Spanish Ministerio de Educación, Cultura y Deporte by means of the FPU fellowship program. C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC 120009, awarded to The Millennium Institute of Astrophysics, MAS. L.G. acknowledges support by CONICYT through FONDECYT grant 3140566. S.F.S. thanks the CONACYT-125180 and DGAPA-IA100815 projects for providing him support in this study. J.M.A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). P.P. is supported by FCT through the Investigador FCT Contract No. IF/01220/2013 and POPH/FSE (EC) by FEDER funding through the program COMPETE. He also acknowledges support by FCT under project FCOMP-01-0124-FEDER-029170 (Reference FCT PTDC/FISAST/3214/2012), funded by FCT-MEC (PIDDAC) and FEDER (COMPETE).Peer Reviewe

The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and T e-based literature data

Astronomy and Astrophysics 559 (2013): A114 reproduced with permission from Astronomy and AstrophysicsThe use of integral field spectroscopy is since recently allowing to measure the emission line fluxes of an increasingly large number of star-forming galaxies, both locally and at high redshift. Many studies have used these fluxes to derive the gas-phase metallicity of the galaxies by applying the so-called strong-line methods. However, the metallicity indicators that these datasets use were empirically calibrated using few direct abundance data points (Te-based measurements). Furthermore, a precise determination of the prediction intervals of these indicators is commonly lacking in these calibrations. Such limitations might lead to systematic errors in determining the gas-phase metallicity, especially at high redshift, which might have a strong impact on our understanding of the chemical evolution of the Universe. The main goal of this study is to review the most widely used empirical oxygen calibrations, O3N2 and N2, by using newdirect abundance measurements. We pay special attention to (1) the expected uncertainty of these calibrations as a function of the index value or abundance derived and (2) the presence of possible systematic offsets. This is possible thanks to the analysis of the most ambitious compilation of Te-based H ii regions to date. This new dataset compiles the Te-based abundances of 603 H ii regions extracted from the literature but also includes new measurements from the CALIFA survey. Besides providing new and improved empirical calibrations for the gas abundance, we also present a comparison between our revisited calibrations with a total of 3423 additional CALIFA H ii complexes with abundances derived using the ONS calibration from the literature. The combined analysis of T e-based and ONS abundances allows us to derive their most accurate calibration to date for both the O3N2 and N2 single-ratio indicators, in terms of all statistical significance, quality, and coverage of the parameters space. In particular, we infer that these indicators show shallower abundance dependencies and statistically significant offsets compared to others'. The O3N2 and N2 indicators can be empirically applied to derive oxygen abundances calibrations from either direct abundance determinations with random errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a large amount of data), reaching an average precision of 0.08 and 0.09 dex (random) and 0.02 and 0.08 dex (systematic; compared to the direct estimations), respectivelyR.A. Marino is funded by the Spanish program of International Campus of Excellence Moncloa (CEI). D. Mast thank the Plan Nacional de Investigación y Desarrollo funding programs, AYA2012-31935 of the Spanish Ministerio de Economía y Competitividad, for the support given to this project. S.F.S thanks the the Ramón y Cajal project RyC-2011-07590 of the spanish Ministerio de Economía y Competitividad, for the support giving to this project. F.F.R.O. acknowledges the Mexican National Council for Science and Technology (CONACYT) for financial support under the program Estancias Postdoctorales y Sabáticas al Extranjero para la Consolidación de Grupos de Investigación, 2010-2012. We acknowledge financial support for the ESTALLIDOS collaboration by the Spanish Ministerio de Ciencia e Innovación under grant AYA2010- 21887-C04-03. BG-L also acknowledges support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AYA2012- 39408-C02-02. J.F.-B. acknowledges financial support from the Ramón y Cajal Program and grant AYA2010-21322-C03-02 from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as to the DAGAL network from the People’s Program (Marie Curie Actions) of the European Union’s Seventh Framework Program FP7/2007-2013/ under REA grant agreement number PITN-GA-2011-289313. CK has been funded by project AYA2010-21887 from the Spanish PNAYA. P.P. acknowledges support by the Fundação para a Ciência e a Tecnologia (FCT) under project FCOMP-01-0124-FEDER-029170 (Reference FCT PTDC/FIS-AST/3214/2012), funded by FCT-MEC (PIDDAC) and FEDER (COMPETE). R.M.G.D. and R.G.B. also acknowledge support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AyA2010-15081. V.S., L.G., and A.M.M. acknowledge financial support from the Fundação para a Ciência e a Tecnologia (FCT) under program Ciência 2008 and the research grant PTDC/CTE-AST/112582/200

