new integral high mass x-ray binaries
DESCRIPTION
New INTEGRAL High Mass X-ray Binaries. Lara Sidoli (INAF-IASF, Milano). Simbol-X Bologna, 2007, 14-16 May. A biased introduction to the INTEGRAL discoveries in the HMXB field: highly obscured Galactic sources and... ....The mistery of the Supergiant Fast X-ray Transients - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/1.jpg)
New INTEGRAL New INTEGRAL High Mass X-ray BinariesHigh Mass X-ray Binaries
Lara Sidoli
(INAF-IASF, Milano)
Simbol-X Bologna, 2007, 14-16 May
![Page 2: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/2.jpg)
● A biased introduction to the INTEGRAL discoveries in the HMXB field: highly obscured Galactic sources and...
● ....The mistery of the Supergiant Fast X-ray Transients ● IGR J11215-5952: a unique SFXT ! ● A possible solution to the SFXTs puzzle
Overview
![Page 3: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/3.jpg)
from Bodaghee et al., 2007, astro-ph/0703043
Sources detected with ISGRI during the first 4 years of observations
![Page 4: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/4.jpg)
from Bodaghee et al., 2007, astro-ph/0703043
Sources detected with ISGRI during the first 4 years of observations
![Page 5: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/5.jpg)
● X-ray pulsations (slow pulsators, with periods ~ few hundred seconds)
● Hard and highly absorbed X-ray spectra sometimes with strong Fe emission lines (Ph.Index ~0.5-1; absorbing column densities NH > 1E23 cm-2)
– the first (discovered on 2003, Jan 29) of these heavily absorbed sources was IGR J16318-4848 (Walter et al 2003, Matt & Guainazzi 2003, Ibarra et al. 2006)
● Optical Identification with Blue Supergiants or Be stars (e.g. Masetti et al. 2005, 2006, Reig et al. 2005)
● They are mainly located in the direction of the spiral arms of our galaxy
About 30% of the new IGRs are HMXRBs
![Page 6: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/6.jpg)
The prototype of the highly obscured IGR sources: IGR J16318-4848
IGR J16318-4848 with XMM-Newton & INTEGRAL from Ibarra et al. 2006
![Page 7: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/7.jpg)
Simulation of a IGR J16318-4848-like spectrum with Simbol-X
Simulated spectrum (50 ks)Nh = 2E24 cm-2cutoffpl :
ph. index = 1.6Ec = 60 keV
3 gaussians at 6.4 keV, 7.099 keV and 7.45 keV
![Page 8: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/8.jpg)
An updated summary of IGR HMXBs with known Pspin or Porb, or both :
![Page 9: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/9.jpg)
Thanks to the Galactic Plane monitoring with INTEGRAL:
heavily obscured sources& transients with short outburst
have been discovered in the first 4 years of observations
![Page 10: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/10.jpg)
The story of the SFXTs begins with XTE J1739-302 ..... an unusual new x-ray transient
Smith et al. 1998:
RossiXTE obs. 1997 Aug 12 – discovery of a new transient, active only 1 day !
~ 3E-9 erg/cm2/s (2-25 keV): the brightest source in the direction of the Galactic Center region on that one day
Thermal bremsstrahlung spectrum kT ~ 21 keV
=> Be/XRB ???
![Page 11: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/11.jpg)
XTE J1739-302 ..... an unusual new x-ray transient
Smith et al. 1998:
RossiXTE obs. 1997 Aug 12 – discovery of a new transient, active only 1 day !
~ 3E-9 erg/cm2/s (2-25 keV): the brightest source in the direction of the Galactic Center region on that one day
Thermal bremsstrahlung spectrum kT ~ 21 keV
=> Be/XRB ???
Negueruela et al. 2005:
Optical counterpart is an O-type supergiant (O8 I ) -> dist ~ 2 kpc
=> a new class of transient sources!?!?!
