Peter Mészáros - Academia.edu (original) (raw)
Papers by Peter Mészáros
Nuclear Physics B - Proceedings Supplements, 2005
We describe gamma-ray bursts (GRB), some of the recent developments, and the standard model used.... more We describe gamma-ray bursts (GRB), some of the recent developments, and the standard model used. We discuss the high energy (> ∼ TeV) neutrino emission expected in such models, and the prospects for their detection.
AIP Conference Proceedings, 2008
We suggest that non-thermal emission can be produced by multiple scatterings of the photons betwe... more We suggest that non-thermal emission can be produced by multiple scatterings of the photons between the supernova ejecta and pre-shock material in supernova shock breakout. Such bulk-Comptonization process may significantly change the original thermal photon spectrum, forming a power-law non-thermal component at higher energies. We then show that the luminous X-ray outburst XRO081009 associated with SN2008D is likely to be such shock breakout emission from an ordinary type Ib/c supernova.
The Astrophysical Journal, 2007
Physical Review D Particles and Fields, 2006
Physical Review D, 2006
The ratio of anti-electron to total neutrino flux, Φν e : Φν , expected from pγ interactions in a... more The ratio of anti-electron to total neutrino flux, Φν e : Φν , expected from pγ interactions in astrophysical sources is ≤ 1 : 15. We point out that this ratio is enhanced by the decay of µ + µ − pairs, created by the annihilation of secondary high energy photons from the decay of the neutral pions produced in pγ interactions. We show that, under certain conditions, the Φν e : Φν ratio may be significantly enhanced in gamma-ray burst (GRB) fireballs, and that detection at the Glashow resonance ofνe in kilometer scale neutrino detectors may constrain GRB fireball model parameters, such as the magnetic field and energy dissipation radius.
Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the... more Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the first time from a supernova connected with a gamma-ray burst (GRB), namely GRB060218/SN2006aj. It has been interpreted as arising from the breakout of a mildly relativistic, radiation-dominated shock from a dense stellar wind surrounding the progenitor star. There is also evidence for the presence of a mildly relativistic ejecta in GRB980425/SN1998bw, based on its X-ray and radio afterglow. Here we study the process of repeated bulk Compton scatterings of shock breakout thermal photons by the mildly relativistic ejecta. During the shock breakout process, a fraction of the thermal photons would be repeatedly scattered between the pre-shock material and the shocked material as well as the mildly relativistic ejecta and, as a result, the thermal photons get boosted to increasingly higher energies. This bulk motion Comptonization mechanism will produce nonthermal gamma-ray and X-ray flashes, which could account for the prompt gamma-ray burst emission in low-luminosity supernova-connected GRBs, such as GRB060218. A Monte Carlo code has been developed to simulate this repeated scattering process, which confirms that a significant fraction of the thermal photons get "accelerated" to form a nonthermal component, with a dominant luminosity. This interpretation for the prompt nonthermal emission of GRB060218 may imply that either the usual internal shock emission from highly relativistic jets in these low-luminosity GRBs is weak, or alternatively, that there are no highly relativistic jets in this peculiar class of bursts.
Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also c... more Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also copious soft photon emitters. We show that young, fast-rotating magnetars whose spin and magnetic moment point in opposite directions emit high energy neutrinos from their polar caps through photomeson interactions. We identify a neutrino cutoff band in the magnetar period-magnetic field strength phase diagram, corresponding to the photomeson interaction threshold. Within uncertainties, we point out four possible neutrino emission candidates among the currently known magnetars, the brightest of which may be detectable for a chance on-beam alignment. Young magnetars in the universe would also contribute to a weak diffuse neutrino background, whose detectability is marginal, depending on the typical neutrino energy.
