Persona: Jimenez-Serra, Izaskun
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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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Jimenez-Serra
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Izaskun
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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.; Jimenez-Serra, Izaskun; 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 Acceso Abierto 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.; Jimenez-Serra, Izaskun; 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 FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5.(Oxford Academics: Oxford University Press, 2020-07-21) Bianchi, S.; Chandler, C. J.; Ceccarelli, C.; Codella, C.; Sakai, N.; López Sepulcre, A.; Maud, L. T.; Moellenbrock, G.; Svoboda, B.; Watanabe, Y.; Sakai, T.; Ménard, F.; Aikawa, Y.; Alves, F.; Balucani, N.; Bouvier, M.; Caselli, P.; Caux, E.; Charnley, S.; Choudhury, S.; De Simone, M.; Dulieu, F.; Durán, A.; Evans, L.; Favre, C.; Fedele, D.; Feng, S.; Fontani, F.; Francis, L.; Hama, T.; Hanawa, T.; Herbst, E.; Hirota, T.; Imai, M.; Isella, A.; Jimenez-Serra, Izaskun; Johnstone, D.; Kahane, C.; Lefloch, B.; Loinard, L.; Maureira, M. J.; Mercimek, S.; Miotello, A.; Mori, S.; Nakatani, R.; Nomura, H.; Oba, Y.; Ohashi, S.; Okoda, Y.; Ospina Zamudio, J.; Oya, Y.; Pineda, Jaime E.; Podio, L.; Rimola, A.; Segura Cox, D.; Shirley, Y.; Taquet, V.; Testi, L.; Vastel, C.; Viti, S.; Watanabe, N.; Witzel, A.; Xue, C.; Zhao, B.; Zhang, Y.; Yamamoto, S.; European Research Council (ERC); Japan Society for the Promotion of Science (KAKENHI); Agencia Estatal de Investigación (AEI); Universidad Nacional Autónoma de México (UNAM); Agence Nationale de la Recherche (ANR); Balucani, N. [0000-0001-5121-5683]; De Oliveira Alves, F. [0000-0002-7945-064X]; Hama, T. [0000-0002-4991-4044]; Ohashi, S. [0000-0002-9661-7958]; Johnstone, D. [0000-0002-6773-459X]; Watanabe, Y. [0000-0002-9668-3592]; Ceccarelli, C. [0000-0001-9664-6292]; Pineda, J. [0000-0002-3972-1978]; Fedele, D. [0000-0001-6156-0034]; Mercimek, S. [0000-0002-0742-7934]; Xue, C. [0000-0003-2760-2119]; Sakai, N. [0000-0002-3297-4497]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737The study of hot corinos in solar-like protostars has been so far mostly limited to the Class 0 phase, hampering our understanding of their origin and evolution. In addition, recent evidence suggests that planet formation starts already during Class I phase, which therefore represents a crucial step in the future planetary system chemical composition. Hence, the study of hot corinos in Class I protostars has become of paramount importance. Here, we report the discovery of a hot corino towards the prototypical Class I protostar L1551 IRS5, obtained within the ALMA (Atacama Large Millimeter/submillimeter Array) Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars). We detected several lines from methanol and its isotopologues (13CH3OH and CH2DOH), methyl formate, and ethanol. Lines are bright towards the north component of the IRS5 binary system, and a possible second hot corino may be associated with the south component. The methanol lines' non-LTE analysis constrains the gas temperature (∼100 K), density (≥1.5 × 108 cm−3), and emitting size (∼10 au in radius). All CH3OH and 13CH3OH lines are optically thick, preventing a reliable measure of the deuteration. The methyl formate and ethanol relative abundances are compatible with those measured in Class 0 hot corinos. Thus, based on this work, little chemical evolution from Class 0 to I hot corinos occurs.Publicación Acceso Abierto