Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/research/Astro2008/Postings/Laura_Blecha.pdf Дата изменения: Thu Jun 26 05:00:27 2008 Дата индексирования: Sat Sep 6 16:00:30 2008 Кодировка: Поисковые слова: южная атлантическая аномалия

Observable Signatures of Ejected Black Holes
Harvard Center for Astrophysics
CSIRO Conference June 18, 2008

Laura Blecha


How Are SMBHs Ejected?


Dynamical kick (3-body SMBH interaction)
­ ­

Requires tmerge,BH > tmerge,galaxy ("dry" mergers?) Ejection of lightest BH less common than merger of two BHs (Hoffman & Loeb 2007)
(Wiseman 1992)



Gravitational-wave (GW) recoil kick
­

­

Results from asymmetrical GW emission during BH merger Relevant mechanism for wider range of systems


GW Recoil Kick Speeds


Kicks up to ~4000 km/s are possible (Campanelli
et al. 2007)



Kick velocity PDF:
(Schnittman & Buonanno 2007)
­ ­

a1 = a2 = 0.9 Random spin orientations



Kicks could be lower if spins aligned
(Bogdanovi et al. 2007)


GW Recoil Kick Speeds


Kicks up to ~4000 km/s are possible (Campanelli
et al. 2007)



Kick velocity PDF:
(Schnittman & Buonanno 2007)
­ ­
2000 km/s

1% c o n to u r

a1 = a2 = 0.9 Random spin orientations
500 km/s



Kicks could be lower if spins aligned
(Bogdanovi et al. 2007)

10% c o n to u r


BHs in Motion: A New Twist on an Old Story


SMBH and galaxy growth tightly linked => feedback processes Feedback will change entirely if BH is in motion





Questions:


BHs in Motion: A New Twist on an Old Story


SMBH and galaxy growth tightly linked => feedback processes Feedback will change entirely if BH is in motion





Questions:
­

How does feedback,

GW and

recoil affect SMBH growth, SMBH/galaxy coevolution?


BHs in Motion: A New Twist on an Old Story


SMBH and galaxy growth tightly linked => feedback processes Feedback will change entirely if BH is in motion





Questions:
­ ­

How does GW recoil affect SMBH growth, feedback, and SMBH/galaxy coevolution? What are the observable signatures of recoil?


BHs in Motion: A New Twist on an Old Story


SMBH and galaxy growth tightly linked => feedback processes Feedback will change entirely if BH is in motion





Questions:
­ ­ ­

How does GW recoil affect SMBH growth, feedback, and SMBH/galaxy coevolution? What are the observable signatures of recoil? Which types of recoiling systems are most likely to be observed?


Observable Signatures


Need EM counterpart Recoiling quasars:
­

"Off-center" quasars (rej ~ G M / vkick2) "Disk-crossing" quasars Observable via spatial or kinematic offsets

­ ­


Observable Signatures


Need EM counterpart Recoiling quasars:
­

"Off-center" quasars (rej ~ G M / vkick2) "Disk-crossing" quasars Observable via spatial or kinematic offsets

(Shields & Bonning 2008)

­ ­



Recoil flares (Lippai et al 2008,
Shields & Bonning 2008)


Observable Signatures


Need EM counterpart Recoiling quasars:
­

"Off-center" quasars (rej ~ G M / vkick2) "Disk-crossing" quasars Observable via spatial or kinematic offsets

(Ferrarese & Ford 2005)

­ ­



Recoil flares (Lippai et al 2008,
Shields & Bonning 2008)



Scatter in MBH- relation


Observational Constraints


"Empty" galaxies generally not seen locally Search for kinematic offsets in quasar spectra => null result
(Bonning et al. 2007)



SDSS quasar with 2650 km/s offset between BLR and NLR => GW recoil candidate
(Komossa et al. 2008)


GW Recoil Kick Speeds


Kicks up to ~4000 km/s are possible (Campanelli
et al. 2007)



Kick velocity PDF:
(Schnittman & Buonanno 2007)
­ ­

a1 = a2 = 0.9 Random spin orientations



Kicks could be lower if spins aligned
(Bogdanovi et al. 2007)


A model for recoiling SMBHs


Integrate trajectory of recoiling BH
­ ­

Smooth potential (stellar bulge + gas disk) Stellar and gaseous dynamical friction



Calculate (-disk +

accretion rate using hybrid model Bondi)



Free parameters: recoil kick speed and inclination Fiducial Model:
­ ­



MBH ~ 108 M Mgas = 0.5 M


Example of SMBH trajectory
Fiducial Model vkick = 440 km/s i = 45o


Example of SMBH trajectory
Fiducial Model vkick = 440 km/s i = 45o

taccr ~ 9 Myr


Example of SMBH trajectory
Fiducial Model vkick = 740 km/s i = 45o


Example of SMBH trajectory
Fiducial Model vkick = 740 km/s i = 45o
Rmax ~ 14 kpc


Example of SMBH trajectory
Fiducial Model vkick = 740 km/s i = 45o taccr ~ 5 Myr



M ~ 10% MBH


-- Ejected-disk
accretion time -- Wandering time -- QSO duty cycle


-- Ejected-disk
accretion time -- Wandering time -- QSO duty cycle


MBH = 10 M
fgas = 0.1 fgas = 0.5
8

9

MBH = 10 M

(Fiducial Model)

MBH = 10 M

6


-- All data -- Off-center

QSO -- Disk-crossing QSO

-- Ejected-disk
accretion time -- Wandering time -- QSO duty cycle


---

All data Off-center QSO -- Disk-crossing QSO

108 M

10 M

9


Conclusions


Recoiling AGN have much larger effective emitting region than stationary AGN => affects feedback processes


Conclusions


Recoiling AGN have much larger effective emitting region than stationary AGN => affects feedback processes Mass accreted by recoiling BHs is ~10% MBH for all vkick => implies that recoiling BHs can self-regulate growth




Conclusions


Recoiling AGN have much larger effective emitting region than stationary AGN => affects feedback processes Mass accreted by recoiling BHs is ~10% MBH for all vkick => implies that recoiling BHs can self-regulate growth "Disk crossings" contribute little to recoiling quasar phases, but may produce additional "recoil flares"






Conclusions


Recoiling AGN have much larger effective emitting region than stationary AGN => affects feedback processes Mass accreted by recoiling BHs is ~10% MBH for all vkick => implies that recoiling BHs can self-regulate growth "Disk crossings" contribute little to recoiling quasar phases, but may produce additional "recoil flares" Largest kicks correspond to shortest duty cycles => observing GW recoil events may be challenging








Conclusions


Recoiling AGN have much larger effective emitting region than stationary AGN => affects feedback processes Mass accreted by recoiling BHs is ~10% MBH for all vkick => implies that recoiling BHs can self-regulate growth "Disk crossings" contribute little to recoiling quasar phases, but may produce additional "recoil flares" Largest kicks correspond to shortest duty cycles => observing GW recoil events may be challenging Observational challenges + self-regulated growth => cannot exclude significant population of moving BHs