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We report the discovery of extended X-ray emission from the planetary nebula BD +30°3639. Analysis of the ROSAT HRI image shows clearly that BD +30°3639 has extended X-ray emission which is well fitted with a Gaussian source of σ = 17-28 (95.4% confidence interval). This size is consistent with being the same as that of the optical nebula as imaged by the Hubble Space Telescope. BD +30°3639 therefore represents the best case for the detection of a shocked-stellar-wind bubble in planetary nebulae.

Results are reported from a search for low-multiplicity neutrino bursts in the Sudbury Neutrino Observatory. Such bursts could indicate the detection of a nearby core-collapse supernova explosion. The data were taken from Phase I (1999 November-2001 May), when the detector was filled with heavy water, and Phase II (2001 July-2003 August), when NaCl was added to the target. The search was a blind analysis in which the potential backgrounds were estimated and analysis cuts were developed to eliminate such backgrounds with 90% confidence before the data were examined. The search maintained a greater than 50% detection probability for standard supernovae occurring at a distance of up to 60 kpc for Phase I and up to 70 kpc for Phase II. No low-multiplicity bursts were observed during the data-taking period. © 2011. The American Astronomical Society. All rights reserved. Printedin the U.S.A.

The s-process nucleosynthesis in Asymptotic giant branch (AGB) stars depends on the modeling of convective boundaries. We present models and s-process simulations that adopt a treatment of convective boundaries based on the results of hydrodynamic simulations and on the theory of mixing due to gravity waves in the vicinity of convective boundaries. Hydrodynamics simulations suggest the presence of convective boundary mixing (CBM) at the bottom of the thermal pulse-driven convective zone. Similarly, convection-induced mixing processes are proposed for the mixing below the convective envelope during third dredge-up (TDU), where the ${}^{13}{\rm{C}}$ pocket for the s process in AGB stars forms. In this work, we apply a CBM model motivated by simulations and theory to models with initial mass M = 2 and $M=3\,{M}_{\odot }$, and with initial metal content Z = 0.01 and Z = 0.02. As reported previously, the He-intershell abundances of ${}^{12}{\rm{C}}$ and ${}^{16}{\rm{O}}$ are increased by CBM at the bottom of the pulse-driven convection zone. This mixing is affecting the ${}^{22}\mathrm{Ne}$(α, n)${}^{25}\mathrm{Mg}$ activation and the s-process efficiency in the ${}^{13}{\rm{C}}$-pocket. In our model, CBM at the bottom of the convective envelope during the TDU represents gravity wave mixing. Furthermore, we take into account the fact that hydrodynamic simulations indicate a declining mixing efficiency that is already about a pressure scale height from the convective boundaries, compared to mixing-length theory. We obtain the formation of the ${}^{13}{\rm{C}}$-pocket with a mass of $\approx {10}^{-4}\,\,{M}_{\odot }$. The final s-process abundances are characterized by $0.36\lt [{\rm{s}}/\mathrm{Fe}]\lt 0.78$ and the heavy-to-light s-process ratio is $-0.23\lt [\mathrm{hs}/\mathrm{ls}]\lt 0.45$. Finally, we compare our results with stellar observations, presolar grain measurements and previous work.

Line-intensity mapping (LIM or IM) is an emerging field of observational work, with strong potential to fit into a larger effort to probe large-scale structure and small-scale astrophysical phenomena using multiple complementary tracers. Taking full advantage of such complementarity means, in part, undertaking line-intensity surveys with galaxy surveys in mind. We consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts (as in COSMOS) or based on spectroscopic data (as with the HETDEX survey of Lyman-$��$ emitters). We find that obtaining $��_z/(1+z)\lesssim0.003$ accuracy in redshifts and $\gtrsim10^{-4}$ sources per Mpc$^3$ with spectroscopic redshift determination should enable a CO-galaxy cross spectrum detection significance at least twice that of the CO auto spectrum. Either a future targeted spectroscopic survey or a blind survey like HETDEX may be able to meet both of these requirements. 19 pages + appendix (31 pages total), 16 figures, 6 tables; accepted for publication in ApJ

