VLA-ANGST: A high-resolution HI Survey of Nearby Dwarf Galaxies

We present the "Very Large Array survey of Advanced Camera for Surveys Nearby Galaxy Survey Treasury galaxies (VLA-ANGST)." VLA-ANGST is a National Radio Astronomy Observatory Large Program consisting of high spectral (0.6-2.6 km/s) and spatial (~6") resolution observations of neutral, atomic hydrogen (HI) emission toward 35 nearby dwarf galaxies from the ANGST survey. ANGST is a systematic HST survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D\lesssim4 Mpc). VLA-ANGST provides VLA HI observations of the sub-sample of ANGST galaxies with recent star formation that are observable from the northern hemisphere and that were not observed in the "The HI Nearby Galaxy Survey" (THINGS). The overarching scientific goal of VLA-ANGST is to investigate fundamental characteristics of the neutral interstellar medium (ISM) of dwarf galaxies. Here we describe the VLA observations, the data reduction, and the final VLA-ANGST data products. We present an atlas of the integrated HI maps, the intensity-weighted velocity fields, the second moment maps as a measure for the velocity dispersion of the HI, individual channel maps, and integrated HI spectra for each VLA-ANGST galaxy. We closely follow the observational setup and data reduction of THINGS to achieve comparable sensitivity and angular resolution. A major difference, however, is the high velocity resolution of the VLA-ANGST observations (0.65 and 1.3km/s for the majority of the galaxies). The VLA-ANGST data products are made publicly available at: https://science.nrao.edu/science/surveys/vla-angst. With available star formation histories from resolved stellar populations and lower resolution ancillary observations from the FIR to the UV, VLA-ANGST will enable detailed studies of the relationship between the ISM and star formation in dwarf galaxies on a ~100 pc scale.Comment: 64 figures, grouped into 32. 115 pages, accepted for publication in the Astronomical Journa

Connecting Gas Dynamics and Star Formation Histories in Nearby Galaxies: The VLA-ANGST Survey

In recent years, HST revolutionized the field of star formation in nearby galaxies. Due to its high angular resolution it has now become possible to construct star formation histories of individual stellar populations on scales of a few arcseconds spanning a range of up to ~600 Myr. This method will be applied to the ANGST galaxies, a large HST volume limited survey to map galaxies up to distances of 3.5-4.0 Mpc (excluding the Local Group). The ANGST sample is currently followed--up by high, ~6'' resolution VLA observations of neutral, atomic hydrogen (HI) in the context of VLA-ANGST, an approved Large VLA Project. The VLA resolution is well matched to that of the spatially resolved star formation history maps. The combination of ANGST and VLA-ANGST data will provide a new, promising approach to study essential fields of galaxy evolution such as the triggering of star formation, the feedback of massive stars into the interstellar medium, and the structure and dynamics of the interstellar medium.Comment: to appear in the proceedings to the conference: "The Evolution of Galaxies through the Neutral Hydrogen Window", Arecibo, PR, US

Poisson boundary of a relativistic diffusion in curved space-times: an example

We study in details the long-time asymptotic behavior of a relativistic diffusion taking values in the unitary tangent bundle of a curved Lorentzian manifold, namely a spatially flat and fast expanding Robertson-Walker space-time. We prove in particular that the Poisson boundary of the diffusion can be identified with the causal boundary of the underlying manifold.Comment: 16 pages, 2 figure

Asymptotic behavior of a relativistic diffusion in Robertson-Walker space-times

We determine the long-time asymptotic behavior of a relativistic diffusion taking values in the unitary tangent bundle of a Robertson-Walker space-time. We prove in particular that when approaching the explosion time of the diffusion, its projection on the base manifold almost surely converges to a random point of the causal boundary and we also describe the behavior of the tangent vector in the neighborhood of this limiting point.Comment: 42 pages, 6 figure

ECB Presidency and Inflation Aversion among the Citizens of European Countries: An Empirical Assessment

Geldpolitik; Zentralbank; Inflationsbekämpfung; Inflation; Angst; EU-Staaten

Growth of layered Lu2_2Fe3_3O7_7 and Lu3_3Fe4_4O10_{10} single crystals exhibiting long-range charge order via the optical floating-zone method

We report the controlled growth of single crystals of intercalated layered Lu$_{1+n}$Fe$_{2+n}$O$_{4+3n-\delta}$ ($n$=1,2) with different oxygen stoichiometries ${\delta}$. For the first time crystals sufficiently stoichiometric to exhibit superstructure reflections in X-ray diffraction attributable to charge ordering were obtained. The estimated correlation lengths tend to be smaller than for not intercalated LuFe$_2$O$_4$. For Lu$_2$Fe$_3$O$_7$, two different superstructures were observed, one an incommensurate zigzag pattern similar to previous observations by electron diffraction, the other an apparently commensurate pattern with ($\frac{1}{3}\frac{1}{3}0$) propagation. Implications for the possible charge order in the bilayers are discussed. Magnetization measurements suggest reduced magnetic correlations and the absence of an antiferromagnetic phase.Comment: 7pages, 7figure

Irrelevant externality angst.

Due to the high transaction cost that would be necessary for large numbers of people to negotiate with each other, even those who are usually sanguine about private markets become reserved when externalities affect large populations. The distinction between private and societal interest is well understood for pecuniary externalities, but neglect of Buchanan and Stubblebine’s article Externality has left the same distinction widely unrecognized for non-pecuniary ones. If only a few parties on either side experience a relevant externality private interactions can appropriately internalize costs and benefits across the entire population. Regardless of the perceptiveness of legal and cultural institutions in placing entitlements, and regardless of the level of transaction cost among the universe of the affected, a surprising number of externalities will readily fix themselves. The desirability of corrective intervention is much too easily conceded.

Universality of the mean number of real zeros of random trigonometric polynomials under a weak Cramer condition

We investigate the mean number of real zeros over an interval $[a,b]$ of a random trigonometric polynomial of the form $\sum_{k=1}^n a_k \cos(kt)+b_k \sin(kt)$ where the coefficients are i.i.d. random variables. Under mild assumptions on the law of the entries, we prove that this mean number is asymptotically equivalent to $\frac{n(b-a)}{\pi\sqrt{3}}$ as $n$ goes to infinity, as in the known case of standard Gaussian coefficients. Our principal requirement is a new Cramer type condition on the characteristic function of the entries which does not only hold for all continuous distributions but also for discrete ones in a generic sense. To our knowledge, this constitutes the first universality result concerning the mean number of zeros of random trigonometric polynomials. Besides, this is also the first time that one makes use of the celebrated Kac-Rice formula not only for continuous random variables as it was the case so far, but also for discrete ones. Beyond the proof of a non asymptotic version of Kac-Rice formula, our strategy consists in using suitable small ball estimates and Edgeworth expansions for the Kolmogorov metric under our new weak Cramer condition, which both constitute important byproducts of our approach