Deeper Chandra Follow-up of Cygnus TeV Source Perpetuates Mystery

Abstract

A 50 ksec Chandra observation of the unidentified TeV source in Cygnus reported by the HEGRA collaboration reveals no obvious diffuse X-ray counterpart. However, 240 Pointlike X-ray sources are detected within or nearby the extended TeV J2032+4130 source region, of which at least 36 are massive stars and 2 may be radio emitters. That the HEGRA source is a composite, having as counterpart the multiple point-like X-ray sources we observe, cannot be ruled out. Indeed, the distribution of point-like X-ray sources appears non-uniform and concentrated broadly within the extent of the TeV source region. We offer a hypothesis for the origin of the very high energy gamma-ray emission in Cyg OB2 based on the local acceleration of TeV range cosmic rays and the differential distribution of OB vs. less massive stars in this association.

arXiv commentSubstantially revised version; incorporates referee suggestions & expanded discussion

References in corpus (10)

• The Southern Galactic Plane Survey: HI Observations and Analysis
• The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA stereoscopic air Cherenkov telescopes
• An unidentified TeV source in the vicinity of Cygnus OB2
• Chandra Spectra of the Soft X-ray Diffuse Background
• The unidentified TeV source (TeVJ2032+4130) and surrounding field: Final HEGRA IACT-System results
• Chandra Multi-wavelength Project (ChaMP). I. First X-ray Source Catalog
• High-energy gamma-rays from stellar associations
• CHANDRA/VLA Follow-up of TeV J2032+4131, the Only Unidentified TeV Gamma-ray Source
• Evidence for TeV gamma ray emission from TeV J2032+4130 in Whipple archival data
• Hadronic processes within collective stellar winds

Cited by in corpus (24)

• Discovery of TeV Gamma-Ray Emission from the Cygnus Region of the Galaxy
• The Massive Star Population of Cygnus OB2
• Radio detection of LAT PSRs J1741-2054 and J2032+4127: no longer just gamma-ray pulsars
• MAGIC observations of the unidentified TeV gamma-ray source TeV J2032+4130
• Observations of the unidentified gamma-ray source TeV J2032+4130 by VERITAS
• A Very High Energy $\gamma$-Ray Survey towards the Cygnus Region of the Galaxy
• TeV gamma-rays and neutrinos from photo-disintegration of nuclei in Cygnus OB2
• Observations of the Unidentified TeV Gamma-Ray Source TeV J2032+4130 with the Whipple Observatory 10 m Telescope
• The Massive Star Forming Region Cygnus OB2. I. Chandra catalogue of association members
• Optical photometric GTC/OSIRIS observations of the young massive association Cygnus OB2
• Suzaku Observations of HESS J1616-508: Evidence for a Dark Particle Accelerator
• The population of radio sources in the field of the unidentified gamma-ray source TeV J2032+4130
• XMM-Newton observations of the first unidentified TeV gamma-ray source TeV J2032+4130
• Neutrino Flux from Cosmic Ray Accelerators in the Cygnus Spiral Arm of the Galaxy
• TeV J2032+4130: a not-so-dark Accelerator?
• Detection of X-Ray Emission from the Unidentified TeV Gamma-Ray Source TeV J2032+4130
• First bounds on the high-energy emission from isolated Wolf-Rayet binary systems
• Deep radio images of the HEGRA and Whipple TeV sources in the Cygnus OB2 region
• Discovery of Extended X-Ray emission from the unidentified TeV source HESS J1614-518 using the Suzaku Satellite
• Transient X-ray sources in the field of the Unidentified Gamma-Ray Source TeV J2032+4130 in Cygnus
• The Molecular Environment of the Gamma-ray Source TeV J2032+4130
• Radio observations of evaporating objects in the Cygnus OB2 region
• Present and Future Gamma-Ray Probes of the Cygnus OB2 Environment
• Oxygen and silicon abundances in Cygnus OB2: Chemical homogeneity in a sample of OB slow rotators