1. Fast Infrared Flickering from GRS 1915+105 The Spirit of Stephen Eikenberry (University of Florida) As Channeled by David Rothstein (Cornell University) 19 October 2006

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

3. GRS 1915+105: Obligatory Jet Slide You know the chorus – sing along! Mirabel & Rodríguez (1994) ~ 6,000 AU Brightness ~ 600 mJy

4. 3 Different Classes of Jets/Flares Class B (“large”) Class C (“medium”) Class A (“extra large”) Mirabel & Rodríguez (1994) ~ 6,000 AU Timescales ~ weeks Brightness ~ 600 mJy Eikenberry et al. (2000) Timescales ~ less than 30 minutes Brightness ~ 5-10 mJy (dereddened) Dhawan, Mirabel & Rodríguez (2000) Eikenberry et al. (1998a) Timescales ~ 30 minutes Brightness ~ 50-200 mJy (dereddened)

5. Class A in the IR?? Sams, Eckart, & Sunyaev (1996) found IR elongation in GRS 1915+105; 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

6. 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

7. Broadband IR Photometry Points w/error bars are comparison star Diamonds show GRS 1915+105 flux

8. High-Speed Photometry NICMOS MultiAccum mode allows  t=8-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

9. Fast Flickering Previous flares have: - total  t >200-2000s - 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 (!) Flare #  (s) Flare #  (s) 1 58  8 9 45  5 2 31  4 10 55  6 3 43  7 11 51  9 4 27  9 12 48  9 5 49  7 13 30  4 6 64  13 14 28  3 7 52  9 15 37  5 8 28  9 Flicker e-fold Rise Times

10. 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 <2-3% RMS IR variation ~4-8%  IR flares not due to reprocessing of X-rays

11. Where Does It Come From – Jet? 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 Accretion Disk Jet (radio, infrared) Radio optically thin @ D ~50 AU R blob ~1 AU Artwork by D. Rothstein Klein-Wolt et al., 2002; Dhawan et al., 2000

12. Conclusions GRS 1915+105 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