Dependence of Chemical Abundance on the Cosmic Ray Ionization Rate in IC 348

Abstract

Ions (e.g., H${}_3^{+}$, H${}_2$O${}^{+}$) have been used extensively to quantify the cosmic-ray ionization rate (CRIR) in diffuse sightlines. However, measurements of CRIR in low-to-intermediate density gas environments are rare, especially when background stars are absent. In this work, we combine molecular line observations of CO, OH, CH, and HCO${}^{+}$ in the star-forming cloud IC~348, and chemical models to constrain the value of CRIR and study the response of the chemical abundances distribution. The cloud boundary is found to have an $A_{\mathrm{V}}$ of approximately 4 mag. From the interior to the exterior of the cloud, the observed ${}^{13}$CO line intensities drop by an order of magnitude. The calculated average abundance of ${}^{12}$CO (assuming ${}^{12}$C/${}^{13}$C = 65) is (1.2$\pm$0.9) $\times$10${}^{-4}$, which increases by a factor of 6 from the interior to the outside regions. The average abundance of CH (3.3$\pm$0.7 $\times$ 10${}^{-8}$) is in good agreement with previous findings in diffuse and translucent clouds ($A_{\mathrm{V}}$ $<$ 5 mag). However, we did not find a decline in CH abundance in regions of high extinction ($A_{\mathrm{V}}\simeq$8 mag) as previously reported in Taurus. By comparing the observed molecular abundances and chemical models, we find a decreasing trend of CRIR as $A_{\mathrm{V}}$ increases. The inferred CRIR of ${\zeta }_{cr}$ = (4.7$\pm$1.5) $\times$ 10${}^{-16}$ s${}^{-1}$ at low $A_{\mathrm{V}}$ is consistent with H${}_3^{+}$ measurements toward two nearby massive stars.

