sylvain chaty (université paris 7 / service d’astrophysique, france) eso - 28 novembre 2006

Sylvain CHATYSylvain CHATY(Université Paris 7 / Service d’Astrophysique, France)

ESOESO - 28 novembre 2006 - 28 novembre 2006

The most obscured high energy sources

Or how infrared observations allow to reveal mysteries of the most obscured X-ray sources of our Galaxy…

S. Chaty - ESO - 28/11/2006S. Chaty - ESO - 28/11/2006

PlanPlan

The INTEGRAL observatoryThe INTEGRAL observatory Discovery of new sources in our GalaxyDiscovery of new sources in our Galaxy How to understand their nature?How to understand their nature? Multi-wavelength optical/NIR/MIR observations:Multi-wavelength optical/NIR/MIR observations:

Obscured X-ray sources: the archetype IGR J16318-4848Obscured X-ray sources: the archetype IGR J16318-4848 Supergiant Fast X-ray Transients: the archetype IGR J17544-Supergiant Fast X-ray Transients: the archetype IGR J17544-

26192619 Results and discussion on new INTEGRAL sourcesResults and discussion on new INTEGRAL sources Conclusions and perspectivesConclusions and perspectives


INTEGRAL satellite: 2 keV – few MeVLaunched on 17 October 2002 by PROTON rocket on excentric orbitby PROTON rocket on excentric orbit

The INTEGRAL observatoryThe INTEGRAL observatory


INTEGRAL observatoryINTEGRAL observatory

4 instruments4 instruments 2 coded mask 2 coded mask

telescopes: imager telescopes: imager IBIS and spectro-IBIS and spectro-imager SPI: 10keV-imager SPI: 10keV-4MeV4MeV Resolution 12’, fov 19°Resolution 12’, fov 19°

1 coded mask X 1 coded mask X telescope JEM-X: 2-telescope JEM-X: 2-100keV100keV

1 optical telescope: 1 optical telescope: OMCOMC


Ground and space…Ground and space… Multi-wavelength Multi-wavelength

observations (radio, observations (radio, infrared and X/infrared and X/raysrays

Multi-wavelength observationsMulti-wavelength observations


PlanPlan





The Milky Way, our Galaxy The Milky Way, our Galaxy (seen from inside)(seen from inside)


The Milky Way, our Galaxy The Milky Way, our Galaxy (seen from outside)(seen from outside)

Side view Face-on


The Milky Way, our Galaxy The Milky Way, our Galaxy


Discovery of a new type of sources Discovery of a new type of sources in the skyin the sky

Observations of the Milky Way:

IR (COBE)

-rays (INTEGRAL/ISGRI)

Zoom on the center

Mystery of the X-ray backgroundMystery of the X-ray background IBIS resolved it in many point sourcesIBIS resolved it in many point sources

(>200: Bird et al. 2006)(>200: Bird et al. 2006) Still present at higher energiesStill present at higher energies

Lebrun et al. 2004 Tomsick et al. 2004

New sources towards the Norma arm of the Galaxy, previously unknown…

And this Norma arm is full of star formation regions!


PlanPlan





Unidentified INTEGRAL sources

Among IGR sources: ~1/10: already known faint ASCA sources

(Sugizaki) A few already known RXTE sources ~1/10: certainly AGNs (Bassani et al.) 25% of INTEGRAL sources have a likely ROSAT

counterpart 50% of the sources detected by par INTEGRAL! (Stephen et al)


X-ray binary: binary system containing a compact object (neutron star or stellar-mass black hole) accreting matter from the companion star. Accreted matter carries angular momentum and on its way to the compact object usually forms an accretion disk, responsible for the X-ray emission.280 X-ray binaries are known (Liu et al. 2000, 2001).

High Mass X-ray Binaries (HMXBs). Optical companion with spectral type O or B. Mass transfer via decretion disk (Be stars) or via strong wind or Roche-lobe overflow (OB SG). 131 known HMXBs.

Low Mass X-ray Binaries (LMXBs). Optical companion with spectral type later than B. Mass transfer via Roche-lobe overflow.149 known LMXBs.

