A5089710588- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Spectroscopy and Laser Applications
- Advanced Chemical Physics Studies
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Atomic and Molecular Physics
- Advanced Combustion Engine Technologies
- Scientific Research and Discoveries
- Space Exploration and Technology
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Atmospheric aerosols and clouds
- Inorganic Chemistry and Materials
- Inorganic Fluorides and Related Compounds
Universidad Nacional Autónoma de México
2016-2025
Universidad de Morelia
2015
Institute of Space Sciences
2010-2014
Atacama Large Millimeter Submillimeter Array
2013
Consejo Superior de Investigaciones Científicas
2009-2010
Universitat de Barcelona
2002-2009
Centro de Astrobiología
2009
Instituto de Física Fundamental
2007-2008
Abstract We present a unified description of the scenario global hierarchical collapse (GHC). GHC constitutes flow regime (non-homologous) collapses within collapses, in which all scales accrete from their parent structures, and small, dense regions begin to contract at later times, but on shorter time-scales than large, diffuse ones. The different allow for most clouds’ mass be dispersed by feedback first massive stars, maintaining cloud-scale star formation rate low. Molecular clouds...
In order to study the fragmentation of massive dense cores, which constitute cluster cradles, we observed with PdBI in most extended configuration continuum at 1.3 mm and CO(2-1) emission four cores. We detect dust condensations down ~0.3 Msun separate millimeter sources 0.4" or ~1000 AU, comparable sensitivities separations reached optical/infrared studies clusters. The high angular resolution images reveal high-velocity knots usually aligned previously known outflow directions. This,...
We combine previously published interferometric and single-dish data of relatively nearby massive dense cores that are actively forming stars to test whether their 'fragmentation level' is controlled by turbulent or thermal support. find no clear correlation between the fragmentation level velocity dispersion, nor observed number fragments expected when gravitationally unstable mass calculated including various prescriptions for 'turbulent support'. On other hand, best found case pure Jeans...
Context. High-mass stars form in clusters, but neither the early fragmentation processes nor detailed physical leading to most massive are well understood. Aims. We aim understand fragmentation, as disk formation, outflow generation, and chemical during high-mass star formation on spatial scales of individual cores. Methods. Using IRAM Northern Extended Millimeter Array (NOEMA) combination with 30 m telescope, we have observed large program CORE 1.37 mm continuum spectral line emission at...
We present the results of combined NH3 (1,1) and (2,2) line emission observed with Very Large Array Effelsberg 100 m telescope infrared dark cloud G14.225−0.506. The reveals a network filaments constituting two hub–filament systems. Hubs are associated gas rotational temperature Trot ∼ 15 K, non-thermal velocity dispersion σNT 1 km s−1, exhibit signs star formation, while appear to be more quiescent (Trot 11 K 0.6 s−1). Filaments parallel in projection distributed mainly along directions, at...
HH 211 is a nearby young protostellar system with highly collimated jet. We have mapped it in 352 GHz continuum, SiO (J = 8 − 7), and HCO+ 4 3) emission at up to ∼02 resolution the Submillimeter Array (SMA). The continuum source now resolved into two sources, SMM1 SMM2, separation of ∼ 84 AU. seen center jet, probably tracing (inner) dusty disk around protostar driving SMM2 southwest may trace an envelope-disk small binary companion. A flattened radius 80 AU perpendicular jet axis. Its...
We report on the long-term X-ray monitoring of outburst decay low magnetic field magnetar SGR 0418+5729 using all available data obtained with RXTE, Swift, Chandra, and XMM-Newton observations from discovery source in 2009 June up to 2012 August. The timing analysis allowed us obtain first measurement period derivative 0418+5729: s s−1, significant at a ∼3.5σ confidence level. This leads surface dipolar Bdip ≃ 6 × 1012 G. confirms as lowest magnetar. Following flux spectral evolution...
Theory predicts, and observations confirm, that the column density ratio of a molecule containing D to its counterpart H can be used as an evolutionary tracer in low-mass star formation process. Since it remains unclear if high-mass process is scaled-up version one, we investigated whether relation between deuteration evolution applied regime. With IRAM-30m telescope, observed rotational transitions N2D+ N2H+ derived deuterated fraction 27 cores within massive star-forming regions understood...
We report on Submillimeter Array observations of the 870 μm continuum and CO (3–2), 13CO (2–1), C18O (2–1) line emission a faint object, SMM2E, near driving source HH 797 outflow in IC 348 cluster. The shows an unresolved for which we estimate mass gas dust 30 MJup, (3–2) reveals compact bipolar centred barely seen also (2–1). In addition, hints possible rotating envelope/disc perpendicular to outflow, infer dynamical ∼16 MJup. order further constrain accreted gathered data from Spitzer,...
In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study density structure 19 selected be at similar evolutionary stages, for which their relative level was assessed in previous work. We inferred cores through simultaneous fit radial intensity profiles 450 and 850 μm (or 1.2 mm two cases) spectral energy distribution, assuming spherical symmetry that temperature decrease with radius following power-laws. Even though...
Context. This paper is dedicated to the study of chemistry intermediate-mass (IM) hot core NGC 7129 FIRS 2, probably most compact warm found in 2−8 M⊙ stellar mass range.
