Characterizing the Circumgalactic Medium of Nearby Galaxies with HST/COS and HST/STIS Absorption-Line Spectroscopy

Abstract

The Circumgalactic Medium (CGM) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z < 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph and ~60 serendipitous absorber/galaxy pairs at z < 0.2 with the Space Telescope Imaging Spectrograph. CGM warm cloud properties are derived, including volume filling factors of 3-5%, cloud sizes of 0.1-30 kpc, masses of 10-1e8 solar masses and metallicities of 0.1-1 times solar. Almost all warm CGM clouds within 0.5 virial radii are metal-bearing and many have velocities consistent with being bound, "galactic fountain" clouds. For galaxies with L > 0.1 L*, the total mass in these warm CGM clouds approaches 1e10 solar masses, ~10-15% of the total baryons in massive spirals and comparable to the baryons in their parent galaxy disks. This leaves >50% of massive spiral-galaxy baryons "missing". Dwarfs (<0.1 L*) have smaller area covering factors and warm CGM masses (<5% baryon fraction), suggesting that many of their warm clouds escape. Constant warm cloud internal pressures as a function of impact parameter ($P/k ~ 10 cm^{-3} K) support the inference that previous COS detections of broad, shallow O VI and Ly-alpha absorptions are of an extensive (~400-600 kpc), hot (T ~ 1e6 K) intra-cloud gas which is very massive (>1e11 solar masses). While the warm CGM clouds cannot account for all the "missing baryons" in spirals, the hot intra-group gas can, and could account for ~20% of the cosmic baryon census at z ~ 0 if this hot gas is ubiquitous among spiral groups.

34 pages, 14 figures, 8 tables; accepted for publication in ApJ

References in corpus (15)

• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• The Universal Rotation Curve of Spiral Galaxies. II The Dark Matter Distribution out to the Virial Radius
• The Search for the Missing Baryons at Low Redshift
• The present-day star formation rate of the Milky-Way determined from Spitzer detected young stellar objects
• A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers
• The Low-z Intergalactic Medium. III. HI and Metal Absorbers at z<0.4
• Do Hot Haloes Around Galaxies Contain the Missing Baryons?
• Seeding the formation of cold gaseous clouds in Milky Way size halos
• Distances to Galactic high-velocity clouds. Complex C
• Physical Properties, Baryon Content, and Evolution of the LyαForest: New Insights from High Resolution Observations at z < 0.4
• The Chandra Deep Protocluster Survey: Ly-alpha Blobs are powered by heating, not cooling
• The Enrichment History of Baryons in the Universe
• Metallicity and Ionization in High Velocity Cloud Complex C
• Confirming the Detection of an Intergalactic X-ray Absorber Toward PKS 2155-304
• Discovery of a Metal-Line Absorber Associated with a Local Dwarf Starburst Galaxy

Cited by in corpus (11)

• The COS-Dwarfs Survey: The Carbon Reservoir Around sub-L* Galaxies
• On the possible environmental effect in distributing heavy elements beyond individual gaseous halos
• Metal-enriched, sub-kiloparsec gas clumps in the circumgalactic medium of a faint z = 2.5 galaxy
• Quasars Probing Quasars VII. The Pinnacle of the Cool Circumgalactic Medium Surrounds Massive z~2 Galaxies
• Hiding in plain sight: An abundance of compact massive spheroids in the local Universe
• New Perspective on Galaxy Outflows From the First Detection of Both Intrinsic and Traverse Metal-Line Absorption
• Tracing the Cosmic Metal Evolution in the Low-Redshift Intergalactic Medium
• Direct Insights into Observational Absorption Line Analysis Methods of the Circumgalactic Medium Using Cosmological Simulations
• HST/COS Spectra of Three QSOs That Probe The Circumgalactic Medium of a Single Spiral Galaxy: Evidence for Gas Recycling and Outflow
• Missing cosmic metals revealed by X-ray absorption towards distant sources
• Halo Mass Dependence of HI and OVI Absorption: Evidence for Differential Kinematics