On the brightness distribution of type ia supernovae from violent white dwarf mergers

We investigate the brightness distribution expected for thermonuclear explosions that might result from the ignition of a detonation during the violent merger of white dwarf (WD) binaries. Violent WD mergers are a subclass of the canonical double degenerate scenario where two carbon-oxygen (CO) WDs merge when the larger WD fills its Roche lobe. Determining their brightness distribution is critical for evaluating whether such an explosion model could be responsible for a significant fraction of the observed population of Type Ia supernovae (SNe Ia). We argue that the brightness of an explosion realized via the violent merger model is mainly determined by the mass of Ni produced in the detonation of the primary COWD. To quantify this link, we use a set of sub-Chandrasekhar mass WD detonation models to derive a relationship between primary WD mass (m) and expected peak bolometric brightness (M). We use this m-M relationship to convert the masses of merging primary WDs from binary population models to a predicted distribution of explosion brightness. We also investigate the sensitivity of our results to assumptions about the conditions required to realize a detonation during violent mergers ofWDs. We find a striking similarity between the shape of our theoretical peak-magnitude distribution and that observed for SNe Ia: our model produces a M distribution that roughly covers the range and matches the shape of the one observed for SNe Ia. However, this agreement hinges on a particular phase of mass accretion during binary evolution: the primary WD gains ~0.15-0.35M? from a slightly evolved helium star companion. In our standard binary evolution model, such an accretion phase is predicted to occur for about 43 per cent of all binary systems that ultimately give rise to binary CO WD mergers. We also find that with high probability, violent WD mergers involving the most massive primaries (?1.3M?, which should produce bright SNe) have delay times ?500 Myr. © 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Sub-luminous type Ia supernovae from the mergers of equal-mass white dwarfs with mass 0.9M

Type Ia supernovae are thought to result from thermonuclear explosions of carbong'oxygen white dwarf stars. Existing models generally explain the observed properties, with the exception of the sub-luminous 1991bg-like supernovae. It has long been suspected that the merger of two white dwarfs could give rise to a type Ia event, but hitherto simulations have failed to produce an explosion. Here we report a simulation of the merger of two equal-mass white dwarfs that leads to a sub-luminous explosion, although at the expense of requiring a single common-envelope phase, and component masses of 0.9M. The light curve is too broad, but the synthesized spectra, red colour and low expansion velocities are all close to what is observed for sub-luminous 1991bg-like events. Although the mass ratios can be slightly less than one and still produce a sub-luminous event, the masses have to be in the range 0.83M to 0.9M. © 2010 Macmillan Publishers Limited. All rights reserved.

Impact of the financial crisis on cross-border mergers and acquisitions and concentration in the global banking industry

The global banking industry has seen dramatic changes in the past 40 years. Most recently, the financial liberalization of emerging markets and the global financial crisis have significantly impacted the market share of banks worldwide. This article investigates the impact of the 2007–2008 financial crisis on cross-border mergers and acquisitions (M&As) in the banking sector and emphasizes the role of emerging-market banks in the postcrisis consolidation trend. Using M&A data and concentration data over the period 2000–2013, our analysis indicates that the financial crisis had a significant impact on worldwide M&As, especially on the direction of the transactions. Emerging-market banks appear to be major acquirers in the postcrisis period, targeting both neighboring countries and developed economies in Europe. We also observe an increase in bank concentration in developed markets most hit by the financial crisis, especially in the United States and the United Kingdom, whereas bank concentration decreased in emerging markets.

Long-term performance of mergers and acquisitions in ASEAN countries

The study looks at mergers and acquisitions (M&As) in ASEAN countries and examines the post-M&A performance using data from 2001 to 2012. The industry-adjusted operating performance tends to decline in the 3 years following an M&A. Yet, the results suggest that M&As completed during the financial crisis are more profitable than those implemented before and/or after the crisis. We argue that this is mainly due to the synergies created between the firms’ resources during the crisis which augur well for firms’ economic performance. We find that, during the crisis, certain characteristics of the firms like the relative size of the target, cross-border nature of deals, acquirer's cash reserves and friendly nature of deals are important determinants of long-term post-M&A operating performance. However, for M&As during the crisis, there appears to be no relationship between performance and firms’ characteristics linked to M&A activity such as payment method, industry relatedness and percentage of target's share acquired.

Management of Cross Border Mergers and Acquisitions

This research thesis analyses the motivation behind the cross-border mergers and acquisitions deals. How mergers and acquisitions of new knowledge and assets, enhance business with expansion into new streams and international markets. Also, how mega deals help them to gain a power in the international markets. The research focuses on understanding the interrelation between motivations which are contributing to M&A activities and how issues like cultural differences and different management styles are overcome by these firms in cross-border settings. Chapter 1, gives a background knowledge on cross-border M&A as popular internationalization strategy choice, continuing with describing the process in Finnish and Japanese cultural context, and how these deals are proceeding in particular cases. Chapter 2, reviews the important findings and touches the common gaps or aspects those are not studied extensively, does play a key role in the success and failure of M&A deals. A methodology is presented in chapter 3, presenting the hurdles faced by many in this research field. Chapter 4, present the case study is presented to show how M&A can play an important role in structuring the entire economy of Japan. At last chapter 5, presents the evidence, if cultural, HRM and geographical aspects really contribute to the success of M&A, based on which managerial implications are suggested and propositions are built for future research references.

Trade Liberalization and the Profitability of Domestic Mergers.

It is often thought that a tariff reduction, by opening up the domestic market to foreign firms, should lessen the need for a policy aimed at discouraging domestic mergers. This implicitly assumes that the tariff in question is sufficiently high to prevent foreign firms from selling in the domestic market. However, not all tariffs are prohibitive, so that foreign firms may be present in the domestic market before it is abolished. Furthermore, even if the tariff is prohibitive, a merger of domestic firms may render it nonprohibitive, thus inviting foreign firms to penetrate the domestic market. In this paper, we show, using a simple example, that in the latter two cases, abolishing the tariff may in fact make the domestic merger more profitable. Hence, trade liberalization will not necessarily reduce the profitability of domestic mergers.

On the Effects of Mergers on Equilibrium Outcomes in a Common Property Renewable Asset Oligopoly

This paper examines a dynamic game of exploitation of a common pool of some renewable asset by agents that sell the result of their exploitation on an oligopolistic market. A Markov Perfect Nash Equilibrium of the game is used to analyze the effects of a merger of a subset of the agents. We study the impact of the merger on the equilibrium production strategies, on the steady states, and on the profitability of the merger for its members. We show that there exists an interval of the asset's stock such that any merger is profitable if the stock at the time the merger is formed falls within that interval. That includes mergers that are known to be unprofitable in the corresponding static equilibrium framework.