The continuing saga of the explosive event(s) in the M87 jet D. E. Harris, SAO

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The continuing saga of the explosive event(s) in
the M87 jet D. E. Harris, SAO

• collaborators/co-authors
• C. C. Cheung J. A. Biretta F.
  Aharonian
• L. Stawarz E. S. Perlman
  S. Wagner
• W. Sparks
  D. Horn
• A. S. Wilson K. Mannheim
• 
  T. Bretz
• 
  H. Krawczynski
• 
  R. Mukherjee
• 
  V. Vassiliev
• 
  J. Carson

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Reminder when viewing radio -

• We think we see (distorted) view of emitting
  volumes containing relativistic electrons and
  magnetic fields.
• distorted shape from projection effects
  aberration
• distorted intensity from relativistic beaming

3
When viewing an X-ray image -

• In addition to the same attributes as the radio,
• We are viewing acceleration regions I.e. high
  energy electrons are being produced throughout
  the emitting volume.

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outline

• UV/HST image, J. Madrid W. Sparks
• Part I X-ray LC of core, HST-1, knots D
  A. - caveats are the instrumental effects.
• Part II Superluminal proper motions of radio
  components within HST-1.
• Part III The TeV connection.

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Photometry

• Straightforward to separate core HST-1 when
  there is no pileup - model the PSF w. ChaRT.
• First order recovery of piled events weight each
  event w. its energy and sum 0.2-17keV use evt1
  file with no grade filtering (mitigate effects of
  grade migration)

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keV/s light curves for core, HST1, knots D and A
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Bleeding from release of trapped charge at
readout time
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Instrumental Problems

• Subtract 5 of HST-1 from the core.
• Bleeding from one side of PSF release of trapped
  charge (not modeled).
• Other losses include ETN (eat-thy-neighbor),
  on-board filtering, and bits of piled events
  which are outside 3x3 pixel region.

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Readout Streak Photometry

• Lousy s/n we get the equivalent of 18s of CC
  mode from a 5ks observation by measuring 40
  rows. Background is high.
• Apparently, true peak is significantly higher
  than what we had thought.

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The Radio Side

• Started VLA in 2003
• To avoid data gaps when VLA is in C D arrays,
  started VLBA in 2005.

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Superluminal Proper Motions

• The inner (vlba) jet is not known to be
  superluminal.
• HST-1 has ßv/c4 for some components.

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HST-1

• 4 epochs shown between 2005.0 and 2006.5 (we have
  about a dozen more coming)
• New bits getting resolved and downstream bit
  moving

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Trajectories on the sky

• A (blue) at 2.5c, then decelerates to 1.4c
• B (green) trails A, same velocity, but different
  PA.
• C (red magenta) splits into 2 components with
  c1 (magenta) moving faster, at 4.3?0.7.

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The TeV connection

• HESS group reported a higher gamma ray flux in
  2005. They argued that because of rapid
  variability, the likely origin was the nucleus
  (close to SMBH) in spite of apparent similarity
  of X-ray and ?-ray light curves.

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Evidence that the HESS ?-rays originated in
HST-1 rather than from the nuclear region.

• The X-ray LC for HST-1 peaked at the same time as
  the ?-ray high state.
• IC is a mandatory process of any relativistic
  plasma both starlight and the synchrotron
  spectrum are most prominent 1014 Hz TeV
  emission is expected from ?106 electrons, and
  the expected intensity is approximately what was
  observed.
• The IC and synchrotron spectral indices have
  similar values.
• The photon-photon opacity for the alternate
  location near the SMBH is much greater than 1.

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Short Timescale Variability

• As often happens, the data are ambiguous. In
  principle we could use similarities in light
  curves to decide the origin of the ?-rays. In
  practice, there is not enough overlap.

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To what extent is M87 a Blazar?

• Defining characteristics
• Large change of amplitude (flare)
• Associated generation of superluminal blobs
• Associated VHE emission.
• Idiosyncrasies
• M87 timescale is longer than typical blazar

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FIN

• Nature has been fairly kind after we find
  something unique like the first pulsar, we then
  find many more and are able to study the class of
  these objects. In the case of M87, it thus seems
  either the flare of 2005 is unique and we now
  have to search for similar events in other jets
  (nothing like this has so far been detected in
  the Cen A jet, despite many observations over
  many years), OR it is just an individual member
  of a known class (e.g. blazars), albeit with some
  extreme values.