A5047901128- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Nuclear reactor physics and engineering
- Scientific Research and Discoveries
- Graphite, nuclear technology, radiation studies
- Spectroscopy and Laser Applications
- Nuclear Physics and Applications
- Cosmology and Gravitation Theories
- Ionosphere and magnetosphere dynamics
- History and Developments in Astronomy
- Spacecraft and Cryogenic Technologies
- Historical Geography and Cartography
- Higher Education in Latin America
- Advanced Theoretical and Applied Studies in Material Sciences and Geometry
- Solar and Space Plasma Dynamics
- Social and Cultural Studies
- Nostalgia and Consumer Behavior
- Impact of Light on Environment and Health
Universidad de Guadalajara
2008-2025
University of Canterbury
1993-2022
Princeton University
2005
Instituto de Astrofísica de Canarias
1998-2002
Universidad de La Laguna
2002
Consejo Superior de Investigaciones Científicas
1998-1999
Queen's University Belfast
1993-1998
University of Patras
1993
University of Manchester
1991
We present contemporaneous optical and infrared (IR) photometric observations of the Type IIn SN 1998S covering period between 11 146 d after discovery. The IR data constitute first ever light curves a supernova. use blackbody spline fits to photometry examine luminosity evolution. During 2–3 months, is dominated by release shock-deposited energy in ejecta. After ∼100 powered mostly deposition radioactive decay from 0.15±0.05 M⊙ 56Ni which was produced explosion. also report discovery an...
We present first-season infrared (IR) and optical photometry spectroscopy of the Type Ia Supernova 1998bu in M96. also report polarimetry this event. SN is one closest type supernovae modern times, distance its host galaxy well determined. find that both photometrically spectroscopically normal. However, extinction to event unusually high, with peaked at an intrinsic Adopting a modulus 30.25 (Tanvir et al.) using Phillips al.'s relations for Hubble constant, we obtain Combination our IR...
Abstract The iconic Wolf–Rayet bubble NGC 6888 represents a classical shell driven by stellar winds. Its unique properties make it an important target for studying the material ejected from its progenitor star. In order to construct comprehensive kinematic model of WR nebula 6888, we report here preliminary results in lines [O iii ], H α and [N ii ] using Manchester Echelle Spectrometer high-resolution spectroscopy OAN-SPM. (Based on observations collected at Observatorio Astronómico...
We present Spitzer Space Telescope archival mid-infrared (mid-IR) spectroscopy of a sample 11 planetary nebulae (PNe). The observations, acquired with the Infrared Spectrograph (IRS), cover spectral range 5.2–14.5 μm that includes H2 0–0 S(2) to S(7) rotational emission lines. This wavelength coverage has allowed us derive Boltzmann distribution and calculate excitation temperature (Tex). derived temperatures have consistent values ≃900 ± 70 K for different sources despite their structural...
We imaged the X-ray error box of GRB 980703, beginning 22.5 hours after gamma--ray event, in both optical R and near-infrared H bands. A fading optical/IR object was detected within box, coincident with variable radio source reported by Frail et al. (1998a), who also transient independently us. Further imagery revealed host galaxy, = 22.49 +/- 0.04 20.5 0.25, brightest so far detected. When excluding its contribution to total flux, H-band light curves are well-fit a power-law decay index...
In this paper we present the results of a morphological study performed on sample 28 ultracompact \hiirs~located near extended free-free emission, using radio continuum observations at 3.6~cm with C and D VLA~configurations, aim determining direct connection between them. By previously published in B compiled final catalogue 21 \hiirs ~directly connected surrounding emission. The observed morphology most \hiirs~in emission is irregular (single or multi-peaked sources) resembles classical...
We present a parallax measurement for the very cool degenerate WD 0346+246, serendipitous discovery of which was reported by Hambly et al. find an absolute 36±5 mas, yielding distance estimate 28±4 pc. The resulting visual magnitude object is MV=16.8±0.3, making it second-lowest luminosity white dwarf currently known. use and measured proper motion to show that has kinematics consistent with membership Galactic halo. 0346+246 therefore far coolest least luminous only handful plausible halo...
