A5064146034- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- History and Developments in Astronomy
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Gamma-ray bursts and supernovae
- Radiation Detection and Scintillator Technologies
- Calibration and Measurement Techniques
- Graphite, nuclear technology, radiation studies
- Historical Studies on Spain
- Astrophysical Phenomena and Observations
- Archaeological and Geological Studies
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Scientific Research and Discoveries
- Atmospheric Ozone and Climate
- Nuclear reactor physics and engineering
- Radiation Dose and Imaging
- Gut microbiota and health
- Spacecraft and Cryogenic Technologies
- Solar and Space Plasma Dynamics
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2007-2023
Universidad Complutense de Madrid
1996-2023
Universidad Juárez Autónoma de Tabasco
2019-2020
University of Hawaii System
2007-2019
Monterey Institute for Research in Astronomy
2004-2016
University of Hawaiʻi at Mānoa
2014
Japan External Trade Organization
2011
Stuttgart Observatory
1989-2006
Ludwig-Maximilians-Universität München
1993-2006
Institute of Astronomy and Space Physics
1978-2006
Narrowband imaging surveys aimed at detecting the faint emission from 5007 Å [O III] line of intracluster planetary nebulae in Virgo also probe high-redshift z ~ 3.1 Lyα emitters. Here we report on spectroscopic identification nine emitters = 3.13 with fluxes between 2 × 10-17 and 10-16 ergs cm-2 s-1 obtained FORS spectrograph Unit 1 ESO Very Large Telescope (VLT UT1). The spectra these objects show a narrow, isolated very (frequently undetected) continuum, indicating large equivalent width....
We have measured the velocities of 19 planetary nebulae (PNs) in outer regions giant early-type galaxy NGC 4406 Virgo cluster. The kinematics outermost regions, at a mean radius 142" or 11 kpc, show rapid rotation and low observed velocity dispersion (∼ 166 96 km s−1, respectively) , compared with central about 210 s−1. This supports classification this as an S0. Although has systemic -227 we found three PNs close to cluster (about 1400 s−1). argue that these may be members intracluster...
We have detected 535 planetary nebulae (PNs) in the flattened elliptical galaxy NGC 4697 using classic on-band, off-band filter technique with Focal Reducer and Spectrograph at Cassegrain focus of first 8 m telescope unit ESO Very Large Telescope. From our photometry, we built [O III] λ5007 nebula luminosity function (PNLF) 4697. It indicates a distance 10.5 ± 1 Mpc to this galaxy, good agreement obtained from surface brightness fluctuations substantially smaller than previous estimate 24...
We have imaged an empty area of 34 × arcmin2 15 north the Virgo Cluster core to survey for intracluster planetary nebula (PN) candidates. implemented and tested a fully automatic procedure selection emission-line objects in wide-field images, based on on-off technique from Ciardullo Jacoby. Freeman et al. spectroscopically confirmed sample nebulae one field. use photometric morphological properties this test our procedure. In newly surveyed field, 75 were identified as best candidates PNe....
We present a dynamical study of NGC 4697, an almost edge-on, intermediate-luminosity, E4 elliptical galaxy, combining new surface brightness photometry, as well published long-slit absorption line kinematic data, and planetary nebulae (PNe) velocity data. The combined data set extends out to ~= 5' 4.5 R_e allows us probe the galaxy's outer halo. For first time, we model such dataset with flexible Chi^2-made-to-measure particle code NMAGIC. extend NMAGIC include seeing effects, introduce...
view Abstract Citations (115) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The binary central star of NGC 2346 and the extinction puzzle. Mendez, R. H. ; Niemela, V. S. New observations A-type planetary nebula have confirmed that it is a single-lined spectroscopic with period 16 days. gamma-velocity system shown to coincide nebular velocity; therefore, there good reason assume are associated. On other hand, observational evidence more...
Neutron peripheral contamination in patients undergoing high-energy photon radiotherapy is considered as a risk factor for secondary cancer induction. Organ-specific neutron-equivalent dose estimation therefore essential reasonable assessment of these associated risks. This work aimed to develop method estimate doses multiple organs patients. The involved the convolution, at 16 reference points an anthropomorphic phantom, normalized Monte Carlo neutron fluence energy spectra with kerma and...
Planetary nebulae (PNe) and their luminosity function (PNLF) in galaxies have been used as a cosmic distance indicator for decades, yet fundamental understanding is still lacking to explain the universality of PNLF among different galaxies. Models generally assumed solar metallicities artificial stellar populations. In this work, we investigate how metallicity helium abundances affect PNe PNLF, importance initial-to-final mass relation (IFMR), resolve tension between observations models. We...
Using the difference between responses to neutrons of TLD-600 and TLD-700, three experimental devices were constructed arranged measure thermal neutron fluences, spectra, doses inside treatment room a radiotherapy 18 MV Linear electron accelerator (Linac). Thermal fluences measured with TLD-600/TLD-700 pairs in both bare cadmium (Cd) foil covered methacrylate box. Neutron spectra 26 energy bins by introducing air into middle five polyethylene spheres diameters 3, 5, 8, 10, 12 inches. A PC...
