HD molecules at high redshift: cosmic-ray ionization rate in the diffuse interstellar medium

Abstract

We present a systematic study of deuterated molecular hydrogen (HD) at high redshift, detected in absorption in the spectra of quasars. We present four new identifications of HD lines associated with known ${\mathrm{H}}_2$-bearing Damped Lyman-$\alpha$ systems. In addition, we measure upper limits on the $\mathrm{HD}$ column density in twelve recently identified ${\mathrm{H}}_2$-bearing DLAs. We find that the new $\mathrm{HD}$ detections have similar $N(\mathrm{HD})/N({\mathrm{H}}_2)$ ratios as previously found, further strengthening a marked difference with measurements through the Galaxy. This is likely due to differences in physical conditions and metallicity between the local and the high-redshift interstellar media. Using the measured $N(\mathrm{HD})/N({\mathrm{H}}_2)$ ratios together with priors on the UV flux ($\chi$) and number densities ($n$), obtained from analysis of ${\mathrm{H}}_2$ and associated CI lines, we are able to constrain the cosmic-ray ionization rate (CRIR, $\zeta$) for the new $\mathrm{HD}$ detections and for eight known HD-bearing systems where priors on $n$ and $\chi$ are available. We find significant dispersion in $\zeta$, from a few $\times 10^{-18}$ s${}^{-1}$ to a few $\times 10^{-15}$ s${}^{-1}$. We also find that $\zeta$ strongly correlates with $\chi$ -- showing almost quadratic dependence, slightly correlates with $Z$, and does not correlate with $n$, which probably reflects a physical connection between cosmic rays and star-forming regions.

arXiv comment40 pages, 51 figures, submitted to MNRAS

References in corpus (72)

