Nonthermal X-radiation of SNR RX J1713.7-3946: The Relations to a Nearby Molecular Cloud

The recent X-ray and CO observations of RX J1713.7-3946 show that a significant fraction of the nonthermal X-ray emission of this unique supernova remnant associates, in one way or another, with a molecular cloud interacting with the west part of the shell. This adds a new puzzle in the origin of X-ray emission which cannot be easily explained within the standard model in accordance of which X-rays are result of synchrotron radiation of multi-TeV electrons accelerated by supernova shock waves. We explore an alternative origin of the X-ray emission assuming that it is produced by secondary electrons resulting from high energy hadronic interactions in the molecular gas. Such a scenario could explain in a quite natural way the apparent correlation between the X-ray and CO morphologies. However, the TeV gamma-ray emission recently reported by H.E.S.S. significantly constrains the parameter space of this model. Namely, this mechanism cannot reproduce the bulk of the observed X-ray flux unless one postulates existence of a PeV cosmic-ray component penetrating with an unusually hard spectrum into the dense cloud.Comment: 6 pages, 3 figures, to appear in Proc. of Int. Symp. on High Energy Gamma-ray Astronomy, Heidelberg (July 2004

Discovery of Strong Radiative Recombination Continua from The Supernova Remnant IC 443 with Suzaku

We present the Suzaku spectroscopic study of the Galactic middle-aged supernova remnant (SNR) IC 443. The X-ray spectrum in the 1.75-6.0 keV band is described by an optically-thin thermal plasma with the electron temperature of 0.6 keV and several additional Lyman lines. We robustly detect, for the first time, strong radiative recombination continua (RRC) of H-like Si and S around at 2.7 and 3.5 keV. The ionization temperatures of Si and S determined from the intensity ratios of the RRC to He-like K-alpha line are 1.0 keV and 1.2 keV, respectively. We thus find firm evidence for an extremely-overionized (recombining) plasma. As the origin of the overionization, a thermal conduction scenario argued in previous work is not favored in our new results. We propose that the highly-ionized gas were made at the initial phase of the SNR evolution in dense regions around a massive progenitor, and the low electron temperature is due to a rapid cooling by an adiabatic expansion.Comment: 5 pages, 5 figures, accepted by ApJ Lette

High-Energy Neutrino Astronomy

Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of $10^{20}$ and $10^{13}$ eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of the completed AMANDA detector and the reach of its extension, IceCube. Similar experiments are under construction in the Mediterranean. Neutrino astronomy is also expanding in new directions with efforts to detect air showers, acoustic and radio signals initiated by super-EeV neutrinos.Comment: 9 pages, Latex2e, uses ws-procs975x65standard.sty (included), 4 postscript figures. To appear in Proceedings of Thinking, Observing, and Mining the Universe, Sorrento, Italy, September 200

Asymptotics and local constancy of characters of p-adic groups

In this paper we study quantitative aspects of trace characters $\Theta_\pi$ of reductive $p$-adic groups when the representation $\pi$ varies. Our approach is based on the local constancy of characters and we survey some other related results. We formulate a conjecture on the behavior of $\Theta_\pi$ relative to the formal degree of $\pi$, which we are able to prove in the case where $\pi$ is a tame supercuspidal. The proof builds on J.-K.~Yu's construction and the structure of Moy-Prasad subgroups.Comment: Proceedings of Simons symposium on the trace formul

Suzaku X-Ray Imaging and Spectroscopy of Cassiopeia A

Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-Kalpha at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4--40 keV band, summed over the entire remnant, and were fitted with a simplest combination of the thermal bremsstrahlung and the non-thermal cut-off power-law models. The spectral fits with this assumption indicate that the continuum emission is likely to be dominated by the non-thermal emission with a cut-off energy at > 1 keV. The thermal-to-nonthermal fraction of the continuum flux in the 4-10 keV band is best estimated as ~0.1. Non-thermal-dominated continuum images in the 4--14 keV band were made. The peak of the non-thermal X-rays appears at the western part. The peak position of the TeV gamma-rays measured with HEGRA and MAGIC is also shifted at the western part with the 1-sigma confidence. Since the location of the X-ray continuum emission was known to be presumably identified with the reverse shock region, the possible keV-TeV correlations give a hint that the accelerated multi-TeV hadrons in Cassiopeia A are dominated by heavy elements in the reverse shock region.Comment: Publ. Astron. Soc. Japan 61, pp.1217-1228 (2009

The effect of Ku on telomere replication time is mediated by telomere length but is independent of histone tail acetylation

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The Ctf18 RFC-like complex positions yeast telomeres but does not specify their replication time

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