Transcript Slide 1

X-raying UFOs in AGNs
Massimo Cappi and Francesco Tombesi
INAF/IASF-Bologna
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(Secret) Outline
1.
Framework
(Multiwavelength) Evidence for UFOs
2.
X-ray Observations:
A variable phenomenon…up to now
Not really clear…up to now
3.
Significance and consequences
Interstellar and intergalactic
feedback…E.T….Mars Attack
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Collaborators (“UFO Hunters”): M. Dadina,
M.Giustini, G. Palumbo, G. Ponti, J. Reeves,
T. Yaqoob, V. Braito (but N.1 is Tombesi)
Qu i c k T i m e ™ a n d a
T IF F (Un c o m p re s s e d ) d e c o m p re s s o r
a re n e e d e d t o s e e th i s p i c tu re .
Framework: Fast winds/outflows/ejecta in AGNs
…known/seen in AGNs since long ago
Jets in radio-loud AGNs
M87 - Jet
Fast (v up to ~ 50000 km/s) winds in BAL QSOs (~
20% of all QSOs)
Sey2 NGC5252
OIII cones
Weymann et al., ’91;
Reichards et al., ‘03
Wide-angle winds
& jets in Seyfert
galaxies
See yesterday’s talks by
Kriss and Gallagher
Tadhunter & Tsvetanov, Nature,
1989; Wilson & Tsvetanov, 1994
Cappi et al. 1995
Framework: Warm absorbers…probe highest-v outflowing/ejected gas
50% of all Sey 1s exhibit WAs
Many details from Chandra/XMM gratings
NGC3783 Exp=900 ks
ASCA
Fabian, et al. ’94
Otani, ’95, PhD
Reynolds et al. '97
Georges et al. '97
Kaspi et al. '01; Netzer et al. '02;
Georges et al. '03; Krongold et al. ‘03
 Clear now that often multiple ionization & kinetic
components: outflows with v~100-1000 km/s
Blustin et al. 2004
Framework: Blue-shifted absorption lines/edges – High-v
New and unexpected results from Chandra and XMM-Newton observations
PG1211+143 (z=0.08) v~0.1c
2
Energy (keV) 5
7
10
Pounds et al. 2003a,b
PDS456 (z=0.18) v~0.1c
(If) interpreted as Kα resonant
absorption by Fe XXV (6.70 keV)
or FeXXVI (6.96 keV)
2
Energy (keV) 5
7
10
Reeves et al. 2003
 massive, high velocity and highly ionized outflows in several RQ AGNs/QSOs
Mass outflow rate: comparable to Edd. Acc. rate (~M◉/yr); velocity ~0.1-0.2 c
Framework: Blue-shifted absorption lines/edges - Variability
Absorbers variability on timescales 1000-10000s
NGC1365
Mrk 509 (long-look, 200ks)
Obs1
Obs2
Obs3
Risaliti et al. 2005
(See also Krongold et al. 2007 on NGC4051)
MC et al., 2009
Dadina et al. ‘05
Variability allows to place limits on location, mass, etc.
Mrk 509:
Among brightest F~2-5x10-11 cgs
and most luminous L~1-3x1044 ergs/s
Type 1 Sey known
EW(FeXXVI)~-20 -60 eV
V~0.14-0.2c
∆t~100 ks
Log~5 erg cm/s, Nh~2-4x1023 cm-2,
v~0.14-0.2c
From absorber parameters and variability,
we estimated:
R<500 Rs
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MC et al. 2009
MRK509 contour plots (MC et al. 2009)
X-ray Observations: Variability
MCG-5-23-16 (XMM+Chandra)
Again, absorber variability on timescales ~20000s
Braito et al., 2007
Data require large Nw, high ,
and vout=0.1c
Interpretation: (Three main) Wind dynamical models
i) Thermally driven winds from BLR or torus
ii) Radiative-driven wind from accretion disk
Murray et al. ‘95, Proga et al. ‘00
…and/or…
iii) Magnetically driven winds from accretion disk
Balsara & Krolik, 93; Woods et al. ‘96
i)  Large R, low v
ii) and iii)  Low R and large v
Emmering, Blandford & Shlosman, ’92; Kato et al. ‘03
Theoretical Interpretation: (Three main) Wind dynamical models
MHD+LD model by
Proga et al. ‘00, ‘03
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Overall numbers (Nh, , vout, etc.) are consistent with observations…
Data Interpretation:
Yes indeed…one expects (mostly/only) strong Fe line absorptions
when accounting for proper wind geometries and physics
Sim et al., 2008
Most important (open) issue
Fundamental to:

