arXiv subjects

E. F. Borra

Publications and source records attributed to E. F. Borra.

21 records · Page 2Linked to original sources

arXiv1994

A Survey of Galaxy Redshifts from Low-Resolution Slitless Spectra: Suggestion of Large-Scale Structures at Z ~0.1

We have conducted a galaxy survey based on low-resolution slitless spectra taken from the automated CFHT-Laval survey. We present redshift distributions for 522 galaxies distributed in 4 distinct regions of the sky. Redshifts are determined from the shifted positions of the 4000 A. stellar break using an automated break-finding algorithm. The redshifts so obtained have a precision of < 3000 km s-1, good enough to trace the large-scale distribution of galaxies. The most striking feature of the survey is an apparent excess of galaxies at z ~ 0.1 in 8 of the 10 fields probed. Although the statistical significance of the peaks appears marginal (~ 2.5s per field) after taken in account the small-scale galaxy clustering, the peaks may nevertheless reveal the existence of large-scale structures at z ~ 0.1, indicating that the known large structures in the local universe are not unusual.

astro-ph↗

arXiv1994

Are BL Lacertae Objects Beamed QSO Remnants?

This paper considers the hypothesis that BL Lacertae objects (BLLs) are the beamed remnants of Quasi Stellar Objects. The hypothesis explains why BLLs do not undergo the strong evolution seen in other active galactic nuclei since it naturally predicts that the space density of BLLs should increase with cosmic time, as shown by recent observations. Numerical models reproduce, with reasonable parameters, the known redshift and magnitude counts of BL Lac objects. It is assumed that radio-quiet as well as radio-loud quasars are capable of generating jets but that jets are snuffed in young radio-quiet objects and only emerge in aged ones. I argue that the observations allow this assumption.

astro-ph↗

arXiv1994

Ubc/Laval 2.7-Meter Liquid Mirror Telescope

We report the successful development and operation of a large astronomical liquid-mirror telescope. Employing a rotating 2.7-meter diameter mirror with a surface of liquid mercury, the telescope images a half-degree diameter field centered at the zenith. Located near Vancouver, British Columbia, it is equipped with a low-noise 2048x2048-pixel CCD detector, operating in TDI mode, which produces continuous imaging of a 20 arcminute-widestrip of sky with 2 minute integration time. Images with FWHM of 2 arcseconds or less are regularly obtained. This image quality is limited only by atmospheric seeing and star-trail curvature. The telescope is equipped with a series of narrow-band filters, designed to produce 40-point spectral energy distributions from 0.4 to 1.0 microns of all detected objects. These will allow classification and redshift estimation of approximately 25,000 galaxies and 1,000 quasars to a limiting magnitude of R~21.

astro-ph↗