X-RAY BINARIESX-RAY BINARIES


131

149

New : -0.9HMXB : -0.6HMXB+new: -0.6HMXB (XTE): -0.6±0.1

Galactic distribution

Walter et al. 2006

A fair fraction of new INTEGRAL sources should be High Mass X-ray Binaries (HMXBs)

Over-density of INTEGRAL sources in the region tangent to the Norma arm (5–8kpc)


Discovery of a new type of sourcesDiscovery of a new type of sources

How to identify all these new INTEGRAL sources?

To observe in X/To observe in X/ rays is not enough: rays is not enough: ISGRI localisation not enough to identify the counterpartISGRI localisation not enough to identify the counterpart

To observe in optical is difficult:To observe in optical is difficult: Sources mainly in the plane (centre) of the Galaxy: too much Sources mainly in the plane (centre) of the Galaxy: too much

absorption (interstellar dust and gas)absorption (interstellar dust and gas)


Programme of study of new high energy binary sourcesProgramme of study of new high energy binary sources Identification of counterparts, nature of system, compact object, companion star, Identification of counterparts, nature of system, compact object, companion star,

distance, accretion type…distance, accretion type… characterize presence, temperature, composition of dustcharacterize presence, temperature, composition of dust

Photometry/Spectroscopy on 15 INTEGRAL sourcesPhotometry/Spectroscopy on 15 INTEGRAL sources

3 domains:3 domains: Optical EMMI (400-800 nm): La Silla (3.5m-NTT)Optical EMMI (400-800 nm): La Silla (3.5m-NTT) Near-infrared SOFI (1-2.5 Near-infrared SOFI (1-2.5 m): La Silla (3.5m-NTT)m): La Silla (3.5m-NTT) Mid-Infrared VISIR (5-20Mid-Infrared VISIR (5-20m): Paranal (8m-VLT/UT3)m): Paranal (8m-VLT/UT3)

2 modes of observations 2 modes of observations (European Southern Observatory)(European Southern Observatory):: « Target of Opportunity mode»: ~16h/semester to observe new binary systems« Target of Opportunity mode»: ~16h/semester to observe new binary systems « Visitor mode »: 3 nights 07/2004, 1 night 06/2005, 2 nights 06/2006« Visitor mode »: 3 nights 07/2004, 1 night 06/2005, 2 nights 06/2006


PlanPlan





The Obscured INTEGRAL source IGR J16318-4848:The Obscured INTEGRAL source IGR J16318-4848:

From INTEGRAL high energy …From INTEGRAL high energy …

… …to Optical/MIR observations.to Optical/MIR observations.

(Chaty & Rahoui, 2006; Chaty & Filliatre, Ap&SS, 2005; Filliatre & Chaty, ApJ, 2004)


Discovery of IGR J16318-4848 by INTEGRALDiscovery of IGR J16318-4848 by INTEGRAL

11stst source discovered by source discovered by INTEGRAL (IBIS/ISGRI) on INTEGRAL (IBIS/ISGRI) on 29 January 200329 January 2003

Position: Position: (l,b)~(336°, 0.5°) (l,b)~(336°, 0.5°) RA=16RA=16hh31.831.8mm, DEC=-, DEC=-

48°48’48°48’ Localisation accuracy: 2’ Localisation accuracy: 2’

with INTEGRAL (Moon: with INTEGRAL (Moon: 30’!)30’!)

Non-absorbed Flux: 15-40 keV Flux: 50-100 15-40 keV Flux: 50-100

mCrab mCrab (Courvoisier et al. 2003)(Courvoisier et al. 2003)

L5kpc = 1-20 1036 erg/s

INTEGRAL/ISGRI (15-40 keV)INTEGRAL/ISGRI (15-40 keV)Norma arm region image (Walter Norma arm region image (Walter et al. 2003)et al. 2003)


ToO observations with XMM-ToO observations with XMM-NewtonNewton XMM observations (28ks ToO on XMM observations (28ks ToO on