The predicted thermal flash from supernova (SN) shock breakout might have been detected for the f... more The predicted thermal flash from supernova (SN) shock breakout might have been detected for the first time by Swift in GRB 060218/SN 2006aj. The detected ther- mal X-ray emission in this event implies emergence of a trans-relativistic (TR) SN shock with kinetic energy of Ek & 1049erg. During TRSN shock breakout, the ther- mal photons could be "accelerated" by the
The Astrophysical Journal, 2007
Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the... more Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the first time from a supernova connected with a gamma-ray burst (GRB), namely GRB060218/SN2006aj. It has been interpreted as arising from the breakout of a mildly relativistic, radiation-dominated shock from a dense stellar wind surrounding the progenitor star. There is also evidence for the presence of a mildly relativistic ejecta in GRB980425/SN1998bw, based on its X-ray and radio afterglow. Here we study the process of repeated bulk Compton scatterings of shock breakout thermal photons by the mildly relativistic ejecta. During the shock breakout process, a fraction of the thermal photons would be repeatedly scattered between the pre-shock material and the shocked material as well as the mildly relativistic ejecta and, as a result, the thermal photons get boosted to increasingly higher energies. This bulk motion Comptonization mechanism will produce nonthermal gamma-ray and X-ray flashes, which could account for the prompt gamma-ray burst emission in low-luminosity supernova-connected GRBs, such as GRB060218. A Monte Carlo code has been developed to simulate this repeated scattering process, which confirms that a significant fraction of the thermal photons get "accelerated" to form a nonthermal component, with a dominant luminosity. This interpretation for the prompt nonthermal emission of GRB060218 may imply that either the usual internal shock emission from highly relativistic jets in these low-luminosity GRBs is weak, or alternatively, that there are no highly relativistic jets in this peculiar class of bursts.
![Research paper thumbnail of G[CLC]e[/CLC]V Emission from T[CLC]e[/CLC]V Blazars and Intergalactic Magnetic Fields](https://attachments.academia-assets.com/114177632/thumbnails/1.jpg)
](The Astrophysical Journal, 2002
Several high-frequency peaked BL Lac objects such as Mrk 501 are strong TeV emitters. However, a ... more Several high-frequency peaked BL Lac objects such as Mrk 501 are strong TeV emitters. However, a significant fraction of the TeV gamma rays emitted are likely to be absorbed in interactions with the diffuse IR background, yielding electron-positron pairs. Hence, the observed TeV spectrum must be steeper than the intrinsic one. Using the recently derived intrinsic gamma-ray spectrum of Mrk 501 during its 1997 high state, we study the inverse Compton scattering of cosmic microwave photons by the resulting electron-positron pairs, which implies the existence of a hitherto undiscovered GeV emission. The typical duration of the GeV emission is determined by the flaring activity time and the energy-dependent magnetic deflection time. We numerically calculate the scattered photon spectrum for different intergalactic magnetic field (IGMF) strengths and find a spectral turnover and flare duration at GeV energies that are dependent on the field strength. We also estimate the scattered photon flux in the quiescent state of Mrk 501. The GeV flux levels predicted are consistent with existing EGRET upper limits and should be detectable above the synchrotron self-Compton component with the Gamma-Ray Large Area Space Telescope for IGMFs Շ10 Ϫ16 G, as expected in voids. Such detections would provide constraints on the strength of weak IGMFs.
The Astrophysical Journal, 2001
The Astrophysical Journal, 2003
![Research paper thumbnail of Multi-G[CLC]e[/CLC]V Neutrinos from Internal Dissipation in Gamma-Ray Burst Fireballs](https://attachments.academia-assets.com/114177631/thumbnails/1.jpg)
](The Astrophysical Journal, 2000
Sub-photospheric internal shocks and transverse differences of the bulk Lorentz factor in relativ... more Sub-photospheric internal shocks and transverse differences of the bulk Lorentz factor in relativistic fireball models of GRB lead to neutron diffusion relative to protons, resulting in inelastic nuclear collisions. This results in significant fluxes of ν µ (ν µ) of ∼ 3 GeV and ν e (ν e) of ∼ 2 GeV, scaling with the flow Lorentz factor η < η π ∼ 400. This extends significantly the parameter space for which neutrinos from inelastic collision are expected, which in the absence of the above effects requires values in excess of η π. A model with sideways diffusion of neutrons from a slower wind into a fast jet can lead to production of ν µ (ν µ) and ν e (ν e) in the 2-25 GeV or higher range, depending on the value of η. The emission from either of these mechanisms from GRB at redshifts z ∼ 1 may be detectable in suitably densely spaced detectors.
