SS 433

1
SS 433 a Supercritically Accreting Microquasar
with Black Hole.
A.M. Cherepashchuk

• Sternberg Astronomical Institute, Moscow
  University

2
Quasar and Microquasar
3
SS 433 30 years after discovery.Clark and
Murdin (1978) Margon et al. (1979).
4
(No Transcript)
5
Pprec 162d.5
6
Milgrom (1979), Fabian and Rees (1979),
Cherepashchuk (1981)
7
SS 433 close binary system. Crampton, Cowley,
Hutching (1980). Porb 13d.1 (LMXB). SS 433
massive eclipsing binary system. Cherepashchuk
(1981). Discovery of optically bright precessing
accretion disk.
8
Optical light curves of SS 433.Goranskij,
Esipov, Cherepashchuk (1998).
9
(No Transcript)
10
Stability of orbital, precessional and mutational
periods.Davydov, Esipov, Cherepashchuk (2008).
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
X-ray data.
15
(No Transcript)
16
(No Transcript)
17
INTRODUCTION SS 433

• A massive eclipsing binary system
• Consists of a massive donor star and a compact
• object, surrounded by precessing accretion
  disk
• Narrow-collimated relativistic jets (v 0.26 c)
• Precessional period P162.5 d
• Orbital period p13.082 d
• A problem with spectral classification of the
  optical star (the disk is significantly more
  luminous)

One of the main questions - the nature of the
relativistic object (BH or NS ?)
18
New high-resolution spectroscopy of SS433
(Hillwig Gies 2008)

• Reliable detection of absorption lines of the
  optical A3-7I star

• Reliable radial velocity curve of the optical
  component

19

• Kv58.2/-3.1 km/s (from absorption lines)
• Kx168/-18 km/s (from HeII emission line)
• Mass ratio qMx/Mv0.35
• Optical star mass function fv(M)0.268 M
• Masses os the components
• Mv12.3/-3.3 M
• Mx4.3 /- 0.8 M

20
Main hard X-ray features revealed by INTEGRAL
AO1-AO5

• First observations gave a surprise SS433 is a
  hard X-ray source with emission clearly detected
  up to 100 keV ? SS433 is galactic microquasar
  with hard X-ray spectrum (AMCh et al 2003)
• Strong precessional variability in hard X-rays
  with an amplitude Lxmax/Lxmin 7
• Peculiar and variable shape of ascending eclipse
  branch
• Wide, deep hard X-ray eclipse
• (wider than in soft X-rays!)
• Hard X-ray spectrum independent
• of the precessional phase

HOT EXTENDED CORONA
21
All INTEGRAL observations
22
Precessional variability

• Strong precessional 162-d variability was found
  with a maximum to minimum flux ratio of 7
• Flux at primary minima is non-zero 3 mCrab,
  suggesting extended hard X-ray emitting region

23
Analysis of hard X-ray spectra

• To increase statistical significance, we splitted
  the precessional light curve on two parts high
  (maximum X-rya flux) and low (lt10 mCrab). Both
  are consistent with power law.

24
T3
Average precessional light curve with AO5 data
added
25
II(1.025lt?prec lt1.125 0.875lt?prec lt0.975)
III (0.5lt?prec lt0.8 1.2lt?prec lt1.5)
I (0.975lt?prec lt1.025)
20-200 keV spectra (IBIS/ISGRI). Power-law
photon index G2.8 for all spectra!
26
Orbital eclipses
primary max.
crossover I

• Several orbital eclispses were observed at
  different precessional phases

Second. max.
crossover II
27
Individual eclipses at T3
IBIS/ISGRI 18-60 keV
28
Mass ratio from hard X-ray eclipses

• In the standard X-ray range 1-10 keV
• q0.1-0.15 (Kawai et al. 1989, Kotani et al.
  1996)
• due to a very wide X-ray eclipse
• In the hard X-ray range (18-60 keV) the eclipse
  form and width are very variable.

29
(No Transcript)
30

• Egress from the primary eclipse is extremely
  variable (presumably due to gaseous streams from
  ther star and stellar wind from the disk)
• Ingress to the primary eclipse is much more
  stable
• Interpretation of the primary eclipse by
  geometrical model should be based on the upper
  envelope of the eclipse ingress

31
Fitting of the primary eclipse (ingress) together
with precessional light curve yields q0.3, in
agreeement with optical spectroscopic
determination by Hillwig Gies
32
Model for variability

• The optical star fills it Roche lobe
• The accretion disk is approximated by an oblate
  spheroid
• X-ray flux is emitted by the hot corona around
  the base
• of the narrow relativistic jets
• The corona is approximated by the spheroid and
• precesses along with disk
• The corona is placed inside the funnel at
  the inner parts
• of the disk
• During the orbital and precessional moving the
  corona is
• eclipsed by the star and disk bodies

33
Results for q0.1 Good fit to eclipse, bad fit
to precessional variability

• In principle, long thick X-ray jet yields a good
  fit to the orbital eclipse, but totally fails to
  describe the precessional light curve!
• ? Joint analysis is needed.

34
Joint analysis of orbital eclipses (ingress only)
and precessional variability q0.3
35
Orbital precessional chi-2 for different q
Mvlt15 M
Sum of the reduced orbital and precessional chi-2
36
Monte-Carlo analysis of broadband (2-100 keV)
X-ray spectrum and parameters of hard X-ray corona
JEMXIBIS May 2003
Corona kTc20 keV Rc6x1011cm tc 0.2-03 ne
4x1012cm-3
Jet dM/dt 10-7 M /yr Lkin1039 erg/s
(Krivosheev et al. 2008)
37
Conclusions

• Our correct analysis of hard X-ray eclipses and
  precessional variability in SS433 allowed
  independent determination of the binary mass
  ratio qMx/Mv0.3, in full agreement with optical
  spectroscopic result by Hillwig Gies (2008).
  The compact object mass is Mx5.3 M , Mv17.7 M
  confirming its nature as a black hole

38

• INTEGRAL orbital and precessional light curves
  of SS433 can be interpreted by an extended
  corona above the superaccreting disk around the
  black hole. Thin relativistic jets shining in
  soft X-rays are generated from the center of the
  corona that is observed in hard X-rays