scholarly journals X-Ray and Optical Properties of Black Widows and Redbacks

2017 ◽  
Vol 13 (S337) ◽  
pp. 43-46 ◽  
Author(s):  
Mallory S.E. Roberts ◽  
Hind Al Noori ◽  
Rodrigo A. Torres ◽  
Maura A. McLaughlin ◽  
Peter A. Gentile ◽  
...  
Keyword(s):  
Optical Properties ◽  
Binary Systems ◽  
Optical Emission ◽  
Close Binary ◽  
X Rays ◽  
Millisecond Pulsar ◽  
Optical Studies ◽  
Optical Photometry ◽  
X Ray ◽  
Pulsar Wind

AbstractBlack widows and redbacks are binary systems consisting of a millisecond pulsar in a close binary with a companion having matter driven off of its surface by the pulsar wind. X-rays due to an intrabinary shock have been observed from many of these systems, as well as orbital variations in the optical emission from the companion due to heating and tidal distortion. We have been systematically studying these systems in radio, optical and X-rays. Here we will present an overview of X-ray and optical studies of these systems, including new XMM-Newton and NuStar data obtained from several of them, along with new optical photometry.

scholarly journals CONSTRAINING THE PULSAR POWER IN GAMMA-RAY BINARIES THROUGH THERMAL X-RAY EMISSION

2012 ◽  
Vol 08 ◽  
pp. 132-137
Author(s):  
VÍCTOR ZABALZA ◽  
VALENTÍ BOSCH-RAMON ◽  
JOSEP MARIA PAREDES
Keyword(s):  
Stellar Wind ◽  
Binary Systems ◽  
Massive Star ◽  
Gamma Ray ◽  
Thermal Emission ◽  
Mass Loss Rate ◽  
X Rays ◽  
Orbital Inclination ◽  
X Ray ◽  
Pulsar Wind

Gamma-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds collide producing non-thermal emission, most likely from the shocked pulsar wind. Thermal X-rays are expected from the shocked stellar wind, with a spectrum akin to the one observed in massive star binaries. The goal of this work is, through the study of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, constrain the pulsar spin-down luminosity and the stellar wind properties. A semi-analytic model is developed to compute the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries. The model results are compared with XMM-Newton observations of LS 5039, a candidate pulsar gamma-ray binary with a strong stellar wind. Exploring the range of possible values for the stellar mass-loss rate and orbital inclination, we obtain an upper limit on the pulsar spin-down luminosity of 6 × 1036 erg s-1. We conclude that, to explain the non-thermal luminosity of LS 5039 in the pulsar wind scenario, a non-thermal to spin-down luminosity ratio very close to unity may be required.

Observational status of black holes

1979 ◽  
Vol 368 (1732) ◽  
pp. 27-32 ◽  
Keyword(s):  
Black Holes ◽  
Binary Systems ◽  
Ad Hoc ◽  
Massive Stars ◽  
High Energy ◽  
Close Binary ◽  
X Rays ◽  
Wave Pulse ◽  
X Ray ◽  
Observational Status

There might be ca. 10 9 stellar-mass black holes - the remnants of massive stars - in our own Galaxy. Unless one is lucky enough to record the gravitational wave pulse signalling their formation, the prospects for detection are remote except for the small fraction th at happen to lie in close binary systems. In such systems, gas captured from the companion star emits X-rays as it swirls inward towards the hole. Cygnus X - 1 has been for some years the best candidate: its mass is estimated as ≥ 6 M ⊙ and the X-rays vary irregularly on timescales th at may be as short as milliseconds. An interesting recent development has been the detection of rapid irregular fluctuations from Circinus XI (Toor 1977), which may be a system similar to Cygnus X - 1. When Cygnus X - 1 is no longer a unique well-studied object, but is established as merely one of a class, it will seem less plausible to advocate ‘ ad hoc ´ models (involving for instance ‘ third bodies ’ in the system) as serious alternative to a black hole interpretation. The current lull in X-ray astronomy should soon end with the results from High Energy Astronomical Observatories 1 and 2.

scholarly journals Inventory of black hole binaries

2003 ◽  
Vol 212 ◽  
pp. 365-371 ◽  
Author(s):  
Jerome A. Orosz
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary Systems ◽  
Compact Object ◽  
X Rays ◽  
Optical Studies ◽  
Dynamical Mass ◽  
X Ray ◽  
Black Hole Binaries ◽  
X Ray Binaries

A small group of X-ray binaries currently provides the best evidence for the existence of stellar-mass black holes. These objects are interacting binary systems where the X-rays arise from accretion of material onto a compact object (i.e., an object with a radius of less than a few hundred km). In some favourable cases, optical studies of the companion star lead to dynamical mass estimates for both components. In 17 cases, the mass of the compact object in an X-ray binary has been shown to exceed the maximum mass of a stable neutron star (about 3 M⊙), which leads to the conclusion that these objects are black holes. In this contribution I will review the basic properties of these black hole binaries.

