Browsing by Author "Rubio, M."

Now showing 1 - 5 of 5
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    A SUBMILLIMETER STUDY OF THE IR DUST BUBBLE S 21 AND ITS ENVIRONS
    (UNIV NACIONAL AUTONOMA MEXICO, INST DE ASTRONOMIA, 2017) Cappa, C. E.; Duronea, N. U.; Vasquez, J.; Rubio, M.; Firpo, V.; Lopez Caraballo, C. H.; Borissova, J.
    Based on the molecular emission in the (CO)-C-12(2-1) and (CO)-C-13(2-1) lines, and on the continuum emission in the MIR and FIR towards the S 21 IR dust bubble, we analyze the physical characteristics of the gas and dust linked to the nebula and the presence of young stellar objects (YSOs) in its environs. The line emission reveals a clumpy molecular shell, 1.4 pc in radius, encircling S 21. The total molecular mass in the shell amounts to 2900 M-circle dot and the original ambient density, 2.1 x10(3) cm(-3), indicating that the bubble is evolving in a high density interstellar medium. The image at 24 mu m shows warm dust inside the bubble, while the emission in the range 250 to 870 mu m reveals cold dust in its outskirts, coincident with the molecular gas. The detection of radio continuum emission indicates that the bubble is a compact Hii region. A search for YSOs using photometric criteria allowed to identify many candidates projected onto the molecular clumps. We analize if the collect and collapse process has triggered a new generation of stars.
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    Extended primordial black hole mass functions with a spike
    (2023) Magana, J.; San Martin, M.; Sureda, J.; Rubio, M.; Araya, I.; Padilla, N.
    We introduce a modification of the Press-Schechter formalism aimed to derive general mass functions for primordial black holes (PBHs). In this case, we start from primordial power spectra (PPS) which include a monochromatic spike, typical of ultra slow-roll inflation models. We consider the PBH formation as being associated to the amplitude of the spike on top of the linear energy density fluctuations coming from a PPS with a blue index. By modelling the spike with a lognormal function, we study the properties of the resulting mass function spikes, and compare these to the underlying extended mass distributions. When the spike is at PBH masses, which are much lower than the exponential cut-off of the extended distribution, very little mass density is held by the PBHs within the spike, and it is not ideal to apply the Press-Schechter formalism in this case as the resulting characteristic overdensity is too different from the threshold for collapse. It is more appropriate to do so when the spike mass is similar to, or larger than the cut-off mass. Additionally, it can hold a similar mass density as the extended part. Such particular mass functions also contain large numbers of small PBHs, especially if stable PBH relics are considered, and they can provide similar to 1000 M-circle dot seeds for the supermassive black holes at the centres of present-day galaxies. The constraints on the fraction of dark matter in PBHs for monochromatic mass functions are somewhat relaxed when there is an additional underlying extended distribution of masses.
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    Kinetics of the Anaerobic Reaction of para-Substituted Phenols with Nitrogen Dioxide
    (2017) Reyes, J.; Lissi, E.; López Alarcón, Camilo Ignacio; Rubio, M.
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    Kinetics of the Reaction of Pyrogallol Red a Polyphenolic, Dye with Nitrous Acid : Role of center dot NO and center dot NO2
    (2015) Hugo, Estefanía; Reyes García, Jael Lucila; Montupil, E.; Bridi, Raquel; Lissi, E.; Denicola, A.; Rubio, M.; López Alarcón, Camilo Ignacio
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    The molecular gas content of blue dwarf galaxies A collapsing detached molecular system in He 2-10?
    (EDP SCIENCES S A, 2009) Vanzi, L.; Combes, F.; Rubio, M.; Kunth, D.
    We present new observations of a sample of blue dwarf galaxies in the lines of CO(3-2) and HCN(4-3). The observations were obtained with the 12 m APEX telescope located at an altitude of 5100 m in Chajnantor (ALMA site). We detected CO(3-2) emission in seven of nine observed galaxies in our sample. In two galaxies, NGC 5253 and He 2-10, we mapped the central 20 '' x 20 '' in the CO(3-2) emission line. In He 2-10, we detected an extended component of molecular gas to the north-east of the main body of the galaxy. Comparing our data with previous HI and CO observations, we speculate that the presence of this detached cloud of molecular gas is produced by the merger already known in He 2-10, and could lead to the formation of a small tidal dwarf galaxy. The HCN(4-3) line was observed in NGC 5253 and He 2-10 only, but not detected.