Astrophysics
The atmospheric Cerenkov imaging technique has been used to search for point-like and diffuse TeV gamma-ray emission from the southern supernova remnant, W28, and surrounding region. The search, made with the CANGAROO 3.8m telescope,…
In 1998 and 1999 the Whipple Observatory 10 m telescope was used to search for diffuse gamma ray emission from the Galactic Plane. No signifiant evidence of emission was found. Assuming the TeV emission profile matches EGRET observations…
We show that the relativistic wind in the Crab pulsar, which is commonly thought to be invisible in the region upstream of the termination shock at R < 0.1 pc, in fact could be directly observed through its inverse Compton gamm-ray…
The International Gravitational Event Collaboration, IGEC, is a coordinated effort by research groups operating gravitational wave detectors working towards the detection of millisecond bursts of gravitational waves. Here we report on the…
We report detection of giant cyclonic vortices in the gaseous disc of the spiral galaxy NGC 3631 in the reference frame rotating with the spiral pattern. A presence of such structures was predicted by the authors for galaxies, where the…
We report the first detailed X-ray and optical observations of the medium-distant cluster A33 obtained with the Beppo-SAX satellite and with the UH 2.2m and Keck II telescopes at Mauna Kea. The information deduced from X-ray and optical…
We present spectrophotometry in the 3600-9700 A region for a sample of 39 H II regions in the Galaxy and Magellanic Clouds, for which independent information is available on the spectral types and effective temperatures of the ionizing…
We have measured the rest-frame B,V, and I-band light curves of a high-redshift type Ia supernova (SN Ia), SN 1999Q (z=0.46), using HST and ground-based near-infrared detectors. A goal of this study is the measurement of the color excess,…
The Palomar Testbed Interferometer (PTI) archive of observations between 1998 and 2005 is examined for objects appropriate for calibration of optical long-baseline interferometer observations - stars that are predictably point-like and…
The amplitude of the Compton-Getting (CG) anisotropy contains the power-law index of the cosmic-ray energy spectrum. Based on this relation and using the Tibet air-shower array data, we measure the cosmic-ray spectral index to be $-3.03 \pm…
A new beam-combination and detection system has been installed in the Sydney University Stellar Interferometer working at the red end of the visual spectrum (wavelength range 500-950 nm) to complement the existing blue-sensitive system…
In this paper we study new infrared spectra of the evolved planetary nebula NGC 6445 obtained with ISO. These data show that the thermal emission from the grains is very cool and has a low flux compared to H beta. A model of the ionized…
We present the results of a wide-field [O III] $\lambda 5007$ survey for planetary nebulae (PN) in M87 and its surrounding halo. We show that the planetary nebula luminosity function (PNLF) of M87's halo is unlike any PNLF observed to date,…
We investigate the dependence of physical properties of galaxies brighter than M_r=-18.0 in the SDSS on environment, as measured by local density using an adaptive smoothing kernel. We find that variations of galaxy properties with…
[Abridged] We present the first direct comparison of the distribution of the gas, as traced by the [OI] 6300 AA emission, and the dust, as traced by the 10 micron emission, in the protoplanetary disk around three intermediate-mass stars: HD…
We present here a new method, MMF, for automatically segmenting cosmic structure into its basic components: clusters, filaments, and walls. Importantly, the segmentation is scale independent, so all structures are identified without…
The HEGRA system of 4 Imaging Atmospheric Cherenkov Telescopes (IACTs) has been used since March 1997 for a comprehensive study of the gamma-ray emission from the BL Lac object Mkn 501 in the energy range above 500 GeV. Taking advantage of…
We report on the optical observations of the gamma-ray pulsar PSR1706-44 performed with the Test Camera of the VLT-UT1 during the telescope Science Verification programme. With a limiting magnitude of V~ 27.5, these are the deepest optical…
We present kinematic observations of H$\alpha$ emission for two early-type galaxies and one disk system, members of the Hickson compact group 90 (HCG 90) obtained with a scanning Fabry-Perot interferometer and samplings of 16 $km$ $s^{-1}$…
Simultaneous modeling of the line and continuum emission from the nuclear region of the Circinus galaxy is presented. Composite models which include the combined effect of shocks and photoionization from the active center and from the…