Nw (cm-2)

Location (R, DeltaR)

Ionization state ()

Velocity

Covering factor

Frequency in AGNs
i)
PHYSICS of accelerated and accreted flows
(winds?, blobs?, etc.), i.e. understand how BHs
accelerate earth-like quantities of gas to
relativistic velocities
ii)
COSMOLOGY: i.e. estimate the mass outflow
rate, thus the impact of AGN outflows on ISM
and IGM enrichment and heating!
Elvis et al. ‘00, Creenshaw et al. ’03, King et al. ‘03, Chartas et al. ‘03,
Yaqoob et al. ‘05, Blustin et al. ‘05, Risaliti et al. ’05, Krongold et al. ‘07
Current estimates have order of magnitude uncertainties, they go from:
dM/dt (Lkin) few % to several times dMacc/dt (Ledd)
This is a fundamental (open) issue
Ejection/outflows: From source-by-sources to representative samples…
We analysed in a systematic and uniform way, a (almost) complete sample
of nearby, X-ray bright, radio-quiet AGNs (Tombesi et al. 2010a,b)
z distribution of sources
4-10keV fluxes
• Selection of all NLSy1, Sy1 and Sy2 in RXTE All-Sky Slew Survey
Catalog (XSS; Revnivtsev et al. 2004)
• Cross-correlation with XMM-Newton Accepted Targets Catalog
• 44 objects for 104 pointed XMM-Newton observations
• Local (z<0.1)
• X-ray bright (F4-10keV=10-12-10-10 erg s-1 cm-2)
Absorption lines search
Uniform spectral analysis:
• Reduction and analysis of all EPIC pn spectra in the 4-10keV
• Baseline model: absorbed power-law + Gaussian Fe K emission
lines
Absorption lines search:
• Addition of narrow line to baseline model stepping energy in 4-10keV
and recording Δχ2 deviations
• Visualization on energy-intensity contour plot (significance 68% red,
90% green, 99% blue) (e.g. Miniutti et al. 2007, MC et al. 2009)
Absorbed power-law
• Selection of narrow lines with F-test confidence levels ≥99%
• Line parameters determined by direct fitting to the data
Example of PG1211+143
(Tombesi et al. 2010a)
Absorbed power-law +
emission line
Absorption lines significance
F-test can overestimate the detection significance for a
blind search of emission/absorption lines over a range
of energies (e.g. Protassov et al. 2002).
Extensive Monte Carlo simulations
(e.g. MC et al. 2009)
• Additional significance test for lines at energies ≥7.1keV
• Null hypothesis that spectra are fitted by model without absorption
lines
• 103 simulated spectra for each case
• Simulated Δχ2 distribution for random generated lines
• Selection of lines with MC confidence levels ≥95%
Global probability for the lines to be generated by random
fluctuations is very low (≤10-8 from Binomial distribution).
• Checked no contamination from pn background and calibration
• Independent confirmation of blue-shifted lines detection from MOS data
(without relying on any statistical method)
Results: Yes, we confirm there are indeed UFOs! (Ultra-Fast Outflows…)
Blue-shift velocity distribution
Cumulative velocity distribution
• 36 absorption lines detected in all 104 XMM observations
• Identified with FeXXV and FeXXVI K-shell resonant absorption
• 19/44 objects with absorption lines (≈43%)
• 17/44 objects with blue-shifted absorption lines (lower limit ≈39%, can
