STFC Summer School 2007 Active Galactic Nuclei IUE

STFC Summer School 2007 Active Galactic Nuclei IUE Paul O’Brien X-ray & Observational Astronomy Group University of Leicester Previously at: University College London [Ph. D, UCL 1987: A study of the UV continuum of quasars] IUE Project, UCL/RAL University of Oxford University of Leicester XMM-Newton, Faulkes Telescopes & Swift

• A little history Active Galactic Nuclei • Taxonomy (split them up) • Unification (join them together again) • Mass, size and structure AGN: an object with nuclear, non-stellar energetic phenomena. Power-source: accretion disc feeding a massive black hole. But why, when, where, how…? Radio mm IR Opt. /UV X-ray

STFC Summer School 2007 History lesson – start (almost) at the beginning Ph. D student goes here Leviathan, 1845, 1. 8 m telescope! Birr Castle, Parsonstown, Eire (wet) Owned by Lord Rosse (optimist) M 51 – example of a “spiral nebula”

STFC Summer School 2007 The first galaxy/AGN spectra • Photography improved (dry plates) by late 1800 s so could be used in a spectrograph stellar spectral classification (Pickering, Cannon etc. ). • Sir William Huggins, 1864 – spectroscopy of M 31 (Andromeda). Saw (faint) absorption lines but unsure if they were reflected Moon-light • Edward Fath, 1909 Ph. D – displayed nebulae spectra showing that galaxies look like stars – i. e. galaxies are made out of stars! But, also found a galaxy (in 1908) that had: “bright lines in its spectrum, has also a strong continuous spectrum which contains absorption lines”. Object: NGC 1068 (M 77) – the first AGN!

STFC Summer School 2007 Seyfert Galaxies • Fath followed by Slipher (M 31 velocity), and Hubble…( fame, fortune? , telescope) • Carl Seyfert (1943) – Postdoc at Mount Wilson Isolated 6 spiral galaxies with blue nuclei which show “high-ionization emission lines much wider than absorption lines in normal galaxies”. • Two basic types: Seyfert 1 - broad permitted lines + narrow forbidden lines Seyfert 2 - narrow permitted and forbidden lines H [OIII]

STFC Summer School 2007 Example Seyfert spectra H Blue continuum Red continuum Wavelength (Å) H

STFC Summer School 2007 NGC 3783 Seyfert Type 1 See a large range in ionization species (too large for normal nebulae)

STFC Summer School 2007 Radio Galaxies M 87 VLA • Discovered after WWII (Ryle, Mills etc. ) • Example: M 87 (NGC 4486). Identified by Bolton, Stanley & Slee (1949). [Optical jet found by Curtis in 1918] • Radio emission is non-thermal (Synchrotron. + Inverse Compton) Quasars/QSOs • 3 C 273 (Mararten Schmidt 1963). • High redshift (0. 158) implied huge luminosity. Also variable small size • Most (~90%) are radio-quiet (QSOs). • Quasars found in elliptical galaxies. • QSOs found in either spirals or ellipticals. M 87 optical

STFC Summer School 2007 The Host Galaxy and the AGN galaxies at same redshift Disturbed morphology Interaction?

STFC Summer School 2007 Need to explain the diverse properties of AGN • AGN can be very luminous (1000 x bright galaxies) • The continuum varies on (fairly) short timescale small objects • Broad-band continuum + wide range in emission line ionisation • See both “broad” ( 10000 km s-1) and “narrow” ( 2000 km s-1) emission lines. The narrow lines are broader than normal galactic lines. Solution: the accreting supermassive black hole (SMBH) model…

STFC Summer School 2007 AGN Type 1 and 2 Unification Size-scales Black-hole: Rs = 3 x 109 M 6 m Accretion disc: ~3 – 104 Rs Broad Line Region: ~1 -100 light-days Molecular Torus: ~1 -10 light-years

STFC Summer School 2007 Type 2 AGN Type 1 AGN Radio loud AGN Obscuring stuff

STFC Summer School 2007 Black holes in every galaxy? M 87 – ionized gas rotation curve. Large dark mass required (~109 M ) Virial theorem: M (r V 2 /G) Magorrian et al. 1998

STFC Summer School 2007 MBH- * relationship Other methods Reverberation Peterson et al. Calibrate AGN method vs. stellar (Ferrarese). AGN follow same relation as in-active galaxies. “Bulge” mass correlates with mass of SMBH

STFC Summer School 2007 PDS 456 – the most powerful object in the local Universe, but unknown until 1997… QSO Luminosity vs. redshift Nearby galaxies Interaction? At z=0. 184, 1'' = 3. 1 kpc Torres et al. (1997); Yun et al. (2004)

STFC Summer School 2007 X-ray and UV observations of PDS 456 3 C 273 CIV 1549 v -5000 km s-1 Ly /NV Massive absorption Ly BAL (12 -22000 km s-1) X-ray spectrum requires a massive, highly-ionized outflow moving at ~0. 15 c. Also see fast outflow in the UV. Outflow mass-loss rate ~ 10 M yr-1 For 10% covering factor, outflow K. E. ~ 1039 J s-1 (10% Lbol) (Reeves et al. 2003; O’Brien et al. 2005)

STFC Summer School 2007 What could outflows mean – the concept of “feedback” • Some outflows have a K. E. comparable to the radiation luminosity: are they common in the early Universe? • Most SMBH mass probably assembled by luminous accretion. So perhaps built when the accretion rate is high/spin low? • Over ~107 years X-ray outflows could deposit a total mechanical energy comparable to the binding energy of a Galactic bulge (~1052 J). • Feedback between outflows and star formation? ?

STFC Summer School 2007 Interaction in action…the Ultraluminous IR Galaxies IRAS revealed a large population of “Ultraluminous IR Galaxies”. Star-formation rate 100 -1000 x. Galactic. Most are interacting or highly disturbed. SMBHs (and galaxies? ) grow through accretion, SF, outflows all driven by mergers, shocks, galactic bars etc.

STFC Summer School 2007 How do we see into the heart of an AGN ? Try radio interferometry e. g. M 87 , only ~18 Mpc away (1" ~ 300 light-years) But, we need to look in the optical/IR

STFC Summer School 2007 Optical interferometry VLTI – 4 x 8. 2 m + 4 x 1. 8 m Baselines up to 200 m, ~10 mas Creech-Eakman et al. 2006 Magdalena Ridge Observatory, NM – 10 x 1. 4 m optical/IR telescopes with baselines up to 340 m. On schedule for 2008/2009 start. Observe from 0. 6 -2. 4 microns with spatial scale of 0. 3 -30 mas.

STFC Summer School 2007 AGN – The Future • More data of all kinds + better models • Deep surveys in sub-mm, IR, X-ray, etc. to find all the AGN • High-resolution imaging in radio, optical, IR (e. g. SKA, VLTI, MRO) Time-dependent, 3 -D, MHD disc(torus) simulation (Hawley et al. ) UK astronomers have UKAFF – the UK Astrophysics Fluids Facility at Leicester – build your own disc, jet, black hole… Have fun!

STFC Summer School 2007 The end