![Page 12: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/12.jpg)
INTEGRAL discoveries and observationsSupergiant Fast X-ray Transients
unusually SHORT outbursts, significantly shorter than Be/NS binaries
● OUTBURST DURATION: ~ few hours, less than a day
● RECURRENT OUTBURSTS
● HARD AND HIGHLY ABSORBED X-RAY SPECTRUM
– reminiscent of an X-ray pulsar
● OPTICAL COUNTERPART: highly reddened O B supergiants
ISGRI SWs (~2 ks) image sequence (20-30 keV)flux at peak=254 mCrab
from Sguera et al. 2005
IGR J17391-3021/XTE J1739-302
![Page 13: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/13.jpg)
A growing number of observationsand a growing number of sources mainly thanks to INTEGRAL !
SFXTs and SFXT candidatesinitially selected because of the short outbursts, then possibly confirmed based
on the optical counterpart from Negueruela et al. 2005Sguera et al. 2005, 2006
Source Dist Sp.Type Peak flux (20-40) (kpc) ISGRI (erg/cm2/s)
IGR J17391-3021/XTE J1739-302 2-3 O8Iab 6.5 E-09IGR J17544-2619 3 O9Ib 3.0 E-09SAX J1818.6-1703 ? supergiant earlier than B3 1.3 E-09IGR J16479-4514 ? ? 2MASS source 2.4 E-10IGR J18410-0535/AX J1841.0-0536 10 B0I 9.0 E-10IGR J17407-2808 (=SBM10) ? 10 ? - 6.0 E-09IGR J16195-4945/AXJ161929-4945 ? 5 - 3.0 E-10AX J1749.1-2733 ? - - 3.0 E-10XTE J1743-363 ? - - 3.0 E-10IGR J16418-4532 ? - supergiant?? 6.0 E-10IGRJ18450-0435/AX J1845.0-0433 3.6 O 9.5 I 6.0E-10IGR J08408-4503 ? Ob5Ib 6.0E-09
IGR J11215-5952 Other possible candidates: IGR J10043-8702, IGR J10500-6410, IGR J15283-4443, IGR J18159-3353, IGR J18159-3353, IGR J 20188+3647, IGR J21117+3427,IGR J17354-3255
![Page 14: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/14.jpg)
A growing number of observationsand a growing number of sources mainly thanks to INTEGRAL !
SFXTs and SFXT candidatesinitially selected because of the short outbursts, then possibly confirmed based
on the optical counterpart from Negueruela et al. 2005Sguera et al. 2005, 2006 et al.
Source Dist Sp.Type Peak flux (20-40) (kpc) ISGRI (erg/cm2/s)
IGR J17391-3021/XTE J1739-302 2-3 O8Iab 6.5 E-09IGR J17544-2619 3 O9Ib 3.0 E-09SAX J1818.6-1703 ? supergiant earlier than B3 1.3 E-09IGR J16479-4514 ? ? 2MASS source 2.4 E-10IGR J18410-0535/AX J1841.0-0536 10 B0I 9.0 E-10IGR J17407-2808 (=SBM10) ? 10 ? - 6.0 E-09IGR J16195-4945/AXJ161929-4945 ? 5 - 3.0 E-10AX J1749.1-2733 ? - - 3.0 E-10XTE J1743-363 ? - - 3.0 E-10IGR J16418-4532 ? - supergiant?? 6.0 E-10IGRJ18450-0435/AX J1845.0-0433 3.6 O 9.5 I 6.0E-10IGR J08408-4503 ? Ob5Ib 6.0E-09
IGR J11215-5952 Other possible candidates: IGR J10043-8702, IGR J10500-6410, IGR J15283-4443, IGR J18159-3353, IGR J18159-3353, IGR J 20188+3647, IGR J21117+3427,IGR J17354-3255
Hard X-ray spectrawith high energy cut off at ~ 10-30 keV
L outburst / L quiesc. ~ 1E3-1E4 (from ASCA archival, or XMM or Chandra obs)but only from few sources!