reach a maximum of ≈60%)
• 11/44 objects with outflow velocity >0.1c (≈25%)
• Blue-shift velocity distribution ~0-0.3c, peak ~0.1c
• Average outflow velocity 0.110±0.004 c
Tombesi et al. 2010a
(The UFO’s hunters
commander in chief)
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Results
Lines EW distribution
• Most frequent detected line is FeXXVI Lyα
• EW is in the range ≈10-100eV, with mean ≈40-50eV
• Estimated global covering factor from fraction of sources with lines (C=Ω⁄4Π)≈0.40.6
• Geometry not very collimated, large opening angles favored (similar to WA)
Physical photo-ionization modelling using XSTAR
Mean phenomenological SED from the radio-quiet
sample:
• SEDs 34 Type 1s from NED database
• scattering due to source variability and different
instruments
• normalized SEDs to near-IR inflection point ~1.25μm
(like Elvis et al. 1994)
• average flux for each energy point
Simple mean SED with three intervals: Radio
to mm (Γ~2), mm to IR (Γ~0.1), IR to X-rays
(Γ~2)
Xstar grid for direct spectral fitting:
• input enenergy band 0.1eV, 106 eV
• mean SED for radio-quiet sources
• power-law Γ=2 for radio-loud sources
• turbulent velocity v=500 km/s
 NH~1022-1024 cm-2, logξ~3-6 erg s-1 cm-2
(vout, NH lower limits, unknown inclination angle)
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Tombesi et al., 2010c,
in prep
WAs in RQ from McKernan et al. (2007) (filled black circles), WA in RL from Torresi et al. (2009) and
Reeves et al. (2009) (filled blue triangle), UFOs in RQ (red crosses)
Ejection/outflows:
• estimated distances: r<0.01-0.1pc (<102-105 rs)
(accretion disk winds?
e.g. Elvis 2000; King & Pounds 2003)
• Often vout > vesc, but not always, material shall fall back sometimes?
(“aborted jet”? e.g. Ghisellini et al. 2004, Dadina et al. 2005)
• variability time scales t~1day – 1year
• Lbol/LEdd~0.1-1; Mout/Macc~0.1-1; Ek~1044-1045 erg s-1 ~0.1 Lbol
(last two estimates depend on covering fraction C)
• Acceleration mechanism? Line, magnetically or momentum driven?
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Cosmological Importance of UFOs?: (on-going work)
Role in feedback in the (co?)evolution of galaxies?
Mbh~
б4
Role in heating groups and custers?
Grav. scaling
With SN
preheating
Magorrian et al. '98
Tremaine '02; Gebhardt '02...etc
With AGN
pre-heating
With QSO
ejection/outflows
(see e.g. King and Pounds '03,
Crenshaw, Kraemer & George '03, ARA&A)
Lapi, Cavaliere & Menci, ‘05
Impact on physics of
ejections/outflows?
Momentum-driven accretion disk
winds/outflows? As in King 2009?
“Eddington winds from AGN are likely to have
velocities ~0.1c and show the presence of helium- or
hydrogen-like iron” (King 2009)
• Eddington accretion episodes Lbol/LEdd~0.1-1
• electron scattering wind τ~1 at infinity
• wind momentuum ~ photon momentuum (Moutv~LEdd/c)
• typical velocity ~0.1c
• typical ionization parameter logξ~4 and linear relation vout and ξ
(Fe XXV, Fe XXVI + Nickel ions?)
• wind interaction with host galaxy, ram pressure
• important for feedback SMBH and host galaxy