ALMA–IRDC – II. First high-angular resolution measurements of the 14N/15N ratio in a large sample of infrared-dark cloud cores(Oxford Academics: Oxford University Press, 2021-03-22) Fontani, F.; Barnes, A. T.; Caselli, P.; Henshaw, J. D.; Cosentino, G.; Jimenez-Serra, Izaskun; Tan, J. C.; Pineda, Jaime E.; Law, C. Y.; European Research Council (ERC); Agencia Estatal de Investigación (AEI)The 14N/15N ratio in molecules exhibits a large variation in star-forming regions, especially when measured from N2H+ isotopologues. However, there are only a few studies performed at high-angular resolution. We present the first interferometric survey of the 14N/15N ratio in N2H+ obtained with Atacama Large Millimeter Array observations towards four infrared-dark clouds harbouring 3 mm continuum cores associated with different physical properties. We detect N15NH+ (1–0) in ∼20−40 per cent of the cores, depending on the host cloud. The 14N/15N values measured towards the millimetre continuum cores range from a minimum of ∼80 up to a maximum of ∼400. The spread of values is narrower than that found in any previous single-dish survey of high-mass star-forming regions and than that obtained using the total power data only. This suggests that the 14N/15N ratio is on average higher in the diffuse gaseous envelope of the cores and stresses the need for high-angular resolution maps to measure correctly the 14N/15N ratio in dense cores embedded in IRDCs. The average 14N/15N ratio of ∼210 is also lower than the interstellar value at the Galactocentric distance of the clouds (∼300–330), although the sensitivity of our observations does not allow us to unveil 14N/15N ratios higher than ∼400. No clear trend is found between the 14N/15N ratio and the core physical properties. We find only a tentative positive trend between 14N/15N and H2 column density. However, firmer conclusions can be drawn only with higher sensitivity measurements.Publicación Acceso Abierto A Low-mass Cold and Quiescent Core Population in a Massive Star Protocluster(IOP Science Publishing, 2021-04-29) Li, S.; Lu, X.; Zhang, Q.; Lee, C. W.; Sanhueza, P.; Beuther, H.; Jimenez-Serra, Izaskun; Qiu, K.; Palau, A.; Feng, S.; Pillai, T.; Kim, K. T.; Liu, H. L.; Girart, J. M.; Liu, T.; Wang, K.; Liu, H. B.; Li, D.; Lee, J. E.; Li, F.; Li, J.; Kim, S.; Yue, N.; National Natural Science Foundation of China (NSFC); National Research Foundation of Korea (NRF); European Research Council (ERC); Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); Li, S. [0000-0003-1275-5251]; Lu, X. [0000-0003-2619-9305]; Zhang, Q. [0000-0003-2384-6589]; Lee, C. W. [0000-0002-3179-6334]; Sanhueza, P. [0000-0002-7125-7685]; Beuther, H. [0000-0002-1700-090X]; Jiménez Serra, I. [0000-0003-4493-8714]; Qiu, K. [0000-0002-5093-5088]; Palau, A. [0000-0002-9569-9234]; Feng, S. [0000-0002-4707-8409]; Pillai, T. [0000-0003-2133-4862]; Kim, K. T. [0000-0003-2412-7092]; Liu, H. L. [0000-0003-3343-9645]; Girart, J. M. [0000-0002-3829-5591]; Liu, T. [0000-0002-5286-2564]; Wang, J. [0000-0001-6106-1171]; Wang, K. [0000-0002-7237-3856]; Liu, H. B. [0000-0003-2300-2626]; Li, D. [0000-0003-3010-7661]; Lee, J. E. [0000-0003-3119-2087]; Li, F. [0000-0002-9832-8295]; Li, J. [0000-0003-3520-6191]; Kim, S. [0000-0001-9333-5608]; Yue, N. [0000-0003-0355-6875]Pre-stellar cores represent the initial conditions of star formation. Although these initial conditions in nearby low-mass star-forming regions have been investigated in detail, such initial conditions remain vastly unexplored for massive star-forming regions. We report the detection of a cluster of low-mass starless and pre-stellar core candidates in a