Fast Infrared Flickering from GRS 1915+105

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

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

5. 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 Class A in the IR??

6. 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 ToO Observations with HST RXTE/ASM Ryle Telescope HST/NICMOS

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

8. 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 High-Speed Photometry

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 (!) Flicker e-fold Rise Times

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

12. 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 Conclusions