fast infrared flickering from grs 1915+105
DESCRIPTION
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. Collaborators. Stephen Eikenberry (U. Florida) Shannon Patel (U. Florida & UC Santa Cruz) David Rothstein (Cornell) - PowerPoint PPT PresentationTRANSCRIPT
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
Collaborators
• Stephen Eikenberry (U. Florida)
• Shannon Patel (U. Florida & UC Santa Cruz)
• David Rothstein (Cornell)
• Ron Remillard (MIT)
• Guy Pooley (Cambridge)
• Ed Morgan (MIT)
GRS 1915+105: Obligatory Jet Slide
• You know the chorus – sing along!
Mirabel & Rodríguez (1994)
~ 6,000 AU
Brightness ~ 600 mJy
3 Different Classes of Jets/Flares
Class B (“large”)
Class C (“medium”)Class A (“extra large”)
Mirabel & Rodríguez (1994)
~ 6,000 AU
Timescales ~ weeksBrightness ~ 600 mJy
Eik
enb
erry
et a
l. (2
00
0)
Timescales ~ less than 30 minutesBrightness ~ 5-10 mJy (dereddened)
Dhaw
an, M
irabel &
Rodríg
uez
(20
00
)Eikenberry et al. (1998a)
Timescales ~ 30 minutesBrightness ~ 50-200 mJy (dereddened)
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
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 (1.9m) variability & flux anti-correlated with X-ray
RXTE/ASM
Ryle Telescope
HST/NICMOS
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
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
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
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
Rblob ~1 AU
Artwork by D. Rothstein
Klein-Wolt et al., 2002; Dhawan et al., 2000
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