CN and HCN in dense interstellar clouds

Gai I. Boger; Amiel Sternberg

doi:10.1086/432864

CN and HCN in dense interstellar clouds

Gai I. Boger^*, Amiel Sternberg

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Review article › peer-review

Abstract

We present a theoretical investigation of CN and HCN molecule formation in dense interstellar clouds. We study the gas-phase CN and HCN production efficiencies from the outer photon-dominated regions (PDRs) into the opaque cosmic-ray-dominated cores. We calculate the equilibrium densities of CN and HCN and of the associated species C⁺, C, and CO, as functions of the far-ultraviolet (FUV) optical depth. We consider isothermal gas at 50 K, with hydrogen particle densities from 10² to 10⁶ cm ^-3. We study clouds that are exposed to FUV fields with intensities (at 1000 Å) from 1 × 10^-18 to 1 × 10^-14 ergs s^-1 cm^-2 Hz^-1 sr^-1, or 20 to 2 × 10⁵ times the mean interstellar FUV intensity. We assume cosmic-ray H₂ ionization rates ranging from 5 × 10 ^-17 s^-1 to an enhanced value of 5 × 10^-16 s^-1. We also examine the sensitivity of the density profiles to the gas-phase sulfur abundance.

Original language	English
Pages (from-to)	302-315
Number of pages	14
Journal	Astrophysical Journal
Volume	632
Issue number	1 I
DOIs	https://doi.org/10.1086/432864
State	Published - 10 Oct 2005

Keywords

Galaxies: ISM
ISM: evolution
Molecular processes

Access to Document

10.1086/432864

Cite this

@article{3c8539f85c0649a9b85dcc2e44985ffb,

title = "CN and HCN in dense interstellar clouds",

abstract = "We present a theoretical investigation of CN and HCN molecule formation in dense interstellar clouds. We study the gas-phase CN and HCN production efficiencies from the outer photon-dominated regions (PDRs) into the opaque cosmic-ray-dominated cores. We calculate the equilibrium densities of CN and HCN and of the associated species C+, C, and CO, as functions of the far-ultraviolet (FUV) optical depth. We consider isothermal gas at 50 K, with hydrogen particle densities from 102 to 106 cm -3. We study clouds that are exposed to FUV fields with intensities (at 1000 {\AA}) from 1 × 10-18 to 1 × 10-14 ergs s-1 cm-2 Hz-1 sr-1, or 20 to 2 × 105 times the mean interstellar FUV intensity. We assume cosmic-ray H2 ionization rates ranging from 5 × 10 -17 s-1 to an enhanced value of 5 × 10-16 s-1. We also examine the sensitivity of the density profiles to the gas-phase sulfur abundance.",

keywords = "Galaxies: ISM, ISM: evolution, Molecular processes",

author = "Boger, {Gai I.} and Amiel Sternberg",

year = "2005",

month = oct,

day = "10",

doi = "10.1086/432864",

language = "אנגלית",

volume = "632",

pages = "302--315",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing Ltd.",

number = "1 I",

}

TY - JOUR

T1 - CN and HCN in dense interstellar clouds

AU - Boger, Gai I.

AU - Sternberg, Amiel

PY - 2005/10/10

Y1 - 2005/10/10

N2 - We present a theoretical investigation of CN and HCN molecule formation in dense interstellar clouds. We study the gas-phase CN and HCN production efficiencies from the outer photon-dominated regions (PDRs) into the opaque cosmic-ray-dominated cores. We calculate the equilibrium densities of CN and HCN and of the associated species C+, C, and CO, as functions of the far-ultraviolet (FUV) optical depth. We consider isothermal gas at 50 K, with hydrogen particle densities from 102 to 106 cm -3. We study clouds that are exposed to FUV fields with intensities (at 1000 Å) from 1 × 10-18 to 1 × 10-14 ergs s-1 cm-2 Hz-1 sr-1, or 20 to 2 × 105 times the mean interstellar FUV intensity. We assume cosmic-ray H2 ionization rates ranging from 5 × 10 -17 s-1 to an enhanced value of 5 × 10-16 s-1. We also examine the sensitivity of the density profiles to the gas-phase sulfur abundance.

AB - We present a theoretical investigation of CN and HCN molecule formation in dense interstellar clouds. We study the gas-phase CN and HCN production efficiencies from the outer photon-dominated regions (PDRs) into the opaque cosmic-ray-dominated cores. We calculate the equilibrium densities of CN and HCN and of the associated species C+, C, and CO, as functions of the far-ultraviolet (FUV) optical depth. We consider isothermal gas at 50 K, with hydrogen particle densities from 102 to 106 cm -3. We study clouds that are exposed to FUV fields with intensities (at 1000 Å) from 1 × 10-18 to 1 × 10-14 ergs s-1 cm-2 Hz-1 sr-1, or 20 to 2 × 105 times the mean interstellar FUV intensity. We assume cosmic-ray H2 ionization rates ranging from 5 × 10 -17 s-1 to an enhanced value of 5 × 10-16 s-1. We also examine the sensitivity of the density profiles to the gas-phase sulfur abundance.

KW - Galaxies: ISM

KW - ISM: evolution

KW - Molecular processes

UR - http://www.scopus.com/inward/record.url?scp=28044468874&partnerID=8YFLogxK

U2 - 10.1086/432864

DO - 10.1086/432864

M3 - ???researchoutput.researchoutputtypes.contributiontojournal.systematicreview???

AN - SCOPUS:28044468874

SN - 0004-637X

VL - 632

SP - 302

EP - 315

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 I

ER -

CN and HCN in dense interstellar clouds

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this