A5083389017- Laser-Plasma Interactions and Diagnostics
- Advanced X-ray Imaging Techniques
- Astrophysics and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Gamma-ray bursts and supernovae
- Laser-Matter Interactions and Applications
- Dark Matter and Cosmic Phenomena
- Crystallography and Radiation Phenomena
- Astrophysical Phenomena and Observations
- Laser Design and Applications
- Laser-induced spectroscopy and plasma
- Advanced Electron Microscopy Techniques and Applications
- High-pressure geophysics and materials
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Diamond and Carbon-based Materials Research
- Radio Astronomy Observations and Technology
- Luminescence Properties of Advanced Materials
- Pulsed Power Technology Applications
- Particle Detector Development and Performance
- Laser Material Processing Techniques
- Terahertz technology and applications
- Pulsars and Gravitational Waves Research
- Photorefractive and Nonlinear Optics
- Atomic and Molecular Physics
University of Nebraska–Lincoln
2014-2024
Karlsruhe Institute of Technology
2023
SLAC National Accelerator Laboratory
2011-2018
Ludwig-Maximilians-Universität München
2007-2012
Max Planck Institute of Quantum Optics
2007-2012
University Medical Center Freiburg
2012
Max Planck Society
2007-2011
Bielefeld University
2009
Deutsche Nationalbibliothek
2009
Wissenschaftliches Institut der AOK
2009
The blazar Mrk 501 was observed at energies above 0.10 TeV with the MAGIC Telescope from 2005 May through July. high sensitivity of instrument enabled determination flux and spectrum source on a night-by-night basis. Throughout our observational campaign, found to vary by an order magnitude. Intranight variability flux-doubling times down 2 minutes during two most active nights, namely, June 30 July 9. These are fastest variations ever in 501. ~20 minute long flare 9 showed indication 4 ± 1...
Microquasars are binary star systems with relativistic radio-emitting jets. They potential sources of cosmic rays and can be used to elucidate the physics We report detection variable gamma-ray emission above 100 gigaelectron volts from microquasar LS I 61 + 303. Six orbital cycles were recorded. Several detections occur at a similar phase, which suggests that is periodic. The strongest not observed when two stars closest one another, implying strong modulation or absorption processes.
X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field ultrafast x-ray atomic molecular physics, largely due to an explosive growth in capabilities past decade. XFELs now provide unprecedented intensity (1020 W cm−2) at wavelengths down ∼1 Ångstrom, HHG provides time resolution (∼50 attoseconds) a correspondingly large coherent bandwidth longer wavelengths. For context, timescales can be referenced Bohr...
We report about very high energy (VHE) γ-ray observations of the Crab Nebula with MAGIC telescope. The flux from nebula was measured between 60 GeV and 9 TeV. spectrum can be described by a curved power law dF/dE = f0(E/300 GeV)[a+blog10(E/300 GeV)] normalization f0 (6.0 ± 0.2stat) × 10−10 cm−2 s−1 TeV−1, − 2.31 0.06stat, b 0.26 0.07stat. peak in spectral distribution is estimated at 77 35 GeV. Within observation time experimental resolution telescope, emission steady pointlike. emission's...
We report on the results from observations in very high energy band (VHE; Eγ ≥ 100 GeV) of black hole X-ray binary (BHXB) Cygnus X-1. The were performed with MAGIC telescope, for a total 40 hr during 26 nights, spanning period between 2006 June and November. Searches steady γ-ray signals yielded no positive result, upper limits to integral flux ranging 1% 2% Crab Nebula flux, depending energy, have been established. also analyzed each observation night independently, obtaining evidence at...
Laser-driven, quasimonoenergetic electron beams of up to approximately 200 MeV in energy have been observed from steady-state-flow gas cells. These emitted within a low-divergence cone 2.1+/-0.5 mrad FWHM display unprecedented shot-to-shot stability (2.5% rms), pointing (1.4 and charge (16% rms) owing highly reproducible gas-density profile the interaction volume. Laser-wakefield acceleration cells this type provides simple reliable source relativistic electrons suitable for applications...
We report the detection of a new source very high energy (VHE; Eγ ≥ 100 GeV) γ-ray emission located close to Galactic plane, MAGIC J0616+225, which is spatially coincident with supernova remnant IC 443. The observations were carried out telescope in periods 2005 December-2006 January and 2006 December-2007 January. Here we present results from this source, leading VHE signal statistical significance 5.7 σ 2006/2007 data measured differential flux consistent power law, described as dNγ/(dA dt...
SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and Facility for Advanced Accelerator Experimental Tests (FACET), providing high-charge, high-peak-current, femtosecond bunches. These characteristics are ideal generating intense broadband terahertz (THz) pulses via coherent transition radiation. For LCLS FACET respectively, THz pulse duration is typically 20 80 fs RMS can be tuned bunch duration; emission spectra span 3–30 0.5 THz–5 THz; energy in a quasi-half-cycle...
