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Microquasars
Gustavo E. RomeroInstituto Argentino de Radioastronomía (CONICET)
University of La Plata
http://www.iar-conicet.gov.ar/garra/
1
São Paulo, FAPESP, August 9, 2011
2
Stellar black holes can produce jets
NGC 7793: Pakull et al. (2010)
3
Stellar black holes can also produce jets
Cygnus X-1: Stirling et al. (2001), Gallo et al. (2005)
4
Stellar black holes can also produce jets
SS 433
Radio (Dubner et al); X-rays (Brinkmann et al)
- ATOMIC NUCLEI MOVING AT 0.26c
- MECHANICAL LUMINOSITY > 1039
erg/sec
- NON RADIATIVE JETS = “DARK” JETS
- >50% OF THE ENERGY IS NOT
RADIATED
5
Stellar black holes can also produce jets
Cygnus X-3: Mioduzewski et al. (2001)
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Stellar black holes can also produce jets
Cygnus X-3: Martí, Paredes, et al. (2001)
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…and gamma-rays
Cygnus X-3: Fermi collaboration (2009)
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…and gamma-rays
Cygnus X-3: AGILE collaboration (2009)
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The Cherenkov Telescope Array (CTA)
El Leoncito, San Juan, Argentina
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Microquasars: accreting stellar black holes with jets
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Be disk
NS or BH
overflow from Be disk
Accretion in Be/X-ray binaries
accretion disk
high energy emission
accretion
Romero et al. 2007, A&A
A “basic” jet model (in a nutshell)
Physical conditions near the jet base are similar to those of the corona (e.g. Bosch-Ramon et al. 2006; Romero & Vila 2008, 2009; Vila & Romero 2010)
The jet launching region is quite close to the central compact object (few Rg)
Thermal plasma injected at the base, equipartitionb/w particles and magnetic field to start with.
Jet plasma accelerates longitudinally due to pressure gradients, expands laterally with sound speed (Bosch-Ramon et al. 2006)
The plasma cools as it moves outward along the jet. Solve the continuity equation for cooling of the electron and proton energy distributions
A “basic” jet model (in a nutshell)
Physical conditions near the jet base are similar to those of the corona (e.g. Bosch-Ramon et al. 2006; Romero & Vila 2008, 2009; Vila & Romero 2010)
The jet launching region is quite close to the central compact object (few Rg)
Thermal plasma injected at the base, equipartitionb/w particles and magnetic field to start with.
Jet plasma accelerates longitudinally due to pressure gradients, expands laterally with sound speed (Falcke 1996, Bosch-Ramon et al. 2006)
The plasma cools as it moves outward along the jet. Solve the continuity equation for cooling of the electron and proton energy distributions
Lepto/hadronic models for LMXRB (Vila & Romero, MNRAS 403, 1457, 2010)
GX 339-4
LLAMA
An application – Vila & Romero, extended-zone model, 2011
Fit to the spectrum of the LMMQ XTE J1118+480
2000 outburst
-5 0 5 10 1528
29
30
31
32
33
34
35
36
37
Log10
(E /eV)
Lo
g 10(L
/er
g s
-1)
disc
synchrotron
SSC
pp
p
Fermi
VERITAS
CTA
LLAMA
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“Dark” HE MQ (Romero & Vila 2008)
However, a strong neutrino source…
The black hole in the Galactic CenterSgr A* Spectrum
Mościbrodzka, Gammie, Dolence et al. (2009)
The physical model is a
geometrically thick, optically thin,
turbulent plasma accreting
onto a rotating black hole in a
statistically steady state. The
angular momentum of the
hole is assumed to be aligned with
the angular momentum of the
accreting plasma.
The ions and electrons are
assumed to have a thermal
distribution function, but with a
temperature ratio Ti/Te that may
be different from one
Future mm-VLBI
Existing facilities:
JCMT, CARMA, SMT, SPT
SPT-JCMT: 15.000km (~5µas)
Under construction:
LMT, ALMA
New ones?
