scholarly journals Fermi-LAT Observation of PSR B1259-63 during Its 2021 Periastron Passage

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 472
Author(s):  
Zhi Chang ◽  
Shu Zhang ◽  
Yu-Peng Chen ◽  
Long Ji ◽  
Ling-Da Kong ◽  
...  
Keyword(s):  
Binary System ◽  
Orbital Period ◽  
Compact Object ◽  
Peak Time ◽  
Γ Ray

PSR B1259-63 is a γ-ray binary system, where the compact object is a pulsar. The system has an orbital period of 1236.7 days and shows peculiar γ-ray flares (in 100 MeV–300 GeV) after its periastron time. We analyzed the Fermi-LAT observation of PSR B1259-63 during its latest periastron passage, as well as its previous three periastrons. The bright GeV flares started about 60 days after the periastron epoch in 2021. This delay is larger than that around the 2017 periastron and much larger than earlier periastrons. The delay of the GeV flux peak time in each periastron passage is apparent in our results. We discussed the possible origin of this delay and made a prediction of the GeV flux peak time in next periastron passage, based on observation of the previous delays.

scholarly journals Mass and Orbit Constraints of the Gamma-ray Binary LS 5039

2011 ◽  
Vol 7 (S282) ◽  
pp. 331-332
Author(s):  
T. Szalai ◽  
G. E. Sarty ◽  
L. L. Kiss ◽  
J. M. Matthews ◽  
J. Vinkó ◽  
...  
Keyword(s):  
Light Curve ◽  
Orbital Period ◽  
Gamma Ray ◽  
Broad Band ◽  
Compact Object ◽  
Physical Parameters ◽  
Photometric Variability ◽  
Γ Ray

AbstractWe present the results of space-based photometric and ground-based spectroscopic observing campaigns on the γ-ray binary LS 5039. The new orbital and physical parameters of the system are similar to former results, except we found a lower eccentricity. Our MOST-data show that any broad-band optical photometric variability at the orbital period is below the 2 mmag level. Light curve simulations support the lower value of eccentricity and imply that the mass of the compact object is higher than 1.8 M⊙.

scholarly journals Evidence for periodic accretion–ejection in LS I +61°303

2020 ◽  
Vol 498 (3) ◽  
pp. 3592-3600 ◽  
Author(s):  
M Massi ◽  
M Chernyakova ◽  
A Kraus ◽  
D Malyshev ◽  
F Jaron ◽  
...  
Keyword(s):  
Binary System ◽  
Compact Object ◽  
Eccentric Orbit ◽  
Physical Processes ◽  
X Ray ◽  
Accretion Flow ◽  
Single Orbit ◽  
Orbital Modulation ◽  
Γ Ray ◽  
Two Peaks

ABSTRACT The stellar binary system LS I +61°303, composed of a compact object in an eccentric orbit around a B0 Ve star, emits from radio up to γ-ray energies. The orbital modulation of radio spectral index, X-ray, and GeV γ-ray data suggests the presence of two peaks. This two-peaked profile is in line with the accretion theory predicting two accretion–ejection events for LS I +61°303 along the 26.5 d orbit. However, the existing multiwavelength data are not simultaneous. In this paper, we report the results of a campaign covering radio, X-ray, and γ-ray observations of the system along one single orbit. Our results confirm the two predicted events along the orbit and in addition show that the positions of radio and γ-ray peaks are coincident with X-ray dips as expected for radio and γ-ray emitting ejections depleting the X-ray emitting accretion flow. We discuss future observing strategies for a systematic study of the accretion–ejection physical processes in LS I +61°303.

scholarly journals Detection of variable VHE γ-ray emission from the extra-galactic γ-ray binary LMC P3

2018 ◽  
Vol 610 ◽  
pp. L17 ◽  
Author(s):  
◽  
H. Abdalla ◽  
A. Abramowski ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
...  
Keyword(s):  
Binary System ◽  
Orbital Period ◽  
Statistical Significance ◽  
Large Magellanic Cloud ◽  
High Energy ◽  
Data Set ◽  
Very High Energy ◽  
Stereoscopic System ◽  
Γ Ray ◽  
Very High

Context. Recently, the high-energy (HE, 0.1–100 GeV) γ-ray emission from the object LMC P3 in the Large Magellanic Cloud (LMC) has been discovered to be modulated with a 10.3-day period, making it the first extra-galactic γ-ray binary. Aim. This work aims at the detection of very-high-energy (VHE, >100 GeV) γ-ray emission and the search for modulation of the VHE signal with the orbital period of the binary system. Methods. LMC P3 has been observed with the High Energy Stereoscopic System (H.E.S.S.); the acceptance-corrected exposure time is 100 h. The data set has been folded with the known orbital period of the system in order to test for variability of the emission. Results. VHE γ-ray emission is detected with a statistical significance of 6.4 σ. The data clearly show variability which is phase-locked to the orbital period of the system. Periodicity cannot be deduced from the H.E.S.S. data set alone. The orbit-averaged luminosity in the 1–10 TeV energy range is (1.4 ± 0.2) × 1035 erg s−1. A luminosity of (5 ± 1) × 1035 erg s−1 is reached during 20% of the orbit. HE and VHE γ-ray emissions are anti-correlated. LMC P3 is the most luminous γ-ray binary known so far.

scholarly journals V479 And: CV, LMXB, or Symbiotic?

