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Article
Open AccessGUASOM: an adaptive visualization tool for unsupervised clustering in spectrophotometric astronomical surveys
We present an adaptive visualization tool for unsupervised classification of astronomical objects in a Big Data context such as the one found in the increasingly popular large spectrophotometric sky surveys. T...
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Article
Photometric Studies of O-type Hot Subdwarfs
We present a photometric study of eight sdOs and one sdOB on which simultaneous photometry in four Strömgren filters was performed. Our study seeks to detect the possible pulsators among the candidates.
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Article
Hot Subdwarfs: Magnetic, Oscillatory and Other Physical Properties
Hot subdwarf stars (hot sds) are blue subluminous objects. Only a few determinations areavailable to date regarding the study of such aspects as rotation,microturbulent velocities or the magnetic nature of the...
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Chapter and Conference Paper
Databases and Neural Networks Applied to Spectral Classification
As a part of an ongoing project, we have carried out a survey by observing low-resolution spectra of about 270 objects, all of which need to be classified in the MK system. We have designed and implemented a r...
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Chapter
Hot Subdwarfs: Further Photometric Observations of Pulsating and Non Pulsating Objects
High-speed photometry BD+254655 was obtained using the TromsØ-Texas photometer during the 2000 campaign at the CST with an integration time of 5 sec, while PG0856+121 and BS16545-49 were observed during the 20...
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Chapter and Conference Paper
Hot Subdwarfs: Magnetic, Oscillatory and Other Physical Properties
Hot subdwarf stars (hot sds) are blue subluminous objects. Only a few determinations are available to date regarding the study of such aspects as rotation, microturbulent velocities or the magnetic nature of t...
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Article
A Closer View of the Nucleus of NGC 4314
We present a high-resolution kinematical study of the ionized gas in the circumnuclear region of NGC 4314. Our spectra reveal the presence of a central structure (apparently a ring or torus) located at ∼ 2 arc...
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Chapter and Conference Paper
ISO Spectroscopy of the Proto-Planetary Nebula IRAS 17423-1755 (Hen 3-1475)
IRAS 17423-1755 is a strong infrared source recently identified as a new bipolar proto-planetary nebula with a very high velocity outflow for which we have obtained low resolution spectroscopy from 2 to 197 μm wi...
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Chapter and Conference Paper
Automatic Classification of Optical Sources Candidates to Be in the post-AGB Stage
As a part of an ongoing program, we have carried out a survey searching for stars in their late stages of evolution (post-Asymptotic Giant Branch; post-AGB stars) by observing low-resolution spectra of about 2...
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Article
Optical Classification of IRAS Post-AGB Candidates
We present the first results of a survey carried out on a sample of optically bright post-AGB candidates selected from the IRAS Point Source Catalogue, many of them previously unidentified in the literature. T...
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Chapter and Conference Paper
Kinematics of the Planetary Nebula Hb 5.
The planetary nebula Hubble 5 shows a very striking bi-symmetry; a 180° rotation around its center would bring the object into fair coincidence. Similar to this nebula is NGC 6537 and, to a lesser degree, NGC ...
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Article
Infrared photometry of open clusters: the main sequence of NGC 752
New infrared photometry of a sample of 39 stars in the open cluster NGC 752 is presented. These observations confirm the bimodality of the Main Sequence previously reported. We analyze the nature of this behav...
