deriving direct mass measurements of black holes in ulxs jeanette gladstone, t. roberts, c....
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Deriving direct mass measurements of black holes in ULXs
Deriving direct mass measurements of black holes in ULXs
Jeanette Gladstone,
T. Roberts, C. Copperwheat, A. Goulding, C. Heinke, A Swinbank, T. Cartwright, A. Levan, M. Goad, M. Ward.
And work by others
Jeanette Gladstone,
T. Roberts, C. Copperwheat, A. Goulding, C. Heinke, A Swinbank, T. Cartwright, A. Levan, M. Goad, M. Ward.
And work by others
Importance of mass measurementsImportance of mass measurements★ All aware of historical aspect★ All aware of historical aspect
Stellar remnant black hole (<~100 Msun)? Beamed emission
(relativistic jets)? (e.g. Körding et al. 2002)
Anisotropic system? (King et al. 2001)
True super-Eddington accretion?
Stellar remnant black hole (<~100 Msun)? Beamed emission
(relativistic jets)? (e.g. Körding et al. 2002)
Anisotropic system? (King et al. 2001)
True super-Eddington accretion?
Intermediate mass black holes (IMBHs)
Intermediate in Luminosity between stellar mass & super-massive black holes
The missing link in the mass scale?
Isotropically, sub-Eddington accretion in a standard accretion state
Intermediate mass black holes (IMBHs)
Intermediate in Luminosity between stellar mass & super-massive black holes
The missing link in the mass scale?
Isotropically, sub-Eddington accretion in a standard accretion state
Indirect measurements gave us ...Indirect measurements gave us ...★ Lead to sub-classification of ULXs,
relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ Lead to sub-classification of ULXs, relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
Indirect measurements gave us ...Indirect measurements gave us ...★ Lead to sub-classification of ULXs,
relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ includes the borderline & transients★ LX < ~ 3 * 1039 erg s-1
★ Lead to sub-classification of ULXs, relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ includes the borderline & transients★ LX < ~ 3 * 1039 erg s-1
sULXssULXs★ majority thought to be stellar remnant black
hole approaching or exceeding Eddington★ majority thought to be stellar remnant black
hole approaching or exceeding Eddington★ number in interacting
galaxies (King 2004) ★ star-formation association
(Swartz et al. 2009)★ X-ray spectra (Gladstone et
al. 2009; Bachetti et al. 2013)★ transient sources showing
evolution to ULX like spectra (Middleton et al. 2012; 2013)
★ number in interacting galaxies (King 2004)
★ star-formation association (Swartz et al. 2009)
★ X-ray spectra (Gladstone et al. 2009; Bachetti et al. 2013)
★ transient sources showing evolution to ULX like spectra (Middleton et al. 2012; 2013)
Composite image - Chandra (purple); Galaxy Evolution Explorer satellite
(ultraviolet/blue); HST (visible/green); Spitzer (infrared/red).
(NASA/JPL/Caltech/P.Appleton et al. X-ray: NASA/CXC/A.Wolter \&
G.Trinchieri et al.
Composite image - Chandra (purple); Galaxy Evolution Explorer satellite
(ultraviolet/blue); HST (visible/green); Spitzer (infrared/red).
(NASA/JPL/Caltech/P.Appleton et al. X-ray: NASA/CXC/A.Wolter \&
G.Trinchieri et al.
Unfolded spectrum of NGC 1313 X-2 containing XMM-Newton & NuSTAR
from Bachetti et al. 2013
Unfolded spectrum of NGC 1313 X-2 containing XMM-Newton & NuSTAR
from Bachetti et al. 2013
Indirect measurements gave us ...Indirect measurements gave us ...★ Lead to sub-classification of ULXs,
relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ includes the borderline & transients★ LX < ~ 3 * 1039 erg s-1
★ extreme ULXs (eULXs)★ ~2 * 1040 erg s-1 < LX < ~ 1041 erg s-1
★ Lead to sub-classification of ULXs, relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ includes the borderline & transients★ LX < ~ 3 * 1039 erg s-1
★ extreme ULXs (eULXs)★ ~2 * 1040 erg s-1 < LX < ~ 1041 erg s-1
eULXseULXs★ mix of stellar remnant & IMBHs?★ mix of stellar remnant & IMBHs?
★ harder spectra★ more variability★ may be IMBHs, and yet★ NGC 5907 ULX show
signs of high energy break - similar to sULXs
★ harder spectra★ more variability★ may be IMBHs, and yet★ NGC 5907 ULX show
signs of high energy break - similar to sULXs
Sutton et al. (2012)Sutton et al. (2013)
Indirect measurements gave us ...Indirect measurements gave us ...★ Lead to sub-classification of ULXs,
relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ includes the borderline & transients★ LX < ~ 3 * 1039 erg s-1
★ extreme ULXs (eULXs)★ ~2 * 1040 erg s-1 < LX < ~ 1041 erg s-1
★ HLXs★ LX > 1041 erg s-1
★ Lead to sub-classification of ULXs, relating to potential explanations of mass/accretion processes
★ standard ULXs (sULXs)★ ~1039 erg s-1 < LX < ~ 2 * 1040 erg s-1
★ includes the borderline & transients★ LX < ~ 3 * 1039 erg s-1
★ extreme ULXs (eULXs)★ ~2 * 1040 erg s-1 < LX < ~ 1041 erg s-1
★ HLXs★ LX > 1041 erg s-1
HLXsHLXs★ strongest candidates for
IMBHs. ★ few known★ Brightest reported ESO 243-
49 HLX-1, reaching ~ 1042 erg s-1
★ strongest candidates for IMBHs.