• emcee: The MCMC Hammer
• The chemical composition of the Sun
• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• Damped Lyman alpha Systems
• The Millennium Arecibo 21-CM Absorption Line Survey. II. Properties of the Warm and Cold Neutral Media
• Precision big bang nucleosynthesis with improved Helium-4 predictions
• Cosmic-ray ionization of molecular clouds
• Investigating the Cosmic-Ray Ionization Rate in the Galactic Diffuse Interstellar Medium through Observations of H3+
• The VLT-UVES survey for molecular hydrogen in high-redshift damped Lyman-alpha systems
• H3+ in Diffuse Interstellar Clouds: a Tracer for the Cosmic-Ray Ionization Rate
• Herschel Survey of Galactic OH+, H2O+, and H3O+: Probing the Molecular Hydrogen Fraction and Cosmic-Ray Ionization Rate
• The MOSDEF Survey: Mass, Metallicity, and Star-formation Rate at z~2.3
• Cosmic-ray ionisation in circumstellar discs
• The VLT-UVES survey for molecular hydrogen in high-redshift damped Lyman-alpha systems: Physical conditions in the neutral gas
• The cosmic ray ionization rate in the Galactic disk, as determined from observations of molecular ions
• First detection of CO in a high-redshift DLA
• A translucent interstellar cloud at z=2.69: CO, H2 and HD in the line-of-sight to SDSS J123714.60+064759.5
• Impact of low-energy cosmic rays on star formation
• Excited OH+, H2O+, and H3O+ in NGC 4418 and Arp 220
• The UVES Large Program for Testing Fundamental Physics II: Constraints on a Change in μ Towards Quasar HE 0027-1836
• The Nature of Damped Lyman Alpha Systems and Their Hosts in the Standard Cold Dark Matter Universe
• The UVES Spectral Quasar Absorption Database (SQUAD) Data Release 1: The first 10 million seconds
• A connection between extremely strong Damped Lyman-alpha Systems and Lyman-alpha Emitting Galaxies at small impact parameters
• Physical conditions in the central molecular zone inferred by H3+
• The elemental abundance pattern in a galaxy at z=2.626
• Discovery of a Perseus-like cloud in the early Universe: HI-to-H2 transition, carbon monoxide and small dust grains at zabs=2.53 towards the quasar J0000+0048
• Excitation mechanisms in newly discovered H2-bearing Damped Lyman-alpha clouds: systems with low molecular fractions
• CO-dark molecular gas at high redshift: very large H${}_2$ content and high pressure in a low metallicity damped Lyman-alpha system
• The Ionization Fraction of Barnard 68: Implications for Star and Planet Formation
• The Second Data Release of the KODIAQ Survey
• Understanding Physical Conditions in High Redshift Galaxies through C I Fine Structure Lines: Data and Methodology
• HD molecules at high redshift: A low astration factor of deuterium in a solar-metallicity DLA system at z=2.418
• Partial coverage of the Broad Line Region of Q1232+082 by an intervening H2-bearing cloud
• VLT/UVES observations of extremely strong intervening damped Lyman-alpha systems: Molecular hydrogen and excited carbon, oxygen and silicon at log N(HI)=22.4
• HD Molecular Lines in an Absorption System at Redshift z = 2.3377
• Molecular hydrogen in the z = 2.66 damped Lyman-alpha absorber toward Q J0643-5041
• Molecular hydrogen absorption systems in Sloan Digital Sky Survey
• Metallicities, dust and molecular content of a QSO-Damped Lyman-α system reaching log N (H i) = 22: An analog to GRB-DLAs
• Spotting high-z molecular absorbers using neutral carbon: Results from a complete spectroscopic survey with the VLT
• Velocity Dispersion of Excited H2
• HD/H2 Molecular Clouds in the Early Universe: The Problem of Primordial Deuterium
• Constraining the H${}_2$ column density distribution at z$\sim$3 from composite DLA spectra
• On the enhanced cosmic-ray ionization rate in the diffuse cloud towards Zeta Persei
• Diffusive Versus Free-Streaming Cosmic Ray Transport in Molecular Clouds
• X-shooter observations of strong H${}_2$-bearing DLAs at high redshift
• HD molecules at high redshift: The absorption system at z=2.3377 towards Q 1232+082
• Molecular gas and star formation in an absorption-selected galaxy: Hitting the bull's eye at z = 2.46
• Direct Evidence of Cold Gas in DLA 0812+32B
• OH+ and H2O+ absorption toward PKS1830-211
• Probing the Physical Conditions of Atomic Gas at High Redshift
• The Magellan Uniform Survey of Damped Lyman alpha Systems II: Paucity of Strong Molecular Hydrogen Absorption
• Cosmological concordance or chemical coincidence? Deuterated molecular hydrogen abundances at high redshift
• Constraints on the Cosmic-Ray Ionization Rate in the $z\sim 2.3$ Lensed Galaxies SMM J2135$-$0102 and SDP 17b from Observations of OH${}^{+}$ and H${}_2$O${}^{+}$
• A New FUSE Survey of Interstellar HD
• Neutral atomic-carbon QSO absorption-line systems at z>1.5: Sample selection, HI content, reddening, and 2175 A extinction feature
• Outflowing OH${}^{+}$ in Markarian 231: the ionization rate of the molecular gas
• HD/H2 as a probe of the roles of gas, dust, light, metallicity and cosmic rays in promoting the growth of molecular hydrogen in the diffuse interstellar medium
• A cold component and the complex velocity structure of DLA1331+170
• Directional Radiation and Photodissociation Regions in Molecular Hydrogen Clouds
• Near Infrared spectroscopic observations of high redshift C~{\sc i} absorbers
• Molecular Cloud Cores with High Deuterium Fraction: Nobeyama Single-Pointing Survey
• Evolution of dispersion in the cosmic deuterium abundance
• The ionization rates of galactic nuclei and disks from Herschel/HIFI observations of water and its associated ions
• Partial covering of emission regions of Q 0528-250 by intervening H${}_2$ clouds
• HST/COS Detection of Deuterated Molecular Hydrogen in a DLA at z = 0.18
• Physical conditions in three high-z H2-bearing DLAs: implications for grain size
• Multicomponent H2 in DLA at zabs = 2.05: physical conditions through observations and numerical models
• HD/H${}_2$ ratio in the diffuse interstellar medium
• Nature of the DLA towards Q0528-250: High pressure and strong UV field revealed by excitation of CI, H2 and SiII
• Estimation of physical conditions in the cold phase of the ISM in the sub-DLA system at z = 2.06 in the spectrum of the quasar J2123-0050
• Extent and structure of intervening absorbers from absorption lines redshifted on quasar emission lines
• Chemical enrichment and host galaxies of extremely-strong intervening DLAs towards quasars

Cited by in corpus (6)

• The cosmic ray ionisation and $\gamma$-ray budgets of star-forming galaxies
• HYACINTH: HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations
• Neutral carbon in diffuse interstellar medium: abundance matching with H2 for DLAs at high redshifts
• Quasar radiation transforms the gas in a merging companion galaxy
• Molecular hydrogen in absorption at high redshifts. Science cases for CUBES
• The CUBES Science Case