Reconstructing the past activity of the supermassive black hole at the Galactic Centre R. Terrier,...
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Transcript of Reconstructing the past activity of the supermassive black hole at the Galactic Centre R. Terrier,...
Reconstructing the past activity of the supermassive black hole
at the Galactic Centre
R. Terrier, APC Paris M. Clavel, A. Goldwurm, M. Morris, G. Ponti, S. Soldi
COSPAR, Aug. 2014, Moscow
Active and inactive SMBH in the Universe
IC 2497: an extinct quasar?
109 Mo SMBH
Light echo of past quasar emission emitted ~ 70 kyr ago
Current luminosity is up to 104 smaller
Timescale of ~ 10 kyr is consistent with state changes observed in Galactic XRB (~1h)
Schawinski et al. (2010)
Transition timescale for Sgr A*: 50 yrs
What timescales for state transition of SMBH?
Active and inactive SMBH in the Universe
GRB 110328a/Sw 1644+57: Stellar disruption by SMBH?
Burrows et al. (2011), Levan et al. (2011) etc
IGR J12480+0134: ~150 days transient
Peak luminosity at 1.5 1042 erg/s ~ 0.2 L
edd
Radiated energy ~ 1050 erg
a tidal capture of Jupiter-like object?Nikolajuk & Walter (2013)
Timescales and recurrence time of catastrophic events near
SMBH?
Diffuse non-thermal emission from the central 100 pc
100 pc
Hard X-ray continuum emission from the central 200pc detected by ART-P: reflection of X-ray source?
Sunyaev+93
Intense 6.4 keV FeK line emission resolved from GC clouds:Past Sgr A* flare (300 yrs ago)?
Koyama+96
ASCA 6.4 keV
100 pc XMM 6.4 keV
Diffuse non-thermal emission from the central 100 pc
Hard X-ray continuum emission from the central 200pc detected by ART-P: reflection of X-ray source?
Sunyaev+93
Intense 6.4 keV FeK line emission resolved from GC clouds:Past Sgr A* flare (300 yrs ago)?
Koyama+96
100 pc XMM 6.4 keV
Diffuse non-thermal emission from the central 100 pc
Hard X-ray continuum emission from the central 200pc detected by ART-P: reflection of X-ray source?
Sunyaev+93
Intense 6.4 keV FeK line emission resolved from GC clouds:Past Sgr A* flare (300 yrs ago)?
Koyama+96
Hard X-rays from Sgr B2
100 pc
Integral discovered hard X-ray emission (up to >100 keV) from Sgr B2 and G0.11-0.11 clouds
Revnivtsev+04, Belanger+06
The 6.4 keV & hard X-ray continuum emission from Sgr B2 is consistent with an echo from some past Sgr A* intense activity 1039 erg/s ~ 300 yrs ago
Are there other possible explanations?
200 pc
Origin of the non thermal X-ray emission from GC clouds?
Cosmic-ray bombardement? Illumination by past bright X-ray source?
1 keV 10 keV 1 keV 10 keV
Key observable is time variability!
SF2A 2004
Hard X-ray echo of past activity
LineContinuum
Clavel 14
SF2A 2004
Hard X-ray echo of past activity
LineContinuum
Clavel 14
SF2A 2004
Hard X-ray echo of past activity
LineContinuum
Clavel 14
Early evidences for variations of the emission
PRELIMINARYSgr B2 (20-60 keV)
6.4 keV flux variations in Sgr B2 region Inui+09
Sgr B2 (20-60 keV)
100 pcXMM 6.4 keV
Moving continuum diffuse clumps seen by Chandra in Sgr A region
Muno+07
Hard X-ray emission from Sgr B2 is fading!
Analysis of 20 Ms of Integral data from 2003 to 2009
PRELIMINARYSgr B2 (20-60 keV) 2009
2005
2003
Sgr B2
Integral IBIS/Isgri : 20-60 keV
2007
Illumination !
Terrier+10
Sgr B2 (20-60 keV)
Oph cluster
= 8.2 ± 1.7 yr
Hard X-ray emission from Sgr B2 is fading!
