Persona: Rivilla, Victor M.
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Centro de Astrobiologia
El Centro de Astrobiología (CAB) es un centro mixto de investigación en astrobiología, dependiente tanto del Instituto Nacional de Técnica Aeroespacial (INTA) como del Consejo Superior de Investigaciones Científicas (CSIC).
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Rivilla
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Victor M.
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Publicación Acceso Abierto Prebiotic Precursors of the Primordial RNA World in Space: Detection of NH2OH(The Institute of Physics (IOP), 2020-08-19) Rivilla, Victor M.; Martín Pintado, J.; Jiménez Serra, I.; Martín, S.; Rodríguez Almeida, L. F.; Requena Torres, Miguel Angel; Rico Villas, F.; Zeng, S.; Briones, C.; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Briones, C. [0000-0003-2213-8353]; Martín Ruiz, S. [0000-0001-9281-2919]; Rico Villas, F. [0000-0002-5351-3497]; Rivilla, V. M. [0000-0002-2887-5859]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737One of the proposed scenarios for the origin of life is the primordial RNA world, which considers that RNA molecules were likely responsible for the storage of genetic information and the catalysis of biochemical reactions in primitive cells, before the advent of proteins and DNA. In the last decade, experiments in the field of prebiotic chemistry have shown that RNA nucleotides can be synthesized from relatively simple molecular precursors, most of which have been found in space. An important exception is hydroxylamine, NH2OH, which, despite several observational attempts, it has not been detected in space yet. Here we present the first detection of NH2OH in the interstellar medium toward the quiescent molecular cloud G+0.693-0.027 located in the Galactic Center. We have targeted the three groups of transitions from the J = 2−1, 3−2, and 4−3 rotational lines, detecting five transitions that are unblended or only slightly blended. The derived molecular abundance of NH2OH is (2.1 ± 0.9) × 10−10. From the comparison of the derived abundance of NH2OH and chemically related species, with those predicted by chemical models and measured in laboratory experiments, we favor the formation of NH2OH in the interstellar medium via hydrogenation of NO on dust grain surfaces, with possibly a contribution of ice-mantle NH3 oxidation processes. Further laboratory studies and quantum chemical calculations are needed to completely rule out the formation of NH2OH in the gas phase.Publicación Acceso Abierto The ionized heart of a molecular disk ALMA observations of the hyper-compact HII region G24.78+0.08 A1(EDP Sciences, 2021-06-21) Moscadelli, L.; Cesaroni, R.; Beltrán, M. T.; Rivilla, Victor M.Context. Hyper-compact (HC) or ultra-compact H II regions are the first manifestations of the radiation feedback from a newly born massive star. Therefore, their study is fundamental to understanding the process of massive (≥8 M⊙) star formation. Aims. We employed Atacama Large Millimeter/submillimeter Array (ALMA) 1.4 mm Cycle 6 observations to investigate at high angular resolution (≈0.′′050, corresponding to 330 au) the HC H II region inside molecular core A1 of the high-mass star-forming cluster G24.78+0.08. Methods. We used the H30α emission and different molecular lines of CH3CN and 13CH3CN to study the kinematics of the ionized and molecular gas, respectively. Results. At the center of the HC H II region, at radii ≲500 au, we observe two mutually perpendicular velocity gradients, which are directed along the axes at PA = 39° and PA = 133°, respectively. The velocity gradient directed along the axis at PA = 39° has an amplitude of 22 km s−1 mpc−1, which is much larger than the other’s, 3 km s−1 mpc−1. We interpret these velocity gradients as rotation around, and expansion along, the axis at PA = 39°. We propose a scenario where the H30α line traces the ionized heart of a disk-jet system that drives the formation of the massive star (≈20 M⊙) responsible for the HC H II region. Such a scenario is also supported by the position-velocity plots of the CH3CN and 13CH3CN lines along the axis at PA = 133°, which are consistent with Keplerian rotation around a 20 M⊙ star. Conclusions. Toward the HC H II