Abstract
γ
-ray observations of the Cygnus Cocoon, an extended source surrounding the Cygnus X star-forming region, suggest the presence of a cosmic-ray accelerator reaching energies up to a few PeV. ...The very-high-energy (VHE; 0.1–100 TeV)
γ
-ray emission may be explained by the interaction of cosmic-ray hadrons with matter inside the Cocoon, but an origin of inverse Compton radiation by relativistic electrons cannot be ruled out. Inverse Compton
γ
-rays at VHE are accompanied by synchrotron radiation peaked in X-rays. Hence, X-ray observations may probe the electron population and magnetic field of the source. We observed 11 fields in or near the Cygnus Cocoon with the Neil Gehrels Swift Observatory’s X-Ray Telescope (Swift-XRT) totaling 110 ks. We fit the fields to a Galactic and extragalactic background model and performed a log-likelihood ratio test for an additional diffuse component. We found no significant additional emission and established upper limits in each field. By assuming that the X-ray intensity traces the TeV intensity and follows a
dN
/
dE
∝
E
−
2.5
spectrum, we obtained a 90% upper limit of
F
X
< 8.7 × 10
−11
erg cm
−2
s
−1
or <5.2 × 10
−11
erg cm
−2
s
−1
on the X-ray flux of the entire Cygnus Cocoon between 2 and 10 keV depending on the choice of hydrogen column density model for the absorption. The obtained upper limits suggest that no more than one-quarter of the
γ
-ray flux at 1 TeV is produced by inverse Compton scattering, when assuming an equipartition magnetic field of ∼20
μ
G.
Gammastrahlung von der Sonne Fleischhack, Henrike; Huentemeyer, Petra
Physik in unserer Zeit,
11/2023, Letnik:
54, Številka:
6
Journal Article
Die Sonne leuchtet im gesamten elektromagnetischen Spektrum. Erstmals gelang mithilfe von Daten des HAWC‐Observatoriums nun der Nachweis, dass die Sonne Photonen mit Energien bis in den TeV‐Bereich ...aussendet. Diese hochenergetischen Gammastrahlen sind intensiver, wenn sich die Sonnenaktivität in einem Minimum befindet. Theoretische Modelle können diesen Effekt noch nicht vollständig erklären.
Gammastrahlung von der Sonne Fleischhack, Henrike; Huentemeyer, Petra
Physik in unserer Zeit,
11/2023, Letnik:
54, Številka:
6
Journal Article
Die Sonne leuchtet im gesamten elektromagnetischen Spektrum. Erstmals gelang mithilfe von Daten des HAWC‐Observatoriums nun der Nachweis, dass die Sonne Photonen mit Energien bis in den TeV‐Bereich ...aussendet. Diese hochenergetischen Gammastrahlen sind intensiver, wenn sich die Sonnenaktivität in einem Minimum befindet. Theoretische Modelle können diesen Effekt noch nicht vollständig erklären.
Galaktische Protonenkanone Fleischhack, Henrike; Huentemeyer, Petra
Physik in unserer Zeit,
11/2022, Letnik:
53, Številka:
6
Journal Article
Schon lange wird nach Pevatronen gesucht, kosmischen Teilchenbeschleunigern, die subatomare Teilchen auf extreme Energien im Bereich von Petaelektronenvolt beschleunigen. Nun gelang der Nachweis, ...dass der Supernovaüberrest SNR G106.3+2.7 solch ein Pevatron enthält.
Galaktische Protonenkanone Fleischhack, Henrike; Huentemeyer, Petra
Physik in unserer Zeit,
November 2022, Letnik:
53, Številka:
6
Journal Article
Schon lange wird nach Pevatronen gesucht, kosmischen Teilchenbeschleunigern, die subatomare Teilchen auf extreme Energien im Bereich von Petaelektronenvolt beschleunigen. Nun gelang der Nachweis, ...dass der Supernovaüberrest SNR G106.3+2.7 solch ein Pevatron enthält.
Schon lange wird nach Pevatronen gesucht, kosmischen Teilchenbeschleunigern, die subatomare Teilchen auf extreme Energien im Bereich von Petaelektronenvolt beschleunigen. Nun gelang der Nachweis, dass der Supernovaüberrest SNR G106.3+2.7 solch ein Pevatron enthält.
The High-Altitude Water Cherenkov (HAWC) TeV Gamma-Ray Observatory located at a site about two hours drive east of Puebla, Mexico on the Sierra Negra plateau (4100 m a.s.l.) was inaugurated in March ...2015. The array of 300 water Cherenkov detectors can observe large portions of the sky simultaneously and, with an energy range of 100 GeV to 100 TeV, is currently one of the most sensitive instruments capable of probing particle acceleration near PeV energies. HAWC has already started science operation in the Summer of 2013 and preliminary sky maps have been produced from 260 days of data taken with a partial array. Multiple > 5 σ (pre-trials) hotspots are visible along the galactic plane and some appear to coincide with known TeV sources from the H.E.S.S. catalog, SNRs and molecular cloud associations, and pulsars wind nebulae (PWNe). The sky maps based on partial HAWC array data are discussed as well as the scientific potential of the completed instrument especially in the context of multi-wavelengths studies.
\(\gamma\)-ray observations of the Cygnus Cocoon, an extended source surrounding the Cygnus X star-forming region, suggest the presence of a cosmic ray accelerator reaching energies up to a few PeV. ...The very-high-energy (VHE; 0.1-100~TeV) \(\gamma\)-ray emission may be explained by the interaction of cosmic-ray hadrons with matter inside the Cocoon, but an origin of inverse Compton radiation by relativistic electrons cannot be ruled out. Inverse Compton \(\gamma\)-rays at VHE are accompanied by synchrotron radiation peaked in X-rays. Hence, X-ray observations may probe the electron population and magnetic field of the source. We observed eleven fields in or near the Cygnus Cocoon with the Neil Gehrels Swift Observatory's X-Ray Telescope (Swift-XRT) totaling 110 ksec. We fit the fields to a Galactic and extra-galactic background model and performed a log-likelihood ratio test for an additional diffuse component. We found no significant additional emission and established upper limits in each field. By assuming that the X-ray intensity traces the TeV intensity and follows an \(dN/dE\propto E^{-2.5}\) spectrum, we obtained a 90\% upper limit of \(F_X < 8.7\times 10^{-11}\rm~erg\,cm^{-2}\,s^{-1}\) or \(< 5.2\times 10^{-11}\rm~erg\,cm^{-2}\,s^{-1}\) on the X-ray flux of the entire Cygnus Cocoon between 2 and 10 keV depending on the choice of hydrogen column density model. This suggests that no more than one quarter of the \(\gamma\)-ray flux at 1 TeV is produced by inverse Compton scattering, when assuming an equipartition magnetic field of \(\sim 20\,\mu\)G.
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