Starburst Energy Feedback Seen Through HCO${}^{+}$/HOC${}^{+}$ Emission in NGC 253 from ALCHEMI

Abstract

Molecular abundances are sensitive to UV-photon flux and cosmic-ray ionization rate. In starburst environments, the effects of high-energy photons and particles are expected to be stronger. We examine these astrochemical signatures through multiple transitions of HCO${}^{+}$ and its metastable isomer HOC${}^{+}$ in the center of the starburst galaxy NGC 253 using data from the ALMA large program ALCHEMI. The distribution of the HOC${}^{+}$(1-0) integrated intensity shows its association with "superbubbles", cavities created either by supernovae or expanding HII regions. The observed HCO${}^{+}$/HOC${}^{+}$ abundance ratios are $\sim 10-150$, and the fractional abundance of HOC${}^{+}$ relative to H${}_2$ is $\sim 1.5\times 10^{-11}-6\times 10^{-10}$, which implies that the HOC${}^{+}$ abundance in the center of NGC 253 is significantly higher than in quiescent spiral-arm dark clouds in the Galaxy and the Galactic center clouds. Comparison with chemical models implies either an interstellar radiation field of $G_0\gtrsim 10^3$ if the maximum visual extinction is $\gtrsim 5$, or a cosmic-ray ionization rate of $\zeta \gtrsim 10^{-14}$ s${}^{-1}$ (3-4 orders of magnitude higher than that within clouds in the Galactic spiral-arms) to reproduce the observed results. From the difference in formation routes of HOC${}^{+}$, we propose that a low-excitation line of HOC${}^{+}$ traces cosmic-ray dominated regions, while high-excitation lines trace photodissociation regions. Our results suggest that the interstellar medium in the center of NGC 253 is significantly affected by energy input from UV-photons and cosmic rays, sources of energy feedback.

arXiv comment57 pages, 32 figures, accepted for publication in ApJ

References in corpus (75)

