Is space really expanding? A counterexample

In all Friedman models, the cosmological redshift is widely interpreted as a consequence of the general-relativistic phenomenon of EXPANSION OF SPACE. Other commonly believed consequences of this phenomenon are superluminal recession velocities of distant galaxies and the distance to the particle horizon greater than c*t (where t is the age of the Universe), in apparent conflict with special relativity. Here, we study a particular Friedman model: empty universe. This model exhibits both cosmological redshift, superluminal velocities and infinite distance to the horizon. However, we show that the cosmological redshift is there simply a relativistic Doppler shift. Moreover, apparently superluminal velocities and `acausal' distance to the horizon are in fact a direct consequence of special-relativistic phenomenon of time dilation, as well as of the adopted definition of distance in cosmology. There is no conflict with special relativity, whatsoever. In particular, INERTIAL recession velocities are subluminal. Since in the real Universe, sufficiently distant galaxies recede with relativistic velocities, these special-relativistic effects must be at least partly responsible for the cosmological redshift and the aforementioned `superluminalities', commonly attributed to the expansion of space. Let us finish with a question resembling a Buddhism-Zen `koan': in an empty universe, what is expanding?Comment: 12 pages, no figures; added Appendix with a calculation of the cosmological redshift in `private space

Application of a Bayesian Method to Absorption Spectral-Line Finding in Simulated ASKAP Data

The large spectral bandwidth and wide field of view of the Australian SKA Pathfinder radio telescope will open up a completely new parameter space for large extragalactic HI surveys. Here we focus on identifying and parametrising HI absorption lines which occur in the line of sight towards strong radio continuum sources. We have developed a method for simultaneously finding and fitting HI absorption lines in radio data by using multi-nested sampling, a Bayesian Monte Carlo algorithm. The method is tested on a simulated ASKAP data cube, and is shown to be reliable at detecting absorption lines in low signal-to-noise data without the need to smooth or alter the data. Estimation of the local Bayesian evidence statistic provides a quantitative criterion for assigning significance to a detection and selecting between competing analytical line-profile models.Comment: 8 pages, 5 figures and 1 table; accepted for publication in PAS

A computer program for a line-by-line calculation of spectra from diatomic molecules and atoms assuming a Voight line profile

Computer program predicts the spectra resulting from electronic transitions of diatomic molecules and atoms in local thermodynamic equilibrium. The program produces a spectrum by accounting for the contribution of each rotational and atomic line considered

Multi-object spectroscopy of the field surrounding PKS 2126-158: Discovery of a z=0.66 galaxy group

The high-redshift radio-loud quasar PKS 2126-158 is found to have a large number of red galaxies in close apparent proximity. We use the Gemini Multi-Object Spectrograph (GMOS) on Gemini South to obtain optical spectra for a large fraction of these sources. We show that there is a group of galaxies at $z\sim0.66$, coincident with a metal-line absorption system seen in the quasar's optical spectrum. The multiplexing capabilities of GMOS also allow us to measure redshifts of many foreground galaxies in the field surrounding the quasar. The galaxy group has five confirmed members, and a further four fainter galaxies are possibly associated. All confirmed members exhibit early-type galaxy spectra, a rare situation for a Mg II absorbing system. We discuss the relationship of this group to the absorbing gas, and the possibility of gravitational lensing of the quasar due to the intervening galaxies.Comment: Monthly Notices of the Royal Astronomical Society, in press. 10 pages, 8 figure

A fourth HI 21-cm absorption system in the sight-line of MG J0414+0534: a record for intervening absorbers

We report the detection of a strong HI 21-cm absorption system at z=0.5344, as well as a candidate system at z=0.3389, in the sight-line towards the z=2.64 quasar MG J0414+0534. This, in addition to the absorption at the host redshift and the other two intervening absorbers, takes the total to four (possibly five). The previous maximum number of 21-cm absorbers detected along a single sight-line is two and so we suspect that this number of gas-rich absorbers is in some way related to the very red colour of the background source. Despite this, no molecular gas (through OH absorption) has yet been detected at any of the 21-cm redshifts, although, from the population of 21-cm absorbers as a whole, there is evidence for a weak correlation between the atomic line strength and the optical--near-infrared colour. In either case, the fact that so many gas-rich galaxies (likely to be damped Lyman-alpha absorption systems) have been found along a single sight-line towards a highly obscured source may have far reaching implications for the population of faint galaxies not detected in optical surveys, a possibility which could be addressed through future wide-field absorption line surveys with the Square Kilometre Array.Comment: Accepted by ApJ Letter

The Income Tax and Accounting Records for Illegal Businesses

The activities of gamblers and other illegal operators have received considerable public notice recently as a result of the Kefauver Committee\u27s investigations. Although the amounts of money involved in these operations are astronomical, no complete records are maintained by these individuals. Amounts entered on income tax returns of this type are completely incapable of verification in the usual method because of the incompleteness of the records and data available. Admittedly these operators are in the unenviable position of being required to keep complete records for income tax purposes, but being afraid to do so because of their evidentiary value to state and local authorities. However, the courts seem to have taken a lenient attitude concerning the requirements for the keeping of records as they are applied to taxpayers engaged in illegal businesses