• does explain the M-σ relation
Future prospects: Astro-H calorimeter
Calorimeter on board Astro-H, next Japanese X-ray
satellite to be launched in 2013: good effective area
(≈250 cm2 @ 6keV) and high energy resolution
(FWHM≈7eV) from 0.1keV up to 12-13keV.
• realistic spectra simulations of UFOs
•absorption lines resolved, measured velocity
broadening (down to ~100-200 km/s @ 6 keV)
• estimates EW, blue-shift, centroid energies ~10 times
better XIS-FI (100ks simulation)
• better constrains on NH, logξ, vturbu
Future pospects: IXO calorimeter
X-ray Microcalorimeter Spectrometer (XMS): high effective area ~0.65m2 (~6500cm2 !!) @ 6keV
and high energy resolution (FWHM≈2.5eV) from 0.1keV up to 12-13keV.
Flux limits (EW=10eV) (Tombesi et al. 2009)
logξ=3 erg s-1 cm, NH=1023cm-2, b=1000km/s (Tombesi et al. 2009)
Flux limits
Spectra simulations
• 2-10keV flux limits for 5σ detection of narrow
absorption lines in the 3-11keV
• Simulations of highly ionized and massive absorbers
• Different EWs, exposure times and responses
• Line details (profile, energy, broadening) measured with hig
accuracy (>30 times Astro-H)
• FeXXV/XXVI K lines detectable with high significance
• Lines of EW=10eV (50eV) in ≈6-9keV for ≈10-12
• Extend study to less bright sources
(10-13) erg s-1 cm-2 (expo 100ks)
• Spectral variability on time-scales of 5 (10) ks
-11
-12
-1
-2
• Time variability, dynamics of absorbers
Future: Time vs. energy maps (in emission and absorption lines)
NGC1365 F(2-10)=10-11cgs S/N>3
Highest throughput for time-resolved detections of abs. lines
 real-time, extreme dynamics, i.e. inward and outward accelerations!?
(line ∆v/∆t) ....blob=test particle to test Kerr vs. Schwarzschild GR
Conclusions
• Search for narrow blue-shifted Fe K absorption
lines in a complete sample of 44 radio-quiet AGNs
observed with XMM-Newton
• 36 detected absorption lines (22 at E≥7.1keV)
• Global veracity is strong and publication bias
solved
Existence of highly ionized, massive and ultra-fast outflows in radio-quiet AGNs:
• ≈40% of sources have blue-shifted absorption lines (≈25% with v≥0.1c)
• Outflow velocities up to relativistic values (≈0.2-0.3c)
• Global covering factor ≈0.4-0.6, large opening angles favored
• Important for: BH accretion physics, AGN feedback with host galaxy, SMBH growth, ...
• Improvement expected from future X-ray missions, such as Astro-H and IXO
Thanks for your attention,
and watch-out for UFOs!
Qu i c k T i m e ™ a n d a
T I F F (Un c o m p re s s e d ) d e c o m p re s s o r
a re n e e d e d t o s e e t h i s p i c t u re .
and don’t be confused by the fact that
UFOs are also called “Ultra-Fast Outflows”…
X-ray Observations (ii/iii): Blue-shifted absorption lines/edges – High-z
Massive outflows…also (mostly?) at high redshift
2 high-z BAL QSOs
PG 1115+080 (z=1.72) v~0.1-0.3c
Chartas et al. 2002,
Hasinger, Schartel & Komossa 2002
APM 08279+5255 (z=3.91) v~0.2-0.4c
MOS
PN
Chartas, Brandt & Gallagher, 2003
See also Wang et al. ’05 (v=0.8c in qso@z=2.6)
N.B.: Would have been undetected at z=0...

