X-ray Absorption Line Spectroscopy of the Galactic Hot Interstellar Medium

Abstract

We present an X-ray absorption line spectroscopic study of the large-scale hot interstellar medium (HISM) in the Galaxy. We detect Ne IX K${}_{\alpha }$ absorption lines in the {\sl Chandra} grating spectra of seven Galactic low-mass X-ray binaries. Three of these sources also show absorption of O VII K${}_{\alpha }$, O VII K${}_{\beta }$, and/or O VIII K${}_{\alpha }$. Both centroid and width of the lines are consistent with a Galactic HISM origin of the absorption. By jointly fitting the multiple lines, accounting for line saturation and assuming the collisional ionization equilibrium, we estimate the average absorbing gas temperature as $\sim 2.4\pm 0.3\times 10^6$ K (90% confidence errors). We further characterize the spatial density distribution of the gas as $6.4_{-1.7}^{+2.4}\exp (-|z|/1.2_{-0.5}^{+1.0}\mathrm{kpc})\times 10^{-3}\mathrm{c}{\mathrm{m}}^{-3}$ (a disk morphology) or $6.2_{-2.1}^{+3.8}[1+(R/2.3_{-1.1}^{+1.6}\mathrm{kpc}{)}^2{]}^{-1}\times 10^{-3}\mathrm{c}{\mathrm{m}}^{-3}$ (a sphere morphology), where $z$ and $R$ are the distances from the Galactic plane and Galactic center (GC) respectively. Since nearly all the sight-lines with significant absorption lines detected are somewhat toward GC and at low Galactic latitudes, these results could be severely biased. More observations toward off-GC sight-lines and at high latitudes are urgently needed to further the study. Nevertheless, the results demonstrate the excellent potential of X-ray absorption line spectroscopy in the study of the HISM.

29 pages, 9 figures, 5 tables, ApJ accepted, 2005 June 1, v625, 2 issue

Cited by in corpus (82)

