tidal disruption events
DESCRIPTION
Tidal Disruption Events. Andrew Levan University of Warwick. r T = R * (M CO / M * ) 1/3. Bound, falls back. Unbound, escapes. r T = R * (M CO / M * ) 1/3. Bound, falls back. Unbound, escapes. WD, NS, BH. r T = R * (M CO / M * ) 1/3. Bound, falls back. Unbound, escapes. - PowerPoint PPT PresentationTRANSCRIPT
Tidal Disruption
Events
Andrew LevanUniversity of Warwick
rT = R* (MCO / M*)1/3
Bound, falls back
Unbound, escapes
rT = R* (MCO / M*)1/3
Bound, falls back
Unbound, escapes
WD, NS, BH
rT = R* (MCO / M*)1/3
Bound, falls back
Unbound, escapes
WD, NS, BH
Asteroid, planet, star (MS, WD, RG, NS)
rT = R* (MBH / M*)1/3
Rs ~ 2 GM / c2
rT = R* (MBH / M*)1/3
tmin ~ R*3/2 MBH
1/2
Duration of event:WD = hoursMS = months - yearsRG = decades - centuries
Tidal disruption events – around massive black holes
Probe of the existence of massive BHs in faint galaxies, even
globular clusters?
Timescales much more rapid than in AGN to probe accretion
physics
Contribution to the AGN LF
Reverberation mapping of circumnuclear material
Signposts of gravitational wave sources
Signatures of merging BHs (disruption rates 1 per decade)
Possible accelerators of ultra-high energy cosmic rays
Finding TDEs
Nuclear X-ray and/or optical flares
Hot blackbody components (UV, soft X-ray spectrum)
Characteristic decay t-5/3
Rates 10-4-5 /yr/L* galaxy (0.1-1% of core collapse SNe rate)
Except……Nuclear AGN and multiple variable X-ray sources.
Often relatively poor X-ray cadence (don’t realise until it is late)
X-ray’s often give poor positions compared to optical/radio
Nuclear supernovae more common than TDEs
Some UV bright at early times, extinction always a concern.
Nuclei are bright, and often excluded from optical transient searches due to difficulties in subtractions
Contributions from disc, wind etc complicate the lightcurve.
Halpern, Gezari & Komossa 2004 ApJ 604 572
Early work(X-ray’s)
Komossa & Bade 1999 A&A 343 775
Recent work(X-ray’s)
Saxton et al. 2012 A&A 541 106
Recent work (optical)
Wavelength (A) Gezari et al. 2012 Nature 485 217
Recent work (optical)
ASASSN-14ae (200 Mpc)HST (13 June 2014)
UVOpt
Holoein et al. 2014 arXiv:1405.1417
Why not both?
Lodato & Rossi 2011 MNRAS 410 359
PS1-10jh
Just disc/wind temperature?Different components at different times?
NUV
X-ray
SGRB LGRB
Galactic Sources
SGR
ULGRB TDE?
Levan et al. 2014 ApJ 781 13
Levan et al. 2011 Science 333 199Levan et al. 2011 Science 333 199, Bloom et al. 2011 Science 333 202
Swift J1644+57
Levan et al. 2011, Cenko et al. 2012, Brown et al. in prep
In context
Levan et al. 2011, Cenko et al. 2012
Host Galaxies
Levan et al. 2011 Science 333 199All 3 events consistent with nuclei of their hosts
Bloom et al 2011 Science 333 202
Relativistic outflow
Zauderer et al. 2011 Nature 476 425
Swift J1644+57
Switch-off Swift J1644+57
Switch-off Swift J2058+0516
ImplicationsHost galaxies with
MB <-18 have massive black holes in their cores
A unique probe of galactic nuclei
Miller & Gultekin 2011 ApJ 738 13; Berger et al. 2012 arXiv 1112.1697
Jets are rare3 relativistic TDEs at z=0.35, 0.89, 1.19
All well detected by Swift
No other compelling candidates in BAT archive
Jetted TDE rate ~10-6 “classical TDEs”
Jet angles much larger than this
Requirements for jet creation unclear
PS1-10jhD23H-1D3-13D1-9
PS1-11afASASSN-14ae
PTF09gePTF09axcPTF09djl
NGC5905RXJ1242-1119RXJ1420+5334
NGC3599SDSSJ1323+4827TDXFJ1347-3254SDSSJ1311-0123
2MMMi J1847-6317
SDSSJ1201+3003
Swift J1644+57Swift J2058+0516Swift J1112-8238
Ultra-long GRBs?
UV/optical X-ray Relativistic
Are these all TDEs? Why are they so diverse?
PTF10iya
A naming convention ala SNe is urgently needed (NT-X 2014A?)
Summary and next steps
TDEs are exceptionally useful astrophysical probes
But: Candidates to date are extremely diverse. X-ray detected events have poor optical follow-up Many optically detected events don’t have detectable X-ray’s Jetted events appear to be extremely rare
We still need to understand the physical mechanisms at play to cleanly identify TDEs from other transients, and deploy them as probes.
Multiwavelength follow-up in close to real time is essential Rule out SNe Tie events to SMBH as tightly as possible Map emission processes