La región central M83 /

Tesis (Doctor en Astronomía)--Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física, 2008.La galaxia espiral M83, una SBb a tan sólo 4,5 Mpc, posee el núcleo starburst más cercano. En esta tesis se presenta un estudio multibanda, utilizando diversas técnicas de espectroscopía 2D-3D.Damián Mast ; dir. por Gustavo José Carranza, Rubén Joaquín Díaz y Horacio A. Dottori

Una nueva perspectiva de la nebulosa del Espirógrafo Observaciones MUSE de IC 418

Las nebulosas planetarias son reliquias esenciales de la evolución estelar y gracias a la espectroscopia de campo integral, técnica que combina las ventajas de la imagen con la espectroscopia, es posible estudiar estos objetos desde un nuevo punto de vista. Aprovechando estas capacidades del espectrógrafo de campo integral MUSE estudiamos la nebulosa planetaria IC 418 con el objetivo de mostrar, con un detalle nunca antes alcanzado, la distribución espacial de los principales parámetros físicos de la nebulosa. Nuestros mapas sugieren una posible evolución hacia una morfología bipolar. Hemos determinado los valores medios de extinción, temperatura y densidad, encontrando valores que concuerdan con estudios anteriores. Se observó una estructura de excitación radial con tres regiones separadas en la burbuja interior y los diagramas de diagnóstico permitieron identificar las diferentes regiones de ionización en la nebulosa.Planetary nebulae are essential relics of stellar evolution and thanks to integral field spectroscopy, a technique that combines the advantages of imaging with spectroscopy, it is possible to study these objects from a new point of view. Taking advantage of these capabilities of the MUSE integral field spectrograph we studied the planetary nebula IC 418 with the aim of showing, with a detail never reached before, the spatial distribution of the main physical parameters of the nebula. Our maps suggest a possible evolution towards a bipolar morphology. We have determined the mean values of extinction, temperature and density, finding values in agreement with previous studies. We observed a radial excitation structure with three separate regions in the inner bubble and diagnostic diagrams allowed us to identify the different ionization regions in the nebula.Asociación Argentina de Astronomí

Ionization state and geometry of the extragalactic HII region SMC-N88A for the interpretation of observations of galaxies in the epoch of reionization

Los fotones ionizantes de las primeras galaxias contribuyeron a la progresiva re-ionización del hidrógeno intergaláctico, que terminó a z~ 6. Una de las principales incógnitas de este proceso es la fracción de fotones ionizantes que escapan de las galaxias y alcanzan el medio intergaláctico durante esta época. Sin embargo, ningún telescopio puede detectar directamente esta radiación en objetos a z ≥ 6 porque es absorbida por el hidrógeno neutro del medio intergaláctico en el mismo proceso de reionización cósmica. Por este motivo se han propuesto varios indicadores alternativos del escape de fotones ionizantes, basados tanto en líneas de emisión como de absorción. En este trabajo, el objetivo a largo plazo es poner a prueba los modelos utilizados en la interpretación de las observaciones de líneas de emisión nebulares de galaxias a muy alto redshift. Hemos observado dos regiones HII compactas de la Nube Menor de Magallanes con la unidad de campo integrado (o IFU) de GMOS-S, para estudiar la física involucrada en el escape de fotones ionizantes producidos por estrellas masivas que habitan en regiones Η II jóvenes. A una distancia de ~ 61 kpc, la cercanía de estos objetos hace posible estudiar la geometría y cinemática del gas en emisión con una resolución espacial inalcanzable en galaxias de la época de reionización. En esta oportunidad, presentamos las bases del proyecto y el estado de los datos obtenidos para SMC-N88A.Ionizing photons from the first galaxies contributed to the progressive re-ionization of the intergalactic hydrogen, which ended by z ~ 6. One of the main unknowns of this process is the fraction of ionizing photons that escape from galaxies and reach the intergalactic medium during this epoch. However, no telescope can directly detect this radiation on objects at z ≥ 6 because it is absorbed by the neutral hydrogen of the intergalactic medium in the same cosmic reionization process. For this reason, several alternative indicators of the escape of ionizing photons have been proposed, based on both emission and absorption lines. In this work, the long-term goal is to test the models used in the interpretation of observations of nebular emission lines from galaxies at very high redshift. We have observed two compact ΗII regions of the Small Magellanic Cloud with the Integral Field Unit (or IFU) of GMOS-S, to study the physics involved in the escape of ionizing photons produced by massive stars inhabiting young ΗII regions. At a distance of ~ 61 kpc, the proximity of these objects makes it possible to study the geometry and kinematics of the gas in emission with a spatial resolution unattainable in galaxies of the reionization epoch. In this opportunity, we present the bases of the project and the data obtained for SMC-N88A.Asociación Argentina de Astronomí

