Super Giant XRay Binaries SGXB

1
Super Giant X-Ray Binaries (SGXB) Super-giant
Fast X-Ray Transient (SFXT)different type of
HMXBs

• HMXB are X-Ray sources composed by young massive
  stars accreting on a compact companion (BH, NS or
  WD)
• A subclass contains an early type supergiant
  accreting via wind (SGXB) they are bright and
  persistent (12 known before Integral).
• Integral detect new SGXBs, but highly absorbed
  and mixture of persistent and variable, with
  slow, weakly magnetised NS as companion
• A new subclass of SGXB is emerging characterised
  by FAST TRANSIENT behaviour, named Supergiant
  Fast X-Ray Transient (SFXT)
• Sharp rise, complex time profile (multi peack)
  with absorbed spectra (lines?) fit compatible
  with pwlcut-off or thermal breemsstrahlung,
  Lx10exp36 at peack.
• What are they? possibly wind clamps on accretion
  disk in a wide orbit NS system to explain low
  emission during quiescence 10 exp 32

2
Super Giant X-Ray Binaries (SGXB) Super-giannt
Fast X-Ray Transient (SFXT)different type of
HMXBs

• The luminosity is very low when off and they are
  difficult to see also with XMM and Chandra
• The spectrum is complex in X-ray and difficult
  to observe if not triggered by ASM or Integral
  becouse of thye short on-time
• One shows recurrent outburst with perdiod of 330
  days gtgtgt orbit period?
• Why ESTREMO to catch and study the spectral and
  time evolution when on periods of ON are from
  1/2 hour to 31 hour
• Important is total absorption vs time gtgt
  accretion process physics
• Line or absorption feature gtgt material of the
  wind, velocity and line width
• Spectral shape and evolution with time is a
  signature of the accretion process power law gtgt
  Jet, magnetic reconnection in disk?- plasma
  ejection? thermal/non thermal Comptonisation gtgt
  electron population
• High energy tail gtgt disentangle between steep
  power law, thermal, comptonosation

3
INTEGRAL/IBIS TRANSIENT IBIS 2nd catalogue lists
43 transient sources on 209 detections?
25 Contrary to BeppoSAX result 20
HMXB 21 LMXB 2? The sample is based on
2 years monitoring, 10 Msec and 50 of sky
coverage Sources have average flux in between
1-200 mCrab in the 20-40 keV band BeppoSAX/WFC
monitored 36 active LMXB transients with peak
in between 10-12000mCrab, duration 0.1-1700 d on
6 years monitoring of the sky within 20 degree
from G.C. for a total of 6 Msec Differences with
BeppoSAX are due either to energy band source
nature (highly absorbed) and to sky coverage
4
Supergiant Fast X-ray transient
?Data base
Sky distribution?
5
Discovery of transient source with Be companion
was expected since they represent the larger
class of HMXB in the Galaxy. INTEGRAL with the
GPS regular scans and instrument characteristic
has discovered this 2 other kinds of HMXB
with supergiant companion missed by previous
Mission because of Energy range/sensitivity
Sky coverage Association with High Mass X-Ray
Binary is due to either identification at
optical/infrared wawelenghts with blu supergiant
or Be star or based on their X-ray properties
typical of HMXB e.g. periodic pulsation or hard
x-? spectra Supergiant HMXB (SGXBs) are believed
to be rare objects because of very short
lifetime of stars in supergiant phase only 12
have been discovered so far associated to
persistent and bright X-ray sources INTEGRAL is
now detecting a new subclass of SGXBs labelled
as Supergiant Fast X-ray transient (SFXT)
characterized by outbursts lasting less that a
day, typically few hours Outbursts from 10
sources detected so far, 4 recently optically
identified as SGXRB 6 still unclassified
but sharing similarities
6
Sources and characteristics IGR J 11215-5952,
identified as supergiant, archival data show
recurrent outburst spaced by intervals of 330
days !!!one of the few covered also by X-ray data
5-100 keV spectrum well described by a cut-off
power law (a0.5), cut-off energy 15-20 KeV,
luminosity 3x 10 36 erg/s. Observed with RXTE
as outburst exepected 15-18 march giving p329
day!! PCA data spectrum in the 2.5-15 keV
consistent with either a bhc in hard state or
accreting puòlsar , NH (113) x 10 22 cm-2 IGR
J 16195-4945, 3 outbursts with duration0.5-1.5 h
and peak 35 mCrab IGR J 16418-4532 2 outburst
duration 1h and peak at 80 mCrab IGR J
16479-4514 8 outbursts, durtaion 0.5-3.5 h ,
peak 60-850 mCrab IGR J 17391-3021XTE 1739-302,
6 outburst with duration 0.5-14h peak flux
60-450 mCrab IGR J 17407-2808 1 outburst
alsting 3 minutes and peak 800 mCrab
7
XTE J 1743-363 1 outburst with duration 2.5 h
and peak 40 mCrab IGR J 1749.1-2733 1 outburst
with duration 31 h and peak 40 mCrab IGR J
17544-2619 5 outburst with duration0.5-10h
peak flux 70-400 mCrab IGR J
18410-0535AX1814.1-0536, 3 outburst with
duration 1.1-7 h 120 mCrab X-ray simultaenous
observation are missed most of the time
8
Most X-ray transients, wheter in HM or LM X-ray
binaries display outbursts lasting from a few
weeks to months. Such durations are compatible
with viscous timescaless in a typical accretion
disc. Fast outbursts must be due to a completly
different mechanism. Now we showed that at least
a fraction of the recurrent fast transient are
associated with luminous OB stars, suggesting the
mass transfer mechanism feeding the accretion
compact object is a radiative wind. We remind
that not every sources showing short X-ray
outburst may be assigned to SFXT Flare stars,
RS CVn binaries and superbursts in LMXB have
similar duration , thogh rather different
luminosity and lightcurve.
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12

• Main BeppoSAX/WFC Highlights
• Superburst, new phenomenon with long duration
  (several h)
• rare (recurrence time 1 y)
• energetic( 10 42 ergs)
• possibly due to unstable burning of a thick layer
  of carbon
• X-ray flashes, new class of transient event
• lasting several seconds to tens of second
• spectral behaviour differes markedly from type
  I burst and
• emission profile resembling x-ray afterglow of
  GRB
• Main IBIS results (so far)
• Supergiant Fast X-ray transient
• recurrent transients characterized by short
  outburst lasting only few hours
• Highly absorbed persistent (mainly) and transient
  sources often showing periodic pulsations