10/02/2003): 10/02/2003): 4”4” localisationlocalisation

Comptonised spectrum: NNhh=1.84+/-0.06x10=1.84+/-0.06x1024 24 cmcm-2-2

kT = 9±0.5 keV Photon index ~ 2Photon index ~ 2

Strong photoelectric absorption:Strong photoelectric absorption: Fe absorption edge at 7.1keVFe absorption edge at 7.1keV Fe KFe K, K, K, Ni K, Ni K Fluorescence lines Fluorescence lines

Variability: RXTE: no oscillation detectedRXTE: no oscillation detected variable flux (factor 20) 10 hours between each flare Sometimes 2-3 days of inactivity Nh-flux correlation? Variations of lines and continuum on Variations of lines and continuum on

temporal scale of 1000s: size of emitting temporal scale of 1000s: size of emitting region < 3 x 10region < 3 x 1013 13 cm cm (Walter et al. 2003)(Walter et al. 2003)

X-ray properties ~ CI Cam, Vela X1, GX X-ray properties ~ CI Cam, Vela X1, GX 301-2301-2

EPIC PN, EPIC MOS2 and ISGRI spectra(Matt & Guainazzi 2003; Walter et al. 2003)(Matt & Guainazzi 2003; Walter et al. 2003)


Discovery of the optical/NIR counterpartDiscovery of the optical/NIR counterpart

photometric observations on 23-photometric observations on 23-25/02/200325/02/2003

Discovery of the R, I, Z counterpartDiscovery of the R, I, Z counterpart Comparison Comparison with USNOUSNO B1.0 plate R band: only one of the two : only one of the two

sources varied in the XMM EPIC 4” uncertainty circle.sources varied in the XMM EPIC 4” uncertainty circle. Confirmation of NIR counterpart proposed by Walter et al. Confirmation of NIR counterpart proposed by Walter et al.

2003 by an improved astrometry2003 by an improved astrometry

B>25.4+/-1; V>21.1+/-0.1R=17.72+/-0.12; I=16.05+/-0.54J=10.33+/-0.14; H=8.33+/-0.10 Ks=7.20+/-0.05

IGR J16318-4848


B, V, R, I, J, H, K B, V, R, I, J, H, K magnitudes of magnitudes of candidate and 4 candidate and 4 neighboursneighbours

IGR source exhibits unusual 17.4mag absorption

•stronger than absorption along line of sight objects (11.4mag), •but 100 x lower than X-rays!!!

Material absorbing in X-rays must Material absorbing in X-rays must be concentrated near the compact be concentrated near the compact objectobject

Absorption in Absorption in optical/NIRoptical/NIR


NIR spectroscopy: 0.95-2.5 NIR spectroscopy: 0.95-2.5 mm

Unusual spectrum very rich in many strong emission linesUnusual spectrum very rich in many strong emission lines Strong H (Br, Pa, Pf) and HeI (P-Cyg): emanate from dense, ionised windStrong H (Br, Pa, Pf) and HeI (P-Cyg): emanate from dense, ionised wind• He II: highly excited region in vicinity of compact objectHe II: highly excited region in vicinity of compact object• [FeII]: indication of shock heated material[FeII]: indication of shock heated material• FeII => densities > 10FeII => densities > 1055-10-1066 cm cm-3-3

• NaI: cool/dense regions shielded from stellar and compact object radiationNaI: cool/dense regions shielded from stellar and compact object radiation• Lines originate from different media (various densities, temperature)Lines originate from different media (various densities, temperature)

• Highly complex, stratified circumstellar environment + enveloppe, wind…Highly complex, stratified circumstellar environment + enveloppe, wind…• =>=> luminous post main sequence star: most likely an uncl/sgB[e] star: luminous post main sequence star: most likely an uncl/sgB[e] star:

High-mass X-ray binary system,High-mass X-ray binary system, similar to CI Camsimilar to CI Cam


Spectral Energy DistributionSpectral Energy Distribution Fit parameters: Fit parameters:

L ~ 10L ~ 106 6 dd226kpc6kpcLLSun Sun

T = 20 250 KT = 20 250 K

M = 30 MM = 30 MSunSun

High L, T and M: High L, T and M: Supergiant starSupergiant star Distance = 6kpcDistance = 6kpc

Av = 17.5 mag Av = 17.5 mag r/D=5x10r/D=5x10-10-10

• Unusual absorption:cocon of dust?