Variabilidad infrarroja del núcleo activo en NGC 2992

Existen galaxias en el Universo que contienen un núcleo activo y presentan variabilidad tanto en el tipo de emisión, variando en su clasificación de tipo Seyfert, como en su magnitud nuclear. En este trabajo, se presenta un estudio fotométrico sobre la galaxia NGC 2992 que, en las últimas décadas, ha atravesado episodios de variabilidad en los rangos óptico, infrarrojo y de rayos X. Se reportan magnitudes nucleares en banda J de observaciones obtenidas en enero de 2022 para distintas aperturas. Además, la comparación con reportes anteriores de la magnitud obtenida en una apertura de 3" revela una variación de 0.8 ± 0.3 magnitudes respecto de 1998.There are galaxies in the Universe that harbour an active nucleus and present variability in the type of emission, varying in their Seyfert type classification, and in their nuclear magnitude. In this work, a photometric study of the galaxy NGC 2992 is presented. In the latest decades, this galaxy has gone through episodes of variability in the optical, infrared, and X-ray ranges. In this contribution, nuclear magnitudes in J band are reported from observations carried on in January 2022 and the magnitude obtained in a 3" aperture is compared with previous reports, finding a variation of 0.8 ± 0.3 magnitudes with respect to 1998.Asociación Argentina de Astronomí

The missing goliath's slingshot : massive black hole recoil at M83

The Fanaroff–Riley II radio source J133658.3−295105, which is also an X-ray source, appears to be projected onto the disk of the barred-spiral galaxy M83 at about 60" from the galaxy’s optical nucleus. J133658.3−295105 and its radio lobes are aligned with the optical nucleus of M83 and two other radio sources, neither of which are supernova remnants or H II regions. Due to this peculiar on-the-sky projection, J133658.3−295105 was previously studied by Gemini+GMOS optical spectroscopy, which marginally revealed the presence of Hα in emission receding at 130 km s-ˡ with respect to the optical nucleus. In this Letter, we reanalyze the Chandra spectroscopy carried out in 2000. We show that J133658.3−295105 presents an Fe Kα emission line at a redshift of z = 0.018. This redshift is compatible with a black hole at the distance of M 83. We discuss similarities to the recently reported micro-quasar in NGC 5408. This finding reinforces the kicked-off black hole scenario for J133658.3−295105

A unified scenario for the origin of spiral and elliptical galaxy structural scaling laws

Elliptical (E) and spiral (S) galaxies follow tight, but different, scaling laws that link their stellar masses, radii, and characteristic velocities. Mass and velocity, for example, scale tightly in spirals with little dependence on galaxy radius (the ‘Tully-Fisher relation’; TFR). On the other hand, ellipticals appear to trace a 2D surface in size-mass-velocity space (the ‘Fundamental Plane’; FP). Over the years, a number of studies have attempted to understand these empirical relations, usually in terms of variations of the virial theorem for E galaxies and in terms of the scaling relations of dark matter halos for spirals. We use Lambda cold dark matter (ΛCDM) cosmological hydrodynamical simulations to show that the scaling relations of both ellipticals and spirals arise as the result of (i) a tight galaxy mass–dark halo mass relation and (ii) the self-similar mass profile of cold dark matter halos. In this interpretation, E and S galaxies of a given stellar mass inhabit halos of similar masses, and their different scaling laws result from the varying amounts of dark matter enclosed within their luminous radii. This scenario suggests a new galaxy distance indicator applicable to galaxies of all morphologies and provides simple and intuitive explanations for long-standing puzzles, such as why the TFR is independent of surface brightness, or what causes the ‘tilt’ in the FP. Our results provide strong support for the predictions of ΛCDM in the strongly non-linear regime, as well as guidance for further improvements to cosmological simulations of galaxy formation