The Astrophysical Journal, 2007
We show that the prompt and afterglow X-ray emission of GRB060218, as well as its early (t 1 d) o... more We show that the prompt and afterglow X-ray emission of GRB060218, as well as its early (t 1 d) optical-UV emission, can be explained by a model in which a radiation-mediated shock propagates through a compact progenitor star into a dense wind. The prompt thermal X-ray emission is produced in this model as the mildly relativistic shock, β ≈ 0.85 carrying few ×10 49 erg, reaches the wind (Thomson) photosphere, where the post-shock thermal radiation is released and the shock becomes collisionless. Adopting this interpretation of the thermal X-ray emission, a subsequent X-ray afterglow is predicted, due to synchrotron emission and inverse-Compton scattering of SN UV photons by electrons accelerated in the collisionless shock. Early optical-UV emission is also predicted, due to the cooling of the outer δM ∼ 10 −3 M ⊙ envelope of the star, which was heated to high temperature during shock passage. The observed X-ray afterglow and the early optical-UV emission are both consistent with those expected in this model. Detailed analysis of the early optical-UV emission may provide detailed constraints on the density distribution near the stellar surface.
The Astrophysical Journal, 2003
Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also c... more Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also copious soft photon emitters. We show that young, fast-rotating magnetars whose spin and magnetic moment point in opposite directions emit high energy neutrinos from their polar caps through photomeson interactions. We identify a neutrino cutoff band in the magnetar period-magnetic field strength phase diagram, corresponding to the photomeson interaction threshold. Within uncertainties, we point out four possible neutrino emission candidates among the currently known magnetars, the brightest of which may be detectable for a chance on-beam alignment. Young magnetars in the universe would also contribute to a weak diffuse neutrino background, whose detectability is marginal, depending on the typical neutrino energy.
Physical Review Letters, 2004
Physical Review Letters, 2001
Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the ... more Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the stellar envelope is a widely discussed scenario for γ-ray burst production. For very extended or slow rotating stars, the jet may be unable to break through the envelope. Both penetrating and choked jets will produce, by photo-meson interactions of accelerated protons, a burst of > ∼ 5 TeV neutrinos while propagating in the envelope. The predicted flux, from both penetrating and choked jets, should be easily detectable by planned 1 km 3 neutrino telescopes.
Nuclear Physics B - Proceedings Supplements, 2005
We describe gamma-ray bursts (GRB), some of the recent developments, and the standard model used.... more We describe gamma-ray bursts (GRB), some of the recent developments, and the standard model used. We discuss the high energy (> ∼ TeV) neutrino emission expected in such models, and the prospects for their detection.
AIP Conference Proceedings, 2008
We suggest that non-thermal emission can be produced by multiple scatterings of the photons betwe... more We suggest that non-thermal emission can be produced by multiple scatterings of the photons between the supernova ejecta and pre-shock material in supernova shock breakout. Such bulk-Comptonization process may significantly change the original thermal photon spectrum, forming a power-law non-thermal component at higher energies. We then show that the luminous X-ray outburst XRO081009 associated with SN2008D is likely to be such shock breakout emission from an ordinary type Ib/c supernova.
The Astrophysical Journal, 2007
Physical Review D Particles and Fields, 2006
Physical Review D, 2006
The ratio of anti-electron to total neutrino flux, Φν e : Φν , expected from pγ interactions in a... more The ratio of anti-electron to total neutrino flux, Φν e : Φν , expected from pγ interactions in astrophysical sources is ≤ 1 : 15. We point out that this ratio is enhanced by the decay of µ + µ − pairs, created by the annihilation of secondary high energy photons from the decay of the neutral pions produced in pγ interactions. We show that, under certain conditions, the Φν e : Φν ratio may be significantly enhanced in gamma-ray burst (GRB) fireballs, and that detection at the Glashow resonance ofνe in kilometer scale neutrino detectors may constrain GRB fireball model parameters, such as the magnetic field and energy dissipation radius.
Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the... more Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the first time from a supernova connected with a gamma-ray burst (GRB), namely GRB060218/SN2006aj. It has been interpreted as arising from the breakout of a mildly relativistic, radiation-dominated shock from a dense stellar wind surrounding the progenitor star. There is also evidence for the presence of a mildly relativistic ejecta in GRB980425/SN1998bw, based on its X-ray and radio afterglow. Here we study the process of repeated bulk Compton scatterings of shock breakout thermal photons by the mildly relativistic ejecta. During the shock breakout process, a fraction of the thermal photons would be repeatedly scattered between the pre-shock material and the shocked material as well as the mildly relativistic ejecta and, as a result, the thermal photons get boosted to increasingly higher energies. This bulk motion Comptonization mechanism will produce nonthermal gamma-ray and X-ray flashes, which could account for the prompt gamma-ray burst emission in low-luminosity supernova-connected GRBs, such as GRB060218. A Monte Carlo code has been developed to simulate this repeated scattering process, which confirms that a significant fraction of the thermal photons get "accelerated" to form a nonthermal component, with a dominant luminosity. This interpretation for the prompt nonthermal emission of GRB060218 may imply that either the usual internal shock emission from highly relativistic jets in these low-luminosity GRBs is weak, or alternatively, that there are no highly relativistic jets in this peculiar class of bursts.
Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also c... more Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also copious soft photon emitters. We show that young, fast-rotating magnetars whose spin and magnetic moment point in opposite directions emit high energy neutrinos from their polar caps through photomeson interactions. We identify a neutrino cutoff band in the magnetar period-magnetic field strength phase diagram, corresponding to the photomeson interaction threshold. Within uncertainties, we point out four possible neutrino emission candidates among the currently known magnetars, the brightest of which may be detectable for a chance on-beam alignment. Young magnetars in the universe would also contribute to a weak diffuse neutrino background, whose detectability is marginal, depending on the typical neutrino energy.
The predicted thermal flash from supernova (SN) shock breakout might have been detected for the f... more The predicted thermal flash from supernova (SN) shock breakout might have been detected for the first time by Swift in GRB 060218/SN 2006aj. The detected ther- mal X-ray emission in this event implies emergence of a trans-relativistic (TR) SN shock with kinetic energy of Ek & 1049erg. During TRSN shock breakout, the ther- mal photons could be "accelerated" by the
The Astrophysical Journal, 2007
Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the... more Thermal X-ray emission which is simultaneous with the prompt gamma-rays has been detected for the first time from a supernova connected with a gamma-ray burst (GRB), namely GRB060218/SN2006aj. It has been interpreted as arising from the breakout of a mildly relativistic, radiation-dominated shock from a dense stellar wind surrounding the progenitor star. There is also evidence for the presence of a mildly relativistic ejecta in GRB980425/SN1998bw, based on its X-ray and radio afterglow. Here we study the process of repeated bulk Compton scatterings of shock breakout thermal photons by the mildly relativistic ejecta. During the shock breakout process, a fraction of the thermal photons would be repeatedly scattered between the pre-shock material and the shocked material as well as the mildly relativistic ejecta and, as a result, the thermal photons get boosted to increasingly higher energies. This bulk motion Comptonization mechanism will produce nonthermal gamma-ray and X-ray flashes, which could account for the prompt gamma-ray burst emission in low-luminosity supernova-connected GRBs, such as GRB060218. A Monte Carlo code has been developed to simulate this repeated scattering process, which confirms that a significant fraction of the thermal photons get "accelerated" to form a nonthermal component, with a dominant luminosity. This interpretation for the prompt nonthermal emission of GRB060218 may imply that either the usual internal shock emission from highly relativistic jets in these low-luminosity GRBs is weak, or alternatively, that there are no highly relativistic jets in this peculiar class of bursts.