region in G24.78+0.08, the coexistence of mass infall (at radii of ~5000 au), an outer molecular disk (from ≲4000 au to ≳500 au), and an inner ionized disk (≲500 au) indicates that the massive ionizing star is still actively accreting from its parental molecular core. To our knowledge, this is the first example of a molecular disk around a high-mass forming star that, while becoming internally ionized after the onset of the H II region, continues to accrete mass onto the ionizing star.Publicación Acceso Abierto The Origin of the E/Z Isomer Ratio of Imines in the Interstellar Medium(IOP Science Publishing, 2021-04-29) García de la Concepción, J.; Jiménez Serra, I.; Corchado, J. C.; Rivilla, Victor M.; Martín Pintado, J.; Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Junta de Andalucía; García de la Concepción, j. [0000-0001-6484-9546]; Jiménez Serra, I. [0000-0003-4493-8714]; Corchado, J. C. [0000-0002-8463-3168]; Rivilla, V. M. [0000-0002-2887-5859]; Martín Pintado, J. [0000-0003-4561-3508]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Recent astronomical observations of both isomers E and Z of imines such as cyanomethanimine, ethanimine, and 2-propyn-1-imine have revealed that the abundances in the interstellar medium (ISM) of these isomers differ by factors of ~3–10. Several theories have been proposed to explain the observed behavior, but none of them successfully explains the [E]/[Z] ratios. In this work we present a detailed study of the kinetics of the one-step E-Z isomerization reactions of cyanomethanimine, ethanimine, and 2-propyn-1-imine under interstellar conditions (in the 10–400 K temperature range). This reaction was previously thought to be nonviable in the ISM due to its associated high-energy barrier (about 13,000 K). In this Letter, we show that considering the multidimensional small curvature tunneling approximation, the tunneling effect enables the isomerization even at low temperatures. This is due to the fact that the representative tunneling energy lies in the vibrational ground state of the least stable isomer up to approximately 150 K, making the reaction constants of the isomerization from the least stable to the most stable isomer basically constant. The predicted [E]/[Z] ratios are almost the same as those reported from the astronomical observations for all imines observed. This study demonstrates that the [E]/[Z] ratio of imines in the ISM strongly depends on their relative stability.Publicación Restringido Thiols in the Interstellar Medium: First Detection of HC(O)SH and Confirmation of C2H5SH(IOP Science Publishing, 2021-04-30) Rodríguez Almeida, L. F.; Jiménez Serra, I.; Rivilla, Victor M.; Martín Pintado, J.; Zeng, S.; Tercero, B.; De Vicente, P.; Colzi, L.; Rico Villas, F.; Martín, S.; Requena Torres, Miguel Angel; Comunidad de Madrid; Agencia Estatal de Investigación (AEI); European Research Council (ERC); European Commission (EC); Rodríguez Almeida, L. F. [0000-0002-9785-703X]; Jiménez Serra, I. [0000-0003-4493-8714]; Rivilla, V. M. [0000-0002-2887-5859]; Martín Pintado, J. [0000-0003-4561-3508]; Tercero, B. [0000-0002-4782-5259]; Martín, S. [0000-0001-9281-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737The chemical compounds carrying the thiol group (-SH) have been considered essential in recent prebiotic studies regarding the polymerization of amino acids. We have searched for this kind of compound toward the Galactic Center quiescent cloud G+0.693–0.027. We report the first detection in the interstellar space of the trans-isomer of monothioformic acid (t-HC(O)SH) with an abundance of ~1 × 10−10. Additionally, we provide a solid confirmation of the gauche isomer of ethyl mercaptan (g-C2H5SH) with an abundance of ~3 × 10−10, and we also detect methyl mercaptan (CH3SH) with an abundance of ~5 × 10−9. Abundance ratios were calculated for the three SH-bearing species and their OH analogs, revealing similar trends between alcohols and thiols with increasing complexity. Possible chemical routes for the interstellar synthesis of t-HC(O)SH, CH3SH, and C2H5SH are discussed, as well as the relevance of these compounds in the synthesis of prebiotic proteins in the primitive Earth.Publicación Restringido Vibrationally excited HC3N emission in NGC 1068: tracing the recent star formation in