![Page 15: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/15.jpg)
1997, Aug, XTE obs 2004, Aug, ISGRI obs
Flux (20-40 keV) at the peak of the outburst, together with the “quiescent” level
quiescent levelmeasured well far away from the outbursts
![Page 16: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/16.jpg)
IGR J17544-2619
in't Zand 2005 Chandra obs
![Page 17: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/17.jpg)
SFXTs properties: absorbing column density from X-ray spectra
NH – NH Gal (1E22 cm-2)
Total NH Galactic (1E22 cm-2) towards the sources
![Page 18: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/18.jpg)
SFXTs properties: X-ray luminosity during the short flares
![Page 19: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/19.jpg)
HMXRB classes: a summary
Persistent wind fed accreting X-ray pulsars with supergiant companions
“typical” HMXRBs, Vela X-1 like
Be/X-ray binariestypically Transient X-ray sourceswith Be companions
A new class -> Supergiant Fast X-ray Transientswith supergiant companionstransient emission, withshort duration outbursts, typically few hours, less than Be/XRBs outbursts
highly absorbed HMXRBsdiscovered with INTEGRAL
a growing number of membershave been discovered
with INTEGRAL
Bright persistent disk-fedmassive X-ray binaries (Cen X-3 like) in close orbits
![Page 20: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/20.jpg)
Supergiant Fast X-ray Transients:proposed interpretations (I)
● Outbursts produced by short ejections from the donor stars in XRBs? or clumpy winds? (in 't Zand 2005) this suggestion is based on optical observations of the clumping nature of the wind from early type stars:
● Owocki et al. 1997, Lamers & Cassinelli 1999: line-driven winds from supergiant stars are highly variable
![Page 21: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/21.jpg)
Supergiant Fast X-ray Transients:proposed interpretations (II)
● A new kind of supergiant HMXRBs in wide eccentric orbits? (wider than “normal” supergiants HMXRBs, like Vela X-1, in nearly circular orbits) also to
explain the large Lmax / Lmin (Negueruela et al. 2005)
Lx expected from an eccentric orbitaround a supergiant with a spherical homogeneous windin the case:30 Msun companion starbeta wind=1 terminal wind velocity=1800 km/sPorb=200 daysWind mass loss rate=2 E-6 Msun/yr
![Page 22: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/22.jpg)
IGR J11215-5952: a unique SFXT
Fast transient discovered on April 22, 2005 (Lubinski et al. 2005):detected with ISGRI in 2 consecutive pointings,
reaching 75 mCrab at peak (20-60 keV)
The companion is a B-type Supergiant: HD 306414 (Negueruela et al. 2005; Masetti et al. 2006)
![Page 23: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/23.jpg)
ISGRI lightcurves (17-40 keV)
1st outburst 3-4 July 2003 2nd outburst
26-27 May 2004
3rd outburst22 Apr 2005
~ 330 ~ 330 days !days !
~ 330 ~ 330 days !days !
330 days = likely orbital period 330 days = likely orbital period
The INTEGRAL lightcurve shows a periodicity of ~ 330 days in the recurrence of the outbursts (Sidoli, Paizis & Mereghetti, 2006, A&A, 450, L9; astro-ph/0603081).
![Page 24: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/24.jpg)
44thth outburst lightcurve outburst lightcurve (Smith et al. 2006, ATel 766 and ATel 773)
from http://scipp.ucsc.edu/~dsmith/atel/atel0306/
XTE/PCA
extreme variability
X-ray spectrum: hard and quite constant through the outburstPh. index ~ 1.7 +/- 0.2 (2.5-15 keV)NH ~ 11 +/- 3 E22 cm-2 (higher than Galactic)Flux at peak ~ 2 x 10-10 erg/cm2/s roughly consistent with previous outbursts
![Page 25: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/25.jpg)
IGR J11215-5952: INTEGRAL spectra
1st outburst 2nd outburst
JEM-X
IBIS/ISGRI IBIS/ISGRI
Energy (keV)5 100 Energy (keV) 10020
ph.index = 2.6 +1.8 -0.6ph.index = 0.5 +0.4 -0.6
F = 2.5 E -10 erg/cm2/s (20-100 keV)F = 6.2 E -10 erg/cm2/s (5-100 keV)
E cutoff = 15 +/-5 keV
2003 2004
L = 3E36 erg/s (5-100 keV)
![Page 26: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/26.jpg)
IGR J11215-5952 is a slow X-ray pulsator in a wide orbit
XTE/PCA pointings performed during the 4th outburst in 2006 showed variability which suggested a pulsation period of approximately 195 +/- 10 s (Smith et al. 2006).
