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Luis Felipe Rodríguez

Publications and source records attributed to Luis Felipe Rodríguez.

3 recordsLinked to original sources

Jets and Outflows in Young Stellar Objects with the SKAO

Jets and outflows are ubiquitous phenomena associated with the formation of young stellar objects (YSOs). They play a crucial role in removing angular momentum from the accreting system and in regulating star-formation efficiency. Theoretical studies and observations with ALMA and VLA have shown that jets and winds may have a crucial role in promoting dust growth in the envelope-disc system and in shaping the physical and chemical properties of the surrounding environment. Despite these significant advances, many fundamental questions remain unanswered regarding the acceleration, collimation, and chemical impact of jets and outflows from YSOs. The SKA-project will overcome the limitations of current mm/cm-facilities by enabling high-angular resolution and high-sensitivity cm-observations, crucial for probing jets/outflows near YSOs. Radio recombination lines, combined with proper motions, offer a unique opportunity to study the 3D-kinematics of jets. Non-thermal linearly polarised synchrotron emission will allow measuring magnetic field strength and morphology at unprecedented scales of a few au. Observations of dust emission in outflow cavities will allow studying how dust grows and is eventually transported from the disc to the envelope and back. Finally, the SKA-project will allow exploring the dust composition and chemical enrichment in shocks, where sputtering/shattering of grains cause the release of their mantles and refractory cores in the gas-phase. Complementary to ALMA's detection of simple and complex organic molecules, the SKAO will probe, for the first time, long carbon chains/rings, several Cl-, Al-, Mg-, and other metal-bearing species (missed by current sub-mm facilities).

astro-ph.GA

A photoionized accretion disk around a young high-mass star

We present high spatial resolution ($52$ au) observations of the high-mass young stellar object (HMYSO) G345.4938+01.4677 made using the Atacama Large Millimeter/sub-millimeter Array (ALMA). This O-type HMYSO is located at 2.38 kpc and it is associated with a luminosity of $1.5\times10^5 L_\odot$. We detect circumstellar emission from the H$38β$ hydrogen recombination line showing a compact structure rotating perpendicularly to the previously detected radio jet. We interpret this emission as tracing a photo-ionized accretion disk around the HMYSO. While this disk-like structure seems currently too small to sustain continued accretion, the data present direct observational evidence of how disks can effectively survive the photo-ionization feedback from young high-mass stars. We also report the detection of a low-mass young stellar object in the vicinity of the HMYSO and suggest that it forms a high-mass and low-mass star binary system.

astro-ph.SR

ALMA observations of two massive and dense MALT90 clumps

We report Atacama Large Millimeter Array observations of 3 mm dust continuum emission and line emission, in HCO$^{+}$, H$^{13}$CO$^{+}$, N$_{2}$H$^{+}$ and CH$_{3}$CN, towards two massive and dense clumps (MDCs) in early but distinct evolutionary phases (prestellar and protostellar), made with the goal of investigating their fragmentation characteristics at angular scales of $\sim$1 $\arcsec$. Towards the prestellar clump we detected ten compact structures (cores), with radius from 1200 to 4500 AU and masses from 1.6 to 20~M$_\odot$. Half of these cores exhibit inverse P Cygni profiles in HCO$^{+}$ and are subvirialized indicating that they are undergoing collapse. Towards the protostellar clump we detected a massive (119~M$_\odot$) central core, with a strong mass infall rate, and nine less massive cores, with masses from 1.7 to 27~M$_\odot$ and radius from 1000 to 4300 AU. CH$_{3}$CN rotational temperatures were derived for 8 cores in the protostellar clump and 3 cores in the prestellar clump. Cores within the prestellar clump have smaller linewidths and lower temperatures than cores within the protostellar clump. The fraction of total mass in cores to clump mass is smaller in the prestellar clump ($\sim$6\%) than in the protostellar clump ($\sim$23\%). We conclude that we are witnessing the evolution of the dense gas in globally collapsing MDCs; the prestellar clump illustrating the initial stage of fragmentation, harboring cores that are individually collapsing, and the protostellar clump reflecting a later stage in which a considerable fraction of the gas has been gravitationally focused into the central region.

astro-ph.GA