Multi-waveband observations of colliding galaxies

Colliding galaxies represent a major challenge to both theorists and observers because of the large variety of phenomena which are expected to come into play during the interaction. Strong gravitational fluctuations may drive non-linear waves and instabilities throughout the stars and gas leading to enhanced star formation, nuclear activity and ultimately a mixing of the morphological components of the original galaxies. One relatively uncomplicated class of colliding galaxy where stellar waves play an important role in star formation are ring galaxies. Ring galaxies are probably formed when a companion galaxy passes through the center of a disk system driving circular waves through the disk (Lynds and Toomre 1976, Toomre 1978, Struck-Marcell 1990). Off-center collisions can generate non-circular waves and can be loosely described as banana-shaped although they may exhibit more complex forms as the waves expand into the disk. The propagation of such stellar and gaseous waves through the disk leads to enhanced star formation (e.g., Appleton and Struck-Marcell 1987a; Jeske 1986) and provides a unique probe of the response of the interstellar medium (ISM) to a propagating wave (see Appleton and Struck-Marcell 1987b). Here, the authors report results for 3 systems; the irregular ring Arp 143 (=VV 117); Wakamatsu's Seyfert ring (A0959-755; see Wakamatsu and Nishida 1987) and the brighter member of the pair of ring galaxies comprising of AM 1358-221. The most complete multi-wavelength data is for Arp 143. Optical charge coupled device (CCD) observations made with the 60 inch Palomar telescope at BV and r band, near-IR images at J (1.25 microns), H (1.65 microns) and k (2.2 microns) bands from the infrared camera (IRCAM) InSb array camera on the 3.8m United Kingdon Infrared Telescope (UKIRT) telescope and very large array (VLA) observations at 20cm in both the neutral hydrogen line and radio continuum are described. The observations of Wakamatsu's ring and AM 1358 were made only in the near-IR, and a comparison is made with available optical plate material

Gold Without the Games: Analyzing Unsuccessful Olympic Bids as Policy Windows

Contemporary scholarship on the Olympic Games has turned to consider the negative long-term effects associated with hosting the Games, but has not looked at unsuccessful Olympic bids. Since bidding for the Games is expensive and time-consuming, cities will only bid if it can be shown to provide positive outcomes. This paper responds to the question “Did the unsuccessful Olympic Bids of Toronto 2008, New York City 2012 and Chicago 2016 act as policy windows for public policy or development projects?” It finds that that Toronto’s and New York City’s bids did function as policy windows. To bolster the likelihood of future Olympic Games bids functioning as policy windows, the paper proposes three recommendations: 1. The United States Olympic Committee and the Canadian Olympic Association should mandate that all future bid organizations will be public-private partnerships. 2. The International Olympic Committee (IOC) should amend the Olympic Charter to require cities to include a detailed legacy plan with as a part of an Olympic Bid. 3. The IOC should amend the Olympic Charter to require that comprehensive legacy plans are accompanied by the creation of a nonprofit legacy organization

Incoherent pion photoproduction on the deuteron with polarization observables I: Formal expressions

Formal expressions are developed for the general five-fold differential cross section of incoherent $\pi$-photoproduction on the deuteron including beam and target polarization. The polarization observables of the cross section are described by various beam, target and beam-target asymmetries for polarized photons and/or polarized deuterons. They are given as bilinear hermitean forms in the reaction matrix elements divided by the unpolarized cross section. In addition, the corresponding observables for the semi-exclusive reaction $\vec d(\vec \gamma,\pi)NN$ are also given.Comment: 11 pages, 1 figur

Psychic Distance and Country Image in Exporter–Importer Relationships

Conflicting evidence on the issue of psychic distance (PD) in international business relationships suggests the existence of misunderstood boundary conditions to its effect. This article argues that country image (CI) is a contingent factor to the effect of PD. Expectancy–value theory provides the theoretical foundations for this argument. Based on structural equation modeling, analyses for a sample of 358 exporter–importer relationships in the global wine industry provide empirical support. Product-related CI mitigates the negative impact of PD on the relational exchange orientation (REO) between firms. Specifically, a high level of PD dampens REO when product-related CI is poor, whereas a strong product-related CI helps firms facing such PD conditions to build REO irrespective. People-related CI has an indirect effect on REO through product-related CI. Our study contributes to explaining the paradox of distance and offers a fresh perspective on how to handle the issue of PD when relevant

Detection of Cosmic Microwave Background Structure in a Second Field with the Cosmic Anisotropy Telescope

We describe observations at frequencies near 15 GHz of the second 2x2 degree field imaged with the Cambridge Cosmic Anisotropy Telescope (CAT). After the removal of discrete radio sources, structure is detected in the images on characteristic scales of about half a degree, corresponding to spherical harmonic multipoles in the approximate range l= 330--680. A Bayesian analysis confirms that the signal arises predominantly from the cosmic microwave background (CMB) radiation for multipoles in the lower half of this range; the average broad-band power in a bin with centroid l=422 (theta = 51') is estimated to be Delta_T/T=2.1^{+0.4}_{-0.5} x 10^{-5}. For multipoles centred on l=615 (theta =35'), we find contamination from Galactic emission is significant, and constrain the CMB contribution to the measured power in this bin to be Delta_T/T <2.0 x 10^{-5} (1-sigma upper limit). These new results are consistent with the first detection made by CAT in a completely different area of sky. Together with data from other experiments, this new CAT detection adds weight to earlier evidence from CAT for a downturn in the CMB power spectrum on scales smaller than 1 degree. Improved limits on the values of H_0 and Omega are determined using the new CAT data.Comment: 5 pages, 5 figures (gif), submitted to MNRA

A historic jet-emission minimum reveals hidden spectral features in 3C 273

Aims. The aim of this work is to identify and study spectral features in the quasar 3C 273 usually blended by its strong jet emission. Method. A historic minimum in the sub-millimetre emission of 3C 273 triggered coordinated multi-wavelength observations in June 2004. X-ray observations from the INTEGRAL, XMM-Newton and RXTE satellites are complemented by ground-based optical, infrared, millimetre and radio observations. The overall spectrum is used to model the infrared and X-ray spectral components. Results. Three thermal dust emission components are identified in the infrared. The dust emission on scales from 1 pc to several kpc is comparable to that of other quasars, as expected by AGN unification schemes. The observed weakness of the X-ray emission supports the hypothesis of a synchrotron self-Compton origin for the jet component. There is a clear soft-excess and we find evidence for a very broad iron line which could be emitted in a disk around a Kerr black hole. Other signatures of a Seyfert-like X-ray component are not detected.Comment: 4 pages. Accepted for publication in A&A Letter

Polarization observables in π0η\pi^0\eta-photoproduction on the proton

For $\pi^0\eta$-photoproduction on the nucleon formal expressions are developed for the five-fold differential cross section and the recoil polarization including beam and target polarizations. The polarization observables are described by various beam, target and beam-target asymmetries for polarized photons and/or polarized nucleons. They are given as bilinear hermitean forms in the reaction matrix elements divided by the unpolarized cross section. Numerical results for the linear and circular beam asymmetries for $\gamma p\to\pi^0\eta p$ are obtained within an isobar model and are compared with existing data. Predictions are also given for the target asymmetry $T_{11}$, and the beam-target asymmetries $T^c_{10}$ and $T^c_{11}$ for circularly polarized photons.Comment: 19 pages, 8 figure