Geminga's puzzling pulsar wind nebula
- Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Department of Physics, Stanford University, Stanford, CA 94305 (United States)
- INAF Osservatorio Astrofisico di Arcetri, L.go E. Fermi 5, I-50125 Firenze (Italy)
- A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021, St. Petersburg State Politechnical University (Russian Federation)
- Department of Physics, The George Washington University, 725 21st Street, NW, Washington, DC 20052 (United States)
- NASA/Marshall Space Flight Center, ZP12, 320 Sparkman Drive, Huntsville, AL 35805 (United States)
We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures—two ≈0.2d{sub 250} pc long lateral tails and a segmented axial tail of ≈0.05d{sub 250} pc length, where d{sub 250}=d/(250 pc). The photon indices of the power-law spectra of the lateral tails, Γ≈1, are significantly harder than those of the pulsar (Γ≈1.5) and the axial tail (Γ≈1.6). There is no significant diffuse X-ray emission between the lateral tails—the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indications of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scenario, the lateral tails could represent an azimuthally asymmetric shell whose hard emission is caused by the Fermi acceleration mechanism of colliding winds. In another scenario, the lateral tails could be luminous, bent polar outflows, while the blobs in the axial tail could represent a crushed torus. In a resemblance to planetary magnetotails, the blobs of the axial tail might also represent short-lived plasmoids, which are formed by magnetic field reconnection in the relativistic plasma of the pulsar wind tail.
- OSTI ID:
- 22869566
- Journal Information:
- Astrophysical Journal, Vol. 835, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rapid X-Ray Variations of the Geminga Pulsar Wind Nebula
Chandra observations of the elusive pulsar wind nebula around PSR B0656+14