Xray Binaries in the Era of Chandra and
X-ray Binaries in the Era of Chandra and XMM High Resolution Spectroscopy Michael A. Nowak MIT Kavli Institute for Astrophysics and Space Research & Chandra X-ray Science Center
What are We Asking with Spectra? Broad Band X-ray Spectra (RXTE, Suzaku, Swift, INTEGRAL, + multi-wavelength) What are the basic components? Corona: Size, Temperature, Optical Depth? Jet: Does it contribute to the X-rays? Disk: Truncated? Measure of relativity? Surface: Differences with respect to BH? Reflection: Relative geometry of above?
Broad-band Spectra Cyg X-1: Classic “Hard State” χχ -1 -2 -1 ke. VPhotonssec sec-1 cm cm-2 ke. V-1 (Markoff, Nowak, & Wilms 2005) (Kubota et al. )
Broad-band Spectra 4 U 1957+11: Classic “Soft State” (Nowak et al. , in prep. )
Broad-band Spectra 4 U 1705 -44 (Fiocchi et al. , 2007)
What are We Asking with Spectra? High Resolution X-ray Spectra: Chandra & XMM What are the physical properties? Velocities, Temperatures, Densities Inflows? Outflows? Rotation? Compositions? Ionization states? Separation of narrow & broad components: Relativity vs. atomic physics Complex interactions among “continuum” components
Outline of Talk Overview of the (Many & Complex) Components of an Accreting Binary System What physics are we studying with each? Examples of Chandra & XMM gratings studies When do we obtain high-resolution features, and when don’t we? (Actually, I don’t really know. . . ) Where do we go from here?
Components of X-ray Binaries:
Components of X-ray Binaries: Neutron stars have surfaces! Continua: Cooling of interior (nuclear physics), contrast to BH implies existence of horizon? (See, however, Jonker et al. 2007) Hi-res spectra: Redshifted features constrain M/R (nuclear physics; Cottam et al. 2002)
Neutron Star Surface: RX J 0720. 4 - EXO 0748 -676 3125 EXO 0748 -676: Only example so far Low spin (45 Hz; Villarreal & Strohmayer 2004) Low temperature burst If the features are real: M/R consistent with “reasonable” EOS RX J 1308. 6+2127 Some exotic EOS ruled out (van Kerwijk et (Cottam al. 2007)et al. 2002)
Components of X-ray Binaries: Disks: No intrinsic hi-res features; more via their interaction with their environment (Xray heating, fluorescence, boundary layers at coronal transition, etc. ) Evidence of MHD turbulence driving accretion? Do they truncate? Are models and observations good enough to measure relativity (i. e. , spin; Shafee et al. 2007, Davis et al. 2006, etc. )
Components of X-ray Binaries: Some (Many? Most? ) disks are warped: Her X-1, LMC X-4, SS 433 Most mechanisms (radiative warping Petterson 1977, Pringle 1996; winds Schandl & Meyer 1994) rely on X-ray heating - testable by hi-res spectroscopy
Her X-1 Observations: Line velocities and widths are small (<290 km s-1) Viewing only the outer region of the disk G = (i+f)/r ratios imply photoionized atmospheres R = f/r ratio is very low, except for higher Z UV radiation coverts f to i, and/or Density leads to collisional depopulation (Jimenez-Garate et al. 2005) High Z-species occupy much greater volume (Jimenez-Garate et al. 2002) Consistent story, but not yet “testing” warp theory
Components of X-ray Binaries: “Hard States” likely have a corona (or equivalently, base of a jet): Geometry & structure are debated “Transition regions” have been hypothesized as possible source of line emission (Perna et al. 2000) But only applied to sources such as Sgr A* (see M 81* talk by A. Young)
Components of X-ray Binaries: Both coronae (Magdziarz & Zdziarski 1995) and jets (Markoff & Nowak 1994) yield reflection features Chief benefit of hi-res may lie in disentangling components
“Ideal” Reflection: GX 301 -2 (Watanabe et al. 2004)
