Searching for Distant Wandering Massive Black Holes with Chandra

Dacheng Lin ([email protected], UNH)

Chandra Workshop, Harvard University August 17, 2016 Intro: Wandering Off-nuclear Massive Black Holes

Produced in various processes, e.g.,: Ø Collapse of massive populaon III stars in the early Universe Ø Runaway merging of massive stars in young compact star clusters Ø Tidal strip of merging satellite galaxies in minor mergers Ø Kicks from major mergers

[email protected] Intro: Ultracompact Dwarf

Ultracompact dwarf galaxies (UCDs): Among the densest stellar systems in the Universe From dally stripped merging satellite galaxies?

M60-UCD1: rh ~ 24 pc d=16.5 Mpc 8 Mtot ~ 2X10 M¤ 7 MBH ~ 2X10 M¤

(Strader et al 2013, Seth et al. 2014)

[email protected] Intro: Hyperluminous X-ray Sources

Ultraluminous X-ray sources (>1039 erg/s): Super-Eddington accreng stellar-mass BH/NS (Middleton et al. 2012, 2013, Bache et al. 2014)

Hyperluminous X-ray sources (HLXs, >1041 erg/s): 2 5 Intermediate-mass BH (10 —10 M¤)?

42 HLX-1: peak LX ~ 10 erg/s in a S0 galaxy d=90 Mpc 4 MBH ~ 10 M¤

[email protected] ESO 243-49 HLX-1 (Farrell et al. 2009, 2012) New HLX: 3XMM J141711.1+522541

Lin et al. 2016, ApJ, 821, 25

[email protected] The Host Beyond Gpc

In the Extended Groth Strip A S0 galaxy

z=0.42, dL=2.3 Gpc

Red: F814W, blue: F606W [email protected] Off-nuclear Nature

In the Extended Groth Strip A S0 galaxy

z=0.42, dL=2.3 Gpc

Circles are 95% posional errors (green: Chandra, red: XMM)

[email protected] 1 arcsec = 5.5 kpc Inacve Host

z=0.42, dL=2.3 Gpc Age: 9 Gyr 11 Mass: 4X10 M¤ 10 Lum: 3X10 L¤ 39 LOIII < 2.3X10 erg/s

41 àLbol<2X10 erg/s

σ★ ~ 247 km/s 8 àMBH~ 4X10 M¤

[email protected] Ultra-compact Opcal Counterpart

Projected Offset: 0.94 arcsec=5.2 kpc 7 Mass: ~6X10 M¤ 8 Lum: ~6X10 L¤ Reff: < 100 pc àUltra-compact dwarf (UCD)

[email protected] 1 arcsec = 5.5 kpc Ultraso X-ray Spectra

2000 July kTdisk=0.13±0.02 keV 43 LX=3.8X10 erg/s

2002 Aug kTdisk=0.17±0.04 keV 43 LX=0.5X10 erg/s

[email protected] Luminosity Curve: Caught in Outburst

Undetected later àVariaon factor >14

-5/3 t

[email protected] Source Nature

q An off-nuclear massive compact counterpart q The ultraso X-ray outburst 5 q Peak LX implies a BH of ~10 M¤

à A massive BH embedded in the nucleus of a stripped satellite galaxy with the X-ray outburst due to dal disrupon of a surrounding star by the BH

Lin et al. 2016, ApJ, 821, 25

[email protected] Source Nature

NOT from the nucleus of the host galaxy:

v Posion inconsistency v X-ray spectra too so to be from standard AGNs v Nuclear inacvity from opcal spectrum v Central SMBH too massive to disrupt the star outside the event horizon

[email protected] Search with Chandra

v New era of discovering wandering massive BHs beyond Gpc, especially through detecon of off- nuclear dal disrupon events (Komossa et al 2008) v Special sources unlike AGNs: off-nuclear HLXs, large X-ray to opcal rao, highly variable, so X-ray spectra v Require Chandra’s high angular resoluon and low background

[email protected] Tanks You

[email protected]