Kinematics of dense gas in the L1495 filament

Abstract

We study the kinematics of the dense gas of starless and protostellar cores traced by the N2D+(2-1), N2H+(1-0), DCO+(2-1), and H13CO+(1-0) transitions along the L1495 filament and the kinematic links between the cores and the surrounding molecular cloud. We measure velocity dispersions, local and total velocity gradients and estimate the specific angular momenta of 13 dense cores in the four transitions using the on-the-fly observations with the IRAM 30 m antenna. To study a possible connection to the filament gas, we use the fit results of the C18O(1-0) survey performed by Hacar et al. (2013). All cores show similar properties along the 10 pc-long filament. N2D+(2-1) shows the most centrally concentrated structure, followed by N2H+(1-0) and DCO+(2-1), which show similar spatial extent, and H13CO+(1-0). The non-thermal contribution to the velocity dispersion increases from higher to lower density tracers. The change of magnitude and direction of the total velocity gradients depending on the tracer used indicates that internal motions change at different depths within the cloud. N2D+ and N2H+ show smaller gradients than the lower density tracers DCO+ and H13CO+, implying a loss of specific angular momentum at small scales. At the level of cloud-core transition, the core's external envelope traced by DCO+ and H13CO+ is spinning up, consistent with conservation of angular momentum during core contraction. C18O traces the more extended cloud material whose kinematics is not affected by the presence of dense cores. The decrease in specific angular momentum towards the centres of the cores shows the importance of local magnetic fields to the small scale dynamics of the cores. The random distributions of angles between the total velocity gradient and large scale magnetic field suggests that the magnetic fields may become important only in the high density gas within dense cores.

arXiv commentAccepted for publication in A&A. The abstract is shortened

References in corpus (33)

• An atomic and molecular database for analysis of submillimetre line observations
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Herschel view of the Taurus B211/3 filament and striations: Evidence of filamentary growth?
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• Cores, filaments, and bundles: hierarchical core formation in the L1495/B213 Taurus region
• Observing the gas temperature drop in the high-density nucleus of L 1544
• The Taurus Spitzer Survey: New Candidate Taurus Members Selected Using Sensitive Mid-Infrared Photometry
• Filamentary structures and compact objects in the Aquila and Polaris clouds observed by Herschel
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• Abundant H2D+ in the pre-stellar core L1544
• Direct observation of a sharp transition to coherence in Dense Cores
• On the internal structure of starless cores. II. A molecular survey of L1498 and L1517B
• Molecular ions in L1544. I. Kinematics
• Chains of dense cores in the Taurus L1495/B213 complex
• The Spitzer c2d Survey of Nearby Dense Cores: II: Discovery of a Low Luminosity Object in the "Evolved Starless Core" L1521F
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• The Magnetic Field in Taurus Probed by Infrared Polarization
• On the frequency of N2H+ and N2D+
• The Different Structures of the Two Classes of Starless Cores
• Deuterated methanol in the pre-stellar core L1544
• A multi-scale filament extraction method: getfilaments
• Observations of L1521F: a highly evolved starless core
• Shells, jets, and internal working surfaces in the molecular outflow from IRAS 04166+2706
• VLBA determination of the distance to nearby star-forming regions V. Dynamical mass, distance and radio structure of V773 Tau A
• Star formation in the Taurus filament L1495: From Dense Cores to Stars
• Hyperfine Structure in H^{13}CO^{+} and ^{13}CO: measurement, analysis, and consequences for the study of dark clouds
• An Ammonia Spectral Map of the L1495-B218 Filaments in the Taurus Molecular Cloud : I. Physical Properties of Filaments and Dense cores
• Laboratory and space spectroscopy of DCO+
• Observation of rotation in star forming regions: clouds, cores, disks, and jets
• Properties of Starless and Prestellar Cores in Taurus Revealed by Herschel SPIRE/PACS Imaging
• Molecular Line Observations of a Carbon-Chain-Rich Core L492
• Kinematics in Partially Ionised Molecular Clouds: Implications for the Transition to Coherence
• Submillimeter Observations of the Quiescent Core - Ophiuchus A-N6

Cited by in corpus (29)

• High sensitivity maps of molecular ions in L1544: I. Deuteration of N2H+ and HCO+ and first evidence of N2D+ depletion
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends
• FRagmentation and Evolution of dense cores Judged by ALMA (FREJA). I (Overview). Inner $\sim$1000 au structures of prestellar/protostellar cores in Taurus
• Ammonia snow-lines and ammonium salts desorption
• Revealing the diverse magnetic field morphologies in Taurus dense cores with sensitive sub-millimeter polarimetry
• L1495 Revisited: A PPMAP View of a Star-Forming Filament
• An Origin for the Angular Momentum of Molecular Cloud Cores: a Prediction from Filament Fragmentation
• Methanol Mapping in Cold Cores: Testing Model Predictions
• Anomalous HCN emission from warm giant molecular clouds
• Investigating the Complex Velocity Structures within Dense Molecular Cloud Cores with GBT-Argus
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VI. A sulphur journey across star-forming regions: study of thioformaldehyde emission
• Multicomponent kinematics in a massive filamentary IRDC
• TRAO Survey of the nearby filamentary molecular clouds, the universal nursery of stars (TRAO FUNS). II. Filaments and Dense cores in IC 5146
• TRAO Survey of Nearby Filamentary Molecular clouds, the Universal Nursery of Stars (TRAO FUNS) I. Dynamics and Chemistry of L1478 in the California Molecular Cloud
• Relative Alignment between Dense Molecular Cores and Ambient Magnetic Field: The Synergy of Numerical Models and Observations
• ALMA ACA and Nobeyama observations of two Orion cores in deuterated molecular lines
• Evolution of the Angular Momentum of Molecular Cloud Cores Formed from Filament Fragmentation
• Alignment of dense molecular core morphology and velocity gradients with ambient magnetic fields
• First BISTRO observations of the dark cloud Taurus L1495A-B10: the role of the magnetic field in the earliest stages of low-mass star formation
• History-independent tracers: Forgetful molecular probes of the physical conditions of the dense interstellar medium
• Cosmic-ray ionisation rate in low-mass cores: the role of the environment
• Independent Core Rotation in Massive Filaments in Orion
• Mapping Synthetic Observations to Prestellar Core Models: An Interpretable Machine Learning Approach
• Hunting pre-stellar cores with APEX: Corona Australis 151, the densest pre-stellar core or the youngest protostar?
• Simulations of the isothermal collapse of magnetic rotating protostellar clouds
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IX. Deuterated compounds of H2S in starless cores
• A High-Mass Young Star-forming Core Escaping from Its Parental Filament
• The Milky Way atlas for linear filaments II. clump rotation versus filament orientation
• Impact of the shape of the prestellar density fluctuations on the core mass function