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Characterization of the inner knot of the crab: the site of the gamma-ray flares?
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Weisskopf, Martin C. |
| Copyright Year | 2015 |
| Description | One of the most intriguing recent discoveries has been the detection of powerful gamma-ray flares from the Crab Nebula. Such events, with a recurrence time of about once per year, can be so dramatic to make the system the brightest source in the gammaâray sky as occurred, e.g. in April 2011. These flares challenge our understanding of how pulsar wind nebulae work and defy current astrophysical models for particle acceleration. We present here our study of the inner knot located within a fraction of an arcsecond from the pulsar with the aim of characterizing the feature and asking if this might be the site of the origin of the gamma-ray flares. We took data using Keck, HST, and Chandra obtained as part of our multiâwavelength campaign to identify the source of the enigmatic flares. We set an upper limit as to the gamma-ray flux from the knot. We also find that the dimensions, surface brightness, flux, etc. of the optical and infrared knot are all correlated with distance from the pulsar. This distance, in turn, varies with time. In addition to this most thorough characterization of the inner knot's properties, we examine the hypothesis that the knot may be the site of the flares by examining the knot separation versus the Fermi/LAT gamma-ray flux. Finally, as part of this research, we make use of a new approach employing singular value decomposition (SVD) for analyzing time series of images and compare the approach to more traditional methods. Our conclusions are only refined but not impacted by using the new approach. |
| File Size | 47905 |
| Page Count | 1 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20150001384 |
| Archival Resource Key | ark:/13960/t84j5h75d |
| Language | English |
| Publisher Date | 2015-01-04 |
| Access Restriction | Open |
| Subject Keyword | Gamma-ray Flares Gamma Ray Spectrometers Astrophysics Time Series Analysis Crab Nebula Brightness Images Decomposition Infrared Astronomy Stellar Flares Gamma Rays Characterization Infrared Telescopes Pulsars Hubble Space Telescope Telescopes X Ray Astrophysics Facility Fermi Gamma-ray Space Telescope Gamma Ray Sources Astronomy Astronomy Gamma Ray Astronomy Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
