Related papers: Pseudoscalar Conversion and Gamma-Rays from Supern…
A light pseudoscalar coupled to two photons would be copiously emitted by the core of a supernova. Part of this flux would be converted to $\gamma-$rays by the galactic magnetic field. Measurements on the SN1987A $\gamma-$ray flux by the…
Pseudoscalar particles $\phi$ usually couple electromagnetically by an interaction of the form $\frc14 g \phi F {\widetilde F}$, allowing them to convert to photons in the presence of magnetic fields. Notably, new low-mass pseudoscalars…
We derive new constraints on light CP-even scalars using old gamma-ray observations in the direction of SN1987A by the Solar Maximum Mission (SMM) satellite. Light scalars can be abundantly produced in the supernova core via the nucleon…
Axions produced copiously in core-collapse supernovae can convert into photons as they propagate through various astrophysical magnetic fields. The cumulative emission from the cosmic population of supernovae can therefore generate a…
It has long been established that axions could have been produced within the nascent proto-neutron-star formed following the type II supernova SN1987A, escaped the star due to their weak interactions, and then converted to gamma-rays in the…
Supernova remnants have long been suggested as a class of potential counterparts to unidentified gamma-ray sources. The mechanisms by which such gamma-rays can arise may include emission from a pulsar associated with a remnant, or a variety…
We investigate the detection of a pseudoscalar $\phi$ that couples electromagnetically via an interaction ${1\over4}g \phi F {\tilde F}$. In particular, we focus on the conversion of pseudoscalars produced in the sun's interior in the…
A future Galactic Supernova (SN) explosion can lead to a gamma-ray signal induced by ultralight Axion-Like Particles (ALPs) thermally produced in the SN core and converted into high-energy photons in the Galactic magnetic field. The…
Gamma-ray instrumentation for astronomical spectroscopy consists of multiple-interaction detectors in space combined with sophisticated post-processing of detector events on ground. Spectral signatures in the MeV regime originate from…
Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV are produced in magnetized environments such as galaxy…
A dark photon is a well-motivated new particle which, as a component of an associated dark sector, could explain dark matter. One strong limit on dark photons arises from excessive cooling of supernovae. We point out that even at couplings…
We discuss the possibility of observing ultra high energy cosmic ray sources inhigh energy gamma rays. Protons propagating away from their accelerators produce secondary electrons during interactions with cosmic microwave background…
Galactic cosmic rays are commonly believed to be accelerated at supernova remnants via diffusive shock acceleration. Despite the popularity of this idea, a conclusive proof for its validity is still missing. Gamma-ray astronomy provides us…
We present numerical calculations of the photon-light-pseudoscalar-boson conversion in the recently discovered binary pulsar system J0737-3039. Light pseudoscalar bosons (LPBs) oscillate into photons in the presence of strong magnetic…
At least three pulsars in supernova remnants were detected at E > 100 MeV by EGRET on the Compton Gamma Ray Observatory. Efforts to search for additional pulsars in the EGRET data have been unsuccessful due to limited statistics. An example…
Axion-like particles (ALPs) coupled to nucleons can be efficiently produced in core-collapse supernovae (SNe) and then, if they couple to photons, convert into gamma rays in cosmic magnetic fields, generating short gamma-ray bursts. Though…
If supernova remnants (SNRs) are the sites of cosmic-ray acceleration, the associated nuclear interactions should result in observable fluxes of TeV gamma-rays from the nearest SNRs. Measurements of the gamma-ray flux from six nearby,…
Recent observations show that hypernovae may deposit some fraction of their kinetic energy in mildly relativistic ejecta. In the dissipation process of such ejecta in a stellar wind, cosmic ray protons can be accelerated up to $\sim…
Scattering relativistic electrons with optical lasers can result in a significant frequency upshift for the photons, potentially producing $\gamma$-rays. This is what linear Compton scattering taught us. Ultra-intense lasers offer nowadays…
Ultra-high energy cosmic ray protons accelerated in astrophysical objects produce secondary electromagnetic cascades during propagation in the cosmic microwave and infrared backgrounds. We show that such cascades can contribute between ~1%…