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Hubble Space Telescope Proper Motion Confirms the Optical Identification of the Nearby Pulsar PSR 1929+10
De Luca, Andrea; Caraveo, Patrizia A.; Becker, Werner +1 more
We report on the proper-motion measurement of the proposed optical counterpart of the X-ray/radio pulsar PSR 1929+10. Using images obtained with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS; average epoch 2001.73), we computed a yearly displacement of +97+/-1 mas yr-1 in right ascension and +46+/-1 mas yr<…
The Sunyaev-Zel'dovich effect as a cosmological discriminator
Diego, J. M.; Martínez-González, E.; Benitez, N. +2 more
We show how future measurements of the Sunyaev-Zel'dovich effect (SZE) can be used to constrain the cosmological parameters. We combine the SZ information expected from the Planck full-sky survey, N (S ), where no redshift information is included, with the N (z ) obtained from an optically identified SZ-selected survey covering less than 1 per cen…
Using a Hipparcos-derived Hertzsprung-Russell Diagram to Limit the Metallicity Scatter of Stars in the Hyades: Are Stars Polluted?
Quillen, A. C.
Hipparcos parallaxes and proper motions have made it possible to construct Hertzsprung-Russell (H-R) diagrams of nearby clusters with unprecedented accuracy. The standard deviation of high-fidelity, nonbinary, nonvariable stars about a model stellar evolution isochrone in the Hyades cluster is about 0.04 mag. We use this deviation to estimate an u…
Ulysses Cosmic Ray and Solar Particle Investigation/Kiel Electron Telescope observations: Charge sign dependence and spatial gradients during the 1990-2000 A > 0 solar magnetic cycle
Kunow, H.; Wibberenz, G.; Ferreira, S. E. S. +10 more
Ulysses, launched in October 1990, began its second out-of-ecliptic orbit in September 1997. From 1991 to mid-2000, solar polar magnetic field observations indicate a magnetic field pointing outward over the northern polar region (A > 0 epoch). While the first fast latitude scan in 1994/1995 was performed around solar minimum, the second Ulysse…
Multi wavelength investigation of the eruption of a sigmoidal quiescent filament
Delaboudinière, J. P.; Marqué, Ch.; Lantos, P.
We report the first observation of a filament eruption in the metric and decimetric range, where the behavior of the filament can be followed during the event via thermal radio emission diagnostics. The event, occurring on February 28th 2001, involved a quiescent filament in a sigmoid magnetic configuration, whose eruption is triggered by the birt…
Young Stellar Nuclei in Lenticular Galaxies: NGC 5574 and NGC 7457
Chavushyan, V. H.; Sil'chenko, O. K.; Afanasiev, V. L. +1 more
The stellar population properties in the centers of NGC 5574 and NGC 7457 (two lenticular galaxies previously shown to have radially homogeneous blue optical-band colors) are studied by means of integral-field spectroscopy. The compact nuclei of the galaxies appear to be chemically distinct: in NGC 5574 the nucleus is distinguished by a higher tha…
The Differential Emission Measure Distribution in the Multiloop Corona
Aschwanden, Markus J.
This is a rebuttal of a recent Letter on the inadequacy of temperature measurements in the solar corona through narrowband filter and line ratios by Martens et al. We simulate the differential emission measure (DEM) distribution of a multiloop corona and find that the temperature profile of individual loops can be retrieved with narrowband filter …
SDSS J124602.54 + 011318.8: A Highly Luminous Optical Transient at z = 0.385
Schneider, Donald P.; York, Donald G.; Hurley, Kevin +30 more
We report the discovery of a highly luminous optical transient (OT), SDSS J124602.54 + 011318.8, associated with a galaxy at a redshift of 0.385. In this paper, we consider the possibility that the OT may be a gamma-ray burst (GRB) afterglow. Three sets of images and two sets of spectra were obtained as part of the normal operations of the Sloan D…
µJy radio sources in the cluster MS1054-03
Franx, M.; van Dokkum, P. G.; Röttgering, H. J. A. +1 more
An extremely deep 5-GHz radio observation is presented of the rich cluster MS1054-03 at redshift 34 radio sources are detected down to a 6σ level of 32µJy, compared with about 25 expected from previous blank-field radio source count determinations; the sources giving rise to these excess counts lie predominantly within 2arcmin (~700kpc) of t…
Extreme X-ray variability in the luminous quasar PDS 456
O'Brien, P. T.; Reeves, J. N.; Pounds, K. A. +1 more
We present evidence from BeppoSAX and XMM-Newton of extreme X-ray variability in the high-luminosity radio-quiet quasar PDS 456, the most luminous known active galactic nucleus (AGN) at z < 0.3. Repeated X-ray flaring is found in PDS 456, over the duration of the 340-ks long BeppoSAX observation. The X-ray flux doubles in just 30 ks, whilst the…