massive star protocluster-forming cloud, NGC 6334S. With the Atacama Large Millimeter/submillimeter Array (ALMA) observations at a ∼0.02 pc spatial resolution, we identified 17 low-mass starless core candidates that do not show any evidence of protostellar activity. These candidates present small velocity dispersions, high fractional abundances of NH2D, high NH3 deuterium fractionations, and are completely dark in the infrared wavelengths from 3.6 up to 70 μm. Turbulence is significantly dissipated and the gas kinematics are dominated by thermal motions toward these candidates. Nine out of the 17 cores are gravitationally bound, and therefore are identified as pre-stellar core candidates. The embedded cores of NGC 6334S show a wide diversity in masses and evolutionary stages.Publicación Acceso Abierto Strong parameter hierarchy in the interstellar phosphorus chemical network(Frontiers in Bioscience Publications, 2025-07-30) Marina, Fernández-Ruz; Jimenez-Serra, Izaskun; Castro, Mario; Ruiz-Bermejo, Marta; Aguirre, Jacobo; European Research Council (ERC); Ministerio de Ciencia e Innovación (MICINN); Consejo Superior de Investigaciones Científicas (CSIC)Phosphorus-bearing molecules are fundamental for life on Earth, yet their astrochemical origins remain poorly understood. Their formation in the interstellar medium has been challenging to elucidate due to limited spectroscopic detections and the reliance on theoretical models that depend on numerous kinetic parameters whose values are very uncertain. Multi-parameter models often suffer from “sloppiness”, where many parameter combinations exhibit negligible influence on model outcomes, while a few dominate system behavior. In this study, we introduce the Fisher Information Spectral Reduction (FISR) algorithm, a novel and computationally efficient method to reduce the complexity of such sloppy models. Our approach exposes the strong parameter hierarchy governing these systems by identifying and eliminating parameters associated with insensitive directions in the parameter space. Applying this methodology to the phosphorus astrochemistry network, we reduce the number of reaction rate coefficients from 14 to 3, pinpointing the key reactions and kinetic parameters responsible for forming PO and PN, the main phosphorus-bearing molecules typically detected in interstellar space. The simplified model retains its predictive accuracy, offering deeper insights into the mechanisms driving phosphorus chemistry in the interstellar medium. This methodology is applicable to multi-parameter models of any kind and, specifically in astrochemistry, facilitates the development of simpler, more realistic and interpretable models to effectively guide targeted observational efforts.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) Jimenez-Serra, Izaskun; 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.Publicación Acceso Abierto FAUST. II. Discovery of a Secondary Outflow in IRAS 15398−3359: Variability in Outflow Direction during the Earliest Stage of Star Formation?(The Institute of Physics (IOP), 2021-03-22) Okoda, Y.; Oya, Y.; Francis, L.; Johnstone, D.; Inutsuka, S. I.; Ceccarelli, C.; Codella, C.; Chandler, C. J.; Sakai, N.; Aikawa, Y.; Alves, F.; Balucani, N.; Bianchi, E.; Bouvier, M.; Caselli, P.; Caux, E.; Charnley, S.; Choudhury, S.; De Simone, M.; Dulieu, F.; Durán, A.; Evans, L.; Favre, C.; Fedele, D.; Feng, S.; Fontani, F.; Hama, T.; Hanawa, T.; Herbst, E.; Hirota, T.; Imai, M.; Isella, A.; Jimenez-Serra, Izaskun; Kahane, C.; Lefloch, B.; Loinard, L.; López Sepulcre, A.; Maud, L. T.; Maureira, M. J.; Ménard, F.; Mercimek, S.; Miotello, A.; Moellenbrock, G.; Mori, S.; Murillo, Nadia