Transcript Program_files/40 Years of Microquasarsembed

40 Years of Microquasars
Ralph Spencer
Jodrell Bank Observatory
School of Physics and Astronomy
University of Manchester
Ierapetra June 2014
Radio Emitting X-ray binaries
(REXRB)
• 1968: discovery of radio emission
from Sco X-1 (Andrew and Purton
1968)
• 1971: radio emission from X-ray
binaries detected by Westerbork
Array and GB Interferometer at ~
mJy levels (Braes and Miley
1971, Hjellming and Wade1971)
April 1971 John applies to
Jodrell Bank for a place on the
MSc course, joins in Sept
1971
Cygnus X-3 Goes Bang!
• Jan 1972: Detection of Cyg X-3
with GBI (Hjellming and Wade
1972) 0.1-0.3 Jy at 11 and 4 cm
• September 1972: –outburst on
Cyg X-3 reaching > 20 Jy. Many
observatories took part.
Oct 1972 John starts PhD
Gregory
et al 1972
Nova Monoceros 1975
A0620-00
• Rapid increase in X-ray emission
reported by Leicester group (Ariel)
• Triggered radio obs at JBO (Davis et
al. 1975)
• Kuulkers et al. 1999 revisited data
Oct 1975 John completes PhD
X-Ray Binaries
• ~300 X-ray emitting binary stars
(XRBS) found in our own Milky
Way galaxy, detected by X-ray
satellites at ~1-10 kev (van
Paradis 1995, Liu et al. 2000,
2001 catalogues)
• High Mass ~ 10 Msun
• Low Mass ~ 1 Msun
• .All powered by accretion onto a
compact object (neutron star or
black hole).
• Roche Lobe overflow or wind?
• ~20 % have been found to have
radio emission
Low Mass XRBs
•
•
•
•
•
Companions around 1 Msun, with a
neutron star or BHC secondary
Neutron star binaries
– Type I X-ray bursts
– Soft X-ray emission (few kev
brightness temp.)
– Short orbital period of < 12 hours
BHCs : no Type 1 bursts, hard X-rays,
transients
X-ray colour-colour diagram useful
diagnostic
Quasi period oscillations in X-ray
intensity
X-ray bursts from Circ X-1
High Mass X-ray
binaries: HMXRB
• Indicators:
– O, B, Be or Wolf-Rayet stellar spectrum
– Strong flaring and absorption variability on a timescale of
minutes
– Transient outbursts
– Hard 1-10 kev spectrum with a power law index at higher
energies of ~0-1
• Periods range from 4.8 hrs (Cygnus X-3) to 187 days
(Hen 715)
• N- star or BHC compact secondaries
• Generally wind fed.
The discovery of radio jets
• SS433 in 1979
• Moving optical lines suggest
precessing jets at 0.26 c
with a period of 162.5 days
(Abell and Margon 1979)
• Cambridge 5km
observations of compact
objects < 1 arcsec, Ryle et
al 1978
• Interesting X-ray behaviour
– Dennis Walsh suggested
we observed it at JB
• Discovered extension in PA
~100 deg – jets? (Spencer
1979)
Margon and Anderson 1989
MkI-Defford 74-cm 1979 visibility curve
SS433 radio jets
• Hjellming and
Johnston 1981
VLA results
• MERLIN 5 GHz
Jowett PhD 1999
Stirling et al
2002
Radio Emission
• ~50 sources have
radio emission
• Most radio
emitters are Low
Mass XRBs with
BHC
I. Brown 2006 PhD Thesis
Microquasars
• Term first used by Martin Elvis
1984 “Microquasars and the Xray Background” (Weak AGN)
• First used in the context of Xray binaries: Geldzahler,
Fomalont and Cohen 1984,
“Sco X-1 The Microquasar”
• Now thought to be unrelated
background sources
VLA 4.8 GHZ
Microquasars
• Why microquasar?
– Radio jets
– Relativistic velocities
– Powered by accretion
– 106 times closer
• Mirabel et al. 1992
1E1740.7-2942
Number of papers with ‘microquasar’ in the title or abstract
No. of papers
Year
Fundamental plane of black
holes
• Radio/X-ray correlation
found in XRBS can be
extended to AGN by the
inclusion of a mass term.
• Correlation very tight for
LLAGN
Merloni, Heinz et al. 2003, Falcke, Koerding, Markoff 2004,
Koerding et al. 2006
Some Individual Objects
•
•
•
•
•
Cygnus X-3
SS433
Cygnus X-1
GRS1915+105
Cygnus X-2
Cygnus X-3
Cygnus X-3 Green Bank Interferometer S-band data
20
Flux density Jy
• Greenbank Interferometer
Waltman et al 1995
• 1983 MERLIN 5 GHz –
model fitting N-S double
showed expansion at 0.3 c
Johnston et al. 1983
• Infra red and radio flares
Fender, Bell-Burnell, Ogley
et al. 1994,1995, 1996,
2001
15
Si
10
5
0
3
710
7.510
3
810
3
Ti
MJD
• 10 Msun WR star and 2.4
Msun BH Zdziarski et al.