The pulsations have been confirmed during the 5 th outburst in Feb 2007 (Swank et al. ATel # 999): Pspin=186.78 +/- 0.3 s
This would imply an X-ray pulsar with:
Porb ~ 329 days
P spin ~ 190 s
thus an accreting pulsar lying in the Be\XRB region of the Corbet diagram ??
BUT the companion is a supergiant! so it is not a Be/NS system !!!
Porb=329 days seem to suggest that outbursts in SFXTs might be related to wide highly eccentric orbits and not to clumpy winds
![Page 27: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/27.jpg)
Monitoring campaign strategy:
- 2 ks / day at the beginning (starting on 4th February)- then exposure up to 10 ks / day during outburst
- Monitoring end planned for 14th February (actually, IGR11215 was kindly observed up to 26th February)
- Thanks to Neil Gehrels and to the Swift Team
Results in Romano, Sidoli, Mangano, Mereghetti & Cusumano , 2007 (A&A in press; astro-ph/0704.0543)
The The periodicperiodic nature of the nature of the outburstsoutbursts from from IGR J11215-5952IGR J11215-5952 allowed us to plan & perform for the first time a allowed us to plan & perform for the first time a
sensitive and complete monitoring sensitive and complete monitoring of the of the entire outburst from a SFXTentire outburst from a SFXT,,
during the latest outburst, expected on during the latest outburst, expected on 2007, 92007, 9thth February Februarywith with Swift/XRTSwift/XRT
![Page 28: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/28.jpg)
Final lightcurve from Swift / XRT observations of IGR J11215-5952IGR J11215-5952
9th February 2007Romano et al. 2007
![Page 29: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/29.jpg)
1st fact: the accretion phase in SFXTs lasts longer than originally thought basedon less sensitive instruments
![Page 30: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/30.jpg)
Note that INTEGRAL would have seen ONLY the bright “orange” region of the lightcurve,lasting less than 1 day and composed of several ``short flares”
9th February 2007
![Page 31: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/31.jpg)
Close-up view of the brightest part of the outburst (9th Feb)
2nd fact: a large variability is present, and the outburst event is composed of short flares, lasting few hours or less
![Page 32: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/32.jpg)
NH=0.85E22 (+0.46 -0.32)=0.94 (+0.31 -0.28)
NH=1.11E22 (+0.79 -0.49)=0.91 (+0.42 -0.32)
NH=0.83E22 (+0.62 -0.42)=0.82 (+0.44 -0.40)
NH=0.88E22 (+0.38 -0.31)=1.03 (+0.32 -0.31)
NH=2.02E22 (+1.01 -0.79)=1.51 (+0.58 -0.53)
![Page 33: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/33.jpg)
The total Galactic absorption towards the source is 0.8 E22 cm-2
![Page 34: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/34.jpg)
Model of accretion from a spherical homogeneous wind in an eccentric orbit around the HD star
How to explain the outburst? The recurrence time of 329 days is the underlying clock of the phoenomenon, which can be interpreted in a natural way as the orbital period of the binary system
![Page 35: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/35.jpg)
A sorta fairytale
3rd fact: the lightcurve is too narrow and steep to be explained within a model of Bondi accretion from a spherical and homogeneous wind in an eccentric binary (even with extreme eccentricities!)
![Page 36: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/36.jpg)
Using the neutron star as a probe of the supergiant wind,the shape of the X-ray lightcurve
implies that the wind from the B supergiant is
NOT spherical nor homogeneousthen.....
