308 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- National ObservatoryBR74 papers
- Centro Brasileiro de Pesquisas FísicasBR28 papers
- Universidade de São PauloBR25 papers
- Centre National de la Recherche ScientifiqueFR24 papers
- Universidade Federal do Rio de JaneiroBR22 papers
- Tel Aviv UniversityIL20 papers
- Universidade Federal do Rio Grande do SulBR17 papers
- Petersburg Nuclear Physics InstituteRU16 papers
- European Organization for Nuclear ResearchCH15 papers
- Fundação de Amparo à Pesquisa do Estado de São PauloBR15 papers
- Instituto Superior TécnicoPT15 papers
- University of California, BerkeleyUS15 papers
65 papers · 1 filter
Coupled quintessence and vacuum decay
F. E. M. Costa, J. S. Alcaniz, J. M. F. Maia
We discuss observational consequences of a class of cosmological models characterized by the dilution of pressureless matter attenuated with respect to the usual scaling d…
Colors of Luminous Bulges in Cluster MS1054-03 and Field Galaxies at Redshifts z ~ 0.83
David C. Koo, Susmita Datta, Christopher N. A. Willmer +3
Using HST images, we separate the bulge-like (pbulge) and disk-like (pdisk) components of 71 galaxies in the rich cluster MS1054-03 and of 21 in the field. Our key finding is that…
The DEEP Groth Strip Galaxy Redshift Survey. VIII. The Evolution of Luminous Field Bulges at Redshift z ~ 1
David C. Koo, Luc Simard, Christopher N. A. Willmer +11
We present a sample of over 50 luminous field bulges (including ellipticals) found in the Groth Strip Survey (GSS), with 0.73< z < 1.04 and with bulge magnitudes I <= 23. The expon…
Instant preheating mechanism and UHECR
A. H. Campos, J. M. F. Maia, R. Rosenfeld
Top-down models assume that the still unexplained Ultra High Energy Cosmic Rays (UHECR's) are the decay products of superheavy particles. Such particles may have been produced by o…
On the Geometry of Dark Energy
M. D. Maia, E. M. Monte, J. M. F. Maia +1
Experimental evidence suggests that we live in a spatially flat, accelerating universe composed of roughly one-third of matter (baryonic + dark) and two-thirds of a negative-pressu…
Eclipses by circumstellar material in the T Tauri star AA Tau. II. Evidence for non-stationary magnetospheric accretion
J. Bouvier, K. N. Grankin, S. H. P. Alencar +12
We report the results of a synoptic study of the photometric and spectroscopic variability of the classical T Tauri star AA Tau on timescales ranging from a few hours to several we…
Current and future supernova constraints on decaying cosmologies
J. S. Alcaniz, J. M. F. Maia
We investigate observational constraints from present and future supernova data on a large class of decaying vacuum cosmologies. In such scenarios the present value of the vacuum e…
The accelerating universe in brane-world cosmology
M. D. Maia, Edmundo M. Monte, J. M. F. Maia
The standard Friedmann universe embedded in a five dimensional and constant curvature bulk is examined without any a priori junction condition between the brane and the bulk. A geo…
Boron in the Small Magellanic Cloud: A Novel Test of Light Element Production
A. M. Brooks, K. A. Venn, D. L. Lambert +3
Hubble Space Telescope STIS observations of the B III resonance line at 2066A have been obtained and analyzed for two Small Magellanic Cloud (SMC) B-type stars. While boron is not…
Exploration of Large Digital Sky Surveys
S. G. Djorgovski, R. J. Brunner, A. A. Mahabal +8
We review some of the scientific opportunities and technical challenges posed by the exploration of the large digital sky surveys, in the context of a Virtual Observatory (VO). The…
Searches for Rare and New Types of Objects
S. G. Djorgovski, A. A. Mahabal, R. J. Brunner +4
Systematic exploration of the observable parameter space, covered by large digital sky surveys spanning a range of wavelengths, will be one of the primary modes of research with a…