Hertzprung-Russel DiagramHertzprung-Russel Diagram


Color-magnitude diagrammeColor-magnitude diagramme

Position computed for 2 Position computed for 2 different absorptions different absorptions (11.8 and 17.4 mag) (11.8 and 17.4 mag) and for distances and for distances between 1 and 8 kpcbetween 1 and 8 kpc

Parameter space indicate Parameter space indicate a hot supergiant a hot supergiant between 1 and 6 kpcbetween 1 and 6 kpc

Absorption <17.4mag Absorption <17.4mag

Compatible with OB type Compatible with OB type supergiantssupergiants


IGR J16318-4848 Optical -> mid-infrared SEDIGR J16318-4848 Optical -> mid-infrared SED

Model:Model: Companion star: sgB[e], T=23500 K, R=20.4 Rsun = 15 10Companion star: sgB[e], T=23500 K, R=20.4 Rsun = 15 1066 km km Dust component: T=900K, R=12 RDust component: T=900K, R=12 R** = 1ua = 1ua Av=17.6, D=1.2 kpc Av=17.6, D=1.2 kpc Result: Fit Result: Fit 22/dof=89.4/99/dof=89.4/99

Need for extra (e.g. dust) component. Need for extra (e.g. dust) component. Extension of this dust component Extension of this dust component seems to suggest that it is enshrouding the whole binary system.seems to suggest that it is enshrouding the whole binary system.

•Unusual absorption:cocoon of dust? ESO/NTT

Spitzer

VLT/VISIR


Nature of the compact objectNature of the compact objectCorrelation in LHS black Correlation in LHS black

hole systems between X-hole systems between X-ray/radio flux densities:ray/radio flux densities:50-100 mCrab X-ray flux 50-100 mCrab X-ray flux => 10 mJy radio flux=> 10 mJy radio flux

Radio ATCA observation on 2003 Feb 9: no detection up to 0.1 mJy associated with low/hard X-ray with low/hard X-ray emission => compact emission => compact object is a neutron starobject is a neutron star

Gallo et al. 2004But correlation not always verified…


Nature of IGR J16318-4848Nature of IGR J16318-4848

High Mass X-ray Binary system:High Mass X-ray Binary system: neutron star + early-type supergiant B[e] starneutron star + early-type supergiant B[e] star

the 2nd HMXB with sgB[e] after CI Camthe 2nd HMXB with sgB[e] after CI Cam Distance 1 to 6 kpcDistance 1 to 6 kpc

Absorption:Absorption: in X-rays 2 orders of magnitude > IRin X-rays 2 orders of magnitude > IR in opt/IR 2 orders of magnitude > line of sightin opt/IR 2 orders of magnitude > line of sight

System surrounded by dense and absorbing dusty System surrounded by dense and absorbing dusty circumstellar material/enveloppe, + circumstellar material/enveloppe, + cold and hot stellar wind components

Because they are obscured, the « Norma arm » sources can only be studied in high-energy and infrared domains.


PlanPlan





The SFXT (Supergiant Fast X-ray Transient) source IGR J17544-The SFXT (Supergiant Fast X-ray Transient) source IGR J17544-2619…2619…

From INTEGRAL high energy …From INTEGRAL high energy …

… …to Optical/MIR observations.to Optical/MIR observations.

(Chaty & Rahoui 2006, proc. INTEGRAL; Pellizza, Chaty, Negueruela, (Chaty & Rahoui 2006, proc. INTEGRAL; Pellizza, Chaty, Negueruela, 2006, A&A)2006, A&A)


IGR J17544-2619IGR J17544-2619Recurrent transient X-ray source discovered

by INTEGRAL (09/2003) near the Galactic center

(Sunyaev et al. 2003, ATel 190)Bursts last ~hours, long quiescence periods, no radio emission reported (Gonzalez-Riestra et al. 2004, A&A 420, 589)

Very hard X-ray spectrum, Nh~2 1022, another highly absorbed galactic XB?