M.; Nakatani, R.; Nomura, H.; Oba, Y.; O´Donoghue, R.; Ohashi, S.; Ospina Zamudio, J.; Pineda, Jaime E.; Podio, L.; Rimola, A.; Sakai, T.; Segura Cox, D.; Shirley, Y.; Svoboda, B.; Taquet, V.; Testi, L.; Vastel, C.; Viti, S.; Watanabe, N.; Watanabe, Y.; Witzel, A.; Xue, C.; Zhang, Y.; Zhao, B.; Yamamoto, S.; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Japan Society for the Promotion of Science (JSPS); Okoda, Y. [0000-0003-3655-5270]; Oya, Y. [0000-0002-0197-8751]; Francis, L. [0000-0001-8822-6327]; Johnstone, D. [0000-0002-6773-459X]; Inutsuka, S. I. [0000-0003-4366-6518]; Ceccarelli, C. [0000-0001-9664-6292]; Codella, C. [0000-0003-1514-3074]; Chandler, C. [0000-0002-7570-5596]; Sakai, N. [0000-0002-3297-4497]; Aikawa, Y. [0000-0003-3283-6884]; Alves, F. [0000-0002-7945-064X]; Balucani, N. [0000-0001-5121-5683]; Bianchi, E. [0000-0001-9249-7082]; Bouvier, M. [0000-0003-0167-0746]; Caselli, P. [0000-0003-1481-7911]; De Simone, M. [0000-0001-5659-0140]; Feng, S. [0000-0002-4707-8409]; Fontani, F. [0000-0003-0348-3418]; Hama, T. [0000-0002-4991-4044]; Hanawa, T. [0000-0002-7538-581X]; Herbst, E. [0000-0002-4649-2536]; Hirota, T. [0000-0003-1659-095X]; Imai, M. [0000-0002-5342-6262]; Isella, A. [0000-0001-8061-2207]; Jiménez Serra, I. [0000-0003-4493-8714]; Kahane, C. [0000-0003-1691-4686]; Loinard, L. [0000-0002-5635-3345]; López Sepulcre, A. [0000-0002-6729-3640]; Maud, L. T. [0000-0002-7675-3565]; Maureira, M. J. [0000-0002-7026-8163]; Menard, F. [0000-0002-1637-7393]; Miotello, A. [0000-0002-7997-2528]; Moellenbrock, G. [0000-0002-3296-8134]; Oba, Y. [0000-0002-6852-3604]; Ohashi, S. [0000-0002-9661-7958]; Pineda, J. E. [0000-0002-3972-1978]; Rimola, A. [0000-0002-9637-4554]; Sakai, T. [0000-0003-4521-7492]; Segura Cox, D. [0000-0003-3172-6763]; Svoboda, B. [0000-0002-8502-6431]; Taquet, V. [0000-0003-0407-7489]We have observed the very low-mass Class 0 protostar IRAS 15398−3359 at scales ranging from 50 to 1800 au, as part of the Atacama Large Millimeter/Submillimeter Array Large Program FAUST. We uncover a linear feature, visible in H2CO, SO, and C18O line emission, which extends from the source in a direction almost perpendicular to the known active outflow. Molecular line emission from H2CO, SO, SiO, and CH3OH further reveals an arc-like structure connected to the outer end of the linear feature and separated from the protostar, IRAS 15398−3359, by 1200 au. The arc-like structure is blueshifted with respect to the systemic velocity. A velocity gradient of 1.2 km s−1 over 1200 au along the linear feature seen in the H2CO emission connects the protostar and the arc-like structure kinematically. SO, SiO, and CH3OH are known to trace shocks, and we interpret the arc-like structure as a relic shock region produced by an outflow previously launched by IRAS 15398−3359. The velocity gradient along the linear structure can be explained as relic outflow motion. The origins of the newly observed arc-like structure and extended linear feature are discussed in relation to turbulent motions within the protostellar core and episodic accretion events during the earliest stage of protostellar evolution.Publicación Acceso Abierto Expanding the C3H6O2 isomeric interstellar inventory: Discovery of lactaldehyde and methoxyacetaldehyde in G+0.693-0.027(EDP Sciences, 2026-02-23) Sanz-Novo, Miguel; Rivilla, Victor M.; Jimenez-Serra, Izaskun; Colzi, Laura; Zeng, Shaoshan; Megías, Andrés; San Andrés, David; López-Gallifa, Álvaro; Martínez-Henares, Antonio; Fried, Zachary; McGuire, Brett; Martin Ruiz, Sergio; Requena Torres, Miguel Angel; Tercero, Belén; de Vicente, Pablo; Kolesniková, Lucie; Alonso, Elena