scholarly journals Face changing companion of the redback millisecond pulsar PSR J1048+2339

2019 ◽  
Vol 621 ◽  
pp. L9 ◽  
Author(s):  
Y. X. Yap ◽  
K. L. Li ◽  
A. K. H. Kong ◽  
J. Takata ◽  
J. Lee ◽  
...  
Keyword(s):  
Orbital Period ◽  
Light Curves ◽  
Optical Observations ◽  
Millisecond Pulsar ◽  
High Quality ◽  
X Ray ◽  
Compact Binary ◽  
Modeling Analysis ◽  
Irradiation Power ◽  
Pulsar Wind

We present optical observations of the redback millisecond pulsar PSR J1048+2339, which is a 4.66 ms radio pulsar in a compact binary with an orbital period of six hours. We obtained high-quality light curves of PSR J1048+2339 with the Lulin 1 m Telescope. The system shows two distinct six-hour orbital modulations, in which an ellipsoidal modulation changes into a sinusoidal-like profile in less than 14 days. In addition to the change, the brightness of the companion increased by one magnitude, suggesting that the latter type of modulation is caused by the pulsar wind heating of the companion and that the heating became dominant in the system. While the changes are not unexpected, such a timescale is the shortest among similar systems. We performed modeling analysis to extract the properties of the system. We obtained a derived pulsar mass of 2.1 M⊙ and a companion star mass of 0.4 M⊙ for the system. The irradiation power increased by a factor of 6 during which the pulsar wind heating dominates. We also report on the two archival Chandra X-ray observations and discuss several possibilities that might cause the varying heating on the companion.

scholarly journals On the vanishing orbital X-ray variability of the eclipsing binary millisecond pulsar 47 Tuc W

2020 ◽  
Vol 500 (1) ◽  
pp. 1139-1150
Author(s):  
P R Hebbar ◽  
C O Heinke ◽  
D Kandel ◽  
R W Romani ◽  
P C C Freire
Keyword(s):  
State Transition ◽  
Uv Light ◽  
Light Curves ◽  
X Rays ◽  
Millisecond Pulsar ◽  
X Ray ◽  
Pulsar Radiation ◽  
Best Fitting ◽  
Pulsar Wind ◽  
Fitting Parameters

ABSTRACT Redback millisecond pulsars (MSPs) typically show pronounced orbital variability in their X-ray emission due to our changing view of the intrabinary shock (IBS) between the pulsar wind and stellar wind from the companion. Some redbacks (‘transitional’ MSPs) have shown dramatic changes in their multiwavelength properties, indicating a transition from a radio pulsar state to an accretion-powered state. The redback MSP 47 Tuc W showed clear X-ray orbital variability in the Chandra ACIS-S observations in 2002, which were not detectable in the longer Chandra HRC-S observations in 2005–06, suggesting that it might have undergone a state transition. However, the Chandra observations of 47 Tuc in 2014–15 show similar X-ray orbital variability as in 2002. We explain the different X-ray light curves from these epochs in terms of two components of the X-ray spectrum (soft X-rays from the pulsar versus harder X-rays from the IBS), and different sensitivities of the X-ray instruments observing in each epoch. However, when we use our best-fitting spectra with HRC response files to model the HRC light curve, we expect a more significant and shorter dip than that observed in the 2005–06 Chandra data. This suggests an intrinsic change in the IBS of the system. We use the icarus stellar modelling software, including calculations of heating by an IBS, to model the X-ray, optical, and UV light curves of 47 Tuc W. Our best-fitting parameters point towards a high-inclination system ($i \sim 60 \deg$), which is primarily heated by the pulsar radiation, with an IBS dominated by the companion wind momentum.

