A Decelerating Jet in the X-Ray Transient XTE J1752-223 - CIRA


A Decelerating Jet in the X-Ray Transient XTE J1752-223 - CIRA

A Decelerating Jet in the X-Ray

Transient XTE J1752-223

J. Yang & Z. Paragi

Joint Institute for VLBI in Europe, Netherlands

C. Brocksopp

University College London, UK

S. Corbel

University Paris, France

T. Tzioumis

ATNF, Australia

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

� Conclusions

X-ray transients:

(1) Mass > 5 M sun

High Mass X-ray binaries

(2) Mass < M sun

Low Mass X-ray binaries

X-Ray Binaries

X-ray binaries are directly analogous to

extragalactic AGN with timescales >10 6 shorter.

Mirabel & Rodriguez, 1994

As source softens,

jet velocity

increases abruptly,

causing internal

shock in jet


soft states

show no jet

Blue: Jet Yellow: Corona

Red: Accretion disc.

More powerful,

hard sources have

more powerful,

steady jets…

Faint, hard




Γ~1 jets

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.)

VLBI Observations

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

Phase-referencing observations

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.

Core: Non-detection

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


r 0



(mas/day 2 )


χ 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

WSRT@1.4 GHz

Gallo et al. Nature 2005

H-alpha and O[III] Line-emitting nebula.

Russell, Fender et al. (2006, 2007)

Detection of the receding jet

Expansion motion

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

VLBI observations

----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.

≤0.2 c

≥ 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

ATCA radio

light curve

Date of the EVN


Dirty map Dirty map


B C +

388 mas

300 mas

560 mas

The inferred core position

Clean image


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

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