Fermi Large Area Telescope Observation of a Gamma-ray Source at the Position of Eta Carinae

Abstract

The Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope detected a gamma-ray source that is spatially consistent with the location of Eta Carinae. This source has been persistently bright since the beginning of the LAT survey observations (from 2008 August to 2009 July, the time interval considered here). The gamma-ray signal is detected significantly throughout the LAT energy band (i.e., up to ~100 GeV). The 0.1-100 GeV energy spectrum is well represented by a combination of a cutoff power-law model (< 10 GeV) and a hard power-law component (> 10 GeV). The total flux (> 100 MeV) is $3.7_{-0.1}^{+0.3}\times 10^{-7}$ photons s${}^{-1}$ cm${}^{-2}$, with additional systematic uncertainties of 10%, and consistent with the average flux measured by AGILE (Tavani et al. 2009). The light curve obtained by Fermi is consistent with steady emission. Our observations do not confirm the presence of a gamma-ray flare in 2008 October as reported by Tavani et al. (2009), although we cannot exclude that a flare lasting only a few hours escaped detection by the Fermi LAT. We also do not find any evidence for gamma-ray variability that correlates with the large X-ray variability of Eta Carinae observed during 2008 December and 2009 January. We are thus not able to establish an unambiguous identification of the LAT source with Eta Carinae.

18 pages, 7 figures, submitted to ApJ on April 23 2010 and accepted on August 29 2010, Corresponding authors: H. Takahashi, J. Knodlseder

References in corpus (8)

• Fermi Large Area Telescope Bright Gamma-ray Source List
• Bright AGN Source List from the First Three Months of the Fermi Large Area Telescope All-Sky Survey
• Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT
• Fermi Large Area Telescope View of the Core of the Radio Galaxy Centaurus A
• Detection of Gamma-ray Emission from the Eta-Carinae Region
• Hard X-ray emission from Eta Carinae
• Possible Implications of Mass Accretion in Eta Carinae
• A Smoking Gun in the Carina Nebula

Cited by in corpus (61)

• Fermi Large Area Telescope Fourth Source Catalog
• Fermi Large Area Telescope Second Source Catalog
• Gamma-ray binaries and related systems
• A Statistical Approach to Recognizing Source Classes for Unassociated Sources in the First Fermi-LAT Catalog
• Spiralling out of control: 3D hydrodynamical modelling of the colliding winds in $\eta$Carinae
• Comparison of Fermi-LAT and CTA in the region between 10-100 GeV
• Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission
• The Fermi All-sky Variability Analysis: A list of flaring gamma-ray sources and the search for transients in our Galaxy
• Non-thermal X-rays from Colliding Wind Shock Acceleration in the Massive Binary Eta Carinae
• The hypersoft state of Cygnus X-3 - A key to jet quenching in X-ray binaries?
• A deep spectromorphological study of the $\gamma$-ray emission surrounding the young massive stellar cluster Westerlund 1
• Large-scale flow dynamics and radiation in pulsar gamma-ray binaries
• Refining the associations of the Fermi Large Area Telescope Source Catalogs
• High-energy radiation from the massive binary system Eta Carinae
• The first full orbit of Eta Carinae seen by Fermi
• Gamma-ray follow-up studies on Eta Carinae
• 3D simulations of clump formation in stellar wind collisions
• The Second AGILE Catalog of Gamma-Ray Sources
• Simulating three-dimensional nonthermal high-energy photon emission in colliding-wind binaries
• Binaries with the eyes of CTA
• Overview of non-transient gamma-ray binaries and prospects for the Cherenkov Telescope Array
• Fermi-LAT upper limits on gamma-ray emission from colliding wind binaries
• Modelling the interaction between relativistic and non-relativistic winds in binary pulsar systems: strong magnetization of the pulsar wind
• H.E.S.S. observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae
• On the origin of γ-ray emission in η Carina
• A radio-map of the colliding winds in the very massive binary system HD 93129A
• Runaway massive stars as variable gamma-ray sources
• 3D magneto-hydrodynamic models of non-thermal photon emission in the binary system ${\gamma }^2$ Velorum
• Is the bowshock of the runaway massive star HD 195592 a Fermi source?
• Extended VHE gamma-ray emission towards SGR1806-20, LBV1806-20, and stellar cluster Cl*1806-20
• Fermi acceleration along the orbit of η Carinae
• Eta Carinae's Thermal X-ray Tail Measured with XMM-Newton and NuSTAR
• Gamma-ray and X-ray constraints on non-thermal processes in $\eta$ Carinae
• Supercritical colliding wind binaries
• Suzaku Monitoring of Hard X-ray Emission from Eta Carinae over a Single Binary Orbital Cycle
• Colliding-wind binary systems: Diffusive shock acceleration and non-thermal emission
• Embedded star clusters as sources of high-energy cosmic rays: Modelling and constraints
• An update on Fermi-LAT transients in the Galactic plane, including strong activity of Cygnus X-3 in mid-2020
• Refining the origins of the gamma-ray binary 1FGL J1018.6-5856
• High energy gamma-ray emission from compact galactic sources in the context of observations with the next generation Cherenkov Telescope Arrays
• Eta Carinae with Fermi-LAT: Two full orbits and the third periastron
• A lepto-hadronic model of gamma rays from the Eta Carinae and prospects for neutrino telescopes
• Is the stellar system WR 11 a gamma-ray source?
• The Galactic high mass X-ray binary population with Fermi -LAT
• Megahertz emission of massive early-type stars in the Cygnus region
• X-ray emission of massive stars and their winds
• Search for variable gamma-ray emission from the Galactic plane in the Fermi data
• Galactic sources of E>100 GeV gamma-rays seen by Fermi telescope
• Possible detection of gamma rays from Epsilon Eridani
• Search for non-thermal X-ray emission in the colliding wind binary Cyg OB2 #8A
• High energy radiation from luminous and magnetized stars
• Detection of very-high-energy gamma-ray emission from Eta Carinae during its 2020 periastron passage
• Probing cosmic ray escape from η Carinae
• Radio study of the colliding wind binary HD93129A near periastron and its surroundings
• Exploring non-thermal emission from the star-forming region NGC 3603 through a realistic modelling of its environment
• $\eta$ Carinae: particle acceleration and multi-messenger aspects
• H.E.S.S.: The High Energy Stereoscopic System
• Limits on the non-thermal emission of the WR-WR system Apep
• INTEGRAL View of TeV Sources: A Legacy for the CTA Project
• Theory and Models of Colliding Stellar Winds
• Expected gamma-ray emission from x-ray binaries