We present a new model atmosphere analysis of nine central stars planetary nebulae. This study is based on generation realistic stellar atmospheres for hot stars; state-of-the-art, hydrodynamically consistent, spherically symmetric that have been shown to correctly reproduce the observed UV spectra massive Population I O-type stars. The information provided by wind features (terminal velocity, mass loss rate) permits derive physical size each star, from which we can luminosity, mass, and...
We create dynamical models of the massive elliptical galaxy, NGC 4649, using N-body made-to-measure code, nmagic, and kinematic constraints from long-slit planetary nebula (PN) data. explore a range potentials based on previous determinations X-ray observations model fitting globular cluster (GC) velocities stellar density profile. The mass distributions are similar in central region but have varying outer slopes, while GC profile is higher upper end further out. Our cannot differentiate...
We present a study of the kinematics outer regions early-type galaxy NGC 1316, based on radial velocity measurements 43 planetary nebulae as well deep integrated light absorption line spectra. The smoothed field 1316 indicates fast rotation at distance 16 kpc, possibly associated with an elongated feature orthogonal to inner dust lanes. mean square stellar is approximately independent radius, and estimated total mass system 2.9 × 1011 M☉ within radius implying mass-to-light ratio M/LB ≃ 8.
Spectrograms, scanner, uvby and ANS ultraviolet measurements of the central stars NGC 2346, He 2-36 3132 are analysed. The observations suggest that first one is a foreground horizontal-branch star, second above horizontal branch, presumably in rapid evolutionary phase. Both objects probably variable.
We surveyed a 50 arcmin2 region in the Virgo cluster core to search for intergalactic planetary nebulae and found 11 candidates area. The measured fluxes of these unresolved sources are consistent with objects being from an population stars, although we cannot exclude some minor contamination our sample by redshifted starburst galaxies. compute cumulative luminosity function nebula candidates. If assume that they belong cluster, their is good agreement luminosity-function simulations typical...
We describe a procedure for the numerical simulation of planetary nebulae luminosity function (PNLF), improving on previous work. Earlier PNLF simulations were based an imitation observed distribution intensities [O III] λ5007 relative to Hβ, generated predominantly using random numbers. are now able replace this by derived from predictions hydrodynamical PN models (Schönberner et al. 2007), which made evolve as central star moves across HR diagram, proper initial and boundary conditions. In...
Multiobject spectroscopic observations of blue supergiants in NGC 3621, a spiral galaxy at distance 6.7 Mpc, carried out with the ESO Very Large Telescope and focal reducer/spectrograph are presented. We demonstrate feasibility quantitative stellar spectroscopy distances approaching tenfold increase over previous investigations by determining chemical composition, parameters, reddening, extinction, wind properties one our targets, supergiant spectral type A1 Ia located on outskirts 3621. The...
view Abstract Citations (51) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Evolutionary versus Dynamical Time Scales for the Evolution of Central Stars Planetary Nebulae McCarthy, J. K. ; Mould, R. Mendez, H. Kudritzki, P. Husfeld, D. Herrero, A. Groth, G. The disagreement between evolutionary and dynamical time scales evolution central stars planetary nebulae (CSPN) through H-R diagram is investigated. Three possible reasons are examined: (1)...
Using a slitless spectroscopy method with (a) the 8.2 m Subaru telescope and its FOCAS Cassegrain spectrograph, (b) ESO Very Large Telescope (VLT) unit 1 (Antu) FORS2 we have detected 326 planetary nebulae (PNs) in giant Virgo elliptical galaxy NGC 4649 (M 60), measured their radial velocities. After rejecting some PNs more likely to belong companion 4647, built catalog kinematic information for 298 M 60. these velocities concluded that they support presence of dark matter halo around Based...
We have analyzed the magnitudes, kinematics, and positions of a complete sample 320 planetary nebulae (PNs) in elliptical galaxy NGC 4697. show following. (1) The PNs 4697 do not constitute single population that is fair tracer distribution all stars. radial velocity distributions, mean velocities, dispersions bright faint subsamples differ with high statistical confidence. (2) Using combined data for brighter than 26.2, we identified subpopulation azimuthally unmixed kinematically peculiar,...
We present photometric and kinematic information obtained by measuring 197 planetary nebulae (PNs) discovered in the flattened Fornax elliptical galaxy NGC 1344 (also known as 1340) with an on-band, off-band, grism + on-band filter technique. build PN luminosity function (PNLF) use it to derive a distance modulus m-M=31.4, slightly smaller than, but good agreement with, surface brightness fluctuation distance. The PNLF also provides estimate of specific formation rate: 6x10^-12 PNs per year...
CPD – 26°389, a hot subdwarf at the centre of planetary nebula NGC 1360, is shown to be single-lined spectroscopic binary with period about 8 day. The primary (visible) component appears less massive than its companion, and total stellar mass system presumably below one solar mass.
We describe the implementation of slitless radial velocity measurements extragalactic planetary nebulae (PNs) with 8.2 m Subaru telescope and its Cassegrain imaging spectrograph, Faint Object Camera Spectrograph (FOCAS). As a first application, we have extended previous search for PNs in NGC 4697 to larger angular distances from center. A total 218 were detected, their velocities measured. added 56 new PN detections existing sample 535, observed previously ESO VLT + FORS spectrograph; 36...