J/ApJ/736/138 RXTE observations of 4U 0142+61 (Gavriil+, 2011)
The 2006-2007 active phase of anomalous X-ray pulsar 4U 0142+61: radiative and
timing changes, bursts, and burst spectral features.
Gavriil F.P., Dib R., Kaspi V.M.
<Astrophys. J., 736, 138 (2011)>
=2011ApJ...736..138G 2011ApJ...736..138G
ADC_Keywords: X-ray sources ; Pulsars
Keywords: pulsars: individual (4U 0142+61) - stars: neutron - X-rays: bursts -
X-rays: stars
Abstract:
After at least six years of quiescence, anomalous X-ray pulsar (AXP)
4U 0142+61 entered an active phase in 2006 March that lasted several
months and included six X-ray bursts as well as many changes in the
persistent X-ray emission. The bursts, the first seen from this AXP in
>11yr of Rossi X-Ray Timing Explorer monitoring, all occurred in the
interval between 2006 April 6 and 2007 February 7. The burst durations
ranged from (0.4-1.8)x103s. The first five burst spectra are well
modeled by blackbodies, with temperatures kT∼2-9keV. However, the
sixth burst had a complicated spectrum that is well characterized by a
blackbody plus two emission features whose amplitude varied throughout
the burst. The most prominent feature was at 14.0keV. Upon entry into
the active phase, the pulsar showed a significant change in pulse
morphology and a likely timing glitch. The glitch had a total
frequency jump of (1.9±0.4)x10-7Hz, which recovered with a decay
time of 17±2 days by more than the initial jump, implying a net
spin-down of the pulsar. Within the framework of the magnetar model,
the net spin-down of the star could be explained by regions of the
superfluid that rotate slower than the rest. The bursts, flux
enhancements, and pulse morphology changes can be explained as arising
from crustal deformations due to stresses imposed by the highly
twisted internal magnetic field. However, unlike other AXP outbursts,
we cannot account for a major twist being implanted in the
magnetosphere.
Description:
4U 0142+61 has been monitored with RXTE (Rossi X-Ray Timing Explorer)
in 1997 and from 2000 to 2007. It has been monitored bi-monthly since
2005 March, with a typical observation length of ∼5ks. On 2006 March
23, the source entered an active phase where many pulsed flux,
spectral, and pulse profile changes were observed. We detected six
bursts in three observations (2006 Apr 6, 2006 Jun 26 and 2007 Feb 7)
after the entry into the active phase. After each burst detection,
several RXTE target-of-opportunity (ToO) observations were made in
addition to the regular monitoring.
We also present an analysis of 91 other observations spanning the 2005
March 21 to 2007 May 15 time period (MJD 53481 to MJD 54235, ObsIDs
91070-05-04-00 to 92006-05-32-00). Thirty-two of these observations
were prior to the entry into the active phase, and the remaining 59
observations were after (Figure 1 and table 3).
Objects:
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RA (2000) DE Designation(s)
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01 46 22.41 +61 45 03.2 4U 0142+61 = PSR J0146+6145
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 85 94 RXTE timing observation log for 4U 0142+61
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2012)
B/xmm : XMM-Newton Observation Log (XMM-Newton Science Operation Center, 2012)
VI/117 : Observation Log from ASCA (PLAIN Center, 2001)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
J/A+A/545/A27 : INTEGRAL/IBIS 9yr Galactic Hard X-Ray Survey (Krivonos+, 2012)
J/AJ/141/129 : Chandra Transmission Grating Data Cat. (Huenemoerder+, 2011)
J/A+A/522/A68 : Variable sources detected by INTEGRAL (Telezhinsky+, 2010)
J/A+A/493/339 : XMM-Newton serendipitous Survey. V. (Watson+, 2009)
J/ApJS/179/360 : Thermonuclear X-ray bursts observed by RXTE (Galloway+, 2008)
J/A+A/467/585 : Sources detected by ISGRI (Bodaghee+, 2007)
J/A+A/416/1037 : BVRIK Photometry for the field of 4U 0142+61 (Hulleman+, 2004)
J/A+A/411/L59 : INTEGRAL reference catalog (Ebisawa+, 2003)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- TOA [1/94] Time of arrival (TOA) number (1)
4- 17 A14 --- RXTE RXTE observation identification number
19- 22 F4.1 ks Exp [0.7/19.7] Exposure time
24 I1 --- PCUs [1/4] Effective number of Proportional Counter Units
(PCUs) on during observation
26- 38 F13.7 d MJD1 Modified Julian Date of Set 1 barycentered pulse (2)
40- 43 F4.2 s e_MJD1 Uncertainty in MJD1
45- 57 F13.7 d MJD2 Modified Julian Date of Set 2 barycentered pulse (2)
59- 62 F4.2 s e_MJD2 Uncertainty in MJD2
64- 76 F13.7 d MJD3 Modified Julian Date of Set 3 barycentered pulse (2)
78- 81 F4.2 s e_MJD3 Uncertainty in MJD3
83- 85 A3 --- PT [Yes/No ] TOA included in partial timing analysis?
(Note that all TOAs were included in the long-term
analysis)
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Note (1): TOA number 33 is the first observation in the active phase. TOAs
number 34, 58, and 78 represent the first, second and third
observation containing bursts.
Note (2): Set 1 corresponds to the TOAs obtained by cross-correlating the
folded pulse profiles with a high signal-to-noise template. Sets 2
and 3 are similar to Set 1, however, we constrained our
cross-correlation to the trough and peak of the pulsations,
respectively. See Section 3.5 for details.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Jan-2013