New insight into the origin of the GeV flare in the binary system PSR B1259-63/LS 2883 from the 2017 periastron passage

2020 ◽  
Vol 497 (1) ◽  
pp. 648-655
Author(s):  
M Chernyakova ◽  
D Malyshev ◽  
S Mc Keague ◽  
B van Soelen ◽  
J P Marais ◽  
...  
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Energy Release ◽  
Broad Band ◽  
Strong Shock ◽  
Optical Observations ◽  
X Rays ◽  
X Ray ◽  
Inverse Compton ◽  
Pulsar Wind

ABSTRACT PSR B1259-63 is a gamma-ray binary system hosting a radio pulsar orbiting around an O9.5Ve star, LS 2883, with a period of ∼3.4 yr. The interaction of the pulsar wind with the LS 2883 outflow leads to unpulsed broad-band emission in the radio, X-rays, GeV, and TeV domains. While the radio, X-ray, and TeV light curves show rather similar behaviour, the GeV light curve appears very different with a huge outburst about a month after a periastron. The energy release during this outburst seems to significantly exceed the spin-down luminosity of the pulsar and both the GeV light curve and the energy release vary from one orbit to the next. In this paper, we present for the first time the results of optical observations of the system in 2017, and also reanalyse the available X-ray and GeV data. We present a new model in which the GeV data are explained as a combination of the bremsstrahlung and inverse Compton emission from the unshocked and weakly shocked electrons of the pulsar wind. The X-ray and TeV emission is produced by synchrotron and inverse Compton emission of energetic electrons accelerated on a strong shock arising due to stellar/pulsar winds collision. The brightness of the GeV flare is explained in our model as a beaming effect of the energy released in a cone oriented, during the time of the flare, in the direction of the observer.

scholarly journals RX J1015.5+0904: A New Polar at the Lower Period Limit

1996 ◽  
Vol 158 ◽  
pp. 229-230
Author(s):  
V. Burwitz ◽  
K. Reinsch ◽  
A. D. Schwope ◽  
K. Beuermann ◽  
S. Mengel ◽  
...  
Keyword(s):  
Orbital Period ◽  
Optical Observations ◽  
Optical Data ◽  
X Ray ◽  
First Results ◽  
Period Limit ◽  
Lower Period

AbstractWe present X-ray and optical observations of the ROSAT discovered polar (AM Her binary) RX J1015.5+0904 and first results of our analysis of the X-ray and optical data. These results indicate a one-pole accretion geometry and an orbital period of P = 79.88 m for this V ~ 17 mag system.

scholarly journals Optical Photometry of LMXBs: UW CrB (=MS 1603+260) and V1408 Aql (=4U 1957+115)

2015 ◽  
Vol 2 (1) ◽  
pp. 50-54
Author(s):  
P. A. Mason ◽  
E. L. Robinson ◽  
S. Gomez ◽  
J. V. Segura
Keyword(s):  
Black Hole ◽  
Orbital Period ◽  
Light Curves ◽  
Optical Data ◽  
Published Data ◽  
Type I ◽  
Optical Photometry ◽  
Mean Intensity ◽  
X Ray ◽  
Low Mass

We present new optical observations of V1408 Aql (= 4U 1957+115), the only low mass X-ray binary, black hole candidate known to be in a persistently soft state. We combine new broadband optical photometry with previously published data and derive a precise orbital ephemeris. The optical light curves display sinusoidal variations modulated on the orbital period as well as large night to night changes in mean intensity. The amplitude of the variations increases with mean intensity while maintaining sinusoidal shape. Considering the set of constraints placed by the X-ray and optical data we argue that V1408 Aql may harbor a very low mass black hole. Optical light curves of UW CrB display partial eclipses of the accretion disk by the donor star that vary both in depth and orbital phase. The new eclipses of UW CrB in conjunction with published eclipse timings are well fitted with a linear ephemeris. We derive an upper limit to the rate of change of the orbital period. By including the newly observed type I bursts with published bursts in our analysis, we find that optical bursts are not observed between orbital phases 0.93 and 0.07, i.e. they are not observable during partial eclipses of the disk.

