The Nature of Weak MgII Absorbing Structures

Abstract

We consider geometries and possible physical models for weak low ionization absorbers based on the relative incidence of low and high ionization absorption systems. We found a total of 16 metal-line systems, with low and/or high ionization absorption detected in our survey of weak low ionization absorption systems from the archive of HST/STIS data. The weak low ionization absorbers trace an abundant population of metal-enriched regions (close to solar metallicity). Generally, models show that these systems have a ~10pc region of higher density gas and a ~1kpc region of lower density phase of higher ionization absorption. We compare absorption systems detected in low and/or high ionization gas and find the following: 1) All but 1 of the 10 weak low ionization systems have a related high ionization phase. In 3 cases the high ionization gas has only a single component, kinematically centered on the low ionization absorption, and in the other 6 cases there are additional high ionization components offset in velocity. The system, toward quasar 3C 273, do not have a high ionization cloud; 2) There are just 6 systems with only a high ionization phase as compared to the 9 systems with both low and high ionization phases; 3) The high ionization absorption in weak low ionization systems is, on average, stronger than in systems with only high ionization absorption; 4) The kinematic structure of the high ionization in weak low ionization systems is similar to that in high ionization only systems. We find that filamentary and sheetlike geometries are favored, due to the relatively small observed cross-section of high ionization only systems. Although low ionization absorbers are not closely associated with luminous galaxies, they arise in their immediate environments within the cosmic web.

25 pages, 19 figures, 4 tables

References in corpus (25)

• Highly-Ionized High-Velocity Gas in the Vicinity of the Galaxy
• Field Galaxy Evolution Since Z~1 from a Sample of QSO Absorption-Selected Galaxies
• The Kinematic Connection Between QSO-Absorbing Gas and Galaxies at Intermediate Redshift
• Mg II Absorption Systems in SDSS QSO Spectra
• Multi-phase High-Velocity Clouds toward HE 0226-4110 and PG 0953+414
• The Population of Weak Mg II Absorbers I. A Survey of 26 QSO HIRES/Keck Spectra
• The Origin of C IV Absorption Systems at Redshifts z<1---Discovery of Extended C IV Envelopes Around Galaxies
• QSO Absorbing Galaxies at z<~1: Deep Imaging and Spectroscopy in the Field of 3C 336
• The Population of Weak MgII Absorbers. II The Properties of Single-Cloud Systems
• Low and High Ionization Absorption Properties of Mg II Absorption-Selected Galaxies at Intermediate Redshifts. II. Taxonomy, Kinematics, and Galaxies
• The Kinematics of Intermediate Redshift Mg II Absorbers
• The Kinematic Composition of MgII Absorbers
• The Heavy Element Enrichment of Lyman alpha Clouds in the Virgo Supercluster
• High Resolution STIS/HST and HIRES/Keck Spectra of Three Weak MgII Absorbers Toward PG 1634+706
• Discovery of a Group of Star-Forming Dwarf Galaxies in Abell 1367
• Absorption-Line Systems and Galaxies in Front of the Second Brightest Quasar, PHL 1811
• Discovery of a Dwarf Post-Starburst Galaxy Near a High Column Density Ly-alpha Absorber
• The Absorption Signatures of Dwarf Galaxies: The z=1.04 Multicloud Weak MgII Absorber toward PG 1634+706
• The Multi-phase Absorption Systems Toward PG 1206+459
• The Absorption Signature of Six MgII-Selected Systems Over 0.5<z<0.9
• MgII Absorption through Intermediate Redshift Galaxies
• Models of Five Absorption Line Systems Along the Line of Sight Toward PG0117+213
• Probing the Size of Low-Redshift Lyman-alpha Absorbers
• A Survey of Analogs to Weak MgII Absorbers in the Present
• Galactic Superwinds Circa 2001

Cited by in corpus (19)

• A large population of metal-rich, compact, intergalactic C IV absorbers - Evidence for poor small-scale metal mixing
• A population of weak metal-line absorbers surrounding the Milky Way
• A Survey of Weak MgII Absorbers at 0.4 < z < 2.4
• The Chemical and Ionization Conditions in Weak Mg II Absorbers
• COS-Weak: Probing the CGM using analogs of weak Mg II absorbers at z < 0.3
• Cloud-by-cloud, multiphase, Bayesian modeling: Application to four weak, low ionization absorbers
• The Milky Way halo as a QSO absorption-line system. New results from an HST/STIS absorption-line catalogue of Galactic high-velocity clouds
• Casting light on the 'anomalous' statistics of Mg II absorbers toward Gamma-Ray Burst afterglows: the incidence of weak systems
• A Bare Molecular Cloud at z~0.45
• The Kinematic Evolution of Strong MgII Absorbers
• Super-Solar Metallicity in Weak Mg II Absorption Systems at z ~ 1.7
• Physical Properties of Weak MgII Absorbers at z~2
• The Redshift Distribution of Intervening Weak MgII Quasar Absorbers and a Curious Dependence on Quasar Luminosity
• Detection of Metal-Rich, Cool-Warm Gas in the Outskirts of Galaxy Clusters
• The z = 0.0777 C III Absorber Towards PHL 1811 as a Case Study of a Low Redshift Weak Metal Line Absorber
• A Catalog of Absorption Lines in Eight HST/STIS E230M 1.0 < z < 1.7 Quasar Spectra
• Solar-Metallicity Gas in the Extended Halo of a Galaxy at $z\sim 0.12$
• The End of the Rainbow: What Can We Say About the Extragalactic Sub-Megahertz Radio Sky?
• Origin of Weak MgII and Higher Ionization Absorption Lines in an Outflow from an Intermediate-Redshift Dwarf Satellite Galaxy