INTEGRAL obscured sources and SFXTs

INTEGRAL sources

499 point sources (20kev-100kev) 147XRBs, 163AGNs, 27CVs, 20 sources of o

ther type: 12 SNs, 2 globular clusters, 2 SGRs and 1GRB, 129 objects remain unidentified.

78 sources are HMXB, one third are new INTEGRAL gamma-ray sources: 24 BeXBs and 19 sgXBs

Two new classes of HMXB

Highly obscured HMXB

Super-giant fast X-ray transients

Highly obscured HMXB

A compact source embedded in dense material The fluorescence region is larger than the orbital radius Spherical geometry Unknown or weakly detected in X-ray surveys prior to INTEGRA

L Strong low energy absorption Predominantly located in the Galactic bulge and along the Norma

/Scutum spiral arms. Long spin periods (typically 100s to 1300s) Short orbital period <10 days Early type stellar super-giant companion

The extreme example: IGR J16318-4848 A strong absorption of Temperature kT=9kev A photon index~2 A significant NIR excess: warm dust around t

he system An unusual spectrum with a continuum very ri

ch in strong emission lines, together with the presence of forbidden lines, points towards an sgB[e] companion star

Super-giant Fast X-ray Transients

Super-giant companion

Exhibiting fast and transient outbursts

The archetpye: IGR J17544-2619 A very hard X-ray specturm A relatively low intrinsic absorption Bursts last for hours Long quiescent periods, more than 70 days A distance of ~3.6kpc, constituted of an O9Ib

supergiant, with a mild stellar wind and the compact object probably a neutron star, without any MIR excess

Results on the sample of IGRs

Fast hard X-ray outbursts

Be transient systems The outbursts exhibited by most Be transient system are of two diff

erent origins: either related the orbital period of the neutron star reaching the disk of the Be star; or they are large, seemingly random, and last a few days; Few Be HMXBs are known to show fast and occasional outburst.

Thermonuclear flashes Type I flashes are shorter and have a much higher peak luminosity,

and much softer than observed in SFXTs Supergiant Fast X-ray Transients The bright flares are fast, with a typical duration of few thousand se

conds The optical counterpart is a supergiant OB star

Two possible new tools to distinguish between Be-HMXBs and Sg-HMXBs Bodaghee-diagrams

The Corbet Diagram

Bodaghee-diagrams

Clumpy wind model

At very low orbital radius <1.5 Rsun: tidal accretion will take place through an accretion disk and the system will soon evolve to a common envelope

At low orbital radius~2 Rsun, classical sgHMXBs

At larger orbital radius~10 Rsun, SFXTs

wind model

Equatorial disk model

Conjecture

For SFXTs

O type companion: clumpy wind model (IGR J08408-4503)

B type companion: equatorial wind+clumpy wind?

when R is small: classical or highly obscured (while the observational NH is not so large) supergiant HMXB (Be X-ray binary system: AX J1749.1-2733?)

when R is large: clumpy wind (other burst may exist? Otherwise very low quiescent luminosity?)

Companion with Corbet diagram?

Conjecture

For SFXT with B type companion:

relate to Be/X ray binary? Population synthesis

under which condition, cocoon form?