Detection of Gamma-Ray Emission From the Eta-Carinae Region

Tavani, M.; Sabatini, S.; Pian, E.; Bulgarelli, A.; Caraveo, P. A.; Viotti, R.; Corcoran, M. F.; Giuliani, A.; Pittori, C.; Verrecchia, F.; Vercellone, S.; Mereghetti, S.; Argan, A.; Barbiellini, G.; Boffelli, F.; Cattaneo, P. W.; Chen, Andrew; Cocco, V.; D’Ammando, F.; Costa, E.; Paris, G. De; Monte, E. Del; Cocco, G. Di; Donnarumma, I.; Evangelista, Y.; Ferrari, A.; Feroci, M.; Fiorini, M.; Froysland, T.; Fuschino, F.; Galli, M.; Gianotti, F.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Longo, F.; Marisaldi, M.; Mastropietro, M.; Morelli, E.; Moretti, E.; Morselli, A.; Pacciani, L.; Perotti, F.; Piano, G.; Picozza, P.; Pilia, M.; Porrovecchio, G.; Pucella, G.; Prest, M.; Rapisarda, M.; Rappoldi, A.; Rubini, A.; Soffitta, P.; Trifoglio, M.; Trois, A.; Vallazza, E.; Vittorini, V.; Zambra, A.; Zanello, D.; Santolamazza, P.; Giommi, P.; Colafrancesco, S.; Antonelli, L. A.; Salotti, L.

doi:10.1088/0004-637x/698/2/l142

Cited by 110 publications

(98 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In particular, the two-day period during which Agile reported a flare from the Carina region was investigated, but no sign of activity could be detected. During these two days, the average flux detected by Fermi/LAT was F = (1.9 ± 0.6) × 10 −7 ph cm −2 s −1 , well below the flux detected by Agile, which is (27.0 ± 6.5) × 10 −7 ph cm −2 s −1 (Tavani et al 2009). Since Fermi and Agile have different orbits and we used an energy threshold of 200 MeV, our analysis cannot exclude a very short and low energy flare.…”

Section: Timing Analysismentioning

confidence: 68%

See 1 more Smart Citation

ηCarinae: a very large hadron collider

Farnier

Walter

Leyder

2010

A&A

109

View full text Add to dashboard Cite

Context. η Carinae is the colliding wind binary with the highest mass-loss rate in our Galaxy and the only one in which hard X-ray emission has been detected. Aims. η Carinae is therefore a primary candidate to search for particle acceleration by probing its gamma-ray emission. Methods. We used the first 21 months of Fermi/LAT data to extract gamma-ray (0.2-100 GeV) images, spectra, and light-curves, then combined them with multi-wavelength observations to model the non-thermal spectral energy distribution. Results. A bright gamma-ray source is detected at the position of η Carinae. Its flux at a few 100 MeV can be modelled by an extrapolation of the hard X-ray spectrum towards higher energies. The spectral energy distribution features two distinct components. The first one extends from the keV to GeV energy range, and features an exponential cutoff at ∼1 GeV. It can be understood as inverse Compton scattering of ultraviolet photons by electrons accelerated up to γ ∼ 10 4 in the colliding wind region. The expected synchrotron emission is compatible with the existing upper limit to the non-thermal radio emission. The second component is a hard gamma-ray tail detected above 20 GeV. It could be explained by π 0 -decay of accelerated hadrons interacting with the dense stellar wind. The ratio of the fluxes of the π 0 to inverse Compton components is roughly as predicted by simulations of colliding wind binaries. This hard gamma-ray tail can only be understood if emitted close to the wind collision region. The energy transferred to the accelerated particles (∼5% of the collision mechanical energy) is comparable to that of the thermal X-ray emission. Conclusions. The electron spectrum responsible for the keV to GeV emission was modelled and the observed emission above 20 GeV strongly suggests hadronic acceleration in η Carinae. These observations are thus in good agreement with the colliding wind scenario proposed for η Carinae.

show abstract

Section: Timing Analysismentioning

confidence: 68%

“…Agile detected the source 1AGL J1043-5931 (α = 161.2, δ = −59.7, with an uncertainty of 0.4 • ), which could be related to η Carinae (Tavani et al 2009). A two-day γ-ray flare was also observed in October 2008, although its origin is unclear.…”

Section: Introductionmentioning

confidence: 97%

ηCarinae: a very large hadron collider

Farnier

Walter

Leyder

2010

A&A

109

View full text Add to dashboard Cite

show abstract

“…The flux of this source, averaged over all the observations, is (3.7 ± 0.5) × 10 −7 photon cm −2 s −1 (above 100 MeV). Tavani et al (2009) claim that this source, located at (l, b) = (287.6, −0.7) (with an error of 0.4 • ), is probably associated with η Car (located 0.07 • away). They also report that a 2-day γ-ray flare was observed in October 2008.…”

