Search Publications

Two Active Nuclei in 3C 294

Stockton, Alan; Canalizo, Gabriela; Ridgway, Susan E. +1 more

The z=1.786 radio galaxy 3C 294 lies < 10" from a 12 mag star and has been the target of at least three previous investigations using adaptive optics (AO) imaging. A major problem in interpreting these results is the uncertainty in the precise alignment of the radio structure with the H- or K-band AO imaging. Here we report observations of the …

Resolving X-Ray Sources from B Stars Spectroscopically: The Example of µ Leporis

Güdel, Manuel; Kahn, Steven M.; Behar, Ehud +4 more

We present high-resolution X-ray observations of the chemically peculiar late-type B star µ Lep. However, we find spectroscopic and astrometric evidence, which shows that the X-rays are not traced back to the B star itself but rather to a previously unresolved companion, µ Lep-B, whose X-ray spectrum resembles that of a coronally activ…

An Optical and X-Ray Examination of Two Radio Supernova Remnant Candidates in 30 Doradus

Chu, You-Hua; Gruendl, Robert A.; Chen, C. -H. Rosie +2 more

The giant H II region 30 Doradus is known for its violent internal motions and bright diffuse X-ray emission, suggesting the existence of supernova remnants (SNRs), but no nonthermal radio emission has been detected. Recently, Lazendic et al. compared the Hα/Hβ and radio/Hα ratios and suggested two small radio sources to be nonthermal and thus SNR…

Newly Identified Forbidden Transitions within the Ground Configuration of Ions of Very Low Abundance P, Cl, K, and Co

Curdt, W.; Landi, E.; Feldman, U.

Forbidden lines from transitions within the ground configuration of highly ionized atoms occupy an important role in diagnosing the properties of astrophysical plasmas. In this paper we report the identification of forbidden lines in the 500-1500 Å range from transitions within the ground configuration of highly ionized ions of the very low abunda…

A Gas+Dust Model of the Peculiar Envelope of HD 62623 Based on Interferometric Observations

Lopez, B.; Stee, Ph.; Bittar, J.

We present an improved model for the circumstellar environment of the peculiar star HD 62623 taking into account the gas around the central star and the dust present in the outer parts of the envelope. We compare our results with photometric observations and near-infrared interferometric observations obtained with aperture masking interferometry p…

Hida Domeless Solar Telescope and SOHO Coronal Diagnostic Spectrometer Observations of Short-Duration Active Region Blinkers. II. Extreme-Ultraviolet Properties

Brooks, D. H.; Kurokawa, H.

X-Ray Luminous Galaxies. II. Chandra and XMM-Newton Observations of the ``Composite'' Galaxy IRAS 20051-1117

Zezas, A.; Georgantopoulos, I.; Papadakis, I. +1 more

We present Chandra and XMM-Newton observations of the composite star-forming/Seyfert galaxy IRAS 20051-1117. The X-ray imaging and spectral properties reveal the presence of an active nucleus. The Chandra image shows a strong nuclear point source [L(2-10keV)~4×10⁴²ergss^-1]. The nuclear X-ray source coincides with a bright, al…

Erratum: ``Looking for Gravity-Mode Multiplets with the GOLF Experiment aboard SOHO'' (ApJ, 604, 455 [2004])

Kosovichev, A. G.; García, R. A.; Provost, J. +12 more

As a result of an error at the Press, the second panel of Figure 9 was repeated twice in the top row of the printed, black-and-white version of this figure, and the first panel was omitted. This error appears in the print edition and the PDF and postscript (PS) versions available with the electronic edition of the journal, although the panels of t…

Collisions among Clouds inside Dusty Tori in Active Galactic Nuclei:Observational Consequences

Wang, Jian-Min

A geometrically thick dusty torus in NGC 1068 has been unambiguously resolved by an infrared interferometry telescope. This implies that clouds composing the dusty torus are undergoing supersonic collisions with each other. We show that the collisions form strong nonrelativistic shocks, which accelerate populations of relativistic electrons. The t…

Mid-Infrared Observations of van Maanen 2: No Substellar Companion

Becklin, E. E.; Farihi, J.; Macintosh, B. A.

The results of a comprehensive infrared imaging search for the putative 0.06 M_solar astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 µm reveal a diffraction-limited core of 0.09" and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50M_J b…