The Astrophysical Journal, 2002
Several high-frequency peaked BL Lac objects such as Mrk 501 are strong TeV emitters. However, a ... more Several high-frequency peaked BL Lac objects such as Mrk 501 are strong TeV emitters. However, a significant fraction of the TeV gamma rays emitted are likely to be absorbed in interactions with the diffuse IR background, yielding electron-positron pairs. Hence, the observed TeV spectrum must be steeper than the intrinsic one. Using the recently derived intrinsic gamma-ray spectrum of Mrk 501 during its 1997 high state, we study the inverse Compton scattering of cosmic microwave photons by the resulting electron-positron pairs, which implies the existence of a hitherto undiscovered GeV emission. The typical duration of the GeV emission is determined by the flaring activity time and the energy-dependent magnetic deflection time. We numerically calculate the scattered photon spectrum for different intergalactic magnetic field (IGMF) strengths and find a spectral turnover and flare duration at GeV energies that are dependent on the field strength. We also estimate the scattered photon flux in the quiescent state of Mrk 501. The GeV flux levels predicted are consistent with existing EGRET upper limits and should be detectable above the synchrotron self-Compton component with the Gamma-Ray Large Area Space Telescope for IGMFs Շ10 Ϫ16 G, as expected in voids. Such detections would provide constraints on the strength of weak IGMFs.
The Astrophysical Journal, 2001
The Astrophysical Journal, 2003
The Astrophysical Journal, 2000
Sub-photospheric internal shocks and transverse differences of the bulk Lorentz factor in relativ... more Sub-photospheric internal shocks and transverse differences of the bulk Lorentz factor in relativistic fireball models of GRB lead to neutron diffusion relative to protons, resulting in inelastic nuclear collisions. This results in significant fluxes of ν µ (ν µ) of ∼ 3 GeV and ν e (ν e) of ∼ 2 GeV, scaling with the flow Lorentz factor η < η π ∼ 400. This extends significantly the parameter space for which neutrinos from inelastic collision are expected, which in the absence of the above effects requires values in excess of η π. A model with sideways diffusion of neutrons from a slower wind into a fast jet can lead to production of ν µ (ν µ) and ν e (ν e) in the 2-25 GeV or higher range, depending on the value of η. The emission from either of these mechanisms from GRB at redshifts z ∼ 1 may be detectable in suitably densely spaced detectors.
The Astrophysical Journal, 2007
We show that the prompt and afterglow X-ray emission of GRB060218, as well as its early (t 1 d) o... more We show that the prompt and afterglow X-ray emission of GRB060218, as well as its early (t 1 d) optical-UV emission, can be explained by a model in which a radiation-mediated shock propagates through a compact progenitor star into a dense wind. The prompt thermal X-ray emission is produced in this model as the mildly relativistic shock, β ≈ 0.85 carrying few ×10 49 erg, reaches the wind (Thomson) photosphere, where the post-shock thermal radiation is released and the shock becomes collisionless. Adopting this interpretation of the thermal X-ray emission, a subsequent X-ray afterglow is predicted, due to synchrotron emission and inverse-Compton scattering of SN UV photons by electrons accelerated in the collisionless shock. Early optical-UV emission is also predicted, due to the cooling of the outer δM ∼ 10 −3 M ⊙ envelope of the star, which was heated to high temperature during shock passage. The observed X-ray afterglow and the early optical-UV emission are both consistent with those expected in this model. Detailed analysis of the early optical-UV emission may provide detailed constraints on the density distribution near the stellar surface.
The Astrophysical Journal, 2003
Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also c... more Magnetars can accelerate cosmic rays to high energies through the unipolar effect, and are also copious soft photon emitters. We show that young, fast-rotating magnetars whose spin and magnetic moment point in opposite directions emit high energy neutrinos from their polar caps through photomeson interactions. We identify a neutrino cutoff band in the magnetar period-magnetic field strength phase diagram, corresponding to the photomeson interaction threshold. Within uncertainties, we point out four possible neutrino emission candidates among the currently known magnetars, the brightest of which may be detectable for a chance on-beam alignment. Young magnetars in the universe would also contribute to a weak diffuse neutrino background, whose detectability is marginal, depending on the typical neutrino energy.
Physical Review Letters, 2004
Physical Review Letters, 2001
Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the ... more Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the stellar envelope is a widely discussed scenario for γ-ray burst production. For very extended or slow rotating stars, the jet may be unable to break through the envelope. Both penetrating and choked jets will produce, by photo-meson interactions of accelerated protons, a burst of > ∼ 5 TeV neutrinos while propagating in the envelope. The predicted flux, from both penetrating and choked jets, should be easily detectable by planned 1 km 3 neutrino telescopes.