(Gonzalez-Riestra et al. 2004, A&A 420, 589)

Similar to other IGR sources (J16318-4848, J16320-4851, J16358-4726) (Chaty 2004, Gonzalez-Riestra et al. 2004, A&A 420, 589; Smith 2005, ATEL 338)

A new kind of XBs? Important to establish their nature

Optical/NIR Target of Opportunity observations 1 day after discovery!

Negueruela, Smith, Reig, Chaty, Torrejon, 2005


IGR J17544-2619 optical/NIR counterpartIGR J17544-2619 optical/NIR counterpart

IGR J17544-2619(Pellizza, Chaty, Negueruela, 2006, A&A)

2’

J-band image 5.5’x5.5’INTEGRAL: 2’ error radiusROSAT: 23” error radiusXMM: 4” error radius

Image Ks

1RXS J175428: ROSAT source not connected with IGR J17544

Chandra: 0.4’’

Ks-band imageXMM: 4” error radius


1 bright candidate (B) identified in USNO & 2MASS3 very faint candidates (F1-3): foreground dwarf stars?1 extended object (E) high-z galaxy?

IGR J17544-2619 optical/NIR counterpartIGR J17544-2619 optical/NIR counterpart


Blue supergiant O9 Ib (25-28 M, T~32000K)High-mass X-ray binaryExistence of a stellar wind: 265 ± 20 km/s (unusually mild for O stars, cf. 400 km/s in IGR J16318-4848: Filliatre & Chaty 2004, ApJ 616, 469)

Candidate B spectrumCandidate B spectrum


IGR J17544-2619 Optical -> mid-infrared SEDIGR J17544-2619 Optical -> mid-infrared SED

Model:Model: Companion star: O9Ib, T=30500K, R=21.9 RsunCompanion star: O9Ib, T=30500K, R=21.9 Rsun Av=5.9, D=3.9kpc Av=5.9, D=3.9kpc Fit result: Fit result: 22/dof=84/48/dof=84/48

no need for extra (e.g. dust) componentno need for extra (e.g. dust) component

Presence of dust?

ESO/NTT

Spitzer

VLT/VISIR


QuickTime™ et undécompresseur TIFF (non compressé)

sont requis pour visionner cette image.•HMXB with companion of 25-28 M supergiant O9Ib

•Presence of mild stellar wind

•Compact object: likely Neutron Star (in’t zand 2005)

•Distance: 3-4 kpc

•Faint intrinsic absorption (1022cm-2), Long Poutburst=165d

•Detection of flux variations during quiescence

•Archetype of “SFXTs”: Supergiant Fast X-ray transients:

O/B supergiant companions,O/B supergiant companions,Compact object = BH or NS,Compact object = BH or NS,faint quiescent emission, outbursts lasting only hours.faint quiescent emission, outbursts lasting only hours.

Nature of IGR J17544-2619Nature of IGR J17544-2619


PlanPlan





•IGR J16318-4848 and IGR J17544-2619 exhibit common characteristics:

•High Mass X-ray Binaries with O/B companion•Compact object: neutron star or black hole•X-ray transients•No radio emission

•But they also exhibit differences:•High intrinsic absorption around the compact object / the binary system

•A new population of sources revealed by INTEGRAL.Because some are obscured, these sources can only be studied at high-energies and IR.

ResultsResults


Characteristics of the studied INTEGRAL sourcesCharacteristics of the studied INTEGRAL sources

