the brightest point x-ray sources in elliptical galaxies and the mass spectrum of accreting black...
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The Brightest point X-ray The Brightest point X-ray sources in elliptical galaxies sources in elliptical galaxies and the mass spectrum of and the mass spectrum of
accreting black holes accreting black holes N. Ivanova, V. Kalogera N. Ivanova, V. Kalogera
astro-ph/0506471astro-ph/0506471
IntroductionIntroduction
X-ray map of the X-ray map of the ChandraChandra era now extends to era now extends to the Virgo cluster (18Mpc) and beyond. the Virgo cluster (18Mpc) and beyond.
Elliptical galaxies out to the Virgo cluster Elliptical galaxies out to the Virgo cluster have surprised us with the large number have surprised us with the large number of point X-ray sources down to Lx~10^37 of point X-ray sources down to Lx~10^37 erg s^-1 erg s^-1
a break of 4-5a break of 4-5×10^38 in the XLF×10^38 in the XLF a high fraction of sources coincident with a high fraction of sources coincident with
identified globular clusters (GCs)identified globular clusters (GCs)
Kim & Fabbiano 2004
InterpretationsInterpretations
For lower end, NS For lower end, NS accretors,accretors,
H rich donor: long H rich donor: long obital period obital period transient, poor transient, poor knowledge of DCknowledge of DC
He/C/O white He/C/O white dwarf donor, dwarf donor, persistentpersistent
Bildsten & Deloye 2004
InterpretationInterpretation
For upper end, BH accretors, For upper end, BH accretors, transienttransientoutburst at L_Eddoutburst at L_Edd constrain on the mass spectrum of constrain on the mass spectrum of BHsBHs
8-12 Gyr old population in ellipticals 8-12 Gyr old population in ellipticals M_donor<1.0~1.5 M_sunM_donor<1.0~1.5 M_sun
MS, RG, WDMS, RG, WD
Assuming the outburst luminosity is equal to Assuming the outburst luminosity is equal to L_Edd,L_Edd,
Duty cycle (DC) prescription,Duty cycle (DC) prescription,
1) 1) ηη=0.01=0.01
2)2)
3)3)
1) MS donor1) MS donor
dd MdRdn ln/ln
MS donorMS donor
RVJ ITM_PT=10 M_sun
MS donorMS donor
Conclusion:Conclusion:
Regardless of the specific MB law, it is Regardless of the specific MB law, it is unlikely that persistent sources unlikely that persistent sources contribute any significant fraction to contribute any significant fraction to the upper end XLF of ellipticals.the upper end XLF of ellipticals.
Only BH-MS transients driven by the IT Only BH-MS transients driven by the IT MB law can populate this X-ray MB law can populate this X-ray luminosity range.luminosity range.
2) RG donor2) RG donor
Webbink, Rappaport, Savonije 1983Webbink, Rappaport, Savonije 1983
Conclusion: transientConclusion: transient
3) WD donor3) WD donor
WD has a mass-radius exponent of -1/3WD has a mass-radius exponent of -1/3
He WD
WD donorWD donor
For CO WD, the evolution is rather similarFor CO WD, the evolution is rather similar
WD donorWD donorConclusion:Conclusion:
BH-WD binaries that contribute to the BH-WD binaries that contribute to the upper end of XLF are expected to be upper end of XLF are expected to be transient, and M_donor<0.03 M_sun.transient, and M_donor<0.03 M_sun.
Note: This would not be true if BH-WD Note: This would not be true if BH-WD continuously formed, but this is not continuously formed, but this is not possible in the galactic field of possible in the galactic field of ellipticals and is not even expected ellipticals and is not even expected in GCs. in GCs.
Mass spectrumMass spectrumL_X=L_Edd~M_BHL_X=L_Edd~M_BH
1) MS donor1) MS donor
MS donorMS donor
MS donorMS donor
MS donorMS donor
MS donorMS donor
MS donorMS donorRobust?
RG donorRG donor
WD donorWD donor
Relative contributionRelative contribution
For the case of a constant DC, WD would dominate the transient population.
Therefore we conclude that the assumption of a constant DC is not
realistic.
discussiondiscussion
Constraints on the accreting BH mass Constraints on the accreting BH mass spectrum could contribute to our spectrum could contribute to our understanding of core collapse, and understanding of core collapse, and the connection of BH masses to their the connection of BH masses to their progenitor masses.progenitor masses.
discussiondiscussion
Origin of the Galactic ridge Origin of the Galactic ridge X-ray emissionX-ray emission
Revnivtsev et al.Revnivtsev et al.