arXiv comment21 pages, 11 figures. Submitted to ApJ

References in corpus (85)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Spitzer Space Telescope Mission
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• The CO-to-H2 Conversion Factor
• A computer program for fast non-LTE analysis of interstellar line spectra
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• Infrared Emission from Interstellar Dust. II. The Diffuse Interstellar Medium
• The UMIST database for astrochemistry 2012
• Planck 2013 results. XI. All-sky model of thermal dust emission
• The Dark Molecular Gas
• The Relation Between Optical Extinction and Hydrogen Column Density in the Galaxy
• Far Infrared and Submillimeter Emission from Galactic and Extragalactic Photo-Dissociation Regions
• How to Calculate Molecular Column Density
• Investigating the Cosmic-Ray Ionization Rate in the Galactic Diffuse Interstellar Medium through Observations of H3+
• A Herschel [CII] Galactic plane survey I: the global distribution of ISM gas components
• Molecular Inventories and Chemical Evolution of Low-mass Protostellar Envelopes
• Ultraviolet Survey of CO and H_2 in Diffuse Molecular Clouds: The Reflection of Two Photochemistry Regimes in Abundance Relationships
• The COMPLETE Survey of Star-Forming Regions: Phase I Data
• The relation between gas and dust in the Taurus Molecular Cloud
• Detection and Characterization of Cold Interstellar Dust and PAH Emission from COBE Observations
• The GALFA-HI Survey: Data Release 1
• The anatomy of the Orion B Giant Molecular Cloud: A local template for studies of nearby galaxies
• Cosmic-ray ionisation in circumstellar discs
• Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6-0.4
• The cosmic ray ionization rate in the Galactic disk, as determined from observations of molecular ions
• Interstellar Hydrides
• Effective destruction of CO by cosmic rays: implications for tracing H${}_2$ gas in the Universe
• Probing X-ray Absorption and Optical Extinction in the Interstellar Medium Using Chandra Observations of Supernova Remnants
• Cosmic-ray induced destruction of CO in star-forming galaxies
• Impact of low-energy cosmic rays on star formation
• ATLASGAL-selected massive clumps in the inner Galaxy: I. CO depletion and isotopic ratios
• 3D-PDR: A new three-dimensional astrochemistry code for treating Photodissociation Regions
• Evolution of OH and CO-dark Molecular Gas Fraction Across a Molecular Cloud Boundary In Taurus
• Molecular absorption lines toward star-forming regions : a comparative study of HCO+, HNC, HCN, and CN
• Cosmic-ray ionisation in collapsing clouds
• SOLIS II. Carbon-chain growth in the Solar-type protocluster OMC2-FIR4
• N(H I)/E(B-V)
• Cold and Warm Atomic Gas around the Perseus Molecular Cloud. II. The Impact of High Optical Depth on the HI Column Density Distribution and Its Implication for the HI-to-H2 Transition
• Dust-Gas Scaling Relations and OH Abundance in the Galactic ISM
• Comparative Chemistry of Diffuse Clouds IV: CH
• CO/H2, C/CO, OH/CO, and OH/O2 in Dense Interstellar Gas: From High Ionization to Low Metallicity
• Herschel-Planck dust optical depth and column density maps - II. Perseus
• A COMPLETE Look at The Use of IRAS Emission Maps to Estimate Extinction and Dust Temperature
• Cosmic rays in molecular clouds probed by H${}_2$ rovibrational lines -- Perspectives for the James Webb Space Telescope
• The Per-Tau Shell: A Giant Star-Forming Spherical Shell Revealed by 3D Dust Observations
• Where is OH and Does It Trace the Dark Molecular Gas (DMG)?
• SOLIS IV. Hydrocarbons in the OMC-2 FIR 4 region, a probe of energetic particle irradiation of the region
• Photon dominated regions in the spiral arms of M83 and M51
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends
• Photodissociation Region Diagnostics Across Galactic Environments
• Dust Emission from the Perseus Molecular Cloud
• A submillimetre survey of the kinematics of the Perseus molecular cloud: I. data
• The relation between column densities of interstellar OH and CH molecules
• Molecules with ALMA at Planet-forming Scales (MAPS) XIII: HCO${}^{+}$ and disk ionization structure
• Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines
• Chemical Abundances in a Turbulent Medium -- H${}_2$, OH${}^{+}$, H${}_2$O${}^{+}$, ArH${}^{+}$
• Dense gas in molecular cores associated with Planck Galactic cold clumps
• PDFchem: A new fast method to determine ISM properties and infer environmental parameters using probability distributions
• Simulating the atomic and molecular content of molecular clouds using probability distributions of physical parameters
• CH as a Molecular Gas Tracer and C-Shock Tracer Across a Molecular Cloud Boundary in Taurus
• Hydroxyl as a Tracer of H2 in the Envelope of MBM40
• The impact of cosmic-ray attenuation on the carbon cycle emission in molecular clouds
• On the Inference of the Cosmic Ray Ionization Rate $\zeta$ from the HCO${}^{+}$-to-DCO${}^{+}$ Abundance Ratio: The Effect of Nuclear Spin
• Observational Evidence for a Thick Disk of Dark Molecular Gas in the Outer Galaxy
• Fingerprinting the effects of hyperfine structure on CH and OH far infrared spectra using Wiener filter deconvolution
• An Estimation of the Star Formation Rate in the Perseus Complex
• Revealing The CO X-factor In Dark Molecular Gas through Sensitive ALMA Absorption Observations
• CH radio emission from heiles cloud 2 as a tracer of molecular cloud evolution
• Dynamical star forming history of Per OB2
• The Photon Dominated Region in the IC 348 molecular cloud
• The CH radical at radio wavelengths: Revisiting emission in the 3.3GHz ground state lines
• Probing the Sea of Cosmic Rays by Measuring Gamma-Ray Emission from Passive Giant Molecular Clouds with HAWC
• OH Evolution in Molecular Clouds
• Planck Cold Clumps in the lambda Orionis Complex. III. A chemical probe of stellar feedback on cores in the lambda Orionis cloud
• Chemical compositions of five Planck cold clumps
• HCO+ and HCN J=3-2 absorption toward the center of Centaurus A
• Parsec-scale Variations in the 7Li/6Li Isotope Ratio Toward IC 348 and the Per OB 2 Association
• Precise Measurements of CH Maser Emission and Its Abundance in Translucent Clouds

Cited by in corpus (9)

• First ALMA maps of cosmic ray ionisation rate in high-mass star-forming regions
• Abundance ratios of OH/CO and HCO+/CO as probes of the cosmic ray ionization rate in diffuse clouds
• The CO-dark molecular gas in the cold HI arc
• A new analytic approach to infer the cosmic-ray ionization rate in hot molecular cores from HCO${}^{+}$, N${}_2$H${}^{+}$, and CO observations
• A new measurement of the Galactic ${}^{12}$C/${}^{13}$C gradient from sensitive HCO${}^{+}$ absorption observations
• The evolution of CH in Planck Galactic Cold Clumps
• Predicting HCN, HCO${}^{+}$, multi-transition CO, and dust emission of star-forming galaxies -- Extension to luminous infrared galaxies and the role of cosmic ray ionization
• Tight correlation of star formation with [Ci] and CO lines across cosmic time
• Fine-tuning the complex organic molecule formation: sulfur and CO ice as regulators of surface chemistry