Chandra-HETGS Observations of LMC X-1 Michael Nowak, Ron Remillard, Norbert Schulz (MIT-Kavli) & Jörn Wilms (University of Bamberg)
One of the few persistent BHC HMXB: Focused Wind-Fed Soft X-ray Dominated State Line of Sight will Often Intersect Secondary Wind
Elmegreen, Kim, Staveley-Smith (2001)
Elmegreen, Kim, Staveley-Smith (2001) 21 cm Map of LMC LMC X-1 Sits Near 30 Doradus Star Forming Region
Mass: 10.9 +/- 1.6 Solar Masses, Inclination 36. o 4 +/- 1. o 9 (Orosz et al. 2009) Distance: 48.1 kpc Absorbed 0.5 8 kev Flux 10% LEdd Orbital Period 3.909 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)
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?
Fit: Absorbed, Comptonized Disks 2 20 0 20 F (ergs cm 2 s 1 ) 10 12 10 11 10 10 0.5 1 2 5 Energy (kev)
Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) 10 12 10 11 10 10 Disk 2 20 0 20 0.5 1 2 5 Energy (kev)
Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) 10 12 10 11 10 10 Disk Corona 2 20 0 20 0.5 1 2 5 Energy (kev)
Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) 10 12 10 11 10 10 Disk ISM & Local Absorption Corona 2 20 0 20 0.5 1 2 5 Energy (kev)
Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) 10 12 10 11 10 10 Disk ISM & Local Absorption Corona Secondary Atmosphere 2 20 0 20 0.5 1 2 5 Energy (kev)
Fit: Absorbed, Comptonized Disks F (ergs cm 2 s 1 ) 10 12 10 11 10 10 No Idea Disk ISM & Local Absorption Corona Secondary Atmosphere 2 20 0 20 0.5 1 2 5 Energy (kev)
Emission from Secondary S XV Si XIV Si XIII F (ergs cm 2 s 1 ) 2 10 10 Fe XXIV? Mg XII 2 0 20 40 5 6 7 8 9 10 Wavelength (Å)
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
Absorption Edge Structure 2 X2 S1 C1 S2 S3 X1 λ F λ [Å photons/s/cm 2 /Å] 0.015 0.02 0.025 0.03 0.035 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 13 14 15 16 Wavelength λ [Å] 1.5 1 1.3 1.2 1.1 1 1.3 1.2 1.1 1 1.3 1.2 1.1 1 diskbb + powerlaw eqpair simpl ( kerrbb ) simpl ( diskbb ) 0 0.2 0.4 0.6 0.8 Orbital phase Hanke et al. (2009) - RGS, Epic, Swift, Chandra
Absorption Edge Structure 2 10 11 5 10 11 F (ergs cm 2 s 1 ) Ne IX Ne III Ne II Chandra-HETGS 2 5 0 5 13.5 14 14.5 15 15.5 Wavelength (Å)
Absorption Edge Structure F (ergs cm 2 s 1 ) 5 10 12 10 11 2 10 11 5 10 11 Chandra-HETGS Fe L 2 5 0 14 15 16 17 18 Wavelength (Å)
Absorption vs. Orbital Phase N Ne (10 18 cm 2 ) 0.5 1 1.5 2 0.2 0.4 0.6 0.8 Orbital Phase
Absorption vs. Orbital Phase 2 X2 S1 C1 S2 S3 X1 N Ne (10 18 cm 2 ) 0.5 1 1.5 2 Column density N H [10 22 cm 2 ] 1.5 1 1.3 1.2 1.1 1 1.3 1.2 1.1 1 1.3 diskbb + powerlaw eqpair simpl ( kerrbb ) 1.2 0.2 0.4 0.6 0.8 Orbital Phase 1.1 1 simpl ( diskbb ) 0 0.2 0.4 0.6 0.8 Orbital phase
Shakura-Sunyaev Disk F = 3Ṁ 8π Ω2 1 β Ri R 1/2
Shakura-Sunyaev Disk Novikov & Thorne F = 3Ṁ 8π Ω2 Spin: a* = 0 1 1 β Ri R 1/2
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
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
LMC X-1 HETGS Spectra F (ergs cm 2 s 1 ) 10 11 10 10 0.5 1 2 5 Energy (kev)
LMC X-1 HETGS Spectra F (ergs cm 2 s 1 ) 10 11 10 10 Note Lack of Differences 0.5 1 2 5 Energy (kev)
Contrast to 4U 1957+11 F (ergs cm 2 s 1 ) 5 10 11 10 10 2 10 10 5 10 10 Suzaku Observations (Nowak et al. 2011) 0.5 1 2 5 Energy (kev)
Soft State = Constant Radius r in cos 1/2 θ [km] 10 20 30 40 50 kt in [kev] 1.2 1.0 0.8 0.6 d) LMC X-3 kt disk (ev) 1200 1400 1600 4U 1957+11 0.4 0 20 40 60 80 100 A disk 2 10 4 5 10 4 Disk Normalization RXTE Observations (Wilms et al. 2001, Nowak et al. 2008)
Soft State = Constant Radius r in cos 1/2 θ [km] 10 20 30 40 50 kt in [kev] 1.2 1.0 0.8 0.6 d) LMC X-3 kt disk (ev) 1200 1400 1600 4U 1957+11 0.4 0 20 40 60 80 100 A disk 2 10 4 5 10 4 Disk Normalization RXTE Observations (Wilms et al. 2001, Nowak et al. 2008)
Chandra: LMC X-1 kt disk (ev) 750 800 850 900 (RXTE the same) 10 3 1.5 10 3 2 10 3 Disk Normalization (Wilms et al. 2001, MNRAS, 320; Nowak et al. in prep)
1.0 // a * = cj/gm 2 0.95 0.9 a a =0.938 ± 0.020 (std. dev.) 0.85 // 1996 1997 1998 1999 2004 2005 1 0.95 0.9 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 0.5 1 1.5 2 M
Chandra: LMC X-1 kt disk (ev) 750 800 850 900 (RXTE the same) 10 3 1.5 10 3 2 10 3 Disk Normalization (Wilms et al. 2001, MNRAS, 320; Nowak et al. in prep)
Chandra: LMC X-1 (RXTE the same) kt disk (ev) 750 800 850 900 10 3 1.5 10 3 2 10 3 Disk Normalization (Wilms et al. 2001, MNRAS, 320; Nowak et al. in prep)
Is This Because it s Wind-Fed? Beloborodov & Illiaronov (2001)
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?
Extra Slides
N Ne (10 18 cm 2 ) 0.5 1 1.5 2 1.25 1.3 1.35 1.4 1.45 N H (10 22 cm 2 )
isk-absorption Correlations kt disk (ev) 750 800 850 900 N H (10 22 cm 2 ) 1.3 1.35 1.4 1.45 1.3 1.35 1.4 1.45 N H (10 22 cm 2 ) 10 3 1.5 10 3 2 10 3 Disk Normalization
Disk-Corona Correlations Disk Normalization 10 3 1.5 10 3 2 10 3 kt disk (ev) 750 800 850 900 0.5 1 Compactness, l h /l s 0.5 1 Compactness, l h /l s