Lines statistical significance? (transient
features, number of trials in time and
energy, etc…)

Identifications of edges/lines energies?
(Kallman et al. 2005, Kaspi et al. for
PG1211)

Local “contamination”? (PDS456 at
risk? McKernan et al. ’04, ‘05)

Publication bias? Only positive
detection, low signif., Vaughan & Uttley
‘08)
Outflow v (km/s)
Critical Issues (i/ii): Observations
cz (km/s)
Last but not least…for those still skepticals on UFOs
Publication bias solved :
• Uniform analysis on complete sample of sources
Not due to local contamination:
• Lines detection assessed by MC simulations
No correlation between cosmological
red-shift and lines blue-shift, no local
(z≈0) absorption.
• Global chance probability very low (≤10-8)
• Detection independently confirmed by MOS data
Future (iv/vii): Better statistics on optically-classified samples:
SDSS’s BALQSOs cross-correlated with 2XMM
 22 spectra and 23 HRs to estimate Nh, , Lx, etc.
Giustini et al., submitted
See poster E17-0049-08 by Giustini et al.
Future (v/vii): Shorter time-scales and better sensitivity…with XEUS
NGC1365 F(2-10)=10-11cgs S/N>3
Future (vi/vii): Con-X, XEUS or IXO?
Area (cm2)
@1 keV
@4 keV
@6 keV
@7 keV
XEUS
IXO
CON-X
58000
30000
15000
40000
15000
11000
30000
9000
7500
20000
6000
5000
XMM(PN)
1150
820
800
650
A  Flength2 x qcrit2 x Refl2 , where qc  0.5/E
eff
Summary
I briefly reviewed the current evidence for blue-shifted
absorption lines from highly ionized Fe in AGNs (in both Sey and QSOs)
These indicate the existence of highly-ionized, high velocity, massive
outflows in AGNs, BUT STILL ORDER OF MAGNITUDES UNCERTAINTIES
on energy/momentum and mass involved.
This topic still requires better measurements of intensity, energy and
frequency/recurrency but has a great potential for the study of:
launching mechanisms/characteristics of outflows/jets
(mechanical energy emerging from BH), important not only for
(relativistic) physics but also for link with cosmology
Prospects for future progress are to:
i)
Confirm/secure these findings with longer XMM/Chandra observations
ii)
Probe lower time-scales (with > 2m**2 @6 keV, i.e. XEUS-like mission)
iii) Probe high-velocity gas with high-energies (with Simbol-X and/or XEUS hxd)
Future (iii/vii): Reduce timescales…
…to probe the flow dynamics (∆v/∆t) of innermost regions
by means of detection and time-resolved spectroscopy
of energy-shifted absorption lines.
Fiducial numbers:
We wish to follow abs. lines from, say, ~1 to ~10 Rs, with intervals of 1Rs
Let assume v~0.2c, then for
BH mass= 108 M●  ∆Time-scale ~ 5000 s
BH mass= 106 M●  ΔTime-scale ~ 50 s (Note: 1µs if 1 M●)
Scaling from Mrk509 and XMM, and assuming EW(Fe)=-100 eV 
F(2-10)=2x10-11cgs (~ 15 sources)
F(2-10)=2x10-12cgs (~ 50 sources)
F(2-10)=2x10-13cgs (~ 250 sources)
Con-X(6000cm2)
1000s
XEUS(25000cm2)@6keV
100s
10000s
1000s
100000s
10000s
N.B.: If v>0.2c, timescales consequently reduced
Really needed because
mostly BH mass≤ 107 M
X-ray spectra of winds/outflows
Future (vi/vii): Simbol-X simulation (SDD+CdTe)
Simulations of narrow emission and absorption lines
Model: PL + 2 emission lines
+ 4 abs. lines
Model with narrow emission and absorption lines: PL (Г=1.9, F(210)=10-11erg/cm2s, Exp.=50 ks) + 2 FeK emission lines (E1=5 keV,
E2=6.4 keV, σ1= σ2=50 eV, EW1=EW2=100eV) + 4 FeK absorption
lines (E1,2,3,4=7, 9, 12, 15 keV, σ1,2,3,4<50 eV, EW1,2,3,4=-100eV)
Edges and absorption lines at E~7.1-9.0 keV
(rest-frame)
+ vout~ 0.1-0.5c
Eobserved~ 8-14 keV !!
Eabs<100 eV
Idee would be to follow
the evolution of blob ejections (or injections)
N.B: Masses involved can be greater than Mearth
(1027g/ejecta) >>10-11g in accelerators
Deceleration
Acceleration
Unfortunately XRS on-board ASTRO-E2 is lost
Mrk 509, Astro-E2 simulation 100 ks
High energy resolution to distinguish
beetwen wind and blob(s) (line profile)
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