2011 ◽  
Vol 7 (S281) ◽  
pp. 113-116
Author(s):  
Diego González Buitrago ◽  
Gagik Tovmassian ◽  
Juan Echevarría ◽  
Sergey Zharikov ◽  
Takamitsu Miyaji ◽  
...  
Keyword(s):  
Orbital Period ◽  
Main Sequence ◽  
Compact Object ◽  
Close Binary System ◽  
Close Binary ◽  
Stellar Winds ◽  
Primary Star ◽  
Giant Star ◽  
X Ray ◽  
Low Mass

AbstractV479 And is a 14.26 hour, close binary system, comprised of a G8-K0 star departing from the main sequence and a compact primary star accreting matter from the donor. The object is an X-ray source, modulated with the orbital period. This, and the presence of an intense He II line, leads us to speculate that the compact object is a magnetic white dwarf. However, we do not find strong constraints on the upper mass limit of the compact object, and we may have a neutron star in a low mass X-ray binary instead of a cataclysmic variable. The orbital period is certainly too short for the donor star to be an evolved giant star, so classifying this object as a symbiotic binary may be a big stretch; however there is an evidence that the mass transfer occurs via stellar winds, rather than through the L1 point of Roche filling secondary, a phenomenon more common for symbiotic stars.

Orbital Period of a Binary System in the Field-Boost Approach.

2004 ◽  
Vol 17 (4) ◽  
pp. 435-441
Author(s):  
J. Lucinda ◽  
D. W. Foryta ◽  
M. G. Rodbard
Keyword(s):  
Binary System ◽  
Orbital Period

scholarly journals Onthe changes in the physical properties of the ionized region around the Weigelt structures in η Carinae over the 5.54-yr spectroscopic cycle

2020 ◽  
Vol 495 (3) ◽  
pp. 2754-2770 ◽  
Author(s):  
M Teodoro ◽  
T R Gull ◽  
M A Bautista ◽  
D J Hillier ◽  
G Weigelt ◽  
...  
Keyword(s):  
Binary System ◽  
Electron Temperature ◽  
Ionization Potential ◽  
Orbital Period ◽  
Equatorial Plane ◽  
Proper Motion ◽  
Emission Lines ◽  
Central Source ◽  
High Ionization ◽  
Orbital Cycle

ABSTRACT We present HST/STIS observations and analysis of two prominent nebular structures around the central source of η Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate- or high-ionization potential ions. The brightness of lines from intermediate- and high-ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low-ionization potential (<13.6 eV) ions over the orbital period. Line ratios suggest that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 106.9 cm−3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 (around periastron) to 7200 K (around apastron). The relative changes in the brightness of the He i lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 au from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called ‘Butterfly Nebula’ surrounding the central binary system.

scholarly journals Sign of Hard-X-Ray Pulsation from the γ -Ray Binary System LS 5039

2020 ◽  
Vol 125 (11) ◽  
Author(s):  
H. Yoneda ◽  
K. Makishima ◽  
T. Enoto ◽  
D. Khangulyan ◽  
T. Matsumoto ◽  
...  
Keyword(s):  
Binary System ◽  
X Ray ◽  
Γ Ray

scholarly journals The multiple system Sk-67°18 in the LMC

1995 ◽  
Vol 163 ◽  
pp. 251-253 ◽  
Author(s):  
V. S. Niemela ◽  
W. Seggewiss ◽  
A. F. J. Moffat
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Spectral Type ◽  
Orbital Period ◽  
Large Magellanic Cloud ◽  
Primary Component ◽  
Magellanic Cloud ◽  
Bright Star ◽  
High Mass ◽  
Eclipsing Binary

The bright star Sk—67°18 (Brey 5) in the Large Magellanic Cloud (LMC) contains an eclipsing binary system. Our radial velocity study reveals that the orbital period is almost exactly two days. The spectra also show that the star's primary component is not of spectral type WN, but that the star is rather an Of+O type binary where the primary is probably of type O3f*. Furthermore, Sk—67°18 appears to be a high-mass multiple system.

scholarly journals Multiwavelength Variability in the Symbiotic Nova V1016 CYG

2004 ◽  
Vol 194 ◽  
pp. 224-224
Author(s):  
Š. Parimucha ◽  
M. Vańko
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Orbital Period ◽  
Uv Spectroscopy ◽  
Infrared Photometry ◽  
Symbiotic System ◽  
Photoelectric Photometry ◽  
Mira Variable ◽  
Multiwavelength Variability

Analysis of the optical and infrared photometry together with UV spectroscopy led to discovery of the 15-years periodicity in the symbiotic system V1016 Cyg. This period could be interpreted as a orbital period in the binary system consisting of the Mira variable and the hot white dwarf.We have analyzed long-term optical photographic and UBV photoelectric photometry of V1016 Cyg. Collected observations cover pre- and post-outburst stages of the system. The light, curve suggests four stages of activity: the pre-out burst flare in 1949, the main nova-like outburst in 1904, and two post-outbursts, decreasing-amplitude flares in 1980 and 1994, respectively. Activity episodes affecting the system repeat with an interval of ~ 15 years. The ephemeris for the activity maxima is (see Parimucha et al., 2000).

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