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Nuclear star formation in NGC 6240
Gallagher, J. S.; de Grijs, R.; Pasquali, A.
We have made use of archival HST BVIJH photometry to constrain the nature of the three discrete sources, A1, A2 and B1, identified in the double nucleus of NGC 6240. STARBURST99 models have been fitted to the observed colours, under the assumption, first, that these sources can be treated as star clusters (i.e. single, instantaneous episodes of st…
On the widths of the Mg X lines near 60 nm in the corona
Dwivedi, B. N.; Wilhelm, K.; Teriaca, L.
We examine the line widths of both components of the Mg X 2s 2S1/2-2p 2P1/2,3/2 doublet at 60.98 nm and 62.50 nm in the low corona of the quiet Sun, and find that the Doppler width (i.e. half 1/e width) broadens from Δ λD ≈ 8.2 pm to ≈9.5 pm (with an estimated relative standard uncertainty of …
Dust in 3CR radio galaxies: On the FR 1 - FR 2 difference
Meisenheimer, K.; Siebenmorgen, R.; Klaas, U. +4 more
We compare three 3CR samples of 11 FR 1 galaxies, 17 FR 2 galaxies and 18 lobe-dominated quasars contained in the ISO Data Archive. In contrast to the powerful FR 2 galaxies with edge-brightened lobes, the low radio power FR 1 galaxies in our sample do not exhibit any high MIR or FIR dust luminosity, which is typical for a buried, intrinsically mo…
Time-resolved Ultraviolet Spectroscopy of the SW Sex Star DW UMa: Confirmation of a Hidden White Dwarf and the Ultraviolet Counterpart to Phase 0.5 Absorption Events
Dhillon, V. S.; Szkody, Paula; Hoard, D. W. +5 more
We present time-resolved ultraviolet (UV) spectroscopy of the SW Sex star DW UMa in the high state. We confirm that shortward of 1500 Å, the high-state UV continuum level is lower than the white dwarf (WD) dominated low-state level. We also do not see the WD contact phases in the high-state eclipse light curves. These results confirm our earlier f…
Barnard's Star and the M Dwarf Temperature Scale
De Robertis, M. M.; Dawson, P. C.
The recently measured angular diameter of Barnard's star, together with its large and precise parallax, and a spectral energy distribution that extends from the near-ultraviolet to almost 12 µm establish some of the star's fundamental properties-we find a bolometric luminosity L=(3.46+/-0.17)×10-3Lsolar, radius R=0.200+…
86 GHz SiO maser survey of late-type stars in the inner Galaxy. II. Infrared photometry of the SiO target stars
Menten, K. M.; Omont, A.; Habing, H. J. +2 more
We present a compilation and study of DENIS, 2MASS, ISOGAL, MSX and IRAS 1-25 µm photometry for a sample of 441 late-type stars in the inner Galaxy, which we previously searched for 86 GHz SiO maser emission \citep{messineo02}. The comparison of the DENIS and 2MASS J and KS magnitudes shows that most of the SiO targets are indeed …
October-November 2003's space weather and operations lessons learned
Barbieri, L. P.; Mahmot, R. E.
The Sun-Earth space weather related to sunspots NOAA 484, 486, and 488 affected a number of NASA spacecraft and instruments between mid-October and early November 2003. Information available from Earth and space science missions indicate that about 59% of the spacecraft and about 18% of the instrument groups experienced some effect from the solar …
The configuration of simple short-duration solar microwave bursts
Nindos, A.; Kundu, M. R.; Grechnev, V. V.
Using data from the Nobeyama Radioheliograph (NoRH) we study the source configuration of four simple short-duration 17 and 34 GHz bursts which have also been observed partially by the Yohkoh Soft X-ray Telescope (SXT). Two events are consistent with a single flaring loop configuration. In one of them the flaring loop is resolved in the SXT images.…
The X-ray, optical and radio evolution of the GRB 030329 afterglow and the associated SN2003dh
O'Brien, P. T.; Osborne, J. P.; Page, K. L. +3 more
Extensive X-ray, optical and radio observations of the bright afterglow of the gamma-ray burst GRB 030329 are used to construct the multifrequency evolution the event. The data are fitted using the standard fireball shock model to provide estimates of the initial energy, ɛ= 6.8 × 1052 erg sr-1, the density of the ambient medi…
On the Spatial Dependence of Low-Degree Solar p-Mode Frequency Shifts from Full-Disk and Resolved-Sun Observations
Korzennik, S. G.; Jiménez-Reyes, S. J.; García, R. A. +1 more
We have analyzed low angular degree (low-l) solar p-mode frequency shifts extracted from two types of observations, both made by instruments on board the ESA/NASA Solar and Heliospheric Observatory satellite during a period that covers the rising phase of activity, cycle 23 (1995-2002). The first are full-disk (Sun-as-a-star) averages made in Dopp…