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The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007

Abstract

PSR B1259-63/SS2883 is a binary system where a 48 ms pulsar orbits a massive Be star with a period of 3.4 years. The system exhibits variable, non-thermal radiation around periastron on the highly eccentric orbit (e=0.87) visible from radio to very high energies (VHE; E>100 GeV). When being detected in TeV {gamma}-rays with the High Energy Stereoscopic System (H.E.S.S.) in 2004 it became known as the first variable galactic VHE source. This thesis presents VHE data from PSR B1259-63 as taken during the years 2005, 2006 and before as well as shortly after the 2007 periastron passage. These data extend the knowledge of the lightcurve of this object to all phases of the binary orbit. The lightcurve constrains physical mechanisms present in this TeV source. Observations of VHE {gamma}-rays with the H.E.S.S. telescope array using the Imaging Atmospheric Cherenkov Technique were performed. The H.E.S.S. instrument features an angular resolution of < 0.1 and an energy resolution of < 20%. Gamma-ray events in an energy range of 0.5-70 TeV were recorded. From these data, energy spectra and lightcurve with a monthly time sampling were extracted. VHE {gamma}-ray emission from PSRB1259-63 was detected with an overall significance of 9.5 standard deviations using  More>>
Publication Date:
Apr 06, 2010
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-1151
Resource Relation:
Other Information: TH: Diss. (Dr.rer.nat.)
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; COSMIC GAMMA SOURCES; COSMIC PHOTONS; COSMIC RAY FLUX; ENERGY SPECTRA; GAMMA RADIATION; GAMMA SPECTRA; GEV RANGE 100-1000; PULSARS; TEV RANGE 01-10; TEV RANGE 10-100; THERMAL RADIATION
OSTI ID:
21472167
Research Organizations:
Humboldt-Universitaet, Berlin (Germany). Mathematisch-Naturwissenschaftliche Fakultaet 1
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE11F9461
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21472167
Submitting Site:
DEN
Size:
153 pages
Announcement Date:
Sep 08, 2011

Citation Formats

Kerschhaggl, Matthias. The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007. Germany: N. p., 2010. Web.
Kerschhaggl, Matthias. The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007. Germany.
Kerschhaggl, Matthias. 2010. "The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007." Germany.
@misc{etde_21472167,
title = {The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007}
author = {Kerschhaggl, Matthias}
abstractNote = {PSR B1259-63/SS2883 is a binary system where a 48 ms pulsar orbits a massive Be star with a period of 3.4 years. The system exhibits variable, non-thermal radiation around periastron on the highly eccentric orbit (e=0.87) visible from radio to very high energies (VHE; E>100 GeV). When being detected in TeV {gamma}-rays with the High Energy Stereoscopic System (H.E.S.S.) in 2004 it became known as the first variable galactic VHE source. This thesis presents VHE data from PSR B1259-63 as taken during the years 2005, 2006 and before as well as shortly after the 2007 periastron passage. These data extend the knowledge of the lightcurve of this object to all phases of the binary orbit. The lightcurve constrains physical mechanisms present in this TeV source. Observations of VHE {gamma}-rays with the H.E.S.S. telescope array using the Imaging Atmospheric Cherenkov Technique were performed. The H.E.S.S. instrument features an angular resolution of < 0.1 and an energy resolution of < 20%. Gamma-ray events in an energy range of 0.5-70 TeV were recorded. From these data, energy spectra and lightcurve with a monthly time sampling were extracted. VHE {gamma}-ray emission from PSRB1259-63 was detected with an overall significance of 9.5 standard deviations using 55 h of exposure, obtained from April to August 2007. The monthly flux of -rays during the observation period was measured, yielding VHE lightcurve data for the early pre-periastron phase of the system for the first time. No spectral variability was found on timescales of months. The spectrum is described by a power law with a photon index of {gamma}=2.8{+-}0.2{sub stat}{+-}0.2{sub sys} and flux normalisation {phi}{sub 0}=(1.1{+-}0.1{sub stat}{+-}0.2{sub sys}) x 10{sup -12} TeV{sup -1}cm{sup -2}s{sup -1}. PSR B1259-63 was also monitored in 2005 and 2006, far from periastron passage, comprising 8.9 h and 7.5 h of exposure, respectively. No significant excess of {gamma}-rays is seen in those observations. PSR B1259-63 has been re-confirmed as a variable TeV {gamma}-ray emitter. The firm detection of VHE photons emitted at a true anomaly {theta}{approx}0.35 of the pulsar orbit, i.e. already {proportional_to}50 days prior to the periastron passage, disfavors the stellar disc target scenario as a primary emission mechanism, based on current knowledge about the companion star's disc inclination, extension, and density profile. In a phenomenological study indirect evidence that PSR B1259-63 could in fact be a periodical VHE emitter is presented using the TeV data discussed in this work. While the TeV energy flux level seems to be only dependent on the binary separation this behavior is not seen in X-rays. Moreover, model calculations based on inverse compton (IC) scattering of shock accelerated pulsar wind electrons and UV photons were performed. The model presented accounts for non-radiative losses possibly at work in the region where the pulsar wind is shocked by stellar outflows and particles are accelerated to very high energies. The presented results show a peculiar non-radiative cooling profile around periastron dominating the VHE emission in PSR B1259-63. The discrepancy between the {gamma}-ray and X-ray lightcurves could be a sign for synchrotron radiation as origin of the X-ray emission. (orig.)}
place = {Germany}
year = {2010}
month = {Apr}
}