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An active M8.5 dwarf wide companion to the M4/DA binary LHS 4039/LHS 4040
Schwope, A.; Lodieu, N.; Scholz, R. -D. +4 more
Low-mass and brown dwarfs have recently been found as wide companions to many nearby stars, formerly believed to be single. Wide binaries are usually found as common proper motion pairs. Sometimes, more than two objects share the same large proper motion, identifying them as nearby systems. We have found a third, low-mass component to a known wide…
Present-day scaling relations for submillimetre galaxies: the origin of spheroidal systems
Takagi, T.; Hanami, H.; Arimoto, N.
We analyse the spectral energy distributions (SEDs) of 23 submillimetre galaxies and three ISO-detected extremely red objects, all of which have the spectroscopic redshifts, using an evolutionary SED model of starbursts. This SED model allows us to investigate the intrinsic properties of starbursts, such as the starburst age and the mean stellar m…
Solar type II and type IV radio bursts observed during 1998-2000 with the ARTEMIS-IV radiospectrograph
Hillaris, A.; Preka-Papadema, P.; Moussas, X. +9 more
A catalogue of the type II and type IV solar radio bursts in the 110-687 MHz range, observed with the radio spectrograph ARTEMIS-IV operated by the University of Athens at Thermopylae, Greece from 1998-2000 is presented. These observations are compared with the LASCO archives of Coronal Mass Ejections and the Solar Geophysical Reports of solar fla…
Flare observation of the Sun as a star by SUMER/SOHO in the hydrogen Lyman continuum
Vial, J. -C.; Wilhelm, K.; Curdt, W. +3 more
During the execution of the programme ``Sun as a star'', while the SUMER (Solar Ultraviolet Emission of Emitted Radiation)/SOHO (SOlar and Heliospheric Observatory) slit