scholarly journals X-ray and optical observations of BY Cam

1996 ◽  
Vol 158 ◽  
pp. 213-214 ◽  
Author(s):  
Gavin Ramsay ◽  
Paul A. Mason
Keyword(s):  
Power Spectrum ◽  
Orbital Period ◽  
White Dwarf ◽  
Optical Observations ◽  
Optical Data ◽  
Spin Orbit ◽  
Side Band ◽  
X Ray ◽  
Beat Period ◽  
Spin Period

We present preliminary results of an analysis of X-ray and optical data of the asynchronous AM Her star BY Cam [1]. We use X-ray data from EXOSAT (0.1… 50 keV), Ginga (1.5… 50 keV) and ROSAT (0.1…2.0 keV) and optical data obtained during a 45-day campaign in 1994.There are 4 known periods: the orbital period (201.30 m), the spin period of the white dwarf (199.3303 m), a spin-orbit beat period (14.15 d) and a side-band period (197.4 m). The detection of this side-band period lends credence to the theory of [2], who suggest that for a stream accreting, diskless, magnetic CV a frequency, f = 2ωspin − Ωorb (=197.399 m), will appear as a strong spike in the power spectrum for certain systems. Wu & Mason (this volume) discuss a competing model where Pspin = 197.4 m.

scholarly journals Unveiling the nature of the 321s Orbital Period X-ray source RX J0806.3+1527

2004 ◽  
Vol 190 ◽  
pp. 338-344
Author(s):  
GianLuca Israel ◽  
Luigi Stella ◽  
Stefano Covino ◽  
Sergio Campana ◽  
Gianni Marconi ◽  
...  
Keyword(s):  
Phase Shift ◽  
Orbital Period ◽  
Black Body ◽  
Light Curves ◽  
X Ray ◽  
Body Component ◽  
First Time ◽  
Irradiation Process ◽  
Good Agreement

AbstractA nearly simultaneous X-ray/optical (Chandra and VLT) observational campaign of RX J0806.3+1527 has been carried out during 2001. These observations allowed us to phase the X-ray and optical light curves for the first time. We measured a phase–shift of ~0.5, in good agreement with the presence of two distinct emission regions and with the X-ray irradiation process predictions. The Chandra data allowed us also to study in details the X-ray spectrum of RX J0806.3+1527, which is consistent with a soft (kT<70eV) and small (RBB <20km) black-body component. We discuss the present findings in the light of the models proposed so far to account for the X-ray emission detected from RX J0806.3+1527, and its twin source RX J1914.4+2456.

scholarly journals Observations of Low Mass X-Ray Binaries

1996 ◽  
Vol 158 ◽  
pp. 349-358
Author(s):  
Alan P. Smale
Keyword(s):  
Neutron Stars ◽  
Orbital Period ◽  
Binary Systems ◽  
Light Curves ◽  
X Ray ◽  
Fast Timing ◽  
Low Mass ◽  
And Behavior ◽  
X Ray Binaries

AbstractIn this paper I review the properties and behavior of low-mass X-ray binary systems (LMXBs) that contain neutron stars (NS), concentrating on the Galactic bulge sources and bursters. I describe the observed characteristics of LMXBs including their light curves, spectra, eclipses, dips, bursts, flares, pulsations, QPO, long-term periodicities and orbital period changes, and explain how fast timing results and the distinction between ‘Z’ and ‘atoll’-type sources provide the key to a unified model of LMXB behavior.

scholarly journals Modelling multiwavelength emissions from PSR B1259–63/LS 2883: Effects of the stellar disc on shock radiations

2019 ◽  
Vol 627 ◽  
pp. A87 ◽  
Author(s):  
A. M. Chen ◽  
J. Takata ◽  
S. X. Yi ◽  
Y. W. Yu ◽  
K. S. Cheng
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
Thermal Emission ◽  
Orbital Plane ◽  
Light Curves ◽  
Double Peak ◽  
Stellar Disc ◽  
X Ray ◽  
Pulsar Wind ◽  
Star Binary