We have performed a dense core survey toward the Infrared Dark Cloud G14.225-0.506 at 3 mm continuum emission with Atacama Large Millimeter/Submillimeter Array (ALMA). This covers two hub-filament systems an angular resolution of $\sim3$\arcsec ($\sim0.03$ pc). identified 48 cores. Twenty out cores are protostellar due to their association young stellar objects (YSOs) and/or X-ray point-sources, while other 28 likely prestellar and unrelated known IR or emission. Using APEX 870 $\mu$m...
The early evolution of massive cluster progenitors is poorly understood. We investigate the fragmentation properties from 0.3 pc to 0.06 scales a homogenous sample infrared-quiet clumps within 4.5 kpc selected ATLASGAL survey. Using ALMA 7m array we detect compact dust continuum emission towards all targets, and find that fragmentation, at these scales, limited. mass distribution fragments uncovers large fraction cores above 40 $M_\odot$, corresponding dense (MDCs) with masses up ~400...
We use sub-arcsecond resolution ($\sim$0.4$''$) observations with NOEMA at 1.37 mm to study the dust emission and molecular gas of 18 high-mass star-forming regions. combine derived physical chemical properties individual cores in these regions estimate their ages. The temperature structure are determined by fitting H2CO CH3CN line emission. density profiles inferred from continuum visibilities. column densities 11 different species lines XCLASS. Within observed regions, we identify 22...
Abstract The Atacama Large Millimeter/submillimeter Array (ALMA) Survey of Star Formation and Evolution in Massive Protoclusters with Blue Profiles (ASSEMBLE) aims to investigate the process mass assembly its connection high-mass star formation theories protoclusters a dynamic view. We observed 11 massive ( M clump ≳ 10 3 ⊙ ), luminous L bol 4 blue-profile (infall signature) clumps by ALMA resolution ∼2200–5500 au (median value 3500 au) at 350 GHz (870 μ m). identified 248 dense cores,...
An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D its hydrogenated counterpart, Dfrac) is an evolutionary indicator both in low- high-mass star formation process. However, role surface chemistry these studies has not been quantified from point view. In order to compare how fractions formed only gas partially or uniquely on grain surfaces evolve with time, we observed rotational...
Context. The Kleinmann-Low nebula in Orion (Orion-KL) is the nearest example of a high-mass star-forming environment. Studying resolved chemical substructures this complex region provides important insight into chemistry regions (HMSFRs), as it relates to their evolutionary states.
NGC 7129 FIRS 2 (hereafter 2) is an intermediate-mass (2 to 8 Msun) protostar located at a distance of 1250 pc. High spatial resolution observations are required resolve the hot core its center. We present molecular survey from 218200 MHz 221800 carried out with IRAM Plateau de Bure Interferometer. These were complemented long integration single-dish spectrum taken 30m telescope. used Local Thermodynamic Equilibrium (LTE) single temperature code model whole dataset. The interferometric...
We carried out a 12CO(3–2) survey of 52 southern stars with wide range IR excesses (LIR/L*) using the single-dish telescopes APEX and ASTE. The main aims were (1) to characterize evolution molecular gas in circumstellar disks LIR/L* values as proxy disk dust evolution, (2) identify new gas-rich systems suitable for detailed study ALMA. About 60% sample (31 systems) have > 0.01, typical T Tauri or Herbig AeBe stars, rest (21 < debris disks. detect CO(3–2) emission from 20 systems, 18 (90%)...
Phosphorus is a crucial element for the development of life, but so far P-bearing molecules have been detected only in few astrophysical objects, hence its interstellar chemistry almost totally unknown. Here we show new detections phosphorus nitride sample dense cores different evolutionary stages intermediate- and high-mass star formation process: starless, with protostellar ultracompact HII regions. All PN line widths are smaller than ~5 km/s , they arise from regions associated kinetic...
We present subarcsecond 1.3 mm continuum ALMA observations towards the Orion Molecular Cloud 1 South (OMC-1S) region, down to a spatial resolution of 74 AU, which reveal total 31 sources. also 7 VLA same allow further study fragmentation 40 AU. By applying Mean Surface Density Companions method we find characteristic scale at ~ 560 and use this define boundary 19 'cores' in OMC-1S as groupings millimeter an additional 2900 is typical filaments OMC-1S, suggesting two-level process. measured...
Abstract Theoretical and numerical works indicate that a strong magnetic field should suppress fragmentation in dense cores. However, this has never been tested observationally relatively large sample of fragmenting massive Here, we use the polarization data obtained Submillimeter Array Legacy Survey Zhang et al. to build 18 cores where both properties are studied uniform way. We measured level, N mm , within view common all regions ∼0.15 pc, with mass sensitivity ∼0.5 M ☉ spatial resolution...
Abstract There is growing evidence that high-mass star formation and hub-filament systems (HFS) are intricately linked. The gas kinematics along the filaments forming star(s) in central hub excellent agreement with new generation of global hierarchical models. In this paper, we present an observational investigation a typical HFS cloud, G310.142+0.758 (G310 hereafter), which reveals unambiguous mass inflow from cloud scale via onto protostar(s) at conforming model predictions. Continuum...
Abstract Only a handful of massive starless core candidates have been discovered so far, but none them fully confirmed. Within the MM1 clump in filamentary infrared dark cloud G34.43+0.24 that was covered by Atacama Large Millimeter/submillimeter Array (ALMA) ATOMS survey at Band 3 (∼2″, 6000 au) and ALMA-QUARKS 6 (∼0.″3, 900 au), two prestellar MM1-C E1 with masses 71 20 M ⊙ radii 2100–4400 au were discovered. The cores show no obvious sign star formation activities. In particular, is very...