Probing the gaseous environment of star-forming galaxies in absorption and emission Michele Fumagalli ICC,CEA – Durham University
What matter(s) around galaxies? - What are the morphological and physical properties of the CGM? - What are the physical processes that shape the CGM on both large (kpc) and small (pc) scales?
Inflows and outflows at z~3: the open question. We want to constrain observationally the physical properties of halo gas near star forming galaxies MF et al. 2011
Inflows and outflows at z~3: the origin of Lyman Limit Systems To unveil the physical properties of inflows and outflows we need to understand the distribution, metallicity and kinematics of LLSs, and compare results against the predictions of simulations MF et al. 2011
The redshift evolution of Lyman Limit Systems Already from the first LLS surveys, it became evident that LLSs are distinct from the IGM and trace the galaxy population Sargent et al. 1989: “we believe that most of the LLSs are produced by galaxies” MF et al. 2013
The metallicity distribution of z > 2 LLSs: the HD-LLS sample We have completed a detailed study of the physical properties of 150 LLSs with high-resolution spectroscopy (…a ten-fold improvement over previous samples…) HD-LLS sample Literature value (See also Quiret et al. 2016 and recent work by N. Lehner et al.) Prochaska et al. 2015; MF et al. 2016a
The metallicity distribution of z > 2 LLSs: the HD-LLS sample LLSs exhibit a spread of metallicity over 5 orders of magnitude, from super-solar to pristine. LLSs have densities comparable to galaxy halos. HD-LLS sample Literature value MF et al. 2016a
The metallicity distribution of z > 2 LLSs: implication for theory The metallicity distribution is consistent with predictions of cold-flows streaming onto galaxies, which seems in some tension with very efficient outflows. (See also Hafen et al. 2016; Shen et al. 2012, 2013) Prediction from simulations (2011) Observations (2016) MF et al. 2011, 2016a
Connecting strong absorbers to galaxy halos via small-scale clustering With quasar pairs, we are mapping the gas distribution around galaxies to test the LLS/galaxy association at z~3 and z~2 Preview of pilot programme at z~3 MF et al. 2014, 2017 in prep
Connecting strong absorbers to galaxy halos via small-scale clustering With quasar pairs, we are mapping the gas distribution around galaxies to test the LLS/galaxy association at z~3 and z~2 Preview of programme at z~2 MF et al. 2017 in prep
Connecting strong absorbers to galaxy halos with MUSE Searching directly for galaxies associated with LLSs in emission. The case of Q0956+122. Very metal poor LLS z ~ 3.22 Log NHI ~ 17.4; log nH ~ -3.3 “Pristine” LLS Log Z/Z ⊙ = -3.35 ± 0.05 z ~ 3.09 Log NHI ~ 17.2; log nH < -2 Log Z/Z ⊙ = < -3.8 Flux Wavelength MF et al. 2016b
Connecting strong absorbers to galaxy halos with MUSE Searching directly for galaxies associated with LLSs in emission. The case of Q0956+122. “Pristine” LLS in Ly 𝛽 “Pristine” LLS z ~ 3.09 Five Ly 𝛽 emitters, but 0.4 expected at random. At least three sources aligned with the LLS. Compelling case of pristine gas in a filament feeding galaxies with low SFRs. MF et al. 2016b
Connecting strong absorbers to galaxy halos with MUSE Searching directly for galaxies associated with LLSs in emission. The case of Q0956+122. “Pristine” LLS in Ly 𝛽 “Pristine” LLS z ~ 3.09 Five Ly 𝛽 emitters, but 0.4 expected at random. At least three sources aligned with the LLS. Compelling case of pristine gas in a filament feeding galaxies with low SFRs. MF et al. 2016b
Connecting strong absorbers to galaxy halos with MUSE Searching directly for galaxies associated with LLSs in emission. The case of Q0956+122. Very metal poor LLS Very metal poor LLS in Ly 𝛽 z ~ 3.22 No galaxies or Ly 𝛽 emitters detected. Very metal poor gas in the IGM or CGM of galaxies at very low SFR (< 0.2 M/yr). Dependency on density to second order! MF et al. 2016b
Connecting strong absorbers to galaxy halos with MUSE Searching directly in emission for galaxies associated with DLAs: an example of a metal rich system (J025518+004847) Multiple galaxies inside extended structure System 10% solar at z ~ 3.25 (DLA) Example of Direct image of a gas-rich large scale (50 kpc) “intermediate” nebulae structure with multiple (interacting) galaxies that enrich the surrounding medium MF et al. 2017b, submitted
Connecting strong absorbers to galaxy halos with MUSE Much more to come: MUSE large programme for z ∼ 3 LLSs (197.A-0384(A); PI Fumagalli) MUSE redshift survey in ~25 quasar fields with ~40 LLSs for statistical analysis of correlation between LLSs and star forming galaxies (covering factors) See FLASH talk by Ruari Mackenzie See talk by Rich Bielby for MgII for more examples of DLA hosts absorption in a group at z~0.3 found with MUSE
The role of gaseous environment around galaxies Going beyond galaxy-absorber associations…
The role of gaseous environment around galaxies Going beyond galaxy-absorber associations… There are not real data!
The role of gaseous environment around galaxies: MUSE’s view of RPS at z~0 MUSE is revolutionizing our view of ram-pressure stripping in clusters H 𝛽 emission from ESO 137-001 in Norma Cluster At only 300 kpc from central cluster galaxy! Real MUSE data MF et al. 2014
The role of gaseous environment around galaxies: MUSE’s view of RPS at z~0 Detailed kinematics studies are now possible, i.e. we can separate RPS from gravitational interactions Gas velocity (line of sight and dispersion) from ESO 137-001 in Norma Cluster MF et al. 2014
The role of gaseous environment around galaxies: MUSE’s view of RPS at z~0 Moreover, we can study the excitation mechanisms that power emission… Fossati, MF et al. 2016
The role of gaseous environment around galaxies: MUSE’s view of RPS at z~0 Moreover, we can study the excitation mechanisms that power emission… H 𝛽 emission from ESO 137-001 in Norma Cluster Real MUSE data MF et al. 2014
The role of gaseous environment around galaxies: MUSE’s view of RPS at z~0 … and the metallicity of HII regions inside and outside galaxies See more examples in the “MUSE sneaks a peek at extreme ram- pressure stripping events” series Fossati, MF et al. 2016
What matter(s) around galaxies? - What are the morphological and physical properties of the CGM? The cold phase of the CGM (as traced by LLSs) is primarily photoionised with mean metallicity of 1% solar, and with a 5 order of magnitude scatter We have preliminary indication that optically-thick gas clusters on scales of dark matter halos, although not all LLSs at z~3 may trace the CGM We have uncovered examples of complex associations between optically-thick gas and galaxies at both ends of the metallicity distribution - What are the physical processes that shape the CGM on both large (kpc) and small (pc) scales? A mix of inflows and outflows are required to reproduce the wide spread in metallicity, although optically-thick gas does not appear to be heavily enriched As we uncover more examples of groups associated to absorbers, we need to consider the role of environmental processes Examples from z~0 reveal complex mix of morphology, excitation mechanisms, and metallicities on kpc scales
Radiation matters too… MUSE detection of UVB at z~0 Talk by Tom Theuns on Thursday afternoon! MF et al. 2017a
The metallicity distribution of z > 2 LLSs: the HD-LLS sample The metallicity distribution of LLSs appears quire robust with respect to ionization corrections. We need to look more into model dependency. MF et al. 2016a
The role of gaseous environment around galaxies Going beyond galaxy-absorber associations…
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