Probing the physics of star formation (ProPStar): I. First resolved maps of the electron fraction and cosmic-ray ionization rate in NGC 1333

Abstract

Electron fraction and cosmic-ray ionization rates (CRIR) in star-forming regions are important quantities in astrochemical modeling and are critical to the degree of coupling between neutrals, ions, and electrons, which regulates the dynamics of the magnetic field. However, these are difficult quantities to estimate. We aim to derive the electron fraction and CRIR maps of an active star-forming region. We combined observations of the nearby NGC 1333 star-forming region carried out with the NOEMA interferometer and IRAM 30-m single dish to generate high spatial dynamic range maps of different molecular transitions. We used the DCO${}^{+}$ and H${}^{13}$CO${}^{+}$ ratio (in addition to complementary data) to estimate the electron fraction and produce cosmic-ray ionization rate maps. We derived the first large-area electron fraction and CRIR resolved maps in a star-forming region, with typical values of $10^{-6.5}$ and $10^{-16.5}$ s${}^{-1}$, respectively. The maps present clear evidence of enhanced values around embedded young stellar objects (YSOs). This provides strong evidence for locally accelerated cosmic rays. We also found a strong enhancement toward the northwest region in the map that might be related either to an interaction with a bubble or to locally generated cosmic rays by YSOs. We used the typical electron fraction and derived a MHD turbulence dissipation scale of 0.054 pc, which could be tested with future observations. We found a higher cosmic-ray ionization rate compared to the canonical value for $N({\mathrm{H}}_2)=10^{21}-10^{23}$ cm${}^{-2}$ of $10^{-17}$ s${}^{-1}$ in the region, and it is likely generated by the accreting YSOs. The high value of the electron fraction suggests that new disks will form from gas in the ideal-MHD limit. This indicates that local enhancements of $\zeta ({\mathrm{H}}_2)$, due to YSOs, should be taken into account in the analysis of clustered star formation.

13 pages, 13 Figures. Accepted to A&A. Abridged abstract. GitHub repo with code available at https://github.com/jpinedaf/NGC1333_NOEMA_Ions

References in corpus (41)

• Theory of Star Formation
• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster
• CO Isotopologues in the Perseus Molecular Cloud Complex: the X-Factor and Regional Variations
• The Large and Small Scale Structures of Dust in the Star-Forming Perseus Molecular Cloud
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• The Distribution of Ortho-H_2D+(1_1,0 - 1_1,1) in L1544: Tracing the Deuteration Factory in Prestellar Cores
• SOLIS II. Carbon-chain growth in the Solar-type protocluster OMC2-FIR4
• Alignment Between Protostellar Outflows and Filamentary Structure
• Formation and Evolution of Disks around Young Stellar Objects
• The Ionization Fraction of Barnard 68: Implications for Star and Planet Formation
• Cosmic rays in molecular clouds probed by H${}_2$ rovibrational lines -- Perspectives for the James Webb Space Telescope
• The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333
• Revealing H2D+ depletion and compact structure in starless and protostellar cores with ALMA
• The Highly Collimated Radio Jet of HH 80-81: Structure and Non-Thermal Emission
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends
• Protoplanetary disk birth in massive star forming clumps: the essential role of the magnetic field
• Physical properties of the ambient medium and of dense cores in the Perseus star-forming region derived from Herschel Gould Belt Survey observations
• Binary system and jet precession and expansion in G35.20-0.74N
• The cosmic-ray ionisation rate in the pre-stellar core L1544
• Protostellar Outflows at the EarliesT Stages (POETS). II. A possible radio synchrotron jet associated with the EGO G035.02+0.35
• Magnetically regulated collapse in the B335 protostar? II. Observational constraints on gas ionization and magnetic field coupling
• Ionization: a possible explanation for the difference of mean disk sizes in star-forming regions
• CALYPSO view of SVS 13A with PdBI: Multiple jet sources
• First ALMA maps of cosmic ray ionisation rate in high-mass star-forming regions
• The Launch Region of the SVS 13 Outflow and Jet
• The Physical Properties of the SVS 13 Protobinary System: Two Circumstellar Disks and a Spiraling Circumbinary Disk in the Making
• A train of shocks at 3000 au scale? Exploring the clash of an expanding bubble into the NGC 1333 IRAS 4 region. SOLIS XIV
• Connecting the Scales: Large Area High-resolution Ammonia Mapping of NGC 1333
• Methanol Mapping in Cold Cores: Testing Model Predictions
• Neutral vs Ion Linewidths in Barnard 5: Evidence for Penetration by MHD Waves
• Tracers of the ionization fraction in dense and translucent gas: I. Automated exploitation of massive astrochemical model grids
• Detection of H2D+ in a massive prestellar core in Orion B
• CARMA Large Area Star Formation Survey: Dense Gas in the Young L1451 Region of Perseus
• The cosmic ray ionisation and $\gamma$-ray budgets of star-forming galaxies
• Transport of Protostellar Cosmic Rays in Turbulent Dense Cores
• The JCMT BISTRO Survey: Evidence for Pinched Magnetic Fields in Quiescent Filaments of NGC 1333
• A panoptic view of the Taurus molecular cloud I. The cloud dynamics revealed by gas emission and 3D dust
• ALMA Observations toward the S-shaped Outflow and the Envelope around NGC1333 IRAS 4A2
• The double signature of local cosmic-ray acceleration in star-forming regions
• Mapping the H${}_2$D${}^{+}$ and N${}_2$H${}^{+}$ emission towards prestellar cores. Testing dynamical models of the collapse using gas tracers
• Feedback of molecular outflows from protostars in NGC 1333, revealed by Herschel and Spitzer spectro-imaging observations

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• PRODIGE - envelope to disk with NOEMA: VII. (Complex) organic molecules in the NGC1333 IRAS4B1 outflow: A new laboratory for shock chemistry
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