COS-AGN: Probing the circumgalactic medium of AGN hosts Trystyn - PowerPoint PPT Presentation

COS-AGN: Probing the circumgalactic medium of AGN hosts Trystyn Berg (Victoria) trystynb@uvic.ca Sara Ellison (Victoria; Supervisor) Jason Tumlinson (STScI) Ben Oppenheimer (Colorado) Joop Schaye (Leiden) Rongmon Bordoloi (MIT)

AGN – Driving galaxy evolution ● AGN feedback critical for galaxy evolution: – M- σ shows growth of galaxy ) M sun tied to BH ( M BH – Feedback required in simulations to regulate growth – AGN associated with cessation of star-formation (km/s) σ McConnell & Ma (2013)

AGN – Driving galaxy evolution ● AGN feedback critical for galaxy evolution: CDM prediction Λ – M- σ shows growth of galaxy tied to BH Observed ) L – Feedback required in distribution ( φ simulations to regulate growth – AGN associated with cessation AGN of star-formation Galaxy Luminosity

AGN – Driving galaxy evolution ● AGN feedback critical for galaxy evolution: – M- σ shows growth of galaxy tied to BH Passive Star-forming – Feedback required in simulations to regulate growth – AGN associated with cessation of star-formation Terrazas et al. (2016)

The circum-galactic medium ● COS-Halos targeted CGM of L * galaxies – Star forming and passive galaxies have different CGM properties for some species Passive Star-forming Tumlinson et al. 2011

The COS-AGN survey ● 10 observed + 9 archival QSO sightlines around SDSS AGN – 52 orbits of COS time (cycle 22); COS-Halos data quality – Wavelength coverage give range of ionization species Berg et al. (in prep.)

The COS-AGN survey ● Systematic comparison to galaxies with and without AGN – Control matching: LogM * and Log ρ imp within 0.2 dex of AGN system ● ρ imp (kpc) log(M * /M sun ) Berg et al. (in prep.)

Ly α equivalent width HI 1215 Not only is HI common, but there is lots of it! Detection Threshold AGN Matches controls Literature Berg et al. (in prep.)

Ly α equivalent width Log (EW AGN ) – Log (median EW controls ) AGN enhanced by ~0.1 dex! = Median Berg et al. (in prep.)

Metal equivalent widths Log (EW AGN ) – Log (EW control ) AGN gas Errorbars enhanced from further out! jackknife = Median Berg et al. (in prep.)

Summary of results ● Signifjcant reservoir of HI gas around AGN – >85% covering fraction (Ly α EW> 200 mÅ) between 75 and 250 kpc – Ly α EW enhanced by 0.1 dex relative to matched galaxies ● Stronger absorption beyond 164 kpc relative to matched galaxies

Interpretations (preliminary) ● Ionizing the gas? – HI offset in wrong direction! – More gas further out , dominated by UV background – Time delay of radiation? Parameter space ● ~0.5 Myr to reach CGM; AGN of COS-AGN HI lifetime <~1 Myr B. Oppenheimer

Interpretations (preliminary) ● Ionizing the gas? ● Winds redistributing gas and metals? Covering Fraction – Lack of metals observed – HI enhanced; simulations EAGLE suggest otherwise simulation – Enhanced EW driven by kinematics? Impact Parameter Rahmati+ 2015

Interpretations (preliminary) ● Ionizing the gas? ● Winds redistributing gas and metals? ● Different galaxy type or environment? – Not represented in control sample?

Summary of results ● Signifjcant reservoir of HI gas around AGN – >85% covering fraction (Ly α EW> 200 mÅ) between 75 and 250 kpc – Ly α EW enhanced by factor of ~2 relative to matched galaxies ● Stronger absorption beyond 164 kpc relative to matched galaxies