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Roldán studied Electronic Engineering at the Universidad Pontificia Bolivariana, Colombia. He joined the Instituto de Astrofísica de Andalucía (IAA-CSIC) on June 2021, after finishing his Master in Physics and Mathematics at the University of Granada, Spain. He is developing his PhD thesis in nascent planetary nebulae under the advising of Dr José Francisco Gómez and Dr Luis Felipe Miranda.
Roldán studied Electronic Engineering at the Universidad Pontificia Bolivariana, Colombia. He joined the Instituto de Astrofísica de Andalucía (IAA-CSIC) on June 2021, after finishing his Master in Physics and Mathematics at the University of Granada, Spain. He is developing his PhD thesis in nascent planetary nebulae under the advising of Dr José Francisco Gómez and Dr Luis Felipe Miranda.
Presentation
Based on special observable characteristics, Roldán is using radio interferometers to search for new objects in our Galaxy that could be considered as nascent planetary nebulae (PNe). These are crucial objects to identify and monitor the earlier mechanisms involved in the evolution of Asymptotic Giant Branch (AGB) stars, when they transform, from a spherical symmetry, into the diverse shapes of PNe. However, only a few cases (~8) of nascent PNe are known among the thousands of PNe detected to date.
He thus uses ATCA and VLA observations, in order to locate them on the Southern and Northern Galactic Plane, respectively. He is following the maser emission of H2O and OH molecules, as well as non-thermal radio continuum in the presence of a photoionized region, because these individual characteristics would be detectable only when an evolved sun-type star, at the post-AGB phase, is just transforming into a PN.
Nascent PNe are easily confused at radio frequencies with young massive objects (in star-forming regions) or with post-AGB stars. Therefore, he requires optical/infrared imaging and (mid-resolution) spectroscopy on most of those newly found Galactic sources, in order to confirm and characterize their nature as bona fide PNe.
Using mid-resolution optical spectroscopy, Roldán is determining physical conditions and chemical abundances of the photoionized gas on Vy 2-2, distinguished for being the first maser-emitting PN detected. Also, he is inspecting (CARMENES) high-resolution optical/infrared spectra in order to infer the spatial distribution of the photoionized gas on this ultra compact PN.
For his thesis, it is planned to explore ALMA data with a resolution ≤ 30 mas, in order to image and resolve for the first time the putative presence of the photoionized region in IRAS 15103-5754, the paradigmatic case of a nascent PN, where both special observable characteristics coexist, H2O masers and non-thermal radio continuum, probably tracing together a very recent (~100 yr) and powerful jet ejection, one of the main proposed mechanisms shaping PNe.
On the long term, he would like to determine with accuracy, for the newly found nascent PNe, their mass-loss history and morphology, in order to reconstruct their particular evolutionary path, emphasized in binary (or multiple) systems that host sun-type stars.
Research interest:
– Radio and infrared interferometry.
– Maser astrometry using very long baseline interferometers.
– Maser emission in PNe.
– Synchrotron radiation in PNe.
– Plasma characterization using optical/infrared spectroscopy.
– Formation mechanisms of [WC] central stars of PNe.
– Evolution of binary (or multiple) systems hosting sun-type stars.
Presentation
Based on special observable characteristics, Roldán is using radio interferometers to search for new objects in our Galaxy that could be considered as nascent planetary nebulae (PNe). These are crucial objects to identify and monitor the earlier mechanisms involved in the evolution of Asymptotic Giant Branch (AGB) stars, when they transform, from a spherical symmetry, into the diverse shapes of PNe. However, only a few cases (~8) of nascent PNe are known among the thousands of PNe detected to date.
He thus uses ATCA and VLA observations, in order to locate them on the Southern and Northern Galactic Plane, respectively. He is following the maser emission of H2O and OH molecules, as well as non-thermal radio continuum in the presence of a photoionized region, because these individual characteristics would be detectable only when an evolved sun-type star, at the post-AGB phase, is just transforming into a PN.
Nascent PNe are easily confused at radio frequencies with young massive objects (in star-forming regions) or with post-AGB stars. Therefore, he requires optical/infrared imaging and (mid-resolution) spectroscopy on most of those newly found Galactic sources, in order to confirm and characterize their nature as bona fide PNe.
Using mid-resolution optical spectroscopy, Roldán is determining physical conditions and chemical abundances of the photoionized gas on Vy 2-2, distinguished for being the first maser-emitting PN detected. Also, he is inspecting (CARMENES) high-resolution optical/infrared spectra in order to infer the spatial distribution of the photoionized gas on this ultra compact PN.
For his thesis, it is planned to explore ALMA data with a resolution ≤ 30 mas, in order to image and resolve for the first time the putative presence of the photoionized region in IRAS 15103-5754, the paradigmatic case of a nascent PN, where both special observable characteristics coexist, H2O masers and non-thermal radio continuum, probably tracing together a very recent (~100 yr) and powerful jet ejection, one of the main proposed mechanisms shaping PNe.
On the long term, he would like to determine with accuracy, for the newly found nascent PNe, their mass-loss history and morphology, in order to reconstruct their particular evolutionary path, emphasized in binary (or multiple) systems that host sun-type stars.
Research interest:
– Radio and infrared interferometry.
– Maser astrometry using very long baseline interferometers.
– Maser emission in PNe.
– Synchrotron radiation in PNe.
– Plasma characterization using optical/infrared spectroscopy.
– Formation mechanisms of [WC] central stars of PNe.
– Evolution of binary (or multiple) systems hosting sun-type stars.
