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HotPlasmaEmissionsintheUltra-compactBinaryPulsar
4U1626-67
NorbertS.Schulz,HermanL.Marshall,DeeptoChakrabarty
Massachuse(sIns,tuteofTechnologyKavliIns,tuteforAstrophysics&SpaceScience
TexasSymposium2015,Dec.14,Geneva,Switzerland MKI
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TexasSymposium2015,Dec.14,Geneva,Switzerland MKI
Ultra-compactbinary:Porbit=42min,aXsini<8lt-ms!ax<<3.4x105km(<Earth-Moonsystem)DegenerateHeorCOwhitedwarf(0.02-0.06Msun)Pspin=7.66sec;i~20o;Macc~10-10Msun;B~6-8x1012G,Rco=6.5x108cmLx>1036erg/sec;D>3kpc[5–13kpc]
(FromChakrabartyetal.1997,Chakrabqrty1998)
Chakrabartyetal.1997 Camer-Arranzetal.2010
3x
Torquereversalhistory:
2008
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1995ApJ...449L..41A
TexasSymposium2015,Dec.14,Geneva,Switzerland MKI
Ultra-compactbinary:Porbit=42min,aXsini<8lt-ms!ax<<3.4x105km(<Earth-Moonsystem)DegenerateHeorCOwhitedwarf(0.02-0.06Msun)Pspin=7.66sec;i~20o;Macc~10-10Msun;B~6-8x1012G,Rco=6.5x108cmLx>1036erg/sec;D>3kpc[5–13kpc]
(FromChakrabartyetal.1997,Chakrabqrty1998)
Angelinietal.1995:ASCA Schulzetal.2002:Chandra
3x
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TexasSymposium2015,Dec.14,Geneva,Switzerland MKI
Schulzetal.2016
3x
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TABLE 1: CHANDRA HETGS X-RAY OBSERVATIONS
Obsid Start Date Start Time Exposure HETG 1st rate
[UT] [UT] [ks] cts s−1
104 Sep 16 2000 14:57:01 40 2.413504 Jun 03 2003 02:30:01 97 1.68
11058 Jan 14 2010 11:53:01 80 6.80
TABLE 2 CONTINUUM: TBNEW*(POWERLAW + BBODYRAD)
OBSID Date NH Apl Γ R2bb/D
2 kTbb fx χ2ν
[UT] (1) (2) – (3) keV (4)
104 Sep 16 2000 1.30+0.14−0.13 1.21+0.01
−0.01 0.87+0.01−0.01 405.3+81.6
−70.0 0.23+0.01−0.01 2.2 0.94
3504 Jun 03 2003 1.21+0.14−0.15 0.82+0.01
−0.01 0.79+0.01−0.01 464.8+83.0
−72.3 0.21+0.01−0.01 1.7 1.05
11058 Jan 14 2010 1.25+0.05−0.05 3.82+0.02
−0.02 1.18+0.01−0.01 89.7+4.2
−4.0 0.48+0.01−0.01 4.6 1.25
(1) 1021 cm−2; (2) 10−2 ph A−1 cm−2 s−1
(3) km2/[10 kpc]2; (4) 10−10 erg cm−2 s−1
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Schulzetal.2016
3x
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TABLE 1: CHANDRA HETGS X-RAY OBSERVATIONS
Obsid Start Date Start Time Exposure HETG 1st rate
[UT] [UT] [ks] cts s−1
104 Sep 16 2000 14:57:01 40 2.413504 Jun 03 2003 02:30:01 97 1.68
11058 Jan 14 2010 11:53:01 80 6.80
TABLE 2 CONTINUUM: TBNEW*(POWERLAW + BBODYRAD)
OBSID Date NH Apl Γ R2bb/D
2 kTbb fx χ2ν
[UT] (1) (2) – (3) keV (4)
104 Sep 16 2000 1.30+0.14−0.13 1.21+0.01
−0.01 0.87+0.01−0.01 405.3+81.6
−70.0 0.23+0.01−0.01 2.2 0.94
3504 Jun 03 2003 1.21+0.14−0.15 0.82+0.01
−0.01 0.79+0.01−0.01 464.8+83.0
−72.3 0.21+0.01−0.01 1.7 1.05
11058 Jan 14 2010 1.25+0.05−0.05 3.82+0.02
−0.02 1.18+0.01−0.01 89.7+4.2
−4.0 0.48+0.01−0.01 4.6 1.25
(1) 1021 cm−2; (2) 10−2 ph A−1 cm−2 s−1
(3) km2/[10 kpc]2; (4) 10−10 erg cm−2 s−1
2003 2010
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Fig. 3.— 2010 line profiles of the H-like Lα lines of Ne (red) and O (blue) on a velocity scalecentered on the the expected rest wavelengths of Ne x and O viii. The O vii flux has been
