Observations of Chemically Enriched QSO Absorbers near z ~ 2.3 Galaxies: Galaxy-Formation Feedback Signatures in the IGM

We present a study of galaxies and intergalactic gas toward the z=2.73 quasar HS1700+6416, to explore the effects of galaxy formation feedback on the IGM. Our observations and ionization simulations indicate that the volume within 100-200 h_71^{-1} physical kpc of high-redshift galaxies contains very small, dense, and metal-rich absorption-line regions. These systems often contain shock-heated gas seen in OVI, and may exhibit [Si/C] abundance enhancements suggestive of Type II supernova enrichment. We argue that the absorbers resemble thin sheets or bubbles, whose physical properties can be explained with a simple model of radiatively efficient shocks propegating through the IGM. Their high metallicities suggest that these shocks are being expelled from--rather than falling into--star forming galaxies. There is a dropoff in the IGM gas density at galaxy impact parameters beyond ~300 physical kpc that may trace boundaries of gas structures where the galaxies reside. The local heavy-element enhancement covers 100-200 kpc; beyond this the observed abundances blend into the general IGM. Supernova-driven winds or dynamical stripping of interstellar gas appears to affect the IGM near massive galaxies, even at R>~100 kpc. However, these feedback systems represent only a few percent of the Lya forest mass at z~2.5. Their mass could be larger if the more numerous metal-poor CIV systems at >~200 kpc are tepid remnants of very powerful winds. Based on present observations it is not clear that this scenario is to be favored over one involving pre-enrichment by smaller galaxies at z>~6.Comment: Accepted for publication in the Astrophysical Journal. 26 pages emulateapj, incl. 5 pages tables, 15 figure

How cold is cold dark matter? Small scales constraints from the flux power spectrum of the high-redshift Lyman-alpha forest

We present constraints on the mass of warm dark matter (WDM) particles derived from the Lyman-alpha flux power spectrum of 55 high- resolution HIRES spectra at 2.0 < z < 6.4. From the HIRES spectra, we obtain a lower limit of mwdm > 1.2 keV 2 sigma if the WDM consists of early decoupled thermal relics and mwdm > 5.6 keV (2 sigma) for sterile neutrinos. Adding the Sloan Digital Sky Survey Lyman-alpha flux power spectrum, we get mwdm > 4 keV and mwdm > 28 keV (2 sigma) for thermal relics and sterile neutrinos. These results improve previous constraints by a factor two.Comment: Some issues clarified (especially resolution related). Conclusions unchanged. Accepted version by PR

The Inner Rings of Beta Pictoris

We present Keck images of the dust disk around Beta Pictoris at 17.9 microns that reveal new structure in its morphology. Within 1" (19 AU) of the star, the long axis of the dust emission is rotated by more than 10 degrees with respect to that of the overall disk. This angular offset is more pronounced than the warp detected at 3.5" by HST, and in the opposite direction. By contrast, the long axis of the emission contours at ~ 1.5" from the star is aligned with the HST warp. Emission peaks between 1.5" and 4" from the star hint at the presence of rings similar to those observed in the outer disk at ~ 25" with HST/STIS. A deconvolved image strongly suggests that the newly detected features arise from a system of four non-coplanar rings. Bayesian estimates based on the primary image lead to ring radii of 14+/-1 AU, 28+/-3 AU, 52+/-2 AU and 82+/-2 AU, with orbital inclinations that alternate in orientation relative to the overall disk and decrease in magnitude with increasing radius. We believe these new results make a strong case for the existence of a nascent planetary system around Beta Pic.Comment: 5 pages, 2 figures, PDF format. Published in ApJL, December 20,200

The Quantum State of an Ideal Propagating Laser Field

We give a quantum information-theoretic description of an ideal propagating CW laser field and reinterpret typical quantum-optical experiments in light of this. In particular we show that contrary to recent claims [T. Rudolph and B. C. Sanders, Phys. Rev. Lett. 87, 077903 (2001)], a conventional laser can be used for quantum teleportation with continuous variables and for generating continuous-variable entanglement. Optical coherence is not required, but phase coherence is. We also show that coherent states play a priveleged role in the description of laser light.Comment: 4 pages RevTeX, to appear in PRL. For an extended version see quant-ph/011115

CO(1-0) line imaging of massive star-forming disc galaxies at z=1.5-2.2

We present detections of the CO(J= 1-0) emission line in a sample of four massive star-forming galaxies at z~1.5-2.2 obtained with the Karl G. Jansky Very Large Array (VLA). Combining these observations with previous CO(2-1) and CO(3-2) detections of these galaxies, we study the excitation properties of the molecular gas in our sample sources. We find an average line brightness temperature ratios of R_{21}=0.70+\-0.16 and R_{31}=0.50+\-0.29, based on measurements for three and two galaxies, respectively. These results provide additional support to previous indications of sub-thermal gas excitation for the CO(3-2) line with a typically assumed line ratio R_{31}~0.5. For one of our targets, BzK-21000, we present spatially resolved CO line maps. At the resolution of 0.18'' (1.5 kpc), most of the emission is resolved out except for some clumpy structure. From this, we attempt to identify molecular gas clumps in the data cube, finding 4 possible candidates. We estimate that <40 % of the molecular gas is confined to giant clumps (~1.5 kpc in size), and thus most of the gas could be distributed in small fainter clouds or in fairly diffuse extended regions of lower brightness temperatures than our sensitivity limit

Temperature and Kinematics of CIV Absorption Systems

We use Keck HIRES spectra of three intermediate redshift QSOs to study the physical state and kinematics of the individual components of CIV selected heavy element absorption systems. Fewer than 8 % of all CIV lines with column densities greater than 10^{12.5} cm^{-2} have Doppler parameters b < 6 km/s. A formal decomposition into thermal and non-thermal motion using the simultaneous presence of SiIV gives a mean thermal Doppler parameter b_{therm}(CIV) = 7.2 km/s, corresponding to a temperature of 38,000 K although temperatures possibly in excess of 300,000 K occur occasionally. We also find tentative evidence for a mild increase of temperature with HI column density. Non-thermal motions within components are typically small (< 10 km/s) for most systems, indicative of a quiescent environment. The two-point correlation function (TPCF) of CIV systems on scales up to 500 km/s suggests that there is more than one source of velocity dispersion. The shape of the TPCF can be understood if the CIV systems are caused by ensembles of objects with the kinematics of dwarf galaxies on a small scale, while following the Hubble flow on a larger scale. Individual high redshift CIV components may be the building blocks of future normal galaxies in a hierarchical structure formation scenario.Comment: submitted to the ApJ Letters, March 16, 1996 (in press); (13 Latex pages, 4 Postscript figures, and psfig.sty included