منابع مشابه
The Faint End of the Qso Luminosity Function At
We present the first measurement of the faint end of the QSO luminosity function at z = 3. The QSOs, which range from M1450 = −21 to M1450 = −27, were discovered in 17 fields totaling 0.43 deg using multicolor selection criteria (the Lyman break technique) and spectroscopic followup. We find that the faintend slope of the luminosity function is βl = 1.24± 0.07 (Φ ∝ L l), flatter than the value ...
متن کاملThe Structure of Galaxies at Faint Light Levels: Probing Galaxy Assembly
Many clues about the galaxy assembly process lurk in the faint outer regions of galaxies. Although quantitative study of these parts has been severely limited in the past, breakthroughs are now being made thanks to the combination of wide-area star counts, deep HST imagery and 8-m class spectroscopy. I highlight here some recent progress made on deciphering the fossil record encoded in the outs...
متن کاملQso Environments at Intermediate Redshifts
We have made a survey of quasar environments at 0.5 ≤ z ≤ 0.8, using a sample of both radio-loud and radio-quiet quasars matched in B-band luminosity. Our observations include images of background control fields to provide a good determination of the field galaxy counts. About 10 per cent of the quasars appear to live in rich clusters, whereas approximately 45 per cent live in environments simi...
متن کاملPattern Formation at Ultra - Low Light Levels
From swarming bacteria to social interactions among humans, the emergence of patterns in nature is ubiquitous. Pattern formation is often governed by collective dynamics, wherein individual components of a system begin to move or organize in a coherent way. The generation of patterns in nonlinear dynamical systems is found in nearly all subfields of science and provides insight into some of the...
متن کاملMotion perception at scotopic light levels.
Although the spatial and temporal properties of rod-mediated vision have been extensively characterized, little is known about scotopic motion perception. To provide such information, we determined thresholds for the detection and identification of the direction of motion of sinusoidal grating patches moving at speeds from 1 to 32 deg/s, under scotopic light levels, in four different types of o...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1988
ISSN: 0074-1809
DOI: 10.1017/s0074180900137052