J/MNRAS/437/3265 Swift J1745-26 polarized jet (Curran+, 2014)
The evolving polarized jet of black hole candidate Swift J1745-26.
Curran P.A., Coriat M., Miller-Jones J.C.A., Armstrong R.P., Edwards P.G.,
Sivakoff G.R., Woudt P., Altamirano D., Belloni T.M., Corbel S.,
Fender R.P., Kording E.G., Krimm H.A., Markoff S., Migliari S.,
Russell D.M., Stevens J., Tzioumis T.
<Mon. Not. R. Astron. Soc., 437, 3265-3273 (2014)>
=2014MNRAS.437.3265C 2014MNRAS.437.3265C (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, X-ray ; Radio sources ; Polarization
Keywords: binaries: close - Swift J1745-26
Abstract:
Swift J1745-26 is an X-ray binary towards the Galactic Centre that was
detected when it went into outburst in 2012 September. This source is
thought to be one of a growing number of sources that display `failed
outbursts', in which the self-absorbed radio jets of the transient
source are never fully quenched and the thermal emission from the
geometrically thin inner accretion disc never fully dominates the
X-ray flux. We present multifrequency data from the Very Large Array,
Australia Telescope Compact Array and Karoo Array Telescope (KAT-7)
radio arrays, spanning the entire period of the outburst. Our rich
data set exposes radio emission that displays a high level of
large-scale variability compared to the X-ray emission and deviations
from the standard radio-X-ray correlation that are indicative of an
unstable jet and confirm the outburst's transition from the canonical
hard state to an intermediate state. We also observe steepening of the
spectral index and an increase of the linear polarization to a large
fraction (∼50%) of the total flux, as well as a rotation of the
electric vector position angle. These are consistent with a
transformation from a self-absorbed compact jet to optically thin
ejecta - the first time such a discrete ejection has been observed in
a failed outburst - and may imply a complex magnetic field geometry.
Description:
Swift J1745-26 was observed by the VLA from 2012 September 18 to
November 17 (16 epochs in the most extended, A, configuration) at
multiple frequency bands from 1 to 48GHz, though on the
majority of the epochs the source was only observed up to 26GHz.
The ATCA carried out a long-term monitoring campaign on Swift
J1745-26 at 5.5 and 9GHz during 24 epochs from 2012 September 19
to 2013 March 27.
Observations with the seven-dish MeerKAT test array, KAT-7 were
performed at a central frequency of 1.822GHz during 13 epochs from
2012 September 13 to November 11.
Objects:
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RA (2000) DE Designation(s)
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17 45 10.85 -26 24 12.6 Swift J1745-26 = SWIFT J174510.8-262411
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 54 156 Radio flux densities of Swift J1745-26
(before systematic errors are added)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d Epoch Epoch (MJD)
11- 15 F5.2 GHz Freq Frequency
17- 21 F5.2 mJy S Flux density
24- 28 F5.2 mJy e_S Flux density error
30- 35 F6.3 mJy SQ ? Stokes Q flux density (in mJy/beam)
37- 41 F5.3 mJy e_SQ ? Stokes Q flux density error (in mJy/beam)
43- 48 F6.3 mJy SU ? Stokes U flux density (in mJy/beam)
50- 54 F5.3 mJy e_SU ? Stokes U flux density error (in mJy/beam)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Jul-2015