• Stellar Feedback in Galaxies and the Origin of Galaxy-scale Winds
• A model for atomic and molecular interstellar gas: The Meudon PDR code
• The 2014 KIDA network for interstellar chemistry
• Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models
• Cosmic-ray ionization of molecular clouds
• Investigating the Cosmic-Ray Ionization Rate in the Galactic Diffuse Interstellar Medium through Observations of H3+
• Variations in the Galactic star formation rate and density thresholds for star formation
• Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate
• The Starburst-Driven Molecular Wind in NGC 253 and the Suppression of Star Formation
• Cold Molecular Outflows in the Local Universe
• A 2 mm spectral line survey of the starburst galaxy NGC 253
• Chandra observations of NGC 253. II: On the origin of diffuse X-ray emission in the halos of starburst galaxies
• Spatially Resolved Chemistry in Nearby Galaxies I. The Center of IC 342
• ALMA Reveals the Molecular Medium Fueling the Nearest Nuclear Starburst
• Chandra observations of NGC 253: New insights into the nature of starburst-driven superwinds
• Three Dimensional Hydrodynamic Simulations of Multiphase Galactic Disks with Star Formation Feedback: I. Regulation of Star Formation Rates
• Molecular Gas Chemistry in AGN I. The IRAM Survey of NGC1068
• Modeling Complex Organic Molecules in dense regions: Eley-Rideal and complex induced reaction
• Modelling CO formation in the turbulent interstellar medium
• Herschel/HIFI observations of interstellar OH+ and H2O+ towards W49N: a probe of diffuse clouds with a small molecular fraction
• Molecules at z=0.89: A 4-mm-rest-frame absorption line survey toward PKS 1830-211
• The cosmic ray ionization rate in the Galactic disk, as determined from observations of molecular ions
• Molecular line emission in NGC1068 imaged with ALMA: II. The chemistry of the dense molecular gas
• The chemistry of vibrationally excited H2 in the interstellar medium
• Spectral Line Identification and Modelling (SLIM) in the MAdrid Data CUBe Analysis (MADCUBA) package: An interactive software for data cube analysis
• Cosmic-ray induced destruction of CO in star-forming galaxies
• High resolution observations of HCN and HCO+ J=3-2 in the disk and outflow of Mrk231 -Detection of vibrationally excited HCN in the warped nucleus
• ALMA Multi-line Imaging of the Nearby Starburst Galaxy NGC 253
• Dense Molecular Gas Tracers in the Outflow of the Starburst Galaxy NGC 253
• A Simple and Accurate Network for Hydrogen and Carbon Chemistry in the ISM
• The Implications of a High Cosmic-Ray Ionization Rate in Diffuse Interstellar Clouds
• Forming Super Star Clusters in the Central Starburst of NGC 253
• Spatially resolved optical IFU spectroscopy of the inner superwind of NGC 253
• The complex chemistry of hot cores in Sagittarius B2(N): Influence of cosmic-ray ionization and thermal history
• Lambda = 3 mm line survey of nearby active galaxies
• Cold CO in circumstellar disks: On the effects of photodesorption and vertical mixing
• Molecular Superbubbles in the Starburst Galaxy NGC 253
• Multi-molecule ALMA observations towards the Seyfert 1 galaxy NGC 1097
• Star-forming Cloud Complexes in the Central Molecular Zone of NGC 253
• Chemistry in Cosmic-Ray Dominated Regions (CRDRs)
• Supernova enhanced cosmic ray ionization and induced chemistry in a molecular cloud of W51C
• ALCHEMI: an ALMA Comprehensive High-resolution Extragalactic Molecular Inventory. Survey presentation and first results from the ACA array
• The Central 300 pc of the Galaxy probed by infrared spectra of H${}_3^{+}$ and CO: part I. Predominance of warm and diffuse gas and high H${}_2$ ionization rate
• Deuterated molecules as a probe of ionization fraction in dense interstellar clouds
• The Stellar Kinematic Center and the True Galactic Nucleus of NGC253
• The ionization fraction gradient across the Horsehead edge: An archetype for molecular clouds
• STATCONT: A statistical continuum level determination method for line-rich sources
• The nucleus of NGC 253 and its massive stellar clusters at parsec scales
• The molecular outflow in NGC253 at a resolution of two parsecs
• Chemical Features in the Circumnuclear Disk of the Galactic Center
• Carbon isotopic fractionation in molecular clouds
• Distributions of molecules in the circumnuclear disk and surrounding starburst ring in the Seyfert galaxy NGC 1068 observed with ALMA
• Photodissociation chemistry footprints in the Starburst galaxy NGC 253
• Infrared H3+ and CO Studies of the Galactic Core: GCIRS 3 and GCIRS 1W
• On the chemistry and distribution of HOC+ in M82: More evidence for extensive PDRs
• The abundance of HOC+ in diffuse clouds
• Super Hot Cores in NGC 253: Witnessing the formation and early evolution of Super Star Clusters
• Spatially resolved images of reactive ions in the Orion Bar
• ALMA view of the ${}^{12}$C/${}^{13}$C isotopic ratio in starburst galaxies
• ALMA Astrochemical Observations of the Infrared-Luminous Merger NGC 3256
• Outflows from Super Star Clusters in the Central Starburst of NGC253
• Fire in the Heart: A Characterization of the High Kinetic Temperatures and Heating Sources in the Nucleus of NGC253
• OH+ and H2O+ absorption toward PKS1830-211
• The Distribution and Origin of C${}_2$H in NGC 253 from ALCHEMI
• A Multi-Transition Study of Molecules toward NGC 1068 based on High-Resolution Imaging Observations with ALMA
• Spatially resolved carbon and oxygen isotopic ratios in NGC 253 using optically thin tracers
• Diverse nuclear star-forming activities in the heart of NGC 253 resolved with ten-pc scale ALMA images
• CO+ in M 82: A Consequence of Irradiation by X-rays
• The Molecular ISM in the Super Star Clusters of the Starburst NGC 253
• The ionization rates of galactic nuclei and disks from Herschel/HIFI observations of water and its associated ions
• Chemical evolution along the circumnuclear ring of M83
• Molecular gas in the northern nucleus of Mrk273: Physical and chemical properties of the disk and its outflow
• Atlas of Cosmic ray-induced astrochemistry
• A chemical study of carbon fractionation in external galaxies
• On the effects of UV photons/X-rays on the chemistry of the Sgr B2 cloud

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• Energizing Star Formation: The Cosmic Ray Ionization Rate in NGC 253 Derived From ALCHEMI Measurements of H${}_3$O${}^{+}$ and SO
• Methanol masers in NGC 253 with ALCHEMI
• AGN-driven Cold Gas Outflow of NGC 1068 Characterized by Dissociation-Sensitive Molecules
• ALCHEMI finds a "shocking" carbon footprint in the starburst galaxy NGC~253
• Reconstructing the shock history in the CMZ of NGC 253 with ALCHEMI
• SUNRISE: The rich molecular inventory of high-redshift dusty galaxies revealed by broadband spectral line surveys
• CON-quest II. Spatially and spectrally resolved HCN/HCO+ line ratios in local luminous and ultraluminous infrared galaxies
• History-independent tracers: Forgetful molecular probes of the physical conditions of the dense interstellar medium
• A recent update of gas-phase chemical reactions and molecular lines in CLOUDY: its effects on millimeter and sub-millimeter molecular line predictions
• An ALCHEMI inspection of sulphur-bearing species towards the central molecular zone of NGC 253
• Molecular isotopologue measurements toward super star clusters and the relation to their ages in NGC253 with ALCHEMI
• Tracing the chemical footprint of shocks in AGN-host and starburst galaxies with ALMA multi-line molecular studies
• Shock-induced HCNH+ abundance enhancement in the heart of the starburst galaxy NGC 253 unveiled by ALCHEMI
• Overtone Transition $2{\nu }_1$ of ${\text{HCO}}^{+}$ and ${\text{HOC}}^{+}$: Origin, Radiative Lifetime, Collisional Quenching
• Complex Organic Molecules towards the central molecular zone of NGC 253
• First detection of a deuterated molecule in a starburst environment within NGC 253