Section: γ-Ray Observationsmentioning

confidence: 92%

“…Tavani et al (2009) report the detection of 1AGL J1043-5931 above 100 MeV, based on observations taken with the GammaRay Imaging Detector instrument (GRID; 30 MeV-30 GeV; Prest et al 2003). The flux of this source, averaged over all the observations, is (3.7 ± 0.5) × 10 −7 photon cm −2 s −1 (above 100 MeV).…”

Section: γ-Ray Observationsmentioning

confidence: 98%

Hard X-ray identification ofη Carinae and steadiness close to periastron

Leyder¹,

Walter²,

Rauw³

2010

A&A

View full text Add to dashboard Cite

Context. The colliding-wind binary η Carinae exhibits soft X-ray thermal emission that varies strongly around the periastron passage. It has been found to have non-thermal emission, thanks to its detection in hard X-rays using INTEGRAL and Suzaku, and also in γ-rays with AGILE and Fermi. Aims. This paper attempts to definitively identify η Carinae as the source of the hard X-ray emission, to examine how changes in the 2-10 keV band influence changes in the hard X-ray band, and to understand more clearly the mechanisms producing the non-thermal emission using new INTEGRAL observations obtained close to periastron passage. Methods. To strengthen the identification of η Carinae with the hard X-ray source, a long Chandra observation encompassing the INTEGRAL/ISGRI error circle was analysed, and all other soft X-ray sources (including the outer shell of η Carinae itself) were discarded as likely counter-parts. To expand the knowledge of the physical processes governing the X-ray lightcurve, new hard X-ray images of η Carinae were studied close to periastron, and compared to previous observations far from periastron. Results. The INTEGRAL component, when represented by a power law (with a photon index Γ of 1.8), would produce more emission in the Chandra band than observed from any point source in the ISGRI error circle apart from η Carinae, as long as the hydrogen column density to the ISGRI source is lower than N H 10 24 cm −2 . Sources with such a high absorption are very rare, thus the hard X-ray emission is very likely to be associated with η Carinae. The eventual contribution of the outer shell to the non-thermal component also remains fairly limited. Close to periastron passage, a 3-σ detection is achieved for the hard X-ray emission of η Carinae, with a flux similar to the average value far from periastron. Conclusions. Assuming a single absorption component for both the thermal and non-thermal sources, this 3-σ detection can be explained with a hydrogen column density that does not exceed N H 6 × 10 23 cm −2 without resorting to an intrinsic increase in the hard X-ray emission. The energy injected in hard X-rays (averaged over a month timescale) appears to be rather constant at least as close as a few stellar radii, well within the acceleration region of the wind.

show abstract

“…Gamma-ray emission and hard X-ray non-thermal emission was detected from η-Carinae (Tavani et al 2009, Abdo et al 2009, Farnier et al 2011, Dubus 2013 which is considered as a likely case of colliding wind binary. No clear evidence for a non-thermal synchrotron component in the observed radio emission of η-Carinae has been reported yet, possibly due to a high free-free absorption (see, e.g., De Becker and Raucq 2013, and references therein).…”

Section: Dougherty Et Al (2005) Presented Milliarcsecond Resolution Vmentioning

confidence: 99%

Nonthermal particles and photons in starburst regions and superbubbles

Bykov

2014

Astron Astrophys Rev

118

102

View full text Add to dashboard Cite

Starforming factories in galaxies produce compact clusters and loose associations of young massive stars. Fast radiation-driven winds and supernovae input their huge kinetic power into the interstellar medium in the form of highly supersonic and superalfvenic outflows. Apart from gas heating, collisionless relaxation of fast plasma outflows results in fluctuating magnetic fields and energetic particles. The energetic particles comprise a long-lived component which may contain a sizeable fraction of the kinetic energy released by the winds and supernova ejecta and thus modify the magnetohydrodynamic flows in the systems. We present a concise review of observational data and models of nonthermal emission from starburst galaxies, superbubbles, and compact clusters of massive stars. Efficient mechanisms of particle acceleration and amplification of fluctuating magnetic fields with a wide dynamical range in starburst regions are discussed. Sources of cosmic rays, neutrinos and multi-wavelength nonthermal emission associated with starburst regions including potential galactic "PeVatrons" are reviewed in the global galactic ecology context.

show abstract

Detection of Gamma-Ray Emission From the Eta-Carinae Region

Cited by 110 publications

References 28 publications

ηCarinae: a very large hadron collider

ηCarinae: a very large hadron collider

Hard X-ray identification ofη Carinae and steadiness close to periastron

Nonthermal particles and photons in starburst regions and superbubbles

Contact Info

Product

Resources

About