SourceSource RegionRegion PspinPspin NhNh NhgalNhgal NhEB-VNhEB-V PorbPorb

Persistent sourcesPersistent sources

IGRJ16318-IGRJ16318-48484848

NormaNorma 193193 2.12.1 <4.2<4.2

IGRJ16320-IGRJ16320-47514751

NormaNorma 1250s1250s 1818 2.12.1 9d9d

IGRJ16393-IGRJ16393-46414641

NormaNorma 912s912s 2424 2.22.2 <2.7<2.7

IGRJ17252-IGRJ17252-36163616

GCGC 413s413s 1515 1.51.5 <5.3<5.3 9.7d9.7d

IGRJ17597-IGRJ17597-22012201

GCGC 55 1.21.2 <2.9<2.9

IGRJ18027-IGRJ18027-20162016

GCGC 139s139s 99 1.11.1 <2.1<2.1 4.6d4.6d

Transient sourcesTransient sources

IGRJ16358-IGRJ16358-47264726

NormaNorma 5880s5880s 3939 2.22.2 <4.2<4.2

IGR J16418-IGR J16418-45324532

NormaNorma 965s965s 1010 2.02.0 <3.6<3.6

IGRJ16465-IGRJ16465-45074507

NormaNorma 228s228s 6060 1.61.6 <1.0<1.0

IGR J16479-IGR J16479-45144514

NormaNorma 88 2.12.1 <4.8<4.8

IGRJ17544-IGRJ17544-26192619

GCGC NSNS 22 1.41.4 <2.5<2.5 165d?165d?

Zurita 2006 adapted


Results of 2004 NTT-SOFI/EMMI and 2005/2006 Paranal UT3-VISIR Results of 2004 NTT-SOFI/EMMI and 2005/2006 Paranal UT3-VISIR observationsobservations

SourceSource TypeType SpectraSpectral typel type

PAH1PAH1

(8.59 (8.59 m)m)

mJymJy

PAH2PAH2

(11.25 (11.25 m) m) mJymJy

Q2Q2

(18.72 (18.72 m)m)

mJymJy

Dust Dust TemTemp (K)p (K)

Dust Dust Radius Radius (R*)(R*)

IGR J16195-IGR J16195-49454945

SFXT?/SFXT?/OBSOBS

OBOB <6<6 <8<8 <50<50 950950 6.16.1

IGR J16318-IGR J16318-48484848

OBSOBS sgB[e]sgB[e] 409409 322322 172172 900900 11.911.9

IGR J16320-IGR J16320-47514751

OBSOBS OBOB 1212 66 --

IGR J17391-IGR J17391-30213021

SFXTSFXT O8Iab(f)O8Iab(f) 7070 4646 --

IGR J17544-IGR J17544-26192619

SFXTSFXT O9IbO9Ib 3636 2020 --

IGR J16207-IGR J16207-51295129

B0B0 22 22 (extended)(extended)

99 <53<53

IGR J16358-IGR J16358-47264726

OBSOBS <7<7 -- -- 880880 10.110.1

IGR J16418-IGR J16418-45324532

SFXTSFXT <6<6 -- --

IGR J16465-IGR J16465-45074507

SFXT/SFXT/OBS?OBS?

B0.5IB0.5I 99 55 --

IGR J16479-IGR J16479-45144514

SFXTSFXT OBOB 1212 77 --

IGR J17252-IGR J17252-36163616

OBSOBS OBOB 66 22 --

IGR J17597-IGR J17597-22012201

Late?Late? <6<6 -- --

IGR J18027-IGR J18027-20162016

sgOBsgOB <6<6 -- --

IGR IGR J19140+0951J19140+0951

OB?OB? 35 (2 35 (2 sources)sources)

19 (2 19 (2 sources)sources)

--

9 sources detected in MIR out of 14 = 2/3:MIR (stellar) emission seems usual around these sources, but the case of IGR J16318-4848 remains exceptional!


30% of sources detected by INTEGRAL/IBIS were not known. 80% of Norma sources are X-ray pulsars, high spin periods Spectra typical of neutron stars No radio emission

85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2

X-ray absorption >> IR => absorbing matter local to neutron star NH variation on short periods? => link with accretion column/geometry?