High-resolution optical spectra of the early-type stars HD 93521 and BD +38° 2182, which lie only 27 arcmin apart on sky in direction high-velocity cloud (HVC) Complex M, reveal presence weak HVC absorption Ca K line towards with a velocity |$V_\textrm{LSR}=-96.0\pm1.5 \enspace\text {km}\enspace\text s^{-1}$| an equivalent width |$W_\lambda=11\pm2$| mÅ. However, is not detected either Na D for 2182 or lines 93521. These observations, combined revised stellar distance estimates, imply that at...
We study the luminous mass as a function of dynamical inside effective radius (re) early-type galaxies (ETGs) to search for differences between these masses. assume Newtonian dynamics and that any difference masses is due presence dark matter. use several samples ETGs – ranging from 19 000 98 objects ninth data release Sloan Digital Sky Survey. perform Monte Carlo (MC) simulations (see Appendix A) galaxy compare them with real samples. The main results are (i) MC show distribution versus...
We study the behaviour of dynamical and stellar mass inside effective radius (re) early-type galaxies (ETGs). use several samples ETGs – ranging from 19 000 to 98 objects ninth data release Sloan Digital Sky Survey. consider Newtonian dynamics, different light profiles initial functions (IMF) calculate mass. assume that any difference between these two masses is due dark matter and/or a non-universal IMF. The main results for in redshift range 0.0024 < z 0.3500 9.5 log(M) 12.5 are: (i)...
view Abstract Citations (24) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optical and H i Observations of the Low-Velocity Intermediate-Velocity Gas toward Globular Cluster M13 Bates, B. ; Shaw, C. R. Kemp, S. N. Keenan, F. P. Davies, D. High-resolution spectra interstellar lines 11 stars in globular cluster three foreground which lie within 3 deg from are reported. The optical compared with an I profile gas recorded direction cluster....
A study of an intermediate-velocity cloud (IVC; VLSR ≈- 70 km s–1) detected in the foreground globular cluster M13 has been made using H I spectra obtained with Lovell Telescope, Jodrell Bank (FWHP beamwidth 12') and spectral maps derived from Dominion Radio Astrophysical Observatory Synthesis Telescope observations synthesised ≈2'.8 × 2'.0). The radio data complement optical absorption line spectroscopy stars reported by Bates et al. show extended emission a broad-velocity component (FWHM ≈...
We have digitally co-added APM scans of 13 Kodak TechPan films the SE region Virgo cluster galaxies. The field R-band combined with resolution arcsec pixel-1 results in data file sizes about 222 MBytes. scanned been aligned, co-added, corrected for vignetting effects and cleaned stellar features. To illustrate astrophysical uses this technique, we present high contrast images a sample background Several very faint, but clearly seen features, such as interaction between IC 3481, 3481A 3483...
We present BV CCD surface photometry, profiles, and images of the galaxy ESO 383-45, together with other galaxies in same field. also a B - V color map field enhanced by self-correlation pixel values digital "unsharp masking." The extended halo system filaments 383-45 are seen clearly. suggest that evidence (radio jets their curvature areas diffuse optical emission) dense intergalactic medium (IGM) this toward center IC 4296 cluster may indicate is still undergoing ram pressure stripping its...
Classification in astrophysics is a fundamental process, especially when it necessary to understand several aspects of the evolution and distribution objects. Over an astronomical image, we need discern between stars galaxies determine morphological type for each galaxy. The spectral classification provides important information about stellar physical parameters like temperature allows us their distance; with this information, possible evaluate other size real 3D In work, present application...
Here we make a new study of the behaviour Na I/K I column density ratio in interstellar medium, using sample observations 28 stars obtained at Nordic Optical Telescope (NOT) 1996 and 1997, previously published (obtained by some authors) 21 stars. The sightlines cover range distances directions, including into Galactic halo. We use ultraviolet (UV) doublet for 18 This is much weaker than D so less susceptible to saturation effects, it well known that can be used obtain more accurate densities...
