Chandra-HETGS Observations of LMC X-1. Michael Nowak, Ron Remillard, Norbert Schulz (MIT-Kavli) & Jörn Wilms (University of Bamberg)

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1 Chandra-HETGS Observations of LMC X-1 Michael Nowak, Ron Remillard, Norbert Schulz (MIT-Kavli) & Jörn Wilms (University of Bamberg)

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4 One of the few persistent BHC HMXB: Focused Wind-Fed Soft X-ray Dominated State Line of Sight will Often Intersect Secondary Wind

5 Elmegreen, Kim, Staveley-Smith (2001)

6 Elmegreen, Kim, Staveley-Smith (2001) 21 cm Map of LMC LMC X-1 Sits Near 30 Doradus Star Forming Region

7 Mass: /- 1.6 Solar Masses, Inclination 36. o 4 +/- 1. o 9 (Orosz et al. 2009) Distance: 48.1 kpc Absorbed kev Flux 10% LEdd Orbital Period Days, O7/8 Giant Companion Sits 0.5 o from 30 Doradus Star Forming Region => Larger column than much of the rest of the LMC (e.g., > LMC X-3)

8 Performed 10 Chandra-HETGS Observations over ~ 1 month: 150 ksec Study Accretion Flow Emission Primarily the Accretion Disk Direct Measure of Absorption Edges Spectroscopic Signatures of Secondary Study Orbital Variations?

9 Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) Energy (kev)

10 Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) Disk Energy (kev)

11 Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) Disk Corona Energy (kev)

12 Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) Disk ISM & Local Absorption Corona Energy (kev)

13 Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) Disk ISM & Local Absorption Corona Secondary Atmosphere Energy (kev)

14 Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) No Idea Disk ISM & Local Absorption Corona Secondary Atmosphere Energy (kev)

15 Emission from Secondary S XV Si XIV Si XIII F (ergs cm 2 s 1 ) Fe XXIV? Mg XII Wavelength (Å)

16 Velocities are Inconclusive: 500 km s -1 Widths: 500 km s -1 No Evidence for Orbital Phase-Dependence This is in contrast to Cyg X-1 Hard State: Orbital Phase-Dependence Soft State: No Lines (Totally Ionized Wind) See Poster # 18 by Ivica Miskovicová

17 Absorption Edge Structure 2 X2 S1 C1 S2 S3 X1 λ F λ [Å photons/s/cm 2 /Å] Ne IX 1s 2 > 1s 2p Ne I edge Column density N H [10 22 cm 2 ] Ne I 1s > 3p Ne II 1s > 2p Wavelength λ [Å] diskbb + powerlaw eqpair simpl ( kerrbb ) simpl ( diskbb ) Orbital phase Hanke et al. (2009) - RGS, Epic, Swift, Chandra

18 Absorption Edge Structure F (ergs cm 2 s 1 ) Ne IX Ne III Ne II Chandra-HETGS Wavelength (Å)

19 Absorption Edge Structure F (ergs cm 2 s 1 ) Chandra-HETGS Fe L Wavelength (Å)

20 Absorption vs. Orbital Phase N Ne (10 18 cm 2 ) Orbital Phase

21 Absorption vs. Orbital Phase 2 X2 S1 C1 S2 S3 X1 N Ne (10 18 cm 2 ) Column density N H [10 22 cm 2 ] diskbb + powerlaw eqpair simpl ( kerrbb ) Orbital Phase simpl ( diskbb ) Orbital phase

22 Shakura-Sunyaev Disk F = 3Ṁ 8π Ω2 1 β Ri R 1/2

23 Shakura-Sunyaev Disk Novikov & Thorne F = 3Ṁ 8π Ω2 Spin: a* = β Ri R 1/2

24 An Aside on Thermodynamic Efficiency of Radiative Processes Blackbody radiation is the most thermodynamically efficient N BB T 3 BB,y 4kT c m e c 2 max(τ es, τ 2 es) For the same average photon energy, and same total luminosity, non-thermal requires greater area

25 An Aside on Thermodynamic Efficiency of Radiative Processes Also true for atmospheric electron scattering: Modified Blackbody F σt 4 κr κ es 1/2, κ R κ es Color Correction : TC = fcteff, fc > 1, Area scales as fc 4 Essentially any correction means the area is bigger than required for just blackbody

26 LMC X-1 HETGS Spectra F (ergs cm 2 s 1 ) Energy (kev)

27 LMC X-1 HETGS Spectra F (ergs cm 2 s 1 ) Note Lack of Differences Energy (kev)

28 Contrast to 4U F (ergs cm 2 s 1 ) Suzaku Observations (Nowak et al. 2011) Energy (kev)

29 Soft State = Constant Radius r in cos 1/2 θ [km] kt in [kev] d) LMC X-3 kt disk (ev) U A disk Disk Normalization RXTE Observations (Wilms et al. 2001, Nowak et al. 2008)

30 Soft State = Constant Radius r in cos 1/2 θ [km] kt in [kev] d) LMC X-3 kt disk (ev) U A disk Disk Normalization RXTE Observations (Wilms et al. 2001, Nowak et al. 2008)

31 Chandra: LMC X-1 kt disk (ev) (RXTE the same) Disk Normalization (Wilms et al. 2001, MNRAS, 320; Nowak et al. in prep)

32 1.0 // a * = cj/gm a a =0.938 ± (std. dev.) 0.85 // Observation Time (a) Gou et al. (2009) - Spin fits really are a comment on emitting area for a given fitted temperature, small emitting area 0.85 RXTE Data M

33 Chandra: LMC X-1 kt disk (ev) (RXTE the same) Disk Normalization (Wilms et al. 2001, MNRAS, 320; Nowak et al. in prep)

34 Chandra: LMC X-1 (RXTE the same) kt disk (ev) Disk Normalization (Wilms et al. 2001, MNRAS, 320; Nowak et al. in prep)

35 Is This Because it s Wind-Fed? Beloborodov & Illiaronov (2001)

36 Summary See Emission Lines at All Orbital Phases, Despite High, Soft Flux => Strong Wind See Absorption Stronger than ISM, with Large Variability => Strong Wind Disk Has a Small, and Highly Variable, Emitting Area => Strong Wind?

37 Extra Slides

38 N Ne (10 18 cm 2 ) N H (10 22 cm 2 )

39 isk-absorption Correlations kt disk (ev) N H (10 22 cm 2 ) N H (10 22 cm 2 ) Disk Normalization

40 Disk-Corona Correlations Disk Normalization kt disk (ev) Compactness, l h /l s Compactness, l h /l s