Search Publications
Infrared Surface Brightness Fluctuations of Magellanic Star Clusters
Liu, Michael C.; Bruzual A., Gustavo; González, Rosa A.
We present surface brightness fluctuations (SBFs) in the near-IR for 191 Magellanic star clusters available in the Second Incremental and All Sky Data releases of the Two Micron All Sky Survey (2MASS) and compare them with SBFs of Fornax Cluster galaxies and with predictions from stellar population models as well. We also construct color-magnitude…
The Nitrogen Isotopic Ratio in Jupiter's Atmosphere from Observations by the Composite Infrared Spectrometer on the Cassini Spacecraft
Flasar, F. M.; Owen, T.; Achterberg, R. K. +9 more
The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft made infrared observations of Jupiter's atmosphere during the flyby of 2000 December to 2001 January. The unique database in the 600-1400 cm-1 region with 0.53 and 2.8 cm-1 spectral resolutions obtained from the observations permits retrieval of global maps …
A Reexamination of the Evidence for Reconnection Inflow
Chen, P. F.; Brooks, D. H.; Shibata, K. +1 more
In the flare event of 1999 March 18, a threadlike structure observed in EUV Imaging Telescope images was found to move inward and collapse to an X-shaped configuration below the ejecta, strongly suggestive of the occurrence of magnetic reconnection. On the basis of the numerical results of a coronal mass ejection (CME) flare model, a similar threa…
Magnetic Footpoint Diffusion at the Sun and Its Relation to the Heliospheric Magnetic Field
Giacalone, J.; Jokipii, J. R.
We discuss the physics associated with the motion of the radial magnetic field footpoints at the Sun and its relation to the heliospheric magnetic field. Using the observed photospheric convection spectrum, we construct a model for the heliospheric magnetic field and relate it to observations made by Ulysses in the outer heliosphere in the fast so…
Physical Conditions in the Narrow-Line Region of M51
Kaiser, M. E.; Bradley, L. D.; Baan, W. A.
We have investigated the physical conditions in the narrow-line region (NLR) of M51 by using long-slit spectra obtained with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope and 3.6 cm radio continuum observations obtained with the Very Large Array.2 Emission-line diagnostics were employed for nine NLR clouds, which exten…
Reconsidering the Origin of the 21 Micron Feature: Oxides in Carbon-rich Protoplanetary Nebulae?
Mutschke, H.; Posch, Th.; Andersen, A.
The origin of the so-called 21 µm feature that is especially prominent in the spectra of some carbon-rich protoplanetary nebulae (PPNs) is the matter of a lively debate. A large number of potential band carriers have been presented and discarded within the past decade. This paper gives an overview of the problems related to the hitherto prop…
An XMM-Newton Observation of the Seyfert 1 Galaxy 1H 0419-577 in an Extreme Low State
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +1 more
Previous observations of the luminous Seyfert 1 galaxy 1H 0419-577 have found its X-ray spectrum to range from that of a typical Seyfert 1 galaxy with a 2-10 keV power-law index of Γ~1.9 to a much flatter power law of Γ~1.5 or less. We report here a new XMM-Newton observation that allows the low-state spectrum to be studied in much greater detail …
Discovery of a Transient U-Band Dropout in a Lyman Break Survey: A Tidally Disrupted Star at z=3.3?
Kneib, J. -P.; Bloom, J. S.; Frail, D. A. +8 more
We report the discovery of a transient source in the central regions of galaxy cluster A267. The object, which we call ``PALS-1,'' was found in a survey aimed at identifying highly magnified Lyman break galaxies in the fields of intervening rich clusters. At discovery, the source had Un>24.7 (2 σ AB), g=21.96+/-0.12, and very blue g-…
Persistent North-South Alignment of the Solar Supergranulation
Toomre, Juri; Lisle, Jason P.; Rast, Mark P.
We have found evidence of an alignment of the solar supergranulation in the direction parallel to the Sun's rotation axis. Signatures of the alignment are apparent in both time-averaged images and in three-dimensional power spectra. The north-south organization is persistent in time, extending over many supergranular lifetimes. It occurs over a wi…
The Unusual Tidal Dwarf Candidate in the Merger System NGC 3227/3226: Star Formation in a Tidal Shock?
Forbes, Duncan A.; Schinnerer, Eva; Mundell, Carole G. +2 more
We report the discovery of active star formation in the H I cloud associated with the interacting Seyfert system NGC 3227/3226 that was originally identified as a candidate tidal dwarf galaxy (TDG) by Mundell et al. and that we name J1023+1952. We present broadband optical B, R, I (from the Isaac Newton Telescope), and ultraviolet images (from XMM…