![Page 37: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/37.jpg)
Using the neutron star as a probe of the supergiant wind,the shape of the X-ray lightcurve
implies that the wind from the B supergiant is
NOT spherical nor homogeneousthen.....
our idea is that there is a second wind component in a “thin equatorial disk”
with lower wind velocity and a higher wind mass loss ratecompared to the “polar wind component”
![Page 38: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/38.jpg)
from Ud-Doula, Townsend & Owocki, 2006, ApJ, 640, L191
Simulation of the radiatively driven outflow from a rotating hot star with a dipole magnetic field
Log (wind density)
![Page 39: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/39.jpg)
The proposed geometry to explain the short SFXT outbursts:
The thin equatorial disk of the B-supergiantis inclined with respect to the orbital plane
The star has also a polar wind with higher velocity and lower mass loss rate (~0.01 * Mass loss rate in the disk)thus, in order to explain the low X-ray emission level out of the outburst, we need anyway a not circular orbit
ns
OB supergiant
Sidoli et al., 2007, in preparation
![Page 40: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/40.jpg)
The thickness “h” of the densest region of this disk
h
orbital plane
“h” can be estimated from the duration of the outburst:the duration t of the brightest part of the outburstis t ~ 1 day, the ns velocity near periatron is roughly vns ~ 100-200 km/s
thus:h ~ 8E11 – 1.7 E12 cm
(0.3-0.6 Ropt, if Ropt ~ 40 Rsun)
![Page 41: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/41.jpg)
The thickness “h” of the densest region of the disk
h
orbital plane
“h” can be estimated from the duration of the outburst:the duration t of the brightest part of the outburstis t ~ 1 day, the ns velocity near periatron is roughly vns ~ 100-200 km/s
thus:h ~ 8E11 – 1.7 E12 cm
(0.3-0.6 Ropt, if Ropt ~ 40 Rsun)
Nh galactic < 0.8 E 22 cm-2; Nh from X-ray spectra ~1-2 * 1E22 cm-2Assuming about 1E22 cm-2 is local and mainly due to the supergiant disk, a
rough estimate of the density of the supergiant disk is:
Nh*mH / h =cm
![Page 42: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/42.jpg)
“disk” wind
“polar” wind
variable wind density along the orbit
![Page 43: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/43.jpg)
Example of the model of wind accretion with the following parameters: B-supergiant mass = 39 Msun“polar wind” mass loss rate = 3.7 E-6 Msun/yrterminal velocity (“polar wind”) = 1800 km/sbeta law exponent = 1.0Porb = 329 dayse = 0.4
Note that along the orbit, the centrifugal barrieris always open (with B ~ 1E12 G, and Pspin=187 s)
“disk wind”with Mdot_wind = 100 * Mdot_polarterminal velocity = 900 km/s
“disk wind”with Mdot_wind = 30 * Mdot_polarterminal velocity = 1600 km/s
![Page 44: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/44.jpg)
![Page 45: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/45.jpg)
few further questions ....
![Page 46: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/46.jpg)
how to explain other SFXTs where a clear periodicity in the outburstshas not been found yet?
probably a different eccentricity & a different geometry of the thin disk withrespect to the orbital plane
![Page 47: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/47.jpg)
how to explain other SFXTs where a clear periodicity in the outburstshas not been found yet?
probably a different eccentricity & a different geometry of the thin disk withrespect to the orbital plane
how to explain the persistent Vela X-1-like HMXBs withsupergiant donors? probably the “equatorial disk” of the supergiant in the persistent systems lies on the orbital plane and the ns always moves inside the disk
![Page 48: New INTEGRAL High Mass X-ray Binaries](https://reader034.vdocument.in/reader034/viewer/2022051516/56812fec550346895d956220/html5/thumbnails/48.jpg)
Conclusions
●INTEGRAL observations opened a new view on High Mass X-ray Binaries
●The new class of SFXTs has been discovered ●The SFXT IGRJ11215-5952 is a key system to understand this new class of X-ray sources
●We proposed a new hypothesis to explain the properties of the SFXTs, where the supergiant has an equatorial component of the wind, besides the “standard” “polar” high velocity wind. ●The enhanced accretion rate when the neutron star cross this disk produces the short duration X-ray outburst