the starburst ring(Oxford Academics: Oxford University Press, 2021-01-25) Rico Villas, F.; Martín Pintado, J.; González Alfonso, E.; Rivilla, Victor M.; Martín, S.; García Burillo, S.; Jiménez Serra, I.; Sánchez García, M.; Agencia Estatal de Investigación (AEI); European Research Council (ERC); Rivilla, V. M. [0000-0002-2887-5859]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Using the ALMA data, we have studied the HC3N and continuum emission in the starburst pseudo-ring (SB pseudo-ring) and the circumnuclear disc (CND) of the SB/active galactic nucleus (AGN) composite galaxy NGC 1068. We have detected emission from vibrationally excited HC3N (HC3N*) only towards one star-forming region of the SB pseudo-ring. Remarkably, HC3N* was not detected towards the CND despite its large HC3N v = 0 column density. From local thermodynamic equilibrium (LTE) and non-LTE modelling of HC3N*, we obtained a dust temperature (Tdust) of ∼250 K and a density (nH2) of 6×105 cm−3 for this star-forming region. The estimated infrared (IR) luminosity of 5.8 × 108 L⊙ is typical of proto-superstar clusters (proto-SSCs) observed in the SB galaxy NGC 253. We use the continuum emissions at 147 and 350 GHz, along with CO and Pa α, to estimate the ages of other 14 SSCs in the SB pseudo-ring. We find the SSCs to be associated with the region connecting the nuclear bar with the SB pseudo-ring, supporting the inflow scenario. For the CND, our analysis yields Tdust ≤ 100 K and nH2∼(3−6)×105 cm−3. The very different dust temperatures found for the CND and the proto-SSC indicate that, while the dust in the proto-SSC is being efficiently heated from the inside by the radiation from massive protostars, the CND is being heated externally by the AGN, which in the IR optically thin case can only heat the dust to 56 K. We discuss the implications of the non-detection of HC3N* near the luminous AGN in NGC 1068 on the interpretation of the HC3N* emission observed in the SB/AGN composite galaxies NGC 4418 and Arp 220.Publicación Acceso Abierto Propargylimine in the laboratory and in space: millimetre-wave spectroscopy and its first detection in the ISM(EDP Sciences, 2020-08-20) Bizzocchi, L.; Prudenzano, D.; Rivilla, Victor M.; Pietropolli Charmet, A.; Giuliano, B. M.; Caselli, P.; Martín Pintado, J.; Jiménez Serra, I.; Martín, S.; Requena Torres, M. A.; Rico Villas, F.; Guillemin, J. C.; Centre National D'Etudes Spatiales (CNES); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Rico Villas, F. [0000-0002-5351-3497]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Context. Small imines containing up to three carbon atoms are present in the interstellar medium (ISM). As alkynyl compounds are abundant in this medium, propargylimine (2-propyn-1-imine, HC ≡C−CH =NH) thus represents a promising candidate for a new interstellar detection. Aims. The goal of the present work is to perform a comprehensive laboratory investigation of the rotational spectrum of propargylimine in its ground vibrational state in order to obtain a highly precise set of rest frequencies and to search for it in space. Methods. The rotational spectra of E and Z geometrical isomers of propargylimine have been recorded in the laboratory in the 83–500 GHz frequency interval. The measurements have been performed using a source-modulation millimetre-wave spectrometer equipped with a pyrolysis system for the production of unstable species. High-level ab initio calculations were performed to assist the analysis and to obtain reliable estimates for an extended set of spectroscopic quantities. We searched for propargylimine at 3 mm and 2 mm in the spectral survey of the quiescent giant molecular cloud G+0.693-0.027 located in the central molecular zone, close to the Galactic centre. Results. About 1000 rotational transitions have been recorded for the E- and Z-propargylimine, in the laboratory. These new data have enabled the determination of a very accurate set of spectroscopic parameters including rotational, quartic, and sextic centrifugal distortion constants. The improved spectral data allowed us to perform a successful search for this new imine in the G+0.693-0.027 molecular cloud. Eighteen lines of Z-propargylimine were detected at level >2.5σ, resulting in a column-density estimate of N = (0.24 ± 