Collective modes of an Anisotropic Quark-Gluon Plasma II

We continue our exploration of the collective modes of an anisotropic quark gluon plasma by extending our previous analysis to arbitrary Riemann sheets. We demonstrate that in the presence of momentum-space anisotropies in the parton distribution functions there are new relevant singularities on the neighboring unphysical sheets. We then show that for sufficiently strong anisotropies that these singularities move into the region of spacelike momentum and their effect can extend down to the physical sheet. In order to demonstrate this explicitly we consider the polarization tensor for gluons propagating parallel to the anisotropy direction. We derive analytic expressions for the gluon structure functions in this case and then analytically continue them to unphysical Riemann sheets. Using the resulting analytic continuations we numerically determine the position of the unphysical singularities. We then show that in the limit of infinite contraction of the distribution function along the anisotropy direction that the unphysical singularities move onto the physical sheet and result in real spacelike modes at large momenta for all "out-of-plane" angles of propagation.Comment: 13 pages, 8 figure

X-ray Constraints on Accretion and Starburst Processes in Galactic Nuclei I. Spectral Results

The results of a 0.4-10.0 keV ASCA spectral analysis of a sample of low-luminosity AGN (LLAGN; M51, NGC 3147, NGC 4258), low-ionization nuclear emission line regions (LINERs; NGC 3079, NGC 3310, NGC 3998, NGC 4579, NGC 4594) and starburst galaxies (M82, NGC 253, NGC 3628 and NGC 6946) are presented. In spite of the heterogeneous optical classifications of these galaxies, the X-ray spectra are fit well by a ``canonical'' model consisting of an optically-thin Raymond-Smith plasma ``soft'' component with T ~ 7 x 10^6 K and a ``hard'' component that can be modeled by either a power-law with a photon index ~ 1.7 or a thermal bremsstrahlung with T ~ 6 x 10^7 K. The soft-component 0.4-10 keV instrinsic luminosities tend to be on the order 10^39-40 ergs/s while the hard-component luminosities tend to be on the order of 10^40-41 ergs/s. The detection of line emission is discussed. An analysis of the short-term variability properties was given in Ptak et al. (1998) and detailed interpretation of these results will be given in Paper II. (abridged)Comment: Accepted for Jan. 99 issue of ApJS. 35 pages with embedded postscript figures. 8 large tables included externally as postscript file

Feedback in the local LBG Analog Haro 11 as probed by far-UV and X-ray observations

We have re-analyzed FUSE data and obtained new Chandra observations of Haro 11, a local (D_L=88 Mpc) UV luminous galaxy. Haro 11 has a similar far-UV luminosity (10^10.3 L_\odot), UV surface brightness (10^9.4 L_\odot kpc^-2), SFR, and metallicity to that observed in Lyman Break Galaxies (LBGs). We show that Haro 11 has extended, soft thermal (kT~0.68 keV) X-ray emission with a luminosity and size which scales with the physical properties (e.g. SFR, stellar mass) of the host galaxy. An enhanced alpha/Fe, ratio of ~4 relative to solar abundance suggests significant supernovae enrichment. These results are consistent with the X-ray emission being produced in a shock between a supernovae driven outflow and the ambient material. The FUV spectra show strong absorption lines similar to those observed in LBG spectra. A blueshifted absorption component is identified as a wind outflowing at ~200-280 km/s. OVI\lambda\lambda1032,1038 emission, the dominant cooling mechanism for coronal gas at T~10^5.5 K is also observed. If associated with the outflow, the luminosity of the OVI emission suggests that <20% of the total mechanical energy from the supernovae and solar winds is being radiated away. This implies that radiative cooling through OVI is not significantly inhibiting the growth of the outflowing gas. In contradiction to the findings of Bergvall et al 2006, we find no convincing evidence of Lyman continuum leakage in Haro 11. We conclude that the wind has not created a `tunnel' allowing the escape of a significant fraction of Lyman continuum photons and place a limit on the escape fraction of f_{esc}<2%. Overall, both Haro 11 and a previously observed LBG analogue VV 114, provide an invaluable insight into the X-ray and FUV properties of high redshift LBGs.Comment: Accepted for publication in ApJ, 40 pages, 17 figure