45 research outputs found
High resolution spectroscopy of the BCD galaxy Haro 15:I. Internal kinematics
Using echelle spectroscopy, obtained at Las Campanas Observatory, we present
a detailed study of the internal kinematics of the nebular material in multiple
knots of the blue compact dwarf galaxy Haro 15. A detailed analysis of the
complex emission line profiles show the presence of an underlying broad
component in almost all knots, and the brightest star-forming region shows
unmistakable signs for the presence of two distinct narrow kinematical
components. We also study the information that our analysis provides regarding
the motion of the individual knots in the Haro 15 galaxy potential, confirming
that they follow galactic rotation. Finally, we examine the relation between
their velocity dispersion and luminosity, finding that almost all knots follow
the relation for virialised systems. This holds for the strong narrow
components identified in complex fits and for single profile fits, although the
latter show a flatter slope. In agreement with previous findings, in this paper
we show that the existence of multiple kinematical components among massive
starbursts cannot be overlooked, as it has a noticeable effect on any
subsequent analysis that relies on basic parameters.Comment: 12 pages, 21 figure
High-resolution spectroscopy of the blue compact dwarf galaxy Haro 15 – I. Internal kinematics
This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. Firpo, V., Bosch, G., Hägele, G.F., Díaz, A.I. and N. Morrell. High-resolution spectroscopy of the blue compact dwarf galaxy Haro 15 –I. Internal kinematics. Monthly Notices of the Royal Astronomical Society 414 (2011): 3288-329
Kinematics of gas and stars in circumnuclear star-forming regions of early type spirals
(Abbr.) We present high resolution (R~20000) spectra in the blue and the far
red of cicumnuclear star-forming regions (CNSFRs) in three early type spirals
(NGC3351, NGC2903 and NGC3310) which have allowed the study of the kinematics
of stars and ionized gas in these structures and, for the first time, the
derivation of their dynamical masses for the first two. In some cases these
regions, about 100 to 150 pc in size, are seen to be composed of several
individual star clusters with sizes between 1.5 and 4.9 pc estimated from
Hubble Space Telescope (HST) images. The stellar dispersions have been obtained
from the Calcium triplet (CaT) lines at 8494,8542,8662 \AA,
while the gas velocity dispersions have been measured by Gaussian fits to the
H and [OIII] 5007 \AA lines on the high dispersion
spectra. Values of the stellar velocity dispersions are between 30 and 68 km/s.
We apply the virial theorem to estimate dynamical masses of the clusters,
assuming that systems are gravitationally bounded and spherically symmetric,
and using previously measured sizes. The measured values of the stellar
velocity dispersions yield dynamical masses of the order of 10 to 10
solar masses for the whole CNSFRs. Stellar and gas velocity dispersions are
found to differ by about 20 to 30 km/s with the H emission lines being
narrower than both the stellar lines and the [OIII] 5007 \AA
lines. The twice ionized oxygen, on the other hand, shows velocity dispersions
comparable to those shown by stars, in some cases, even larger. We have found
indications of the presence of two different kinematical components in the
ionized gas of the regions...Comment: 4 pages, proceeding of the meeting "Young massive star clusters -
Initial conditions and environments", Granada, Spain, 200
Kinematics of metal-rich circumnuclear regions from future 8-m class observations
This is an electronic version of an article published in Revista Mexicana de Astronomía y Astrofísica. Terlevich, E. et al. Kinematics of metal-rich circumnuclear regions from future 8-m class observations. Revista Mexicana de Astronomía y Astrofísica 29 (2007): 16
Metallicity Determination in Seyfert 2 AGNs
Aims: To study calibrations of line ratios that can estimates metallicities of galaxies even in large redshift where the measurement of faint emission lines is not easy to obtain. Methods: We use the Cloudy Code to build a grid of photoionization models with lines ratios from the UV and, we compare with a sample of 77 object AGNs Seyfert 2. Results: We build semi-empirical calibrations between the metallicity of studied objects and the rest-frame intensity of the line ratios N V λ1240 / HeII λ1640, C43=log[(Civ λ1549 + CIII] λ1909) / HeII λ1640] and CIII] λ1909 / C IV λ1549.Fil: Monteiro, A. F.. Universidade Do Vale Do Paraíba; BrasilFil: Dors, O. L.. Universidade Do Vale Do Paraíba; BrasilFil: Cardaci, Monica Viviana. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Hägele, Guillermo Federico. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaII workshop on Chemical abundances in gaseous nebulae: open problems in nebular astrophysicsSao Jose dos CamposBrasilUniversidade do Vale do Paraíb
The jet-cloud interaction in 3CR galaxies: Preliminary results in four galaxies
We present preliminary results of the Gemini/GMOS longslit spectra for four radiogalaxies: 3C 135, 3C 180, 3C 234 and 3C 284. These objects are a subsample of a set of galaxies with noticeable extended structure selected from the HST/WFPC2 3CR Snapshot Survey, data taken with the filters F555W, F702W and narrow-ramp. All of these objects show large regions of [Oiii]5007 emission (narrow ramp filter) and the broad-band filters data show similar structures indicating the presence of strong emission in several lines over these regions. The morphology observed seems to be related (e.g. same position angle, direct overlapping or similar shape) with the radio-jet. For some candidates with these properties GMOS/Gemini spectroscopy was taken. These data (both HST direct imaging and Gemini spectroscopy) can be tested with diagnostic diagrams and total UV photons budget to understand the source of energy that is ionizing the gas. This source of ionization was commonly believed to be the UV photons emitted by the powerful AGN, but several of these objects shows clearly that shocks produce by the radio jet are the main cause of the observed gas line emission.Facultad de Ciencias Astronómicas y Geofísica
The jet-cloud interaction in 3CR galaxies: Preliminary results in four galaxies
We present preliminary results of the Gemini/GMOS longslit spectra for four radiogalaxies: 3C 135, 3C 180, 3C 234 and 3C 284. These objects are a subsample of a set of galaxies with noticeable extended structure selected from the HST/WFPC2 3CR Snapshot Survey, data taken with the filters F555W, F702W and narrow-ramp. All of these objects show large regions of [Oiii]5007 emission (narrow ramp filter) and the broad-band filters data show similar structures indicating the presence of strong emission in several lines over these regions. The morphology observed seems to be related (e.g. same position angle, direct overlapping or similar shape) with the radio-jet. For some candidates with these properties GMOS/Gemini spectroscopy was taken. These data (both HST direct imaging and Gemini spectroscopy) can be tested with diagnostic diagrams and total UV photons budget to understand the source of energy that is ionizing the gas. This source of ionization was commonly believed to be the UV photons emitted by the powerful AGN, but several of these objects shows clearly that shocks produce by the radio jet are the main cause of the observed gas line emission.Facultad de Ciencias Astronómicas y Geofísica
The temperature and ionization structure of the emitting gas in H II galaxies: implicatins for the accuracy of abundance determinations
This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. Hägele, G.F., Pérez-Montero, E., Díaz, A.I., Terlevich, E. and R. Terlevich. The temperature and ionization structure of the emitting gas in H II galaxies: implicatins for the accuracy of abundance determinations. Monthly Notices of the Royal Astronomical Society 372 (2006): 293-31