scaled by a factor 10 in order to match with Ne x for the purpose of comparison.TexasSymposium2015,Dec.14,Geneva,Switzerland MKI
-20000 10000-10000 200000
O/NeDopplerlines:+/-4000kms-1
FeKFluorescenceline:narrow,resolved?[1.7sigma]
NobroadrelafvisfcOVIIIobservedasinotherUCB(Madejetal.2010,2011;Schulzetal.2010)
SeeKoliopanosetal.,nexttalk
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Photo-ionizedmodel:XSTAR Collisionalmodel:APED
Ne/OEmissionisfromcollisionalionizedplasmaPlasmaisCOdominated,noHPlasmaishot:T=[1.1,10.0]MKinallobservafonsVEMlimitsemissionvolume
EmissionmeasureislimitedtoNeXandCIV,i.e.nolowertemperaturesthan1MK
10 10.5 11 11.5 12 12.5 13 13.5 14
2000
Wavelength (Å)
Cou
nts/
bin Ne X Ne IX
17 18 19 20 21 22 23
1000
500
Wavelength (Å)
Cou
nts/
bin
O VIII O VII
29 30 31 32 33 34 35 36 37100
200
Wavelength (Å)
Cou
nts/
bin
C VI
36 37 38 39 40 41 42 43 44100
200
Wavelength (Å)
Cou
nts/
bin
C V
10 20 30 40 50 60 70
100
1000
Wavelength (Å)
Cou
nts/
bin Ne X
Ne IX
O VIIIO VII C VI
C V
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OVIIIajertorquereversalRin=3.7x108cmRin<Rco
OVIIIbeforetorquereversalRin=8.3x108cmRin>Rco
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TABLE 5 DISKLINE FIT PARAMETERS BEFORE AND AFTER THE 2008TORQUE REVERSAL
Line Torque λDl ADl q Rin(M) Rout(M) i χ2ν
reversal A (1) 103GM/c2 103GM/c2 deg.
Ne x before 12.13±0.01 0.17±0.04 -4.6 3,9+0.7−0.9 94.3+5.6
−81.0 38.2+6.7−4.5 1.21
O viii 18.97±0.01 0.18±0.05 -4.6 4.0+1.6−0.9 4.0+19.1
−1.1 tied –Ne x after 12.13±0.01 0.19±0.01 -3.6 1.8+0.2
−0.5 10.9+10.2−2.8 tied –
O viii 18.97±0.01 0.22±0.03 -3.6 1.7+0.2−0.1 3.8+1.3
−0.6 tied –
(1) 10−2 ph cm−2 s−1
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TexasSymposium2015,Dec.14,Geneva,Switzerland MKI
Summary-Whathavewelearnedsofar
1. PlasmalineemissionsfromNe/O/Carefromacollisionallyionizedplasmaofverylimitedvolumelocatedclosetothemagnetosphericradius.2.Theheatedplasmahastemperaturesrangingfrom~1MKto10MK.Theheafngmechanismisunknown.TheclosenesstoRmagmaysuggestshockheafngofdiskplasmaatthemagnetosphere3. TheDopplerlinesfromNe,O,andCarenowclearlyidenffiedasdisklinesreinforcingthenofonthatweobserveadiskplasmaatRmagandplasmadensityof1015gcm-34.Thedisklinesbeforeandajertorquereversalrevealaninclinafonof38oalmosttwicethevaluepreviouslyassumed.ItappearsconsistentwithaCOwhitedwarfcompanion.5. ThedisklinesalsoshowthattheinnerradiusofthehotplasmaregioncrossestheRcobeforeandajertorquereversalsuggesfngthatRmagisalsocrossing.6.ThedataajertorquereversalalsoshowabarelyresolvednarrowFeKlinewithanoriginintheaccrefondisk,butlikelynotattheinnerdiskradius(seealsoKoliopanos&Gilfanov2015).7. NeappearstobeenhancedinthecollisionalheatedplasmasuggesfngageneralenhancementintheplasmaandamoreevolvedCOwhitedwarf.8. Finally,thedataajerthe2008torquereversal(spinup)allowadistancedeterminafonof4.5to5.5kpc,clearlyrulingoutsignificantlylargervalues.