Suzaku observes similar decay in 2009 at 6.4 keV and in hard continuum band
PRELIMINARY 2009
2005
2003
Sgr B2
Integral IBIS/Isgri : 20-60 keV
2007
Nobukawa+11
Sgr B2 (20-60 keV)
A past flare of the SMBH is illuminating Sgr B2!
Distance implies
•Sgr A* is the most likely candidate•
to Earth
L X ∝10 39erg.s−1 d100pc
2
Photons scattered by Sgr B2 were emitted ~ 100 yrs
•Parallax measurement: Sgr B2 is 130 ± 60 pc in front of Sgr A*•
direct pathscattered path
Delay 100 yrs (70-150)
•(H2O maser, VLBI, Reid et al, 2009)
Time variability in the Sgr A complex?
100 pc
Sgr A
PRELIMINARY
the central 30 pc observed for 8 years
XMM-NewtonFe K 6.4 keV: 2000-2004
30 pc
PRELIMINARY
Flux variations in the central 30 pc
Fe K 6.4 keV: 2000-2004
30 pc
Fe K flux
Fe K flux
PRELIMINARY
Some propagation effects?
Fe K 6.4 keV: 2000-2004
30 pc
PRELIMINARY
Apparent superluminal motion!
Most solid proof that Fe K emission is caused by illumination
Sgr A* is illuminating most of the clouds in the GCPonti+10
To the GC
Apparent superluminal motion? Effect discussed by Sunyaev & Churazov (1998)
Curves of constant delay (isochrons) : parabola
Apparent light crossing times:
120 yrs70 yrs45 yrs
•If the « bridge » and Sgr B2 are illuminated by the same flare (1039 erg/s): Bridge located 60 pc behing Sgr A* & flare began 400 years ago?
A possible lightcurve of Sgr A* over past centuries?
Ponti+10
SF2A 2004
Sgr A* is fed by winds of surrounding massive stars:•Intrinsic accretion rate variability likely to weak•Stochastic infall of clumps from nearby massive stellar winds?
Cuadra et al. (2008)
Origin of the high Sgr A* state?
SF2A 2004
Deceleration of jet produced by stellar tidal disruption event?Yu et al (2011)
Asteroids and planet disruption?Zubovas et al (2012)
Accretion of debris produced by stellar collisions? Sazonov et al. (2012)
Multiple cloud accretion events?•Czerny et al. (2013)
Origin of the high Sgr A* state?
SF2A 2004
Intrinsic accretion rate variability due to stochastic infall of clumps from nearby massive stellar winds?
Cuadra et al. (2008)
Deceleration of jet produced by stellar tidal disruption event?Yu et al (2011)
Asteroids and planet disruption?Zubovas et al (2012)
Accretion of debris produced by stellar collisions? Sazonov et al. (2012)
Multiple cloud accretion events?•Czerny et al. (2013)
Origin of the high Sgr A* state?
Can we determine the light curve of Sgr A* over the last centuries?
PRELIMINARY
Constraining Sgr A* light curve over the past centuries
To reconstruct Sgr A* past activity:L
Sgr A* is a function of cloud N
H and radius
Time delay given by cloud position along LoS
3D distribution of GC molecular clouds is critical!
or or ?
Sofue95 Molinari+11
Existing 3D models from radio measurements are very uncertain
PRELIMINARY
Constraining Sgr A* light curve over the past centuries
Solution:
Use X-rays to constrain the GC clouds Line of Sight (LoS) position
Different approaches:
•Use angular dependency of 6.4 keV Equiv. Width Capelli+12
•Use X-ray intrinsic NH and measure partial absorption of GC thermal
plasmas to locate cloud along LoSRyu+09, Ryu+13
•Use lightcurve of echoes to associate clouds with similar delays:•X-ray tomography of GC ISM
Clavel+13
SF2A 2004
•Constrain cloud position along the line of sight using EW of Fe K line, and deduce Sgr A* luminosity from N
H deduced from X-ray spectrum
Towards a Sgr A* lightcurve
Capelli+12
SF2A 2004
Towards a Sgr A* lightcurve
Ryu+13
Clavel+13
Detailed timing of the echoes with Chandra
Chandra Fe Kα line flux: 1999-2011
Variations & propagation in all Sgr A complex clouds
More complex pattern than previous studies suggest
30pc
Clavel+13
Propagation follow-up in 2011
Chandra Fe Kα line flux: 1999-2011
A new thin (0.2 pc!) filament : Flux increases by a factor greater than 10
Filament illuminated by LX>1039 erg/s
30pc
Size: 0.2 x 1.0 pc2
dSgrA*
≥ 23 pcN
H ≤ 1023 cm-2
2011
1999-2010
Clavel+13
Distinct timing behaviours in the Sgr A complex echoes
2 distinct time behaviours: 10 yr linear increase or decrease2 yr peaked variation
Systematic lightcurve extraction in 15'' boxes (4-8 keV)
Clavel+13
Two distinct events reflected in Sgr A complex!