scholarly journals Stellar X-ray and Radio Activities and Coronal Magnetic Field

1986 ◽  
Vol 7 ◽  
pp. 461-465
Author(s):  
Yutaka Uchida
Keyword(s):  
Binary Systems ◽  
Coronal Magnetic Field ◽  
Stellar Atmospheres ◽  
Close Binary ◽  
X Rays ◽  
Active Longitude ◽  
Flux Tubes ◽  
X Ray ◽  
Enhanced Production ◽  
Magnetic Flux Tubes

AbstractActivities due to the magnetic effects in the stellar atmospheres are discussed with a special emphasis on the enhanced X-rays and radio activities in RS CVn binaries. Enhanced activities in these close binary systems are proposed to be due to an enhanced production of the twist of the subphotospheric magnetic flux tubes by the large differential rotation in radius, created between the inertially rotating core and more or less synchronously rotating envelope. The magnetic twist of the emerged flux tubes in the “active-longitude-belt” will be dynamically released into inter-star flux tubes together with the driven-out mass heated in the events of magnetic reconnections which are mediated by the magnetic fields of the companion star.

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.

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

scholarly journals X-Ray Sources in Close Binary Systems

1974 ◽  
Vol 3 ◽  
pp. 89-107
Author(s):  
M. J. Rees
Keyword(s):  
Binary Systems ◽  
Close Binary ◽  
Rapid Variability ◽  
X Ray ◽  
Close Binary Systems ◽  
General Order ◽  
Typical Distances ◽  
Astronomical Research ◽  
Orbital Periods ◽  
Galactic Sources

The discovery by Giacconi and his colleagues of variable X-ray sources in close binary systems certainly ranks as one of the highlights of astronomical research during the last 3 years. These remarkable objects have already been extensively studied, by optical and radio observations as well as in the X-ray band; and they seem likely to prove as significant and far-reaching in their implications as pulsars.The ‘Third Uhuru Catalogue’ (Giacconi et al., 1973a) contains about 160 sources, of which about 100 lie in our Galaxy. Their distribution over the sky (together with other arguments) suggests that these sources have luminosities of the general order 1036–1038 erg s−1, and that their typical distances are ˜ 10kpc. These galactic sources generally display rapid variability. Little else is known about most of them, but they are probably of the same general class as systems such as Her X1, Cen X3, Cyg X1 and Cyg X3. These sources have been investigated in detail, and in all cases one infers a system where the X-ray source is orbiting around a relatively ordinary star. Six sources have been optically identified, and there are some others whose binary nature is established by the occurrence of an X-ray eclipse. Orbital periods range from 4.8 h (Cyg X3) up to ˜ 10 days.

scholarly journals Constraining Soft and Hard X-Ray Irradiation in Ultraluminous X-Ray Sources

2021 ◽  
Vol 922 (2) ◽  
pp. 91
Author(s):  
Yanli Qiu ◽  
Hua Feng
Keyword(s):  
Optical Emission ◽  
Current Data ◽  
Compact Objects ◽  
X Rays ◽  
Optical Counterpart ◽  
X Ray ◽  
Outer Disk ◽  
Stringent Constraint ◽  
Supercritical Accretion ◽  
Key Questions

Abstract Most ultraluminous X-ray sources (ULXs) are argued to be powered by supercritical accretion onto compact objects. One of the key questions regarding these objects is whether or not the hard X-rays are geometrically beamed toward the symmetric axis. We propose testing the scenario using disk irradiation to see how much the outer accretion disk sees the central hard X-rays. We collect a sample of 11 bright ULXs with an identification of a unique optical counterpart, and model their optical fluxes considering two irradiating sources: soft X-rays from the photosphere of the optically thick wind driven by supercritical accretion, and if needed in addition, hard X-rays from the Comptonization component. Our results indicate that the soft X-ray irradiation can account for the optical emission in the majority of ULXs, and the fraction of hard X-rays reprocessed on the outer disk is constrained to be no more than ∼10−2 in general. Such an upper limit is well consistent with the irradiation fraction expected in the case of no beaming. Therefore, no stringent constraint on the beaming effect can be placed according to the current data quality.

scholarly journals ROSAT observation of the HII region RCW 49 Possible discovery of a new Wolf-Rayet ring nebula

1995 ◽  
Vol 163 ◽  
pp. 76-77
Author(s):  
S. Mereghetti ◽  
T. Belloni
Keyword(s):  
Optical Emission ◽  
Young Star ◽  
Star Cluster ◽  
X Rays ◽  
Diffuse Emission ◽  
Hii Region ◽  
X Ray ◽  
Ring Nebula

We have observed the southern HII region RCW 49 with the ROSAT PSPC instrument. Part of the diffuse X-ray and optical emission present in this region might be associated with the X-ray selected WR star Th35-42 (WR20c). The young star cluster Westerlund 2 (which contains WR20a) is seen in X-rays as a centrally peaked, resolved source, surrounded by fainter diffuse emission.

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.

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