★ few known★ Brightest reported ESO 243-
49 HLX-1, reaching ~ 1042 erg s-1
Composite HST image of ESO 243-49 constructed from all UV, optical and near-IR WFC3 data, with position of HLX-1 marked
So what is there still to do?
So what is there still to do?
Evidence is indirect, need to confirm this to convince wider
community
Evidence is indirect, need to confirm this to convince wider
community Dynamical mass measurements
using the optical companion Dynamical mass measurements
using the optical companion
Start where we have the more information, and most sources ...
sULXs
Start where we have the more information, and most sources ...
sULXs
Optical CounterpartsOptical Counterparts★ First stage - identify optical counterparts★ First stage - identify optical counterparts
M81 X-6
NGC 3034 ULX6
★ number of individual sources identified
★ need bright nearby objects
★ Gladstone et al. (2013) presented catalogue of of nearby counterparts
★ number of individual sources identified
★ need bright nearby objects
★ Gladstone et al. (2013) presented catalogue of of nearby counterparts
Optical counterpart catalogueOptical counterpart catalogue
★ combines Hubble & Chandra to identify potential counterparts to ULXs in ~ 5 Mpc
★ mV ≈ 20-26
★ 22 ULX have possible optical counterparts (40 identified; 13 +/- 5 are true)
★ SED & MV suggest most are OB-type star - one rule this out
★ X-ray irradiation modelling suggests 10 (of 18) candidate companions are not O stars, while all (18) could be B-type
★ combines Hubble & Chandra to identify potential counterparts to ULXs in ~ 5 Mpc
★ mV ≈ 20-26
★ 22 ULX have possible optical counterparts (40 identified; 13 +/- 5 are true)
★ SED & MV suggest most are OB-type star - one rule this out
★ X-ray irradiation modelling suggests 10 (of 18) candidate companions are not O stars, while all (18) could be B-type
Gladstone et al. (2013)
Only a handful bright enough for spectroscopic
followup
Pilot spectroscopyPilot spectroscopy
★ Most spectra appear almost featureless & non-stellar
★ Nebula lines are present★ He II feature visible in some
★ Most spectra appear almost featureless & non-stellar
★ Nebula lines are present★ He II feature visible in some
Roberts et al. 2011
Dynamical massesDynamical masses
Early Cyg X-1 data (Bolton 1975) from stellar absorption lines
K*
P
From companion star:
From compact object:
Radial velocity curve of GRO J1655 from He II line (Soria et al. 1998)
To ‘weigh’ a BH – measure binary period and radial velocity shifts
Varying He II emission (Ho IX X-1)?Varying He II emission (Ho IX X-1)?
The problemThe problem★ A deeper look reveals
extended He II emission★ Single He II line
contains 2 components★ Currently don’t have
the resolution to separate the two
★ Need next generation if telescope/instruments
★ We can work with limits however …
★ A deeper look reveals extended He II emission
★ Single He II line contains 2 components
★ Currently don’t have the resolution to separate the two
★ Need next generation if telescope/instruments
★ We can work with limits however …
Ho IX X-1 Moon et al 2011
Current constraintsCurrent constraints
Ho IX X-12σ upper limits: K < 97 km s-1
What about more transient souces?What about more transient souces?★ M101 ULX
★ Distance ~7 Mpc★ Peak LX ~ 3 * 1039 erg s-1
★ Low state LX ~ 2 * 1037 erg s-1
★ X-ray outburst occurs every ~6 months, lasting ~10 - 30 days
★ Luminosity in high state far exceeds that of other transients
★ Affords opportunity to study in low state
★ M101 ULX★ Distance ~7 Mpc★ Peak LX ~ 3 * 1039 erg s-1
★ Low state LX ~ 2 * 1037 erg s-1
★ X-ray outburst occurs every ~6 months, lasting ~10 - 30 days
★ Luminosity in high state far exceeds that of other transients
★ Affords opportunity to study in low state
Optical observations of M101 ULX1Optical observations of M101 ULX1★ Observed with Gemini Feb - May 2010,
when in low state★ Combined spectra confirms secondary is
Wolf-Rayet star
★ Observed with Gemini Feb - May 2010, when in low state
★ Combined spectra confirms secondary is Wolf-Rayet star
Text
Mass ~ 18Msun
Radius ~ 10.7 Rsun
Period?Period?
★ orbital period of ~8.2 days★ K ~ 61 km/s
★ M ≳ 5 Msun
★ orbital period of ~8.2 days★ K ~ 61 km/s
★ M ≳ 5 Msun
M101 ULX1M101 ULX1★ Average LX ~ 3 * 1038 erg s-1
★ Average rate ~ (1/ƞ) 6 * 10-9 Msun/yr
★ By folding in estimates for the average mass accretion rate obtain a likely mass of 20 - 30 Msun
★ Similar mass range to IC 10 X-1 & NGC 300 X-1
★ Average LX ~ 3 * 1038 erg s-1
★ Average rate ~ (1/ƞ) 6 * 10-9 Msun/yr
★ By folding in estimates for the average mass accretion rate obtain a likely mass of 20 - 30 Msun
★ Similar mass range to IC 10 X-1 & NGC 300 X-1
The difficulties in obtaining mass estimatesThe difficulties in obtaining mass estimates
★ ULXs are bright in X-rays★ Create fascinating systems to observe and
investigate★ tend to cause problems with He II emission ★ need the next generation instruments /
equipment for study of most systems★ can get round this by studying transient
systems ★ seems to show slightly larger stellar remnant
black holes★ as for other sub-classes, there is still much
to do
★ ULXs are bright in X-rays★ Create fascinating systems to observe and
investigate★ tend to cause problems with He II emission ★ need the next generation instruments /
equipment for study of most systems★ can get round this by studying transient
systems ★ seems to show slightly larger stellar remnant
black holes★ as for other sub-classes, there is still much
to do