0.02) × 1014 cm−2. An upper limit was retrieved for the higher energy E isomer, which was not detected in the data. The fractional abundance (with respect to H2) derived for Z-propargylimine is 1.8 × 10−10. We discuss the possible formation routes by comparing the derived abundance with those measured in the source for possible chemical precursors.Publicación Acceso Abierto Discovery in space of ethanolamine, the simplest phospholipid head group(National Academy of Sciences, 2021-06-01) Rivilla, Victor M.; Jiménez Serra, I.; Martín Pintado, J.; Briones, C.; Rodríguez Almeida, L. F.; Rico Villas, F.; Tercero, B.; Zeng, S.; Colzi, L.; De Vicente, P.; Martín, S.; Requena Torres, Miguel Angel; European Commission (EC); Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Rivilla, V. M. [0000-0002-2887-5859]; Tercero, B. [0000-0002-4782-5259]; Martín, S. [0000-0001-9281-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Cell membranes are a key element of life because they keep the genetic material and metabolic machinery together. All present cell membranes are made of phospholipids, yet the nature of the first membranes and the origin of phospholipids are still under debate. We report here the presence of ethanolamine in space, NH2CH2CH2OH, which forms the hydrophilic head of the simplest and second-most-abundant phospholipid in membranes. The molecular column density of ethanolamine in interstellar space is N = (1.51 +/- 0.07) x 1013 cm-2, implying a molecular abundance with respect to H2 of (0.9 - 1.4) x 10-10. Previous studies reported its presence in meteoritic material, but they suggested that it is synthesized in the meteorite itself by decomposition of amino acids. However, we find that the proportion of the molecule with respect to water in the interstellar medium is similar to the one found in the meteorite (10-6). These results indicate that ethanolamine forms efficiently in space and, if delivered onto early Earth, could have contributed to the assembling and early evolution of primitive membranes.Publicación Acceso Abierto Cloud–cloud collision as drivers of the chemical complexity in Galactic Centre molecular clouds.(Oxford Academics: Blackwell Publishing, 2020-07-29) Zeng, S.; Zhang, Q.; Jiménez Serra, I.; Tercero, B.; Lu, X.; Martín Pintado, J.; De Vicente, P.; Rivilla, Victor M.; Li, S.; European Research Council (ERC); Agencia Estatal de Investigación (AEI); European Commission (EC); Japan Society for the Promotion of Science (KAKENHI); De Vicente, P. [0000-0002-5902-5005]; Rivilla, V. M. [0000-0002-2887-5859]; Li, S. [0000-0003-1275-5251]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737G+0.693-0.03 is a quiescent molecular cloud located within the Sagittarius B2 (Sgr B2) star-forming complex. Recent spectral surveys have shown that it represents one of the most prolific repositories of complex organic species in the Galaxy. The origin of such chemical complexity, along with the small-scale physical structure and properties of G+0.693-0.03, remains a mystery. In this paper, we report the study of multiple molecules with interferometric observations in combination with single-dish data in G+0.693-0.03. Despite the lack of detection of continuum source, we find small-scale (0.2 pc) structures within this cloud. The analysis of the molecular emission of typical shock tracers such as SiO, HNCO, and CH3OH unveiled two molecular components, peaking at velocities of 57 and 75 km s(-1). They are found to be interconnected in both space and velocity. The position-velocity diagrams show features that match with the observational signatures of a cloud-cloud collision. Additionally, we detect three series of class I methanol masers known to appear in shocked gas, supporting the cloud-cloud collision scenario. From the maser emission we provide constraints on the gas kinetic temperatures (similar to 30-150 K) and H-2 densities (10(4)-10(5) cm(-2)). These properties are similar to those found for the starburst galaxy NGC 253 also using class I methanol masers, suggested to be associated with a cloud-cloud collision. We conclude that shocks driven by the possible cloud-cloud collision is likely the most important mechanism responsible for the high level of chemical complexity observed in G+0.693-0.03.Publicación Acceso Abierto