天体物理学
Pulsars are commonly regarded as highly magnetized neutron stars, rotating up to several hundred times per second. Over 1,500 radio pulsars have been found so far, about 70 of which are X-ray pulsars, but only a handful have been observed…
A key assumption in the reconstruction of extensive air showers using the air fluorescence technique is the hypothesis that fluorescence is proportional to energy deposition at all depths in the shower. This ansatz, along with the…
Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the ombined effects of all detector components in a single measurement. The calibrated 2.5…
The dependence of atmospheric conditions on altitude and time have to be known at the site of an air shower experiment for accurate reconstruction of extensive air showers and their simulations. The height-profile of atmospheric depth is of…
The Milagro gamma-ray observatory employs a water Cherenkov detector to observe extensive air showers produced by high energy particles interacting in the Earth's atmosphere. Milagro has a wide field of view (2 sr) and high duty cycle (>…
We measure the topology of volume-limited galaxy samples selected from a parent sample of 314,050 galaxies in the Sloan Digital Sky Survey(SDSS), which is now complete enough to describe the fully three-dimensional topology and its…
Cosmic ray air showers are known to emit pulsed radio emission which can be understood as coherent geosynchrotron radiation arising from the deflection of electron-positron pairs in the earth's magnetic field. Here, we present simulations…
The MAGIC Telescope, now taking data with an energy threshold well below 100 GeV, will soon be able to take full advantage of the fast slewing capability of its altazimuthal mount. Exploiting the link with the GCN network, the MAGIC…
The Milagro gamma-ray observatory employs a water Cherenkov detector to observe extensive air showers produced by high-energy particles impacting in the Earth's atmosphere. A 4800 m$^{2}$ pond instrumented with 723 8" PMTs detects Cherenkov…
We present initial results of galaxy clustering at 24um by analyzing statistics of the projected galaxy distribution from counts-in-cells. This study focuses on the ELAIS-N1 SWIRE field. The sample covers ~5.9 square-degrees and contains…
The blazar 1ES 1959+650 was observed in a flaring state with the Whipple 10 m Imaging Atmospheric Cherenkov Telescope during May of 2002. A spectral analysis has been carried out on the data from that time period and the resulting very high…
We present an analysis of large-scale structure from the Spitzer Wide-area Infrared Extragalactic legacy survey, SWIRE. The two-point angular correlation functions were computed for galaxies detected in the 3.6-micron IRAC band, on angular…
We have detected gamma-ray emission at the 6sigma level at energies greater than 500GeV from the supernova remnant RX J0852.0-4622 (G266.2-1.2) using the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). The flux was 0.12 times of…
The EDELWEISS experiment is a Direct Dark Matter search using 320 g heat-and-ionization Ge cryogenic detectors. The final results obtained by the EDELWEISS-I stage corresponding to a total of 62 kg.day are presented. The status of…
The Carnegie Supernova Project (CSP) is aimed at providing an independent measure of change in the the Hubble expansion as a function of redshift, and setting constraints dark energy contribution to the total energy content of the universe.…
The Supernova Legacy Survey (SNLS; http://cfht.hawaii.edu/SNLS) will discover and obtain g'r'i'z' lightcurves for more than 700 spectroscopically confirmed SNe Ia (0.3<z<0.9) to differentiate between competing models for Dark Energy. We fit…
Type Ia supernovae (SNe Ia) currently provide the most direct evidence for an accelerating Universe and for the existence of an unknown "dark energy" driving this expansion. The 5-year Supernova Legacy Survey (SNLS;…
Recent results from the KASCADE experiment on measurements of cosmic rays in the energy range of the knee are presented. Emphasis is placed on energy spectra of individual mass groups as obtained from an two-dimensional unfolding applied to…
The ANTARES project aims to build a deep-sea Cherenkov Telescope for High Energy Neutrino Astronomy located in the Mediterranean Sea. The experiment, currently in the construction phase, has recently achieved an important milestone : the…
We conducted a daily monitoring campaign on Mrk 421 in 2003 and 2004 with the Whipple 10 m telescope and the large-area instruments aboard RXTE, simultaneously covering TeV and X-ray energies. Supporting observations at optical and radio…