LLAMA (Argentina)
Peru …?
21
Images of the accretion flow at
230 GHz for models with SEDs
that are consistent
with observations of SgrA*. The
images have been averaged over
time and over four separate
realizations of each model. The
images show inner 40GM/c2 .
The white circle marks
FWHM=37 µas of a symmetric
Gaussian brightness profile
centered at the image centroid.
Simulated 350 GHz VLBI
Scatter-Broadened best-fit Model Reconstructed Image
PSF
a=0.94, i=85°, Tp/Te=3
Mościbrodzka, Gammie, Dolence et al. (2009)
Simulated 350 GHz VLBI
“best-fit” model seen from above
…a=0.94, i=5°, Tp/Te=3
Reconstructed Image
Final comments MQs produce gamma-rays, likely in the jets. This emission is
related to the sub-mm synchrotron radiation.
The consistency of the models outlined can be tested with present and future sub-mm, gamma-ray and neutrino observations (LLAMA, IceCube, Fermi, CTA…).
MQs can be sources of comic rays up to energies of the order of the knee (Auger infield array).
25
Thank you
Particle losses
Romero & Vila, A&A, 494, L33 (2009)
Spectral energy distributions
Magnetic field effects on neutrinoproduction
Reynoso & Romero A&A, 493, 1 (2009)
29
Internal absorption (Vila & Romero, 2010)
Absoption effects: annihilation (Vila & Romero 2011)
Log10
(z /cm)
Lo
g 10(E
/eV
)
9.5 10 10.5 11 11.5 12 12.5 13
-8
-6
-4
-2
0
2
4
6
8
10
Lo
g10 (N
/ erg-1 cm
-3)
-15
-10
-5
0
5
10
15
20
25
30
Log10
(z /cm)
Lo
g 10(E
/eV
)
9.5 10 10.5 11 11.5 12 12.5 13-6
-4
-2
0
2
4
6
8
10
12
14
exp
(-)
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
Log10
(z /cm)
Lo
g 10(E
/eV
)
9.5 10 10.5 11 11.5 12 12.5 13
-8
-6
-4
-2
0
2
4
6
8
10
Lo
g10 (N
/ erg-1 cm
-3)
-15
-10
-5
0
5
10
15
20
25
30
35
Log10
(z /cm)
Lo
g 10(E
/eV
)
9.5 10 10.5 11 11.5 12 12.5 13-6
-4
-2
0
2
4
6
8
10
12
14
exp
(- )
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
High-mass donor star
Bosch-Ramon, Romero, Paredes, 2006, A&A 447, 263
High-mass donor star: Cygnus X-1
Romero, del Valle, & Orellana, 2010, A&A 518, A12; see also
Bosch-Ramon, Khangulyan & Aharonian, 2008, A&A, 489, L21
External absorption
33
Z>1012 cm
A microquasar with a clumped wind
34
Araudo, Bosch-Ramon & Romero A&A, 503, 673 (2009),
Owocki et al. 2009, ApJ, 696, 690 (2009)
35
MA
GIC
HE
SS
Cygnus X-1
LSI+61303
LS 5039
Flaring TeV emission?
Season I + Season II
If the wind has a clumpy structure,
then jet-clump interactions can
produce rapid flares of gamma-rays
Romero et al. 2007, astro-ph/0708.1525
Effects of the stellar wind
36Owocki et al. 2009, ApJ, 696, 690
A microquasar with a clumped wind
37Araudo, Bosch-Ramon & Romero A&A, 503, 673 (2009)
A microquasar with a clumped wind
38Araudo, Bosch-Ramon & Romero A&A, 503, 673 (2009)
Local particle re-acceleration
A microquasar with a clumped wind
39Araudo, Bosch-Ramon & Romero A&A, 503, 673 (2009)
Average 2D GRMHD Results
Mościbrodzka, Gammie, Dolence et al. (2009)