Using quadrupole scan measurements we show laser-wakefield accelerated electrons to have a normalized transverse emittance of ${0.21}_{\ensuremath{-}0.02}^{+0.01}\ensuremath{\pi}\text{ }\mathrm{mm}\text{ }\mathrm{mrad}$ at 245 MeV. We demonstrate multishot and single-shot method, the mean values for both methods agree well. A simple model beam dynamics in plasma density downramp accelerator exit matches source size divergence inferred from measurement. In energy range 300 MeV remains constant.
We report clear experimental evidence for second harmonic generation at hard x-ray wavelengths. Using a 1.7 Å pumping beam generated by free electron laser, we observe in diamond. The is of order 10 times the background radiation, scales quadratically with pump pulse energy, and over narrow phase-matching condition. Of importance future experiments, our results indicate that it possible to nonlinear processes crystals intensities exceeding 1016 W/cm2.
The MAGIC telescope took data of very high energy gamma-ray emission from the blazar Markarian 421 (Mkn 421) between November 2004 and April 2005. We present a combined analysis samples recorded under different observational conditions, down to energies 100 GeV. flux was found vary 0.5 -- 2 Crab units (integrated above 200 GeV), considered low state when compared known data. Although varied on day-by-day basis, no short-term variability observed, although there is some indication that not...
We report experimental results on laser-driven electron acceleration with low divergence. The beam was generated by focussing 750 mJ, 42 fs laser pulses into a gas-filled capillary discharge waveguide at densities in the range between 10 18 and 19 cm 3 . Quasi-monoenergetic bunches energies as high 500 MeV have been detected, features reaching up to 1 GeV, albeit large shot-to-shot fluctuations. A more stable regime higher bunch charge (20-45 pC) less energy (200-300 MeV) could also be...
We investigate the influence of a tilted laser-pulse-intensity front on laser-wakefield acceleration. Such asymmetric light pulses may be exploited to obtain control over electron-bunch-pointing direction and in our case allowed for reproducible electron-beam steering an all-optical way within 8 mrad opening window with respect initial laser axis. also discovered evidence collective electron-betatron oscillations due off-axis electron injection into wakefield induced by pulse-front tilt....
The MAGIC collaboration observed BL Lacertae for 22.2 hr during 2005 August to December and 26 2006 July September. source is the historical prototype eponym of a class low-frequency-peaked (LBL) objects. A very high energy (VHE) γ-ray signal was discovered with 5.1 σ excess in data. Above 200 GeV, an integral flux (0.6 ± 0.2) × 10-11 cm-2 s-1 measured, corresponding approximately 3% Crab flux. differential spectrum between 150 900 GeV rather steep photon index -3.6 0.5. light curve shows no...
We searched for very high energy (VHE) gamma-ray emission from the supernova remnant Cassiopeia A. The shell-type A was observed with 17 meter MAGIC telescope between July 2006 and January 2007 a total time of 47 hours. source detected above an 250 GeV significance 5.2sigma photon flux 1 TeV (7.3+-0.7_stat+-2.2_sys)10^-13 cm^-2s^-1. spectrum is compatible power law dN/dE = E^-Gamma index Gamma=2.3+-0.2_stat+-0.2_sys. point-like within angular resolution telescope.
The high-frequency-peaked BL Lacertae object Markarian~180 (Mrk~180) was observed to have an optical outburst in 2006 March, triggering a Target of Opportunity observation with the MAGIC telescope. source for 12.4 hr and very high energy $γ$-ray emission detected significance 5.5 $σ$. An integral flux above 200 GeV $(2.3\pm0.7)\times10^{-11} {cm}^{-2} {s}^{-1}$ measured, corresponding 11% Crab Nebula flux. A rather soft spectrum photon index $-3.3\pm0.7$ has been determined. No significant...
We report on the discovery of very high energy (VHE) γ-ray emission from BL Lacertae object 1ES 1011+496. The observation was triggered by an optical outburst in 2007 March and source observed with MAGIC telescope to May. Observing for 18.7 hr, we find excess 6.2 σ integrated flux above 200 GeV (1.58 ± 0.32) × 10-11 photons cm-2 s-1. VHE is >40% higher than 2006 March-April (reported elsewhere), indicating that state may be related state. have also determined redshift 1011+496 based spectrum...
We present the results from a multiwavelength campaign on TeV blazar 1ES 1959+650, performed in May, 2006. Data optical, UV, soft- and hard-X-ray very high energy (VHE) gamma-ray (E > 100 GeV) bands were obtained with SUZAKU SWIFT satellites, MAGIC telescope other ground based facilities. The source spectral distribution (SED), derived observations at end of May 2006, shows usual double hump shape, synchrotron peak higher flux level than Compton peak. With respect to historical values,...