Navegação Ciências Exatas e da Terra por Assunto "Poeira cosmica"
Resultados 1-20 de 30
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Anchors for the cosmic distance scale : the Cepheids U Sagittarii, CF Cassiopeiae, and CEab Cassiopeiae
(2013) [Artigo de periódico]New and existing X-ray, UBVJHKsW(1−4), and spectroscopic observations were analyzed to constrain fundamental parameters for M25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance ... -
A catalogue of dust clouds in the Galaxy
(2002) [Artigo de periódico]In this study 21 catalogues of dust clouds in the Galaxy were cross-identified by taking into account available properties such as position, angular dimensions, opacity class and velocity. An initial list of ≈6500 entries ... -
Constraints on the broad-line region properties and extinction in local Seyferts
(2016) [Artigo de periódico]We use high-spectral resolution (R>8000) data covering 3800–13 000 Å to study the physical conditions of the broad-line region (BLR) of nine nearby Seyfert 1 galaxies. Up to six broad HI lines are present in each spectrum. ... -
Dust extinction of the stellar continua in Starburst galaxies : the ultraviolet and optical extinction law
(1994) [Artigo de periódico]We analyze the IUE UV and the optical spectra of 39 starburst and blue compact galaxies in order to study the average properties of dust extinction in extended regions of galaxies. The optical spectra have been obtained ... -
Dust obscuration in starburst galaxies from near-infrared spectroscopy
(1996) [Artigo de periódico]We present new observations of the near-infrared hydrogen recombination lines Paβ and Bry in the central starburst regions of 13 galaxies. The near-infrared data are supplemented with data on the optical Balmer line emission ... -
Estimating dust attenuation from galactic spectra : II. stellar and gas attenuation in star-forming and diffuse ionized gas regions in MaNGA
(2021) [Artigo de periódico]We investigate the dust attenuation in both stellar populations and ionized gas in kiloparsec-scale regions in nearby galaxies using integral field spectroscopy data from MaNGA MPL-9. We identify star-forming (H II) and ... -
Extinction within 10 of the Galactic centre using 2MASS
(2003) [Artigo de periódico]We extract J and Ks magnitudes from the 2MASS Point Source Catalog for approximately 6×106 stars with 8 < - Ks < - 13 in order to build an AK extinction map within 10◦ of the Galactic centre. The extinction was determined ... -
Foreground and background dust in star cluster directions
(2000) [Artigo de periódico]This paper compares reddening values E(B-V) derived from the stellar content of 103 old open clusters and 147 globular clusters of the Milky Way with those derived from DIRBE/IRAS 100 μm dust emission in the same directions. ... -
Infrared emission in Seyfert 2 galaxies : reprocessed radiation from a dusty torus?
(1992) [Artigo de periódico]The nature of the infrared continuum in Seyfert 2 galaxies is not well understood. An attractive model is one in which dust grains near the nucleus are heated by optical and ultraviolet photons from a central source and ... -
Insights on the dusty torus and neutral torus from optical and X-ray obscuration in a complete volume limited hard X-ray AGN sample
(2015) [Artigo de periódico]We describe a complete volume limited sample of nearby active galaxies selected by their 14–195 keV luminosity, and outline its rationale for studying the mechanisms regulating gas inflow and outflow. We also describe a ... -
Intermediate-age stars as origin of the low-velocity dispersion nuclear ring in Mrk 1066
(2010) [Artigo de periódico]We report the first two-dimensional stellar population synthesis in the near-infrared of the nuclear region of an active galaxy, namely, Mrk 1066. We have used integral field spectroscopy with adaptative optics at the ... -
Low-extinction windows in the inner Galactic Bulge
(2002) [Artigo de periódico]We built K band extinction maps in the area of two candidate low-extinction windows in the inner Bulge: W0.2-2.1 at (l, b) = (0.25°, –2.15° ), and W359.4-3.1 at (l, b) = (359.40°, −3.10°). We employed JH Ks photometry from ... -
New star clusters projected close to the galactic centre
(2000) [Artigo de periódico]Abstract. We carried out a systematic search for new star clusters in a field of 5 5 centred close to the Galactic Nucleus using the infrared JHKs 2MASS Survey archive. In addition we searched for embedded clusters in the ... -
NTT infrared imaging of star cluster candidates towards the central parts of the Galaxy
(2003) [Artigo de periódico]We address the issue whether the central parts of the Galaxy harbour young clusters other than Arches, Quintuplet and the Nuclear Young Cluster. A large sample of centrally projected cluster candidates has been recently ... -
On the calibration of the COBE/IRAS dust emission reddening maps
(2003) [Artigo de periódico]In this work we study the spectral properties (3600–6800 Å) of the nuclear region of early-type galaxies at low (|b| < 25◦), intermediate (including surroundings of the Magellanic Clouds) and high (South Polar Cap) Galactic ... -
Optical and far-infrared emission of IRAS Seyfert galaxies
(1997) [Artigo de periódico]This paper presents an analysis of moderately large samples of type 1 and 2 Seyfert galaxies through optical observations and far-infrared IRAS data, also taking into account theoretical color indices derived from dust ... -
A photometric and kinematic study of the stars and interstellar medium in the central 2 kiloparsecs of NGC 3379
(2000) [Artigo de periódico]Hubble Space Telescope images of NGC 3379 show that the V and I luminosity profiles in the inner 13" of this E1 galaxy are represented by two di†erent components : a stellar bulge following a Sérsic law with exponent n=2.36 ... -
Probing the active galactic nucleus unified model torus properties in Seyfert galaxies
(2017) [Artigo de periódico]We studied the physical parameters of a sample comprising of all Spitzer/Infrared Spectrograph public spectra of Seyfert galaxies in the mid-infrared (5.2–38 μm range) under the active galactic nucleus (AGN) unified model. ... -
Separating c-Stars from dust in the central region of the Seyfert 2 galaxy NGC 1241
(2005) [Artigo de periódico]The Seyfert 2 galaxy NGC 1241 presents a 1.5 kpc large circumnuclear ring (CNR) of star formation embracing a small bar plus leading arms. Those structures are Paα emitters but barely seen in Haα. It also presents stellar ... -
Spitzer space telescope measurements of dust reverberation lags in the Seyfert 1 galaxy NGC 6418
(2015) [Artigo de periódico]We present results from a 15 month campaign of high-cadence (∼3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the ...