The Karl Jansky Very Large Array (VLA), Owens Valley Radio Observatory (OVRO), Atacama Millimetric (ALMA), and the infrared \textit{Spitzer} observatories, are powerful facilities to study massive star formation regions related objects such as ultra--compact (UC) \hii regions, molecular clumps, cores. We used these telescopes \uchiir G43.89--0.78. morphological at arcminute scales using NVSS data shows that this region is similar those observed in \textit{ bubble--like} structures revealed...
Using H I spectra obtained with the Lovell telescope (FWHM ∼ 12 arcmin) we present maps showing distribution and velocity structure of an intermediate-velocity cloud (IVC; vLSR 70 km s−1) which is observed in general direction globular cluster M15. The gas shown to be clumpy nature examine its position structure. IVC detected absorption Ca II K line towards five stars intermediate resolution ISIS/WHT high UES/WHT Na D two (II-75; IV-38). indicated by II-75 IV-38 sightlines, have angular...
Eight IIIaJ sky-limited plates of the same field taken with UK 1.2-m Schmidt telescope have been scanned by APM machine and digitally co-added. The contains cD galaxy MCG 05–33–002, central in cluster A3571. A giant faint halo, dimensions |$\sim 600 \times 200\enspace \text {kpc}$|, has found to envelop most cluster. It is estimated that at least a mass |$2\times 10^{12}M_\odot$| contained within which would account for some 'missing' such clusters terms purely luminous baryonic matter.
We have undertaken visual spectroscopy of the highly evolved planetary nebulae (PNe) A8, A13, A62, A72, A78 and A83 over a wavelength range 4330 < λ 6830Å. This permits us to specify relative line intensities in various sectors nebular shells, investigate variation emission as function radius. determine that spectrum central star has varied appreciably period 25 yr. There is now evidence for strong P Cygni absorption λ4589 λ5412 transitions Heii, implying terminal velocities order V∞≅ 3.83 ×...
NGC 4660, in the Virgo cluster, is a well-studied elliptical galaxy which has strong disk component (D/T about 0.2-0.3). The central regions including have stellar populations with ages 12-13 Gyr from SAURON studies. However we report discovery of long narrow tidal filament associated deep co-added Schmidt plate images and CCD frames, implying that undergone interaction merger within last few Gyr. relative narrowness implies wet at least one spiral involved, but current state system little...
We present Na D and Hα stellar line profiles for a sample of 19 stars in M55 M13, search spectral features indicative mass motions the atmospheres red giants. combine observations these two clusters with those made previously ω Cen, M22 M4 to give total 63 globular cluster From this we deduce that only luminosity above log(L/L⊙)≈2.8 show emission. The limit onset significant coreshift is log(L/L⊙)≈2.9, while coreshifts ≈0.4 dex lower at log(L/L⊙)≈2.5, therefore represents threshold first...
This paper discusses the arguments for and against development of space-based weapons in US. It has been suggested that military advantages might be gained from are outweighed by political economic price US would have to pay. Deploying such also create new, asymmetric vulnerabilities armed forces a significant strategic departure 50 years international law diplomatic relations. An attractive alternative using space protect valuable communications, imaging other satellites, however, is reduce...
ABSTRACT We study the behaviour of dynamical and stellar mass inside effective radius early-type galaxies (ETGs) as a function environment considering Newtonian dynamics, different surface-brightness profiles, initial functions (IMF), redshift ranges. use several samples ETGs – ranging from 19 000 to 98 objects ninth data release Sloan Digital Sky Survey. assume that any difference between is due dark matter and/or non-universal IMF. The main results, in range 0.0024 ≤ z 0.35, are follows:...
Differential reddening across the globular cluster M4 is studied using KI column density measurements towards 16 stars in and empirical N(KI)– E(B-V) relationship presented by Chaffee & White for Sco-Oph region. A value of each star obtained, which reveals existence a patchy variation face. We report range E(B– V) ≈0.16 mag an average E(B- V)≈0.32 ± 0.01 cluster. Using HI observations cluster, we have derived N(KI)/N(HI) ≈ 2.3 × 10-10. also investigate distribution dust this direction IRAS...