Fast Infrared Flickering from GRS 1915 105

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Fast Infrared Flickering from GRS 1915105

• The Spirit of Stephen Eikenberry
• (University of Florida)
• As Channeled by David Rothstein
• (Cornell University)
• 19 October 2006

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Collaborators

• Stephen Eikenberry (U. Florida)
• Shannon Patel (U. Florida UC Santa Cruz)
• David Rothstein (Cornell)
• Ron Remillard (MIT)
• Guy Pooley (Cambridge)
• Ed Morgan (MIT)

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GRS 1915105 Obligatory Jet Slide

• You know the chorus sing along!

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3 Different Classes of Jets/Flares
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Class A in the IR??

• Sams, Eckart, Sunyaev (1996) found IR
  elongation in GRS 1915105 direction lies along
  radio jet axis
• Eikenberry Fazio (1997) found that it was gone
  a few months later
• Transient resolved IR jet?
• Inspired HST/NICMOS ToO proposal
• Use plateau state RXTE/ ASM hardness evolution
  to try and catch an outburst

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ToO Observations with HST

• Feb-June 2003 GRS 1915 entered plateau and
  showed trigger signs
• Outburst aborted and returned to plateau
• Tried again at the second end
• No major relativistic outflow seen
• IR (1.9?m) variability flux anti-correlated
  with X-ray

RXTE/ASM
Ryle Telescope
HST/NICMOS
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Broadband IR Photometry

• Points w/error bars are comparison star
• Diamonds show GRS 1915105 flux

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High-Speed Photometry

• NICMOS MultiAccum mode allows ?t8-sec photometry
• In 3 visits, find evidence of small (10-30
  1-3 mJy) IR flickering
• Comparison star is steady (w/in uncertainties)
• GRS1915 is variable at the 5? to 15? level
• These flares are much faster than previous IR
  variability in GRS1915

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Fast Flickering

• Previous flares have
• - total ?t gt200-2000s
• - e-fold rise/fall ? 300s
• 15 Flickers here have
• - total ?t fast as 16-s
• - e-fold rise/fall ?min 30s
• This is an order of magnitude faster than seen
  before at long wavelengths (!)

Flicker e-fold Rise Times
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Where Does It Come From Disk?

• X-rays often fast enough
• Could this be IR reprocessing of X-ray flares in
  the inner disk on the outer disk?
• X-ray shows strong QPO at 1-Hz during this time

• But not much excess X-ray power at 0.1 Hz
• Smooth X-ray lightcurve to 8-sec resolution ? RMS
  deviations lt2-3
• RMS IR variation 4-8 ? IR flares not due to
  reprocessing of X-rays

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Where Does It Come From Jet?
Jet (radio, infrared)Radio optically thin _at_ D
50 AURblob 1 AU

• Previous IR variability definitely linked to jet
• IR flickering only during plateau state, when we
  know jet is present
• Perhaps the flickers are jet-driven
• Assume standard opening angle ?1-degree
• If light-crossing time 30-s here, then D ?2.5
  AU ? IR flickers from base of jet

Klein-Wolt et al., 2002 Dhawan et al., 2000
Accretion Disk
Artwork by D. Rothstein
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Conclusions

• GRS 1915105 has shown a range of IR variability
  related to jets, typically with ? 200-300s
• In 2003, GRS1915 showed higher and more variable
  IR flux in the plateau state than during
  X-ray/radio flares
• In the plateau state, IR variability included
  fast IR flickering on timescales with ?30s
• This is x10 faster than previous types of IR
  flaring
• IR does not seem to be directly correlated with
  any particular X-ray variability (i.e. not
  reprocessed X-rays)
• If the IR flickering comes from the jet, then it
  seems likely that it arises near the base of the
  jet, ?2.5 AU from the black hole