Search Publications
Hubble Space Telescope Observations of Chromospheres in Metal-Deficient Field Giants
Smith, Graeme H.; Dupree, A. K.; Li, Timothy Q.
Hubble Space Telescope high-resolution spectra of metal-deficient field giants more than double the stars in previous studies, span ~3 mag on the red giant branch, and sample an abundance range [Fe/H] = -1 to -3. These stars, in spite of their age and low metallicity, possess chromospheric fluxes of Mg II (λ2800) that are within a factor of 4 of P…
Orbits and System Masses of 14 Visual Double Stars with Early-Type Components
Docobo, J. A.; Ling, J. F.
This paper presents revised orbits and system masses of 14 visual double stars, in all of which at least one component is of early spectral type: WDS 00546+1911 (STT 20 AB), WDS 01040+3528 (HO 213), WDS 02039+4220 (STT 38 BC), WDS 03503+2535 (STT 65), WDS 06393+4200 (STT 150), WDS 08285-0231 (A551 AB), WDS 15088-4517 (SEE 219 AB), WDS 15416+1940 (…
A Catalog of New M33 Star Clusters Based on Hubble Space Telescope WFPC2 Images
Lee, Myung Gyoon; Park, Won-Kee
We present the results of a survey for star clusters in M33 using HST WFPC2 archive images. We have found 104 star clusters, including 32 new ones, in the images of 24 fields that were not included in previous studies. Combining these with previous data in the literature, we increase the number of M33 star clusters found in the HST images to 242. …
Surface Brightness Profiles for a Sample of LMC, SMC, and Fornax Galaxy Globular Clusters
Gebhardt, K.; Noyola, E.
We use Hubble Space Telescope archival images to measure central surface brightness profiles of globular clusters around satellite galaxies of the Milky Way. We report results for 21 clusters around the LMC, five around the SMC, and four around the Fornax dwarf galaxy. The profiles were obtained using a recently developed technique based on measur…
Silicates in D-Type Symbiotic Stars: An Infrared Space Observatory Overview
Ciroi, S.; Rafanelli, P.; Angeloni, R. +1 more
We investigate the IR spectral features of a sample of D-type symbiotic stars in order to constrain the emitting properties of coupled dust-gas particles across the whole system. In particular, by analyzing unexploited ISO Short Wavelength Spectrometer data, deriving the basic observational parameters of dust bands, and comparing them with respect…
X-Ray Properties of the Quasar HE 0450-2958
Zhou, Xin-Lin; Wang, Jian-Min; Yang, Fang +1 more
We present an XMM-Newton EPIC observation of HE 0450-2958, which may be a ``naked'' quasar as suggested by Magain and coworkers. The XMM-Newton EPIC spectra show a substantial soft X-ray excess and a steep photon index, as well as marginal evidence for a weak Fe Kα line. The X-ray absorption is consistent with the Galactic level. The 0.3-10 keV EP…
Spectral Analysis of the Pre-WN Candidate HD 326823
Marcolino, W. L. F.; de Araújo, F. X.; Lorenz-Martins, S. +1 more
We present a spectral analysis of the peculiar emission-line star HD 326823. As has been reported in the literature, this object seems to be a rare, massive star entering the Wolf-Rayet (W-R) phase. In order to confirm its evolutionary status, we used the radiative transfer code CMFGEN to obtain its physical parameters and chemical abundances for …
Stellar Populations Found in the Central Kiloparsec of Four Luminous Compact Blue Galaxies at Intermediate z
Hoyos, C.; Koo, D. C.; Guzmán, R. +2 more
We investigate the star formation history of the central regions of four luminous compact blue galaxies (LCBGs) at intermediate redshift using evolutionary population synthesis techniques. LCBGs are blue (B - V <= 0.6), compact (µB <= 21.0 mag arcsec-2) galaxies with absolute magnitudes MB brighter than…
The Ultraviolet Spectra of the Weak Emission Line Central Stars of Planetary Nebulae
Marcolino, W. L. F.; de Araújo, F. X.; Junior, H. B. M. +1 more
The UV spectra of all "weak emission line central stars of planetary nebulae" (WELSs) with available IUE data are presented and discussed. We performed line identifications and equivalent-width and flux measurements for several features in the spectra. We found that the WELSs can be divided into three different groups regarding their UV spectra: (…
Rest-Frame R-band Light Curve of a z ~ 1.3 Supernova Obtained with Keck Laser Adaptive Optics
Lidman, C.; Rubin, D.; Aldering, G. +24 more
We present Keck diffraction-limited H-band photometry of a z~1.3 Type Ia supernova (SN) candidate, first identified in a Hubble Space Telescope search for SNe in massive high-redshift galaxy clusters. The adaptive optics (AO) data were obtained with the Laser Guide Star facility during four observing runs from 2005 September to November. In the an…