Toward the RNA-World in the Interstellar Medium—Detection of Urea and Search of 2-Amino-oxazole and Simple Sugars(Mary Ann Liebert Publishers, 2020-09-15) Jiménez Serra, I.; Martín Pintado, J.; Rivilla, Victor M.; Rodríguez Almeida, L. F.; Alonso Alonso, E. R.; Zeng, S.; Cocinero, E. J.; Martín, S.; Requena Torres, Miguel Angel; Martín Doménech, R.; Testi, L.; Gobierno Vasco; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Cocinero, E. J. [0000-0001-7632-3728]; Martín Doménech, R. [0000-0001-6496-9791]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737In the past decade, astrochemistry has witnessed an impressive increase in the number of detections of complex organic molecules. Some of these species are of prebiotic interest such as glycolaldehyde, the simplest sugar, or aminoacetonitrile, a possible precursor of glycine. Recently, we have reported the detection of two new nitrogen-bearing complex organics, glycolonitrile and Z-cyanomethanimine, known to be intermediate species in the formation process of ribonucleotides within theories of a primordial RNA-world for the origin of life. In this study, we present deep and high-sensitivity observations toward two of the most chemically rich sources in the galaxy: a giant molecular cloud in the center of the Milky Way (G + 0.693-0.027) and a proto-Sun (IRAS16293-2422 B). Our aim is to explore whether the key precursors considered to drive the primordial RNA-world chemistry are also found in space. Our high-sensitivity observations reveal that urea is present in G + 0.693-0.027 with an abundance of similar to 5 x 10(-11). This is the first detection of this prebiotic species outside a star-forming region. Urea remains undetected toward the proto-Sun IRAS16293-2422 B (upper limit to its abundance of <= 2 x 10(-11)). Other precursors of the RNA-world chemical scheme such as glycolaldehyde or cyanamide are abundant in space, but key prebiotic species such as 2-amino-oxazole, glyceraldehyde, or dihydroxyacetone are not detected in either source. Future more sensitive observations targeting the brightest transitions of these species will be needed to disentangle whether these large prebiotic organics are certainly present in space.Publicación Acceso Abierto The Ionized Warped Disk and Disk Wind of the Massive Protostar Monoceros R2-IRS2 Seen with ALMA(The Institute of Physics (IOP), 2020-07-13) Jiménez Serra, I.; Báez Rubio, A.; Martín Pintado, J.; Zhang, Q.; Rivilla, Victor M.; Agencia Estatal de Investigación (AEI); European Research Council (ERC); Jiménez Serra, I. [0000-0003-4493-8714]; Zhang, Q. [0000-0003-2384-6589]; Rivilla, V. M. [0000-0002-2887-5859]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Theories of massive star formation predict that massive protostars accrete gas through circumstellar disks. Although several cases have been found already thanks to high angular-resolution interferometry, the internal physical structure of these disks remains unknown, in particular whether they present warps or internal holes, as observed in low-mass protoplanetary disks. Here, we report very high angular-resolution observations of the H21 alpha radio recombination line carried out in Band 9 with the Atacama Large Millimeter/submillimeter Array (beam of 80 mas x 60 mas, or 70 au x 50 au) toward the IRS2 massive young stellar object in the Monoceros R2 star-forming cluster. The H21 alpha line shows maser amplification, which allows us to study the kinematics and physical structure of the ionized gas around the massive protostar down to spatial scales of similar to 1-2 au. Our ALMA images and 3D radiative transfer modeling reveal that the ionized gas around IRS2 is distributed in a Keplerian circumstellar disk and an expanding wind. The H21 alpha emission centroids at velocities between -10 and 20 km s(-1)deviate from the disk plane, suggesting a warping for the disk. This could be explained by the presence of a secondary object (a stellar companion or a massive planet) within the system. The ionized wind seems to be launched from the disk surface at distances similar to 11 au from the central star, consistent with magnetically-regulated disk wind models. This suggests a similar wind-launching mechanism to that recently found for evolved massive stars such as MWC349A and MWC922.
