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 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 Discovery in space of ethanolamine, the simplest phospholipid head group(National Academy of Sciences, 2021-06-01) Rivilla, Victor M.; Jimenez-Serra, Izaskun; Martín Pintado, J. ; Briones, C.; Rodríguez Almeida, L. F.; Rico Villas, F.; Tercero, B.; Zeng, Shaoshan; Colzi, Laura; 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 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 Synthesis and Spectroscopic Characterization of Interstellar Candidate Ethynyl Thiocyanate: HCCSCN(IOP Publishing, 2024-11-14) Alonso, Elena Rita; Insausti, Aran; Kolesniková, Lucie; León, Iker; McGuire, Brett A.; Shingledecker, Christopher N.; Agúndez, Marcelino ; Cernicharo, José; Rivilla, Victor M.; Cabezas, Carlos ; Jimenez-Serra, Izaskun; Martín-Pintado, Jesús; Guillemin, Jean Claude; National Science Foundation (NSF); Junta de Castilla y León; European Commission (EC); El Consejo Superior de Investigaciones Científicas (CSIC); Centre National de la Recherche Scientifique (CNRS); Ministerio de Ciencia e Innovación (MICINN)This work aims to spectroscopically characterize and provide for the first time direct experimental frequencies of the ground vibrational state and two excited states of the simplest alkynyl thiocyanate (HCCSCN) for astrophysical use. Both microwave (8-16 GHz) and millimeter-wave regions (50-120 GHz) of the spectrum have been measured and analyzed in terms of Watson’s semirigid rotor Hamiltonian. A total of 314 transitions were assigned to the ground state of HCCSCN, and a first set of spectroscopic constants have been accurately determined. Spectral features of the molecule were then searched for in Sgr B2(N), NGC 6334I, G+0.693−0.027, and TMC-1 molecular clouds. Upper limits to the column density are provided.Publicación Restringido Detection of the elusive dangling OH ice features at ~2.7 μm in Chamaeleon I with JWST NIRCam(Nature Publishing Group, 2024-09-01) Noble, Jennifer; Fraser, Helen; Smith, Z. L.; Dartois, E.; Boogert, A. C. A.; Cuppen, Herma; Dickinson, Hugh J.; Dulieu, F.; Egami, E.; Erkal, Jessica; Giuliano, B. M.; Husquinet, Basile; Lamberts, T.; Maté, B.; McClure, Melissa; Palumbo, M. E.; Shimonishi, T.; Sun, Fengwu; Bergner, Jennifer; Brown, Wendy; Caselli, P.; Congiu, E.; Drozdovskaya, Maria Nikolayevna; Herrero, V. J.; Ioppolo, Sergio; Jimenez-Serra, Izaskun; Linnartz, Harold; Melnick, G. J.; McGuire, Brett; Oberg, Karin; Perotti, G.; Qasim, D.; Rocha, Will Robson Monteiro; Urso, Riccardo GiovanniAscertaining the morphology and composition of the icy mantles covering dust grains in dense, cold regions of the interstellar medium is essential to developing accurate astrochemical models, determining conditions for ice formation, constraining chemical interactions in and on icy grains and understanding how ices withstand space radiation. The widely observed infrared spectroscopic signature of H2O ice at ~3 μm discriminates crystalline from amorphous structures in interstellar ices. Weaker bands seen only in laboratory ice spectra at ~2.7 μm, termed ‘dangling OH’ (dOH), are attributed to water molecules not fully bound to neighbouring water molecules and are often considered as tracing the degree of ice compaction. We exploit the high sensitivity of JWST NIRCam to detect two dOH features at 2.703 and 2.753 μm along multiple lines of sight probing the dense cloud Chamaeleon I, attributing these signatures to unbound dOH in cold water ice and dOH in interaction with other molecular species. These detections open a path to using the dOH features as tracers of the formation, composition, morphology and evolution of icy grains during the star and planet formation process.Publicación Acceso Abierto ALMA–IRDC: dense gas mass distribution from cloud to core scales(Oxford Academics: Oxford University Press, 2021-03-22) Barnes, A. T.; Henshaw, J. D.; Fontani, F.; Pineda, Jaime E.; Cosentino, G.; Tan, J. C.; Caselli, P.; Wang, K.; Jimenez-Serra, Izaskun; Law, C. Y.; Avison, A.; Bigiel, F.; Feng, S.; Kong, S.; Longmore, Steven N.; Moser, L.; Parker, R. J.; Sánchez Monge, Álvaro ; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Deutsche Forschungsgemeinschaft (DFG); East Asia Core Observatories Association (EACOA); National Natural Science Foundation of China (NSFC); National Key Research and Development Program of China; Peking University; Avison, A. [0000-0002-2562-8609]Infrared dark clouds (IRDCs) are potential hosts of the elusive early phases of high mass star formation (HMSF). Here, we conduct an in-depth analysis of the fragmentation properties of a sample of 10 IRDCs, which have been highlighted as some of the best candidates to study HMSF within the Milky Way. To do so, we have obtained a set of large mosaics covering these IRDCs with Atacama Large Millimeter/submillimeter Array (ALMA) at Band 3 (or 3 mm). These observations have a high angular resolution (∼3 arcsec; ∼0.05 pc), and high continuum and spectral line sensitivity (∼0.15 mJy beam−1 and ∼0.2 K per 0.1 km s−1 channel at the N2H+ (1 − 0) transition). From the dust continuum emission, we identify 96 cores ranging from low to high mass (M = 3.4−50.9 M⊙) that are gravitationally bound (αvir = 0.3−1.3) and which would require magnetic field strengths of B = 0.3−1.0 mG to be in virial equilibrium. We combine these results with a homogenized catalogue of literature cores to recover the hierarchical structure within these clouds over four orders of magnitude in spatial scale (0.01–10 pc). Using supplementary observations at an even higher angular resolution, we find that the smallest fragments (<0.02 pc) within this hierarchy do not currently have the mass and/or the density required to form high-mass stars. None the less, the new ALMA observations presented in this paper have facilitated the identification of 19 (6 quiescent and 13 star-forming) cores that retain >16 M⊙ without further fragmentation. These high-mass cores contain trans-sonic non-thermal motions, are kinematically sub-virial, and require moderate magnetic field strengths for support against collapse. The identification of these potential sites of HMSF represents a key step in allowing us to test the predictions from high-mass star and cluster formation theories.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, Santiago; 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 2-aminooxazole in Astrophysical Environments: IR Spectra and Destruction Cross Sections for Energetic Processing(IOP Science Publishing, 2021-03-11) Maté, B.; Carrasco Herrera, R.; Timón, V.; Tanarro, I.; Herrero, V. J.; Carrascosa, H. ; Muñoz Caro, G. M.; González Díaz, Cristobal; Jimenez-Serra, Izaskun; Agencia Estatal de Investigación (AEI); 0000-0002-5478-8644; 0000-0002-1217-6834; 0000-0002-1888-513X; 0000-0002-7456-4832; 0000-0002-2885-4847; 0000-0001-7003-7368; 0000-0002-8789-9148; 0000-0003-4493-8714; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-07372-aminooxazole (2AO), a N-heterocyclic molecule, has been proposed as an intermediate in prebiotic syntheses. It has been demonstrated that it can be synthesized from small molecules such as cyanamide and glycoaldehyde, which are present in interstellar space. The aim of this work is to provide infrared (IR) spectra, in the solid phase for conditions typical of astrophysical environments and to estimate its stability toward UV photons and cosmic rays. IR (4000–600 cm−1) absorption spectra at 20 K, 180 K, and 300 K, IR band strengths, and room-temperature UV (120–250 nm) absorption spectra are given for the first time for this species. Destruction cross sections of ≈9.5 10−18 cm2 and ≈2 10−16 cm2 were found in the irradiation at 20 K of pure 2AO and 2AO:H2O ices with UV (6.3–10.9 eV) photons or 5 keV electrons, respectively. These data were used to estimate half-life times for the molecule in different environments. It is estimated that 2AO could survive UV radiation and cosmic rays in the ice mantles of dense clouds beyond cloud collapse. In contrast, it would be very unstable on the surface of cold solar system bodies like Kuiper Belt objects, but the molecule could still survive within dust grain agglomerates or cometesimals.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.
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