Rita; Cocinero, E. J.; Guillemin, Jean-Claude; Kleiner, I.; Agencia Estatal de Investigación (España); Comunidad de Madrid; Centre National D'Etudes Spatiales (CNES); Consejo Superior de Investigaciones Científicas (CSIC); Gobierno Vasco; Instituto Geográfico Español (IGN); European Commission (EC); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737Aims. The tentative detection of 3-hydroxypropanal (HO(CH2)2C(O)H) toward the Galactic center molecular cloud G+0.693-0.027 prompts a systematic survey in this source aimed at detecting all C3H6O2 isomers with available spectroscopy. Methods. We used an ultra-deep broadband spectral survey of G+0.693-0.027, carried out with the Yebes 40 m and IRAM 30 m telescopes, to conduct the astronomical search. Results. We report the first interstellar detection of lactaldehyde (CH3CH(OH)C(O)H) and methoxyacetaldehyde (CH3OCH2C(O)H), together with the second detections (i.e., confirmation) of methyl acetate (CH3C(O)OCH3) and hydroxyacetone (CH3C(O)CH2OH), and new detections in this source of both anti - and g auche - conformers of ethyl formate (CH3CH2OC(O)H; the latter being tentative). For these species, we derived a fractional abundance relative to H2 of ~(0.81, 0.24, 16, 1.6, 1.3, 1.4) × 10−10, respectively. In contrast, neither propionic acid, CH3CH2C(O)OH, nor glycidol, c-CH2OCHCH2OH (i.e., the most and the least stable species within the C3H6O2 family, respectively) were detected, and we provide upper limits on their fractional abundances of ≤1.5 × 10−10 and ≤3.7 × 10−11. Interestingly, all C3H6O2 isomers can be synthesized through radical-radical reactions on the surface of dust grains, ultimately tracing back to CO as the parent molecule. We suggest that formation of the detected isomers is mainly driven by successive hydrogenation of CO, producing CH3OH and CH3CH2OH as the primary parent species. Conversely, propionic acid is thought to originate from the oxygenation of CO via the HOCO intermediate, which help us rationalize its non-detection. Overall, our findings notably expand the known chemical inventory of the interstellar medium and provide direct observational evidence that increasingly complex chemistry involving O-bearing species occurs in space.Publicación Acceso Abierto A chemical study of carbon fractionation in external galaxies(Oxford Academics: Blackwell Publishing, 2020-07-18) Viti, S.; Fontani, F.; Jimenez-Serra, Izaskun; Agencia Estatal de Investigación (AEI); European Research Council (ERC); Science and Technology Facilities Council (STFC); 0000-0003-4493-8714; 0000-0003-0348-3418; 0000-0001-8504-8844; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737In the interstellar medium carbon exists in the form of two stable isotopes 12C and 13C and their ratio is a good indicator of nucleosynthesis in galaxies. However, chemical fractionation can potentially significantly alter this ratio and in fact observations of carbon fractionation within the same galaxy has been found to vary from species to species. In this paper, we theoretically investigate the carbon fractionation for selected abundant carbon-bearing species in order to determine the conditions that may lead to a spread of the 12C/13C ratio in external galaxies. We find that carbon fractionation is sensitive to almost all the physical conditions we investigated, it strongly varies with time for all species but CO, and shows pronounced differences across species. Finally, we discuss our theoretical results in the context of the few observations of the 12C/13C in both local and higher redshift galaxies.
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