2013
Fender et al 1996
8.510
3
910
3
Relationship to X-rays
• Ryle telescope and
RXTE (Pooley)
• Quenching of radio
before outburst
• Hardening of X-rays
Radio/Hard X and γ-ray Quenching
• Corbel et al 2012- hard X-rays and γ-rays
suppressed just before a major flare
Cygnus X-3 Images
• Mioduszewski et al
2001
• 15 GHz VLBA
• Evolving N-S jet
• 2-sided N-S structure
also seen in 5 GHz
VLA images (AM).
• Expansion at ~0.5 c
(Marti et al 2002)
www.aoc.nrao.edu/~amiodusz/
NB 90 deg rotation
• EVN at 5 GHZ
1st e-VLBI observations at 5 GHz
Complex changes in the core- more to do!
SS433
•
•
•
•
•
Another WR star and compact companion
24 Msun WR and 16 Msun BH
162.5 d precession period
13 d binary period
Proper motion if at 0.26 c gives distance
of 4.6 kpc
VLA 5 GHz Blundell and Bowler 2004
The Ruff – Equatorial emission
VLA, MERLIN VLBA 6 cm March 1998
Blundell et al 2001
MERLIN+EVN 18 cm June 1998
Stirling et al 2004
Present in ~25% of images, no obvious relationship to jet knots and
PA Spencer 2006
W50 and SS433 – the jets slow down?
Velocity of filaments in
the ears < 0.04c
Goodhall et al. 2011
More observations needed!
Fit to ephemeris including
nutation suggests
deceleration at 0.04c/yr
Stirling et al. 2004
Cygnus X-1 – a radio jet in a persistent black hole
XRB
15 Msun Black hole +19 Msun O star companion
VLBA 8.4 GHz
August 1998
-discovery of jet
in Cyg X-1 on
~15 mas scale
(Stirling et al
2001)
VLBA 15 GHz
Showing compact jet
~3 mas long
Also a weak
compact jet
in the soft
state
(Rushton et
al 2012
(in low/hard X-ray state)
Optical line
emission
Cyg X-1
Nebula
White:
continuum
Red: Ha
Green: O[III]
(Russell,
Fender et al.
2007)
1.4 GHz
Westerbork
image
Gallo et al 2005
GRS1915+105
10 Msun BH +2 Msun companion
Superluminal expansion
Mirabel & Rodriguez 1994
Fender et al 1999 0.9c, 11kpc
Radio emission in plateau states
(Migliari & Belloni 2003 Xray state χ)
Rushton et al 2010
0.2-0.4 Jy Flares
and 0.05-0.1 Jy
plateaus
Typically
1-3 months
Flares decay in 3-4 days, followed by a suppressed flux before recovering
Occurs during plateau state as well as at beginning or end
GRS1915 – log normal flux
distribution
Compare with power law for Cyg X-3
A Radio Jet in the Cyg X-2 Neutron Star X-ray Binary
Spencer et al. MNRAS 435L, 48, 2013
Horizontal Branch (HB) jet launched here
Z-track on
hardnessintensity
diagram
Normal Branch (NB) mass accretion rate increases
Flaring Branch (FB) unstable nuclear burning
on the neutron star
6 cm EVN 22 Feb 2013
Jet ejected
SWIFT hardness –
intensity diag.
Source in HB
23 Feb 2013
Hard Apex - Jet ejected
X-ray, UV and radio vs time
1.7 Msun neutron star
and a 0.6 Msun companion
To summarise so far
• Radio emission can be relatively steady or in
flares
• Flaring often associated with the formation of
relativistic jets on > 100 mas scales
• Steady mas (10’s au) jets can also occur
• At least one object shows precessing jets
• Strong association with X-ray emission: jet-disk
coupling
• Changing accretion conditions have a causal
relationship with the radio jets
q- diagram or Turtles Head
Gallo, Fender et al 2005
Miller et al. 2012 model for CygX-1
Radio
Reflected
X-rays
Hard
X-rays
Magnetic
loops
>0.3c
wind
0.3c
disk
O Star
companion
Hot e+- plasma lifted by unstable loops formed by magnetic rotational instability
GRS1915 evolution
High Soft X-ray state
No radio
X-ray Intensity
Flaring outburst with
relativistic ejection
Dominated
by radiation
form disk
Hot corona
and jet formed
- Blandford
Znajek 1977
mechanism
Hardness
Low Hard X-rays
Inner disk
instability
leads to
major ejection
Weak inner jet
Stronger inner jet
Plateau state
Future
• Do all galactic XRBs have radio emission at some level?
Need much better sensitivity to bring the 20% detections
up!
• Microquasars in other galaxies e.g. M31 (Middleton et al
2013), IC10 (Bernard et al 2008), NGC300 (Crowther et
al. 2010) – should be lots, especially in star forming
galaxies.
• E.g. an equivalent 10 Jy flare in IC10 from a CygX-3
type object would give 240 microJy on Earth – can be
studied with JVLA and e-MERLIN, but not quiescent
emission
• Relationship to ULXs – extending the fundamental plane
• Need the SKA!!