We present mid/far-infrared photometry of nine FeLoBAL QSOs, taken using the Spitzer space telescope. All nine objects are extremely bright in the infrared, with rest-frame 1-1000 micron luminosities comparable to those of Ultraluminous Infrared Galaxies. Furthermore, a significant fraction of the infrared emission from many, and possibly all of the sample is likely to arise from star formation, with star formation rates of order several hundred solar masses per year. We combine these results with previous work to propose that FeLoBALs mark galaxies and QSOs in which an extremely luminous starburst is approaching its end, and in which a rapidly accreting supermassive black hole is in the last stages of casting off its dust cocoon. FeLoBAL signatures in high redshift QSOs and galaxies may thus be an efficient way of selecting sources at a critical point in their evolution. 12 pages, two figures, two tables. ApJ Letters, accepted

Hubble Space Telescope imaging of 11 fields in M31 were reduced to color-magnitude diagrams. The fields were chosen to sample all galactocentric radii to 50 kpc. Assuming that the bulk of the sampled stellar populations are older than a few Gyr, the colors of the red giants map to an abundance distribution with errors of order 0.1 dex in abundance. The radially sampled abundance distributions are all about the same width, but show a mild abundance gradient that flattens outside ~20 kpc. The various distributions were weighted and summed with the aid of new surface brightness profile fits to obtain an abundance distribution representative of the entirety of M31. M31 is a system near chemical maturity. This ``observed closed box'' is compared to analytical closed box models. M31 suffers from a lack of metal-poor stars and metal-rich stars relative to the simplest closed-box model in the same way as the solar neighborhood.Comparing to several simple chemical evolution models, neither complete mixing of gas at all times nor zero mixing, inhomogeneous models give the most convincing match to the data. As noted elsewhere, the outer disk of M31 is a factor of ten more metal-rich than the Milky Way halo, ten times more metal-rich than the dwarf spheroidals cospatial with it, and more metal-rich than most of the globular clusters at the same galactocentric radius. Difficulties of interpretation are greatly eased if we posit that the M31 disk dominates over the halo at all radii out to 50 kpc. In fact, scaling from current density models of the Milky Way, one should not expect to see halo stars dominating over disk stars until beyond our 50 kpc limit. A corollary conclusion is that most published studies of the M31 "halo" are actually studies of its disk.

A detection of excess cosmic microwave background (CMB) B-mode polarization on large scales allows the possibility of measuring not only the amplitude of these fluctuations but also their scale dependence, which can be parametrized as the tensor tilt $n_T$. Measurements of this scale dependence will be hindered by the secondary B-mode polarization anisotropy induced by gravitational lensing. Fortunately, these contaminating B modes can be estimated and removed with a sufficiently good estimate of the intervening gravitational potential and a good map of CMB E-mode polarization. We present forecasts for how well these gravitational lensing B modes can be removed, assuming that the lensing potential can be estimated either internally from CMB data or using maps of the cosmic infrared background (CIB) as a tracer. We find that CIB maps are as effective as CMB maps for delensing at the noise levels of the current generation of CMB experiments, while the CMB maps themselves will ultimately be best for delensing at polarization noise below $��_P$=1 $��$K-arcmin. At this sensitivity level, CMB delensing will be able to measure $n_T$ to an accuracy of 0.02 or better, which corresponds to the tensor tilt predicted by the consistency relation for single-field slow-roll models of inflation with $r=0.2$. However, CIB-based delensing will not be sufficient for constraining $n_T$ in simple inflationary models. 6 pages, 3 figures; minor corrections to the text, references added to match published version

