Resumen:

Starbursts occur in galaxies that during certain periods in their lives form stars at rates 3-100 times higher than their average during cosmic history. In the z=0 universe they take place mostly when gas is injected into the central regions of galaxies by toques associated with bars or gravitational interactions. Starbursts cannot be observed well in the optical thanks to the high columns of dust that obscure these regions, but observations at infrared and submillimeter wavelengths show that significant fractions of the new stars are formed in massive compact clusters. The mechanisms regulating the formation and dissipation of these clusters are not well understood. The cumulative effects of radiation, stellar winds, and supernovae created by their massive stars set up high pressures in the interstellar medium of these starburst regions that result in galactic scale winds and the ejection of enriched material to the circumgalactic medium. In this presentation I will show interferometric (ALMA, NOEMA, SMA) and JWST results in the central starburst regions of two of the closest starburst galaxies: M82 and NGC253.

Resumen:

Massive stars can determine the evolution of molecular clouds by eroding and photo-evaporating their surfaces with strong UV radiation fields. Thus, probing the fundamental structure of nearby molecular clouds is crucial to understand how massive stars shape their surrounding mediums and how fast molecular clouds are destroyed. By combining CO $J=3-2$ and HCO$^{+}$ $J=4-3$ data from the ALMA 12m array, the Atacama Compact Array (ACA) and Total Power (single-dish), we present the highest angular resolution ($\sim 0.5^{\prime\prime}$, corresponding to $207$~au) and velocity-resolved images of the molecular gas emission in the Horsehead nebula. We find that CO and HCO$^{+}$ are present at the edge of the cloud, very close to the ionization (H$^{+}$/H) and dissociation fronts (H/H$_{2}$), suggesting a very thin layer of neutral atomic gas and almost no CO-dark H$_{2}$ gas at the molecular cloud edge. Notably, the HCO$^{+}$ emission map exhibits a bimodal behavior, tracing the cold and dense gas shielded from UV radiation and a more diffuse gas component interacting directly with the UV radiation field. Additionally, using CO as a proxy of the C$^{+}$/C/CO front, we conclude that the distances between the fronts can be reproduced by isobaric stationary models, which confirms the presence of a steep density gradient, as suggested by previous observations. Still, dynamical effects cannot be completely ruled-out, and even higher angular observations will be needed to unveil their role.

Resumen:

We present an atlas of integrated H$\alpha$ fluxes for planetary nebulae (PNe) in the Magellanic Clouds (MC) using data from the Southern Photometric Local Universe Survey (S-PLUS), a comprehensive 12-band imaging survey. One of the key aspects of our study lies in the detailed spectroscopic analysis of the weak nebular emission in the PNe. Through spectroscopic data, we were able to quantify various emission lines, including H$\alpha$ and [N II], which play a pivotal role in understanding the ionization state and elemental abundances within these nebulae. The spectroscopic data not only enhances the accuracy of our flux measurements but also provides crucial insights into the physical and chemical properties of the MC PNe. By studying the distribution of ionized gas within the nebulae and examining density variations, we gained valuable information about their structures and evolutionary processes. Furthermore, the comparison of our findings with previous spectroscopic measurements from the literature validates the robustness of our results and reinforces the significance of spectroscopy in unraveling the mysteries of these intriguing celestial objects. In conclusion, our combination of imaging data from S-PLUS with extensive spectroscopic analysis has enriched our knowledge of MC PNe, shedding light on their intricate properties and providing new dimensions to our understanding of their diverse population.

Resumen:

Almost 80\% of the planetary nebulae (PNe) are non-spherical - elliptical, bipolar, point-symmetric, among others - sometimes showing knots, filaments and jets of low ionization (the low-ionization structures, LIS), and others features of small scales. The presence of stellar jets in PNe has been investigated through morpho-kinematic studies, from narrow-band images and position-velocity maps constructed from high-dispersion, long-slit spectroscopic observations. However, this spectroscopic technique limits the understanding of the global three-dimensional structure of the PNe, since the spatial and spectral information are only obtained along a given orientation. Integral field units (IFU) allow the spatial and kinematics mappi­­ng of PNe, for both their small- and large-scale components, to determine their morphology, kinematics, density distribution and the interaction zone of the jets with the surroundings. Many of the stellar jets have only been unveiled through this modern instrumental technique. In this talk I will present results obtained with the optical IFU MEGARA, which highlight the hidden ways that PNe ejecta return their products to the interstellar medium, in a variety of morphologies. In particular: i) the extension of the extremely faint bipolar jet in NGC 2392, mapped for the first time; ii) the kinematic dissection of the born-again HuBi 1; iii) the multiple structures of the M 2–31; iv) the presence of a fast outflow aligned with the symmetry axis of M3-38; and finally, v) the advances obtained for the myriad of shells and LIS in NGC 6543.

Resumen:

V5668 Sgr is a classical nova that erupted on 2015 March 15. Since then, it was detected along the whole elctromagnetic spectrum, from radio to $\gamma$ rays. On day 927 after eruption, it was observed with ALMA in the 230 GHz continuum with high spatial resolution, showing for the first time that an evolved classical nova shell is formed by a large number of small clumps of dense ionized plasma. In this work we analyse the evolution of the radio spectra (1-35 GHz) of V5668 Sgr obtained with the VLA, and show that they are compatible with the assumption that the clumps were formed in the early epochs of the nova evolution, when fast winds from the surface of the white dwarf overtook the slower shell ejected during the eruption, producing radiative shocks. The time evolution of the density in the clumps is compatible with the existence of tenuous and hot material in pressure equilibrium with the clumps, which at early epochs was responsible for the observed (1-10) keV X-rays.

Resumen:

Nova eruptions occur in Cataclysmic Variables when enough material has been accreted onto the surface of the White Dwarf primary. As a consequence, the material that has been accumulated until then is expelled into the Interstellar Medium (ISM), forming an expanding nova shell around the system. Understanding the physical process that shapes the morphology of nova shells is essential to fully comprehending how the ejection mechanism operates during nova eruptions. The use of Integral Field Spectroscopy (IFS) is a technique that has received little attention in the study of nova shells, despite its advantages in studying their morphology and kinematics. In this talk, I will present our preliminary results regarding an IFS study of several nova shells, with particular emphasis on the study of their morphology. These shells were observed using the Multi-Unit Spectroscopic Explorer (MUSE) instrument located at the ESO-VLT observatory. All these shells have been previously observed almost 2 decades ago, which allows us not only to study how they look today but also how have they evolved during this time. The MUSE observations were able to detect a nova shell in the H$\rm\alpha$ line in most of our selected systems, and in some cases also in H$\rm\beta$, [O{\sc iii}] and/or [N{\sc ii}]. Comparison with previous images supports a free expansion of these nova shells, which allows us to convert the observed space within the datacube into a proper physical space. Each nova shell within our sample shows a characteristic and unique geometry, though some present similarities between them. Many of them show morphologies that challenge the common perception of nova shells with simple prolate geometries. Taking account of these new results will help us to have a better understanding of the ejection mechanism and/or the interaction with the ISM that shapes the geometry of nova shells.