• The Baryon Census in a Multiphase Intergalactic Medium: 30% of the Baryons May Still Be Missing
• The Vertical Structure of Warm Ionised Gas in the Milky Way
• A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers
• Constraining the Milky Way's Hot Gas Halo with OVII and OVII Emission Lines
• The Structure of the Milky Way's Hot Gas Halo
• The Fermi Bubbles. I. Possible Evidence for Recent AGN Jet Activity in the Galaxy
• X-Ray Absorption from the Milky Way Halo and the Local Group
• Suzaku observations of the diffuse x-ray emission across the fermi bubbles' edges
• High-Resolution X-ray Spectroscopy of the Interstellar Medium II: Neon and Iron Absorption Edges
• ISM composition through X-ray spectroscopy of LMXBs
• Confirmation of X-Ray Absorption by WHIM in the Sculptor Wall
• Detection of Ne VIII in the Low-Redshift Warm-Hot IGM
• Warm-Hot Gas in and around the Milky Way: Detection and Implications of OVII Absorption toward LMC X-3
• Properties of O VI Absorption in the Local Interstellar Medium
• XMM-Newton observation of 4U 1820-30: Broad band spectrum and the contribution of the cold interstellar medium
• A Galactic Origin for the Local Ionized X-ray Absorbers
• Analysing the atolls: X-ray spectral transitions of accreting neutron stars
• The Rotation of the Hot Gas Around the Milky Way
• The Interaction of the Fermi Bubbles with the Milky Way's Hot Gas Halo
• The Fermi Bubbles as Starburst Wind Termination Shocks
• A Census of Baryons and Dark Matter in an Isolated, Milky Way-sized Elliptical Galaxy
• The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations
• XMM-Newton Survey of Local O VII Absorption Lines in the Spectra of Active Galactic Nuclei
• X-ray and UV spectroscopy of Galactic diffuse hot gas along the LMC X--3 sight line
• A Method for Deriving Accurate Gas-Phase Abundances for the Multiphase Interstellar Galactic Halo
• Simulations of High-Velocity Clouds. I. Hydrodynamics and High-Velocity High Ions
• Where Do Galaxies End?
• Abundance and temperature of the outer hot circum-Galactic medium: The SRG/eROSITA view of the soft X-ray background in the eFEDS field
• X-ray Absorption Spectroscopy of the Multi-phase Interstellar Medium: Oxygen and Neon Abundances
• The Non-isothermality and Extent of Galactic Diffuse Hot Gas Toward Mrk~421
• Limits on Hot Galactic Halo Gas from X-ray Absorption Lines
• High resolution X-ray spectroscopy of the multiphase interstellar medium toward Cyg X-2
• X-Ray Detection of Warm Ionized Matter in the Galactic Halo
• The Dispersion of Fast Radio Bursts from a Structured Intergalactic Medium at Redshifts z < 1.5
• PSR J0357+3205: the tail of the turtle
• Confirming the Detection of an Intergalactic X-ray Absorber Toward PKS 2155-304
• X-ray Spectroscopy of Galactic Hot Gas along the PKS 2155-304 Sight Line
• Dust absorption and scattering in the silicon K-edge
• Absorption and scattering by interstellar dust in the silicon K-edge of GX 5-1
• The Properties of the Galactic Hot Gaseous Halo from X-ray Emission
• Warm-Hot Intergalactic Medium Associated with the Coma Cluster
• Wavelength Measurements of K Transitions of Oxygen, Neon, and Magnesium with X-ray Absorption Lines
• X-raying Galaxies: A Chandra Legacy
• Detecting the warm-hot intergalactic medium through X-ray absorption lines
• Narrow absorption features in the co-added XMM-Newton RGS spectra of isolated Neutron Stars
• Constraints on hot metals in the Vicinity of the Galaxy
• The Galactic Halo's O VI Resonance Line Intensity
• Physical properties of the interstellar medium using high-resolution Chandra spectra: O K-edge absorption
• The Dearth of Chemically Enriched Warm-Hot Circumgalactic Gas
• High Resolution X-ray Spectroscopy of the Local Hot Gas along the 3C 273 Sightline
• XMM-Newton RGS spectrum of RX J0720.4-3125: An absorption feature at 0.57 keV
• The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations
• Simulations of Mixed Morphology Supernova Remnants With Anisotropic Thermal Conduction
• Strategies for Detecting the Missing Hot Baryons in the Universe
• XMM-Newton and INTEGRAL observations of the black hole candidate XTE J1817-330
• Simulating Anisotropic Thermal Conduction in Supernova Remnants, Implications for the Interstellar Medium
• X-raying the Intergalactic OVI Absorbers
• Suzaku X-ray Observations of the Fermi Bubbles: Northernmost Cap and Southeast Claw Discovered with MAXI-SSC
• Investigating the nature of absorption lines in the Chandra X-ray spectra of the neutron star binary 4U 1820-30
• Structual Study of Galactic Hot Gas toward Markarian 421 from X-Ray Absorption and Emission Lines
• Chandra Detection of Fe XVII in Absorption: Iron Abundance in the Hot Gaseous Interstellar Medium
• Suzaku and XMM-Newton Observations of the North Polar Spur: Charge Exchange or ISM Absorption?
• On the Origin of Highly Ionized X-ray Absorbers Detected in the Galactic X-ray Binaries
• Possible features of galactic halo with electric field and observational constraints
• The highly ionized disk wind of GRO J1655-40
• Multiwavelength Campaign on Mrk 509 X. Lower limit on the distance of the absorber from HST COS and STIS spectroscopy
• Multiwavelength campaign on Mrk 509 IX. The Galactic foreground
• Spectroscopic evidence of charge exchange X-ray emission from galaxies
• The warm absorber in the radio-loud quasar 4C +74.26
• Ionized Gas in the First 10 Kiloparsecs of the Interstellar Galactic Halo: Metal Ion Fractions
• Anisotropic Thermal Conduction in Supernova Remnants: Relevance to Hot Gas Filling Factors in the Magnetized ISM
• The hot interstellar medium towards 4U 1820-30: a Bayesian analysis
• XMM-Newton/RGS Detection of the Missing Interstellar OVII Kalpha Absorption Line in the Spectrum of Cyg X-2
• XMM-Newton Survey of Local OVII Absorption Lines in the Spectra of Galactic X-ray Sources
• Probing the Halo Gas Distribution in the Inner Galaxy with Fermi Bubble Observations
• V5116 Sgr: a disc-eclipsed SSS post-outburst nova?
• Astrophysics in 2005
• Leveraging High Resolution Spectra to Understand Black Hole Spectra
• A Possible Supernova Remnant high above the Galactic Disk
• Multiple Absorption-Line Spectroscopy of the Intergalactic Medium. I. Model
• The Warm-Hot Disk-Halo Interface Below the Perseus Spiral Arm
• Classifying Unidentified Gamma-ray Sources