A Decelerating Jet in the X-Ray
Transient XTE J1752-223
J. Yang & Z. Paragi
Joint Institute for VLBI in Europe, Netherlands
University College London, UK
University Paris, France
R. P. Fender
University of Southampton, UK
� Introduction to X-ray binaries
� The 1st known outburst of XTE J1752-223
� Rapid-response EVN and VLBA observations
� Direct evidence for jet deceleration
� Detection of the brightened receding jet
� Preliminary results of follow-up observations
(1) Mass > 5 M sun
High Mass X-ray binaries
(2) Mass < M sun
Low Mass X-ray binaries
X-ray binaries are directly analogous to
extragalactic AGN with timescales >10 6 shorter.
Mirabel & Rodriguez, 1994
As source softens,
shock in jet
show no jet
Blue: Jet Yellow: Corona
Red: Accretion disc.
hard sources have
Fender, Belloni & Gallo (2004 , 2009)
XTE J1752-223: A New Galactic Black Hole Candidate
# Discovered by RXTE on 23 Oct 2009----right at the start of an outburst.
(Markwardt et al. 2009)
# MAXI and Swift were also triggered to monitor its outburst.
# MAXI: Monitor of All-sky X-ray Image
Rossi X-ray Timing Explorer
# Monitored by ATCA too
Australia Telescope Compact Array
MAXI Monitoring Observations
(Nakahira et al. 2010)
X-ray Hard State X-ray Soft State
2009 Dec 20 – 2010 Jan 19 2010 Jan 20 – 2010 Feb 28
Red: 2-4 keV Green: 4-10 keV Blue: 10-20 keV
X-ray Hard Soft Hard Hardness-Intensity Diagram
Around 21 Jan 2010
(INAF-OAB T. Belloni)
Hard (non-thermal): 5.7-9.5 keV
Soft (thermal): 2.8-5.7 keV
Multiple Radio Outbursts
(Brocksopp et al. in prep.)
Rapid-Response VLBI Observations
Date Array N antenna Bandwidth
2010-02-11 e-EVN 5 1024 1.2
2010-02-18 VLBA 6 512 3
2010-02-23 VLBA 7 512 6
2010-02-26 VLBA 7 512 6
2010-03-22 EVN 8 1024 6
2010-04-25 VLBA 7 512 6
2010-04-29 VLBA 7 512 6
Providing phase solutions and a reference origin
� Reference source: PMN J1755-2232
� Separation: 0.8 degree
� Cycle time: 240 seconds (Target: 160 s; Ref. source: 80 s)
� Total flux density: ~0.2 Jy at 5 GHz
� Size: 4.2 mas, well fitted by a circular Gaussian model
The resolved structure is most
likely due to scatter broadening
Angular Size ∞ Wavelength 2
No fringe-fitting solutions on the
long baselines to Mk and Sc.
VLBI Data Calibration
� A-priori amplitude calibration (Tsys and gain curves).
� Correction for the EOP model error for the VLBA data.
� Correction for the parrallactic angle.
� Fringe-fitting NRAO 530 data.
� Bandpass calibration with NRAO 530.
� Solving for instrumental phase and delay.
� Fringe-fitting PMN J1755-2232 with bandpass solutions.
� Applying fringe-fitting solutions to the target.
� Self calibration and imaging PMN J1755-2232.
� Applying the self-calibration solutions to the target again.
First VLBI detection of a decelerating jet
Another possible jet component.
Component B was not seen before 26 Feb 2010.
The reference date MJD 55238.4 is 11 Feb 2010.
Cross: position of the first detection of component A
Contour levels: 3σ rms X (-1.4, -1, 1, 1.4, 2.8, 4) . Deceleration rate: dμ/dt
dμ/dt ≠ 0
dμ/dt = 0
Kinematics of Component A
Model Proper motion
(mas/day 2 )
r 0 + μt μ = 6.90 ± 0.05 2.16 ± 0.39 None 118.4
r 0 + μ 0 t + 0.5(dμ/dt) t 2 μ 0 = 9.15 ± 0.15 0.06 ± 0.41 –0.34 ± 0.02 3.9
Strong evidence for jet interaction with the interstellar
medium or with residual material from previous ejection.
Jet deceleration in XTE J1550-564
On the arcsecond scale with the Chandra observations
Corbel et al. 2002, Nature; Kaaret et al. 2003, ApJ; Hao et al. 2009
Bow shock front inflated by the jet in Cyg X-1
Gallo et al. Nature 2005
H-alpha and O[III] Line-emitting nebula.
Russell, Fender et al. (2006, 2007)
Detection of the receding jet
in Component A
----Nature of component B
# Angular size of B: 12±1 mas
----An evolved component.
# ATCA observations show steep
(ν -1 ) and stable spectral index
between 5 and 9 GHz during our
----No hint of new ejection.
� The expansion rate of Component A is 0.9±1 mas/day----pretty smaller
than its proper motion and supporting the constrained expansion.
� Assuming linear expansion, the outburst started 8.7 days earlier and the
average separation speed between components A and B was
μ app + μ rec = 20.4 mas/day, i.e. μ app ≥ 10.2 mas/day
The lower limit of the initial velocity at the base
If the jet expansion is linear and symmetric on both sides, the ratio of their
angular size (R) at the same observing time is (e.g. Miller-Jones et al. 2004):
where t is the intrinsic time in the source frame and β(0, t) is the average jet
speed from its birth to time t.
R app =21.3 mas, extrpolated from the expansion model.
R rec =11.9 mas, not likely affected by the limited sensitivity as it was brightening.
Given t rec ≤ t app and the jet deceleration, we can obtain:
β(0, t rec ) cos θ ≥ 0.3 c
The lower limit of the initial velocity at the base is 0.3 c
The ratio of the flux density measured at R app = R rec =
11.9 mas (t app = t rec , free from its intrinsic luminosity
evolution effect, Mirabel & Rodríguez 1999):
In the observer’s frame, the corresponding time for the
approaching jet is between first two VLBI observations.
Thus, the jet deceleration is on both sides.
≥ 0.3 c
0 trec ≥ 0.3 c
Doppler deboosting factor:
The observed flux density is proportion to:
If β ↓, then δ rec ↑. The Doppler deboosting effect is getting
weak----brightening of the receding jet.
Note that the non-detection at first epoch may be also
because it stayed at an earlier stage and it’s intrinsic
luminosity was low.
One month later, still in X-ray soft state, another receding
ejecta was detected by the EVN observations.
Peak: 0.25 mJy/beam
Date of the EVN
Dirty map Dirty map
B C +
The inferred core position
Four days later
After the X-ray soft-hard state transition, we detected a compact jet
component----most likely a hot spot. Surprisingly, the radio core was not
The black hole candidate in XTE J1752-223
# Mass: 8-11 M sun
# Distance: 3.5 kpc
## ~0.2c for component A at the first epoch.
## Consisting with our estimation.
Note that the measurements of distance and mass
are from model-dependent estimations: spetral-timing
correlation (Shaposhnikov et al. 2010)
� XTE J1752-223 exhibits rapid deceleration (0.34±0.02
mas/day 2 ), providing strong evidence for the existence of
interaction around the jet at an early stage of its evolution.
� The detection of the receding ejecta can be explained as a
result of the jet deceleration on the receding side
� A compact jet feature detected after the X-ray soft-hard state
transition is more like a hot spot in a lobe than the radio core.
MNRAS Letters, 2010, accepted, arXiv: 1009.1367