2 distinct events are required (<2 yrs and ~10 yrs timescale) with LX>1039 erg/s
Absolute timing still unkown
short var.long var.
SF2A 2004
Intense hard non-thermal X-ray emission (~1.6 up to 30 keV) around the Arches cluster
Capelli+10, Tatischeff+12, Krivonos+13
Inverse bremstrahlung emission of subrelativistic ions? Required power in CR ions:
PCR
= (0.5 – 1.8)×1039 erg s-1
Powered by collision between the Arches cluster and ambient cloud?
The Arches cluster: an accelerator of CR ions?
Archescluster
• CR energy density: ~ 1000 eV cm-3 The Arches cluster: an extreme CR dominated
region?Tatischeff+12
SF2A 2004
The Arches cluster: an accelerator of CR ions?
Look for time variability of 6.4 keV and continuum emission over 13 yrs
A 30% flux variation observed in 2011-2013
Most of the non-thermal X-ray flux from Arches cluster surroundings is due to reflection of Sgr A* past flare
Clavel+14, see poster STW-S-132, presentation by R. Krivonos
continuum
Fe K
The Fe K emission of the CMZ 10 years apart
2000
2012
Comparison of XMM surveys reveals variations over the whole CMZ:•Overall decrease•Strong variations in Sgr C complex
See S. Soldi presentation
100 pc XMM, 6.4 keV FeK line
2012
Solid proof that Sgr A* activity has changed in recent past Hard X-ray and Fe K emission is highly variable in the central 200pc
Reflection of hard & energetic events from Sgr A* Arches emission is dominated by reflection
Towards a lightcurve of Sgr A* over the last millenium? Strong uncertainties in the LoS distribution of clouds
X-rays can be used to constrain it
Use X-ray echoes timing (tomography) and large scale surveys to improve knowledge on cloud position
Detailed Chandra monitoring reveal at least 2 distinct events High luminosities >1039 erg/s Durations: <2 yrs, ~10 yrs respectively
Disruption events? Strong fluctuations in accretion rate? Further constraints from XMM (Soldi's talk), Suzaku (Nobukawa's talk)
Conclusions
Sgr A* : the dormant SMBH of the Milky Way
0.3 pc
Faint Galactic Centre source Sgr A* powered by a 4 106 Mo SMBH
(Ghez et al., 2008, Gillessen et al, 2009)
Sgr A*: a laboratory to study dormant SMBH and their possible state transitions
Sgr A*: quiescent emission
Quiescent emission luminosity ~ 1036 erg/s i.e. a few 10-8 Ledd
Resolved by Chandra (r~1.4'' ~ Rbondi
), aligned with massive star disk
LX ~ 2 1033 erg/s Baganoff et al. (2003) , Wang et al. (2013)
Massive stars wind accretion rate at Bondi radius 10-5 Mo/yr
Accretion rate at the SMBH < 10-7 Mo/yr!
Sgr A*
Chandra
Genzel et al (2010)
Wang et al. (2013)
Looking for Sgr A* flares in hard X-rays
• Sgr A* exhibits flaring activity in X-rays
• Flare frequency: 1.1± 0.2 day-1 Typical duration: ~ 1 ks• dN/dL L-1.9
• Neilsen et al. (2013)
• Most intense flare detected at LX ~ 5 1035 erg/s
• (e.g. Goldwurm et al. 2003, Porquet et al. , 2008, Nowak et al 2012)
XMM-NewtonApr. 2007
Trap et al. (2010)
X-ray spectrum w.r.t. to LoS position
Constrain geometry with the full spectrum X-ray – hard X-rayNuStar/Astro-H?