Are financial services over-regulated?

As the Equitable Life saga drags on, accounting scandals break over Enron and WorldCom and allegations of self-serving analysts reports swirl around Merrill Lynch and other US investment banks, this may seem an extraordinary question to ask. But this is the very time that one must beware of the ‘dangerous dogs’ reaction1. It is easy to forget in the immediate aftermath of scandals that extra regulation may achieve little beyond satisfying the call for ‘something to be done’ and can cumulatively cost a lot, even perversely increase the chances of future disasters2. With the EU’s Financial Services Action Plan, the DTI’s consultation on Company Law, the Sandler review of savings and the FSA’s review of polarisation, Listing Rules and simplified product selling, the opportunity for radical change, good or bad, is all to apparent. This article seeks to give an overview of the current position and assess the danger of an over-reaction

Market abuse

On 1st December 2001, the Financial Services and Markets Act 2000 (‘FSMA’) came into force. One of its most controversial sections is Part VIII which gives the Financial Services Authority (‘FSA’) the power to impose civil penalties for market abuse. Despite the many doubts raised about these provisions and their as yet untested nature, the European Commission has proposed a European Directive on Market Abuse1, to extend the concept of ‘administrative sanctions’ for market abuse across the whole European Economic Area (‘EEA’). This paper looks at the issues currently raised by the UK legislation and any further problems the European legislation may bring

Are there MACHOs in the Milky Way halo?

Microlensing searches aim to detect compact halo dark matter via its gravitational lensing effect on stars within the Large Magellanic Cloud. The most recent results have led to the claim that roughly one fifth of the galactic halo dark matter may be in the form of compact, solar-mass objects. We analyze this hypothesis by considering the goodness-of-fit of the best-fit halo dark matter solutions to the observational data. We show that the distribution of the durations of the observed microlensing events is narrower than that expected to result from a standard halo lens population at 90 to 95% confidence. Only when the fraction of expected background (non-halo) events is significantly increased does the discrepancy between the observed and theoretical event duration distributions disappear. This indicates that it is possible that most of the lenses responsible for the observed microlensing events are not located within the Milky Way halo.Comment: 5 pages, 2 figures, minor changes to discussion and additional references, version to appear in Astronomy and Astrophysic

Not enough stellar mass Machos in the Galactic halo

We present an update of results from the search for microlensing towards the Large Magellanic Cloud (LMC) by EROS (Experience de Recherche d'Objets Sombres). We have now monitored 25 million stars over three years. Because of the small number of observed microlensing candidates (four), our results are best presented as upper limits on the amount of dark compact objects in the halo of our Galaxy. We discuss critically the candidates and the possible location of the lenses, halo or LMC . We compare our results to those of the MACHO group. Finally, we combine these new results with those from our search towards the Small Magellanic Cloud as well as earlier ones from the EROS1 phase of our survey. The combined data is sensitive to compact objects in the broad mass range $10^{-7} - 10$ solar masses. The derived upper limit on the abundance of stellar mass MACHOs rules out such objects as the dominant component of the Galactic halo if their mass is smaller than 2 solar masses.Comment: 7 pages, 4 figures, presented at the XIX International Conference on Neutrino Physics and Astrophysics, Sudbury, Canada, June 200

Finite-source and finite-lens effects in astrometric microlensing

The aim of this paper is to study the astrometric trajectory of microlensing events with an extended lens and/or source. We consider not only a dark lens but also a luminous lens as well. We find that the discontinuous finite-lens trajectories given by Takahashi (2003) will become continuous in the finite-source regime. The point lens (source) approximation alone gives an under (over)estimation of the astrometric signal when the size of the lens and source are not negligible. While the finiteness of the source is revealed when the lens transits the surface of the source, the finite-lens signal is most prominent when the lens is very close to the source. Astrometric microlensing towards the Galactic bulge, Small Magellanic Cloud and M31 are discussed, which indicate that the finite-lens effect is beyond the detection limit of current instruments. Nevertheless, it is possible to distinguish between self-lensing and halo lensing through a (non-)detection of the astrometric ellipse. We also consider the case where the lens is luminous itself, as has been observed where a lensing event was followed up with the Hubble Space Telescope. We show that the astrometric signal will be reduced in a luminous-lens scenario. The physical properties of the event, such as the lens-source flux ratio, the size of the lens and source nevertheless can be derived by fitting the astrometric trajectory.Comment: 12 pages, 12 figures, 1 table, published in MNRA

X-ray Pulsations in the Supersoft X-ray Binary CAL 83

X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4 minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations the white dwarf. This is the first detection of pulsations in a classical supersoft X-ray binary.Comment: revised text; 11 pages and 3 figures; accepted for publication in the Astronomical Journa