IntroductionIntroduction
CXB and GRXECXB and GRXEGRXE: GRXE: Extending tens of degrees in longitude Extending tens of degrees in longitude
and a few degrees in latitudeand a few degrees in latitudeEnergy spectrum contains a number of Energy spectrum contains a number of
emission lines of highly ionized heavy emission lines of highly ionized heavy elements, indicating a thermal elements, indicating a thermal component of up to 5-10 keV.component of up to 5-10 keV.
The total GRXE luminosity ~ 1-The total GRXE luminosity ~ 1-2×10^38 erg s^-12×10^38 erg s^-1
GRXEGRXEThe GRXE has been detected at least up to The GRXE has been detected at least up to
20-25 keV energies, and its spectrum in 3-20-25 keV energies, and its spectrum in 3-20 keV range consists of … Gama~2.1 and 20 keV range consists of … Gama~2.1 and powerful lines at 6-7 keV. powerful lines at 6-7 keV.
It consists of qLMXBs, HMXBs, CVs, and It consists of qLMXBs, HMXBs, CVs, and coronally active binaries (ABs) etc. or truly coronally active binaries (ABs) etc. or truly diffuse?diffuse?
EbisawaEbisawa
Difficulty met by the hypothesis of diffuse Difficulty met by the hypothesis of diffuse origin of the GRXEorigin of the GRXE
Other difficultiesOther difficulties
RXTE observations and RXTE observations and analysisanalysis
The best instrument so far for large-scale The best instrument so far for large-scale mapping of the X-ray sky is the PCA mapping of the X-ray sky is the PCA (Proportional Counter Array) spectrometer (Proportional Counter Array) spectrometer abroad the RXTE (Rossi X-ray Timing abroad the RXTE (Rossi X-ray Timing Explorer).Explorer).
~6400 cm^2 at 6 keV ~6400 cm^2 at 6 keV
1 degree field of view1 degree field of view
Data are from the first layers of all PCAData are from the first layers of all PCA
Map of GRXEMap of GRXE
Map of the GRXEMap of the GRXE
Henceforth we reserve the term Henceforth we reserve the term “GRXE” to describe Galactic X-ray “GRXE” to describe Galactic X-ray emission which cannot be resolved emission which cannot be resolved into discrete sources with flux higher into discrete sources with flux higher than 10^-12 erg s^-1 cm^-2.than 10^-12 erg s^-1 cm^-2.
Disk/bulge-like componentDisk/bulge-like component
Galactic bulgeGalactic bulge
Mask out bright point sources. To this Mask out bright point sources. To this end we filtered out 1.5 deg radius end we filtered out 1.5 deg radius regions around point sources with regions around point sources with flux higher than ~1 flux higher than ~1 cnts/s/PCU/beam~1.2×10^-11 erg cnts/s/PCU/beam~1.2×10^-11 erg s^-1 cm^-2, corresponding to…s^-1 cm^-2, corresponding to…
10% systematics10% systematics
bulgebulge
bulgebulge
bulgebulgeAn analytic model of the bulge/bar stellar An analytic model of the bulge/bar stellar
volume emissivity developed by Dwek et volume emissivity developed by Dwek et al. 1995 according to the near-IR surface al. 1995 according to the near-IR surface brightness distribution of the Galaxy brightness distribution of the Galaxy measured by COBE/DIRBE,measured by COBE/DIRBE,
bulgebulge
Galactic diskGalactic disk
Galactic diskGalactic disk
Y. Xu et al. 2005
diskdisk
diskdisk
diskdisk
Cosmic Background Explorer (COBE)
/Diffuse Infrared
Background Experiment (EIRBE)
diskdisk
Broad-band spectrum of the GRXEBroad-band spectrum of the GRXE
A Galactic center “point source” (innermost A Galactic center “point source” (innermost 30 pc) measured by Integral/IBIS with hard 30 pc) measured by Integral/IBIS with hard X-ray luminosity L_20-60keV=4×10^35 erg X-ray luminosity L_20-60keV=4×10^35 erg s^-1s^-1
Deriving from the bulge/bar data, L_3-Deriving from the bulge/bar data, L_3-20keV~3.5×10^27 erg s^-1 M_sun^-1, the 20keV~3.5×10^27 erg s^-1 M_sun^-1, the “cusp” contains 10^8 M_sun, this predicts a “cusp” contains 10^8 M_sun, this predicts a 3-20keV luminosity of 4×10^35 erg s^-1. 3-20keV luminosity of 4×10^35 erg s^-1. Assuming a Gama=2.1 power law, L_20-60 Assuming a Gama=2.1 power law, L_20-60 keV=2×10^35 erg s^-1 keV=2×10^35 erg s^-1
Broad-band spectrumBroad-band spectrum
Thank you!Thank you!