A big fraction of these sources are close to the galactic plane |b|< 1° They are HMXBs, some identified with OB types (Opt/NIR observations)

The systems


Nature of systems: Nature of systems: Corbet DiagrammeCorbet Diagramme 80% of Norma sources are X-ray pulsars High spin periods Star Porb=10d, M=20Msol, a=50Rsol < Rdust

(Rdust=240RSunfor IGR J16318)

Underfilled Roche lobe Supergiants

•HMXBs Pspin vs Porb:•Be Binaries•supergiant Roche lobe overflow systems•super-giant wind accretors


So, what are these sources?Different geometries, different possible scenarii

A new population of sources of our Galaxy revealed by INTEGRALA new population of sources of our Galaxy revealed by INTEGRAL ~15 ~15 sources with same characteristics: not by chance!sources with same characteristics: not by chance! 80% are neutron stars orbiting around super-giant stars (hot, massive, luminous):80% are neutron stars orbiting around super-giant stars (hot, massive, luminous):

Presence of a cocoon of dense and absorbing dust concentrated:Presence of a cocoon of dense and absorbing dust concentrated:

1) Either around the 1) Either around the compact object: SFXTs (~IGR J17544):: Wide orbit, neutron star penetrates inside the atmosphere/envelope of companion star, causing outbursts?Wide orbit, neutron star penetrates inside the atmosphere/envelope of companion star, causing outbursts?

2) Or enshrouding the whole system: obscured sources (2) Or enshrouding the whole system: obscured sources (~IGR J16318) :~IGR J16318) : neutron star orbits within a dense equatorial windneutron star orbits within a dense equatorial wind density 10density 1011–1211–12 cm cm–3–3

Disc thickness 10Disc thickness 1012–1312–13 cm (10-100 R cm (10-100 RSunSun)) Disc radius 10Disc radius 1013–1413–14 cm (1-10 a.u.) cm (1-10 a.u.)

The answer will be given by orbital periods of these sources…The answer will be given by orbital periods of these sources…

High and persistent column density => special wind configuration Many such sources => geometry favours accretion


PlanPlan





Conclusions

• Obscured sources and SFXTs share similar properties:• High Mass X-ray Binaries with O/B supergiant secondaries

• But they are not the same!• Intrinsic absorption around the compact object / whole

system• Extension of the absorbing material (dust…)• X-ray transient/persistent (due to geometry?)

INTEGRAL doubled the population of massive binaries with supergiant in our Galaxy, and revealed a class of highly absorbed binaries.

• This new population will constrain the geometry and evolution of X-ray binaries:

• dominant population born with two very massive components?dominant population born with two very massive components?• Primary progenitors of NS/NS or NS/BH mergers:Primary progenitors of NS/NS or NS/BH mergers:

• Link with short/hard gamma-ray bursts?Link with short/hard gamma-ray bursts?• Good candidates of gravitational waves emitters?Good candidates of gravitational waves emitters?


And then? Still many questions:

What is the geometry of these systems (size of orbit, orbital period…)?

No radio emission: does geometry or dust prevent jet formation? And also, where does this dust come from?And also, where does this dust come from?

How were they formed? Link with region of stellar formation of Norma arm?

How will they evolve? (neutron star decelerated?)

Does this circumstellar environment result from Does this circumstellar environment result from binarity or stellar evolution?binarity or stellar evolution?

These sources will allow to better understand birth, evolution and geometry These sources will allow to better understand birth, evolution and geometry of HMXB with supergiants.of HMXB with supergiants.

To answer to these questions: new observing campaigns foreseen or pending, To answer to these questions: new observing campaigns foreseen or pending, in high energies and NIR/MIR, during and inbetween flaresin high energies and NIR/MIR, during and inbetween flares


Naturaleza Azul, Naturaleza Azul, Francisco Brugnoli

Se acabo… gracias!Se acabo… gracias!

El universo es tremendamente El universo es tremendamente creativo, lo que nos obliga a creativo, lo que nos obliga a abrirnos a lo desconocido…abrirnos a lo desconocido…(Alberto Ludwig Urquieta, 1926)(Alberto Ludwig Urquieta, 1926)

http://www.mac.uchile.cl/virtual/b14/index.html

http://www.mac.uchile.cl/virtual/b14/index.html

sylvain chaty (université paris 7 / service d’astrophysique, france) eso - 28 novembre 2006

Documents

chaty eso

obscured xray sources

new type of sources

rxte sources

integral satellite

par integral

archetype igr j16318

archetype igr j17544