Microquasars

Gustavo E. RomeroInstituto Argentino de Radioastronomía (CONICET)

University of La Plata

romero@iar-conicet.gov.ar

romero@fcaglp.unlp.edu.ar

http://www.iar-conicet.gov.ar/garra/

1

São Paulo, FAPESP, August 9, 2011

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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)

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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 …?

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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).

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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)

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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

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Z>1012 cm

A microquasar with a clumped wind

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Araudo, Bosch-Ramon & Romero A&A, 503, 673 (2009),

Owocki et al. 2009, ApJ, 696, 690 (2009)

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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)