We have simulated the formation of an X-ray cluster in a cold dark matter universe using 12 different codes. The codes span the range of numerical techniques and implementations currently in use, including SPH and grid methods with fixed, deformable or multilevel meshes. The goal of this comparison is to assess the reliability of cosmological gas dynamical simulations of clusters in the simplest astrophysically relevant case, that in which the gas is assumed to be non-radiative. We compare images of the cluster at different epochs, global properties such as mass, temperature and X-ray luminosity, and radial profiles of various dynamical and thermodynamical quantities. On the whole, the agreement among the various simulations is gratifying although a number of discrepancies exist. Agreement is best for properties of the dark matter and worst for the total X-ray luminosity. Even in this case, simulations that adequately resolve the core radius of the gas distribution predict total X-ray luminosities that agree to within a factor of two. Other quantities are reproduced to much higher accuracy. For example, the temperature and gas mass fraction within the virial radius agree to about 10%, and the ratio of specific kinetic to thermal energies of the gas agree to about 5%. Various factors contribute to the spread in calculated cluster properties, including differences in the internal timing of the simulations. Based on the overall consistency of results, we discuss a number of general properties of the cluster we have modelled.

We present stellar rotation curves and velocity dispersion profiles for 104 quiescent galaxies at z = 0.6-1 from the Large Early Galaxy Astrophysics Census (LEGA-C) spectroscopic survey. Rotation is typically probed across 10-20 kpc, or to an average of 2.7R(e). Combined with central stellar velocity dispersions (sigma(0)) this provides the first determination of the dynamical state of a sample selected by a lack of star formation activity at large lookback time. The most massive galaxies (M-star > 2 x 10(11) M-circle dot) generally show no or little rotation measured at 5 kpc (vertical bar V-5 vertical bar /sigma(0) < 0.2 in eight of ten cases), while similar to 64% of less massive galaxies show significant rotation. This is reminiscent of local fast-and slow-rotating ellipticals and implies that low-and high-redshift quiescent galaxies have qualitatively similar dynamical structures. We compare vertical bar V-5 vertical bar sigma(0) distributions at z similar to 0.8 and the present day by re-binning and smoothing the kinematic maps of 91 low-redshift quiescent galaxies from the Calar Alto Legacy Integral Field Area (CALIFA) survey and find evidence for a decrease in rotational support since z similar to 1. This result is especially strong when galaxies are compared at fixed velocity dispersion; if velocity dispersion does not evolve for individual galaxies then the rotational velocity at 5 kpc was an average of 94 +/- 22% higher in z similar to 0.8 quiescent galaxies than today. Considering that the number of quiescent galaxies grows with time and that new additions to the population descend from rotationally supported star-forming galaxies, our results imply that quiescent galaxies must lose angular momentum between z similar to 1 and the present, presumably through dissipationless merging, and/or that the mechanism that transforms star-forming galaxies also reduces their rotational support.

Recent observations have revealed a superbubble associated with the young stellar cluster OCl 352 near the W4 H II region: a void in H I emission (Normandeau, Taylor, and Dewdney), and a bright shell in H alpha emission (Dennison, Topasna, and Simonetti). We investigate the hypothesis that the bubble is blown by stellar winds from the O-type stars in the association. The Kompaneets approximation is adapted to model a wind-blown bubble in a stratified interstellar medium. We describe some general principles necessary for understanding the dynamics of an expanding bubble and the associated ionization structure in a stratified atmosphere. The Kompaneets model can be used to determine the mean scale height of the ambient medium as well as the age of the bubble. The ionization structure also places constraints on the ambient density near the cluster. We also estimate the surface brightness of the shell and the fraction of ionizing photons which escape the bubble. The prescription we use can be applied to any observed bubble that is blown by the effectively continuous energy output of stellar winds or multiple supernovae. Application to the W4 superbubble shows that the mean scale height of the ambient gas around the cluster is remarkably small, 25 pc for a cluster distance of 2.35 kpc. The age of the bubble is estimated to be about 2.5 Myr, consistent with the notion that the bubble is blown by stellar winds from a very young cluster in which no supernovae have yet occurred. 36 pages, 12 figures, AASTeX, to appear in the Astrophysical Journal