“Hard State” BHC Observations: Cyg X-1 GX 339 -4 4 U 1705 -44 (Di Salvo et al. , 2005) (Miller et al. 2004) (Miller et al. 2002)
Low-res Data Used to Challenge Lines MCG-6 -30 -15 XTE J 1650 -500 (Done & Gierlin´ski (Young et 2006) al. 2005)
Components of X-ray Binaries: Accretion Disk Coronae Distinct from Inner Corona/Jet Ionized Disk Atmospheres “Dipping Sources”
ADC Sources Show Orbital Modulation X 1822 -371: HETG Lightcurve (Heinz & Nowak 2001)
HETG Observations of X 1822 -371 (Cottam et al. 2001)
Going a Little Away from the Disk Plane: EXO 0748 -676 (Garate et al. 2001) * Continuum consistent with absorbed, point source * Line emission consistent with unabsorbed, extended region, 500 km s-1 < velocity broadening < 1200 km s 1 * Absorbers have neutral and ionized components
Ionized Absorption in Many “Dippers” 4 U 1916 -05 Models to XMM (both PN and RGS data) have been successfully applied to many dipper sources X 1323 -619, X 1916 -053, X 1254 -690, MXB 1659298, X 1624 -490 (Boirin et al. 2004, 2005; Díaz Trigo et al. 2006) Fe XXV & Fe XXVI absorption commonly detected Chandra studies of X 1916 -053 show rather narrow features (Juett et al. 2006, Iaria et al. 2006) (Juett & Chakrabarty 2006)
Components of X-ray Binaries: Winds!
Seen in Both Neutron Stars & Black Holes P Cygni profiles in Cir X-1 with V = 200 -2000 km s-1 (Brandt & Schulz 2000, Schulz & Brandt 2002) Blue shifted Fe XXVI line in GRS 1915+105 with V = 770± 400 km s-1, (Lee et al. 2002) Blue-shifted absorption in GRO J 1655 -40, seen by both XMM (Díaz Trigo et al. 2006) and Chandra (Miller et al. 2006), with V = 300 -1600 km s-1
Wind Examples: GRS 1915+105 Cir X-1 GRO J 1655 -40 (Schulz & Brandt 2002) (Díaz Trigo et al. 2006) (Lee et al. 2002)
Extreme Example of Absorption Lines: Disk-dominated, 4% LEdd state GRO J 1655 -40 90 significant absorption lines, 76 identified (32 charge states), blue shifted 300 -1600 km s-1, FWHM 300 km s-1, no emission lines Modeled with a highly ionized wind at R = 400 GM/c 2 Too close to be thermal, too ionized to be line driven • Hypothesized to be magnetically driven Netzer (2006) instead modeled the spectrum with (Miller et al. 2006) R = 105 GM/c 2 , with • But not a true “fit” to the data
Components of X-ray Binaries: Accretion Streams & Secondary Winds
Winds & Flows from the Secondary Most relevant to High Mass X-ray Binaries (HMXB) Examples of both Neutron Star and Black Hole sources Vela X-1 (Schulz et al. 2002, Goldstein et al. 2004, Watanabe et al. 2006) Cyg X-3 (Paerels et al. 2000) Example of Cyg X-1 at Phase 0 (Hanke et al. , in prep. )
2 Rate (cps) 4 6 Dipping in Cyg X-1 104 2× 104 3× 104 Time (sec) 4× 104 (Hanke et al. , in prep. )
Why We Need Con-X (Simulations by Manfred Hanke)
Components of X-ray Binaries: * Absorption also Not intrinsic depends upon to the X-ray Binary direction of view -in the plane, or But important through the halo to (see Daniel Wang’s understand to talk) determine what is intrinsic * Absorption from Cold & Warm Phases of ISM (Juett et al. 2004, 2006; Yao et al. 2006, 2007; Wang et al. 2005, etc. ) ‘Warm Absorber’ or ‘WHIM’? * Dust Scattering Halos & ‘Solid State Astrophysics’ (Predehl & Schmitt 1995, Lee & Ravel 2005, Xiang et al. 2005, Smith et al. 2006, etc. )
Multi-phase ISM GX 339 -4 (Miller et al. 2004)
Summary X-ray binaries have many components, interacting in complex, interesting ways High resolution X-ray spectroscopy is addressing all of them Continuum spectroscopy is perhaps “ahead” in that we’ve had time for multiple observations: States, orbital phases, inclinations, etc. But that means there is lots to do with Chandra, XMM, and on into Constellation X
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