Browsing by Author "Flores, H"

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    An unusual iron Lo-BAL quasar detected by ISOCAM
    (2002) Duc, PA; Hall, PB; Fadda, D; Chanial, P; Elbaz, D; Monaco, P; Pompei, E; Poggianti, BM; Flores, H; Franceschini, A; Biviano, A; Moorwood, A; Cesarsky, C
    We report the discovery of an unusual low-ionization broad absorption line quasar at z = 1.776 which exhibits absorption lines from many excited states of Fe II. This member of the rare class of "FeLoBAL" quasars was serendipitously found in a mid-infrared (MIR) survey of distant clusters carried out with the ISOCAM camera. ISO J005645.1-273816 has a high MIR to UV luminosity ratio, suggesting a strong dust obscuration plus emission from very hot dust. This characteristic makes MIR surveys particularly efficient at detecting LoBAL quasars.
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    Canada-France redshift survey .14. Spectral properties of field galaxies up to z=1
    (1997) Hammer, F; Flores, H; Lilly, SJ; Crampton, D; LeFevre, O; Rola, C; MallenOrnelas, G; Schade, D; Tresse, L
    The spectral properties of more than 400 Canada-France Redshift Survey (CFRS) galaxies and their changes over the redshift interval 0 less than or equal to z less than or equal to 1.3 are investigated. Emission-line intensities and equivalent widths for accessible lines have been measured as well as continuum color indices based on 200 Angstrom wide spectral regions. Within the CFRS sample, the comoving fraction of galaxies with significant emission lines [W-0(O II)> 15 Angstrom] increases from about 13% locally to over 50% at z > 0.5. The fraction of luminous (M-B < -20) quiescent galaxies (those without [O II] 3727 emission) decreases with redshift from 53% at z = 0.3 to 23% at z > 0.5, the latter fraction being similar to that of early-type galaxies at that redshift. There is considerable evidence in the data presented here that star formation increases from z = O to z > 0.5 in disk galaxies. However, the absence of extremely blue colors and the presence of significant Balmer absorption suggests that the star formation is primarily taking place over long periods of time, rather than in short-duration, high-amplitude '' bursts.''