Variability of Southern T Tauri Stars I: The Continuum and the H Inverse PCygni Profile of GQ LUPI
C. Batalha, D. F. Lopes, N. M. Batalha
We present time series spectrophotometric observations of GQ Lupi, a typical representative of the YY Ori subgroup of T Tauri stars that show conspicuous inverse PCygni profiles. T…
Light Element Abundance Patterns in the Orion Association: I) HST Observations of Boron in G-dwarfs
K. Cunha, V. Smith, E. Parizot +1
The boron abundances for two young solar-type members of the Orion association, BD -6 1250 and HD 294297, are derived from HST STIS spectra of the B I transition at 2496.771 A. The…
The Narrow Line Region of Narrow-Line Seyfert 1 Galaxies
A. Rodriguez-Ardila, L. Binette, M. G. Pastoriza +2
This work studies the optical emission line properties and physical conditions of the narrow line region (NLR) of seven narrow-line Seyfert 1 galaxies (NLS1). Our results show that…
The mass surface density in the local disk and the chemical evolution of the Galaxy
D. Romano, F. Matteucci, P. Salucci +1
We have studied the effect of adopting different values of the total baryonic mass surface density in the local disk at the present time in a model for the chemical evolution of th…
Spatially-resolved spectra of the accretion disc of the novalike UU Aquarii
Raymundo Baptista, C. Silveira, J. E. Steiner +1
Time-resolved spectroscopy of the novalike variable UU Aquarii is analyzed with eclipse mapping techniques to produce spatially resolved spectra of its accretion disc and gas strea…
Eta Carinae: Binarity Confirmed
Augusto Damineli, Andreas Kaufer, Bernhard Wolf +3
We report the recovery of a spectroscopic event in eta Carinae in 1997/98 after a prediction by Damineli (1996). A true periodicity with P = 2020+-5 days (0.2% uncertainty) is obta…
Accretion-Induced Lithium Line Enhancements in Classical T Tauri Stars: RW Aur
N. M. Stout-Batalha, C. C. Batalha, G. S. Basri
It is widely accepted that much of the stochastic variability of T Tauri stars is due to accretion by a circumstellar disk. The emission line spectrum as well as the excess continu…
A Quantitative Evaluation of the Galaxy Component of COSMOS and APM Catalogs
Cesar A. Caretta, Marcio A. G. Maia, Christopher N. A. Willmer
We have carried out an independent quantitative evaluation of the galaxy component of the "COSMOS/UKST Southern Sky Object Catalogue" (SSC) and the "APM/UKST J Catalogue" (APM). Us…
Near-infrared Spectral Features in Single-aged Stellar Populations
Ricardo P. Schiavon, Beatriz Barbuy, Gustavo Bruzual
Synthetic spectra for single-aged stellar populations of metallicities [M/H] = -0.5, 0.0 and +0.5, ages = 3 to 17 Gyrs, and initial mass function exponents x = 0.1 to 2.0 were buil…
BVRI-Halpha surface photometry of peculiar ring galaxies. I. HRG 2302
M. L. M. Myrrha, L. P. R. Vaz, M. Faúndez-Abans +2
Detailed BVRI-Halpha photometry has been obtained for the ring galaxy HRG 2302. This is probably a still interacting system which shows two principal components: the target, which…
A photometric and kinematic study of the stars and interstellar medium in the central two kpc of NGC 3379
Miriani G. Pastoriza, Claudia Winge, Fabricio Ferrari +2
HST images of NGC 3379 show that the V and I luminosity profiles in the inner 13 arcsec of this E1 galaxy are represented by two different components: a stellar bulge following a S…
Quasar-Marked Protoclusters and Biased Galaxy Formation
S. G. Djorgovski, S. C. Odewahn, R. R. Gal +2
We report on the current status of our search for protoclusters around quasars at z > 4. While the search is still very incomplete, clustered companion galaxies are found in virtua…
Study of the interacting system NGC 6845
Irapuan Rodrigues, Horacio Dottori, Elias Brinks +1
We present optical spectroscopy, B, V, R and I CCD photometry and VLA neutral hydrogen observations of the interacting quartet NGC 6845, also know as Klemola 30. NGC 6845 A, the do…