PSR B1259–63/LS 2883 is an elliptical pulsar/Be star binary that emits broadband emissions from radio to TeV γ-rays. The massive star possesses an equatorial disc that is inclined with the orbital plane of the pulsar. Non-thermal emission from the system is believed to be produced by pulsar wind shock and double-peak profiles in the X-ray, and TeV γ-ray light curves are related to the phases of the pulsar passing through the disc region of the star. In this paper, we investigate the interactions between the pulsar wind and stellar outflows, especially with the presence of the disc, and present a multiwavelength modelling of the emission from this system. We show that the double-peak profiles of X-ray and TeV γ-ray light curves are caused by the enhancements of the magnetic field and soft photons at the shock during the disc passages. As the pulsar is passing through the equatorial disc, the additional pressure of the disc pushes the shock surface closer to the pulsar, which causes the enhancement of magnetic field in the shock, and thus increases the synchrotron luminosity. The TeV γ-rays due to the inverse-Compton (IC) scattering of shocked electrons with seed photons from the star are expected to peak around periastron, which is inconsistent with observations. However, the shock heating of the stellar disc could provide additional seed photons for IC scattering during the disc passages, and thus produces the double-peak profiles as observed in the TeV γ-ray light curve. Our model can possibly be examined and applied to other similar gamma-ray binaries, such as PSR J2032+4127/MT91 213, HESS J0632+057, and LS I+61°303.

scholarly journals New JHK Photometry of LS I +61 303

2000 ◽  
Vol 175 ◽  
pp. 727-730
Author(s):  
S. Martínez-Núñez ◽  
J. Fabregat
Keyword(s):  
Orbital Period ◽  
Compact Object ◽  
Light Curves ◽  
Circumstellar Envelope ◽  
Be Stars ◽  
X Ray ◽  
Close Orbit ◽  
Infrared Wavelengths ◽  
Ir Light

AbstractWe present new JHK photometry of the Be/X-ray binary L SI +61 303, obtained during the period 1994-1998. The IR light curves do not show the modulation with the orbital period apparently present in the smaller photometry set analyzed by Paredes et al. (1994).The reddening-corrected standard photometric values indicate that the circumstellar envelope is optically thick at infrared wavelengths, and much denser than those of isolated Be stars. It is argued that this higher density is produced by disk truncation due to the presence of the compact object in a close orbit.

scholarly journals A Shapiro delay detection in the pulsar binary system PSR J1811–2405

2020 ◽  
Vol 493 (1) ◽  
pp. 1261-1267
Author(s):  
C Ng ◽  
L Guillemot ◽  
P C C Freire ◽  
M Kramer ◽  
D J Champion ◽  
...  
Keyword(s):  
Binary System ◽  
Orbital Period ◽  
Binary Systems ◽  
Millisecond Pulsar ◽  
Orbital Inclination ◽  
Compact Binary ◽  
A Value ◽  
Delay Detection ◽  
Pulsar Timing ◽  
Compact Binary Systems

ABSTRACT This paper presents the first detection of Shapiro delay from the binary millisecond pulsar PSR J1811–2405. We report a 11σ measurement of the orthometric amplitude, h3 = 6.8(6) × 10−7, and a 16σ measurement of the orthometric ratio, ς = 0.81(5). Given the relatively high orbital inclination, i = 79(2)°, of this binary system, we obtain constraints on the companion mass of $m_{\rm {c}}=0.31^{+0.08 }_{ -0.06}\, \mathrm{M}_{\odot }$. The pulsar mass is currently less well constrained, with a value of $2.0^{+0.8 }_{ -0.5}\, \mathrm{M}_{\odot }$. The companion mass and the orbital period are in agreement with the prediction made by previous numerical calculations of the evolution of compact binary systems. From a study of the polarization, we find that the orbital inclination angle is ∼100° and that PSR J1811–2405 is an orthogonal rotator. In addition, the μs-level timing precision together with its narrow profile makes PSR J1811–2405 a good candidate for inclusion in the pulsar timing arrays being used to detect nHz gravitational waves.

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