846 research outputs found
Caltech Faint Galaxy Redshift Survey XV: Classification of Galaxies with 0.2 < z < 1.1 in the Hubble Deep Field (North) and its Flanking Fields
To circumvent the spatial effects of resolution on galaxy classification, the
images of 233 objects of known redshift in the Hubble Deep Field (HDF) and its
Flanking Fields (FF) that have redshifts in the range 0.20 < z < 1.10 were
degraded to the resolution that they would have had if they were all located at
a redshift z= 1.00. As in paper XIV of the present series, the effects of
shifts in rest wavelength were mitigated by using R-band images for the
classification of galaxies with 0.2 < z < 0.6 and I-band images for objects
with redshifts 0.6 < z < 1.1. A special effort was made to search for bars in
distant galaxies. The present data strongly confirm the previous conclusion
that the Hubble tuning fork diagram only provides a satisfactory framework for
the classification of galaxies with z ~< 0.3. More distant disk galaxies are
often difficult to shoehorn into the Hubble classification scheme. The paucity
of barred spirals and of grand-design spirals at large redshifts is confirmed.
It is concluded that the morphology of disk galaxies observed at look-back
times smaller than 3--4 Gyr differs systematically from that of more distant
galaxies viewed at look-back times of 4--8 Gyr. The disks of late-type spirals
at z >0.5 are seen to be more chaotic than those of their nearer counterparts.
Furthermore the spiral structure in distant early-type spirals appears to be
less well-developed than it is in nearby early-galaxies.Comment: Accepted for publication in the A
Sous la direction de Line JANELLE, La location d'un logement au Québec: Lois règlements, notes et jurisprudence, Montréal, Les Éditions Yvon Blais Inc., 1985, 303 pages, ISBN 2-89073-525-7
Some aspects of reprodutive biology of Clidemia hirta were observed. It was noticed: a) The anthesis begins at about 6:00 PM and ends at about 9:(X) AM of the next day; b) Clidemia hirta is preferentially allogamous, but .shows no genetic autoincompatibility; c) Clidemia hirta is pollinated by bees of Apidae (Bombus, Melipona. Euglossa, Trigona) and Halictidae families.Este trabalho foi desenvolvido com a finalidade de apresentar algumas considerações sobre a biologia reprodutiva de Clidemia Iurta, Conclui-se queI ) A ântese tem inĂcio em torno das 18:00 h e termina por volta das 09:00 h do dia seguinte; 2) Esta Ă© uma espĂ©cie preferencialmente alĂłgama, porĂ©m nĂŁo apresenta auto-incompatibilidade genĂ©tica; 3) A polinização parece depender de agentes polinizadores, principalmente abelhas das famĂlias Apidae (Bambus, Melipona, Euglossa, Trigona) e Halictidae
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