Gamma-ray emission from binaries in context

Dubus, G.

doi:10.1016/j.crhy.2015.08.014

Cited by 37 publications

(48 citation statements)

References 132 publications

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“…Existence of such beamed emission in gammaray binaries has been suggested (e.g., Dubus et al 2015;Dubus 2015), and similar phenomena have been seen in some pulsar binaries (e.g., Romani & Sanchez 2016) as well. Modeling the spike allows us to infer the properties of the fast flow and the orbital parameters; the maximum bulk Lorentz factor of the flow is ∼7 and the inclination is ∼50…”

Section: Discussionmentioning

confidence: 97%

“…A second effect can also boost the observed TeV flux at these phases: secondary e + /e − pairs produced in TeV absorption on stellar photons can emit in the ∼ 10 24 − 10 25 Hz band (e.g., Bednarek 2013;Dubus 2013). This cascade emission can be especially important near pulsar superior conjunction and so may also contribute to the lower energy TeV emission at φ ∼ 0.3 − 0.5.…”

Section: Discussionmentioning

confidence: 99%

“…At first sight this might be surprising, since the EC emission (upscatter of stellar photons) should peak at periastron (broad hump, φ orb = 0.39). However, photon-photon absorption (Gould & Schréder 1967;Dubus 2006a) by the stellar photons strongly suppresses this component (and the SSC emission from this phase). The absorbed EC and SSC components are shown by the green and blue lines and the total Compton emission shows the phase 0 spike.…”

Section: Light Curve Modelingmentioning

confidence: 99%

“…For this, we assumed that the optical star is a point source and all the highenergy TeV photons are emitted at the apex of the shock for simplicity. We calculate the differential optical depth given in Dubus (2006a) at each point along the LoS and integrate it out to ∼10× the distance between the star and the emitting region. Beyond this distance, the blackbody photon field becomes negligibly weak, as does the absorption.…”

Section: Phase-resolved Sed Modelmentioning

confidence: 99%

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Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

Romani

2017

ApJ

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We present broadband spectral energy distributions (SEDs) and light curves of the gamma-ray binary 1FGL J1018.6−5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explain the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. The model requires inclination ∼50• and orbital eccentricity ∼0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Light Curve Modelingmentioning

confidence: 99%

Section: Phase-resolved Sed Modelmentioning

confidence: 99%

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Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

Romani

2017

ApJ

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“…They provide a unique astrophysical laboratory to study the pulsar wind (PW) at subparsec scale through its interaction with the stellar wind. Currently, there are seven known γ-raybinaries (five listed in Dubus 2015, plus P3 in LMC (Corbet et al 2016) and PSR J2032+4127, which has an orbital period of 45-50 years (Ho et al 2016)), but the PSRB1259−63/LS2883 system remains the only γ-raybin-ary that (i) contains a pulsar and (ii) emits repetitive orbital phase-dependent radio, X-ray and γ-rayflares seen more than once. PSRB1259−63(with a spin period of 47.8 ms) orbits around the Be star LS2883 with a period of 3.4 years in a highly eccentric orbit (e∼0.87).…”

Section: Introductionmentioning

confidence: 99%

The Hour-timescale GeV Flares of PSR B1259–63 in 2017

Tam

Pal

et al. 2018

ApJ

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GeV flares from PSRB1259−63/LS2883 were seen starting around 30 days after the two periastron passages in 2010 and 2014. The flares are clearly delayed compared to the occurrence of the X-ray and TeV flux peaks during the post-periastron disk crossing. Although several attempts have been put forward to explain this phenomenon, the origin of these GeV flares remains a puzzle. Here we present a detailed analysis of the observational data taken by the Fermi and Swift observatories over the 2017 September periastron passage. For the first time, we find shortlived but powerful GeV flares on timescales of down to three hours. The onset of the GeV flaring period in 2017 is also delayed compared to that seen in 2011 and 2014. Supplemented by a reanalysis of previous data, we compare the Fermi/LAT, Swift/XRT, and Swift/UVOT light curves in 2017 with those taken over the 2010 and 2014 periastrons, and differences in UVOT light curves are noted.

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Revealing the Most Energetic Light from Pulsars and Their Nebulae

Fidalgo

2019

Springer Theses

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© David Carreto Fidalgo, 2018 157 8.1 The young and energetic gamma-ray pulsar psr j0631+1036 158 8.2 Observational hints of a TeV pulsar wind nebula 161 9 MAGIC observations of PSR J0631: analysis and results 165 9.1 Data set and quality selection 166 9.2 Moonlight data and extended source analysis 168 9.3 Analysis results and discussion 172 Summary and conclusions 177 Appendix 183 A Interaction processes in very-high-energy astrophysics 185 B Pulsar timing 191 C The on-site analysis chain of MAGIC 195 D Details on the Crab pulsar analysis 201 References 207 viii Thesis advisor: Abstract Background. The observation of Very-High-Energy (vhe, >100 GeV) gamma raysis key in studying the non-thermal sources of radiation in our Universe. Pulsars and Pulsar Wind Nebulae (pwne) are two source classes that are known to emit vhe gamma rays. While pulsar wind nebulae are the dominant vhe gamma-ray source class in our galaxy, only two pulsars have been detected above 100 GeV so far. Most pulsar models explain gamma-ray emission via synchro-curvature radiation in the radiation-reaction limited regime, which leads to a sharp cut-off in the pulsar spectrum at energies of a few GeV.However, the detection of pulsed emission from the Crab pulsar up to hundreds of GeV by magic and veritas, suggests that classical pulsar models do not provide a full picture of the emission mechanisms at work. TeV pulsar wind nebulae, on the other hand, are observed via their inverse Compton radiation and are primarily found around young and energetic pulsars located towards the inner Milky Way. Detections of TeV pwne in the outer part of our galaxy are scarce, but could provide valuable input for the connection between the interstellar radiation field and the pwn luminosity.Aims. The principle goal of this thesis is to study the very-high-energy emission of the Crab pulsar. We aim to answer the long-standing question up to what energies pulsars are able to radiate and what is the emission mechanism behind it. We further exploit the pulsed vhe emission from the Crab to investigate fundamental physics testing for Lorentz Invariance Violation (liv), in terms of a wavelength dependent speed of light. To deepen our understanding of the pulsar emission mechanism at the highest energies, further pulsars have to be discovered above 100 GeV. To this end we search among pulsars already detected at around 1 GeV for the best candidates to emit gamma-rays in the vhe range.Another aim of this thesis is to discover a new pulsar wind nebula towards the outer part of our galaxy with the magic telescopes.ix Thesis advisor:Methods. We analyzed more than 400 hours of good-quality data of the Crab pulsar obtained by the magic telescopes between 2007 and 2016. This unprecedented large data set allowed us to effectively explore the Crab pulse profile and spectrum above 400 GeV.To test for Lorentz invariance violation, primarily foreseen by theories of quantum gravity, we modeled the vhe emission of the Crab pulsar and employed Bayesian inference to derive lower limits on...

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Gamma-ray emission from binaries in context

Cited by 37 publications

References 132 publications

Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

The Hour-timescale GeV Flares of PSR B1259–63 in 2017

Revealing the Most Energetic Light from Pulsars and Their Nebulae

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