Deriving direct mass measurements of black holes in ULXs Jeanette Gladstone, T. Roberts, C. Copperwheat, A. Goulding, C. Heinke, A Swinbank, T. Cartwright,

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





★ 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





★ 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)






★ HLXs★ 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

Documents

Deriving direct mass measurements of black holes in ULXs Jeanette Gladstone, T. Roberts, C. Copperwheat, A. Goulding, C. Heinke, A Swinbank, T. Cartwright,