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

COS-AGN: Probing the circumgalactic medium

• f 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

tied to BH

– Feedback required in

simulations to regulate growth

– AGN associated with cessation

• f star-formation

McConnell & Ma (2013)

(km/s) σ MBH ( Msun )

AGN – Driving galaxy evolution

• AGN feedback critical for galaxy

evolution:

– M-σ shows growth of galaxy

tied to BH

– Feedback required in

simulations to regulate growth

– AGN associated with cessation

• f star-formation

Galaxy Luminosity

φ ( L )

Observed distribution CDM prediction Λ AGN

AGN – Driving galaxy evolution

• AGN feedback critical for galaxy

evolution:

– M-σ shows growth of galaxy

tied to BH

– Feedback required in

simulations to regulate growth

– AGN associated with cessation

• f star-formation

Terrazas et al. (2016) Passive Star-forming

The circum-galactic medium

• COS-Halos targeted CGM of L* galaxies

–Star forming and passive galaxies have different CGM properties for

some species

Tumlinson et al. 2011

Star-forming Passive

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 Logρimp within 0.2 dex of AGN

system

Berg et al. (in prep.)

log(M*/Msun)

• ρimp (kpc)

Lyα equivalent width

Detection Threshold Berg et al. (in prep.)

Not only is HI common, but there is lots of it! HI 1215

AGN Matches controls Literature

Lyα equivalent width

Berg et al. (in prep.)

Log (EWAGN) – Log (median EWcontrols)

= Median

AGN enhanced by ~0.1 dex!

Metal equivalent widths

Berg et al. (in prep.)

Log (EWAGN) – Log (EWcontrol)

= Median

AGN gas enhanced further out!

Errorbars from jackknife

Summary of results

• Signifjcant reservoir of HI gas around AGN

– >85% covering fraction (Ly

α EW> 200 mÅ) between 75 and 250 kpc

– Lyα 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?

• ~0.5 Myr to reach CGM; AGN

lifetime <~1 Myr

• B. Oppenheimer

HI Parameter space

• f COS-AGN

Interpretations (preliminary)

• Ionizing the gas?
• Winds redistributing gas

and metals?

– Lack of metals observed – HI enhanced; simulations

suggest otherwise

– Enhanced EW driven by

kinematics?

Rahmati+ 2015 Covering Fraction Impact Parameter EAGLE simulation

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

– Lyα EW enhanced by factor of ~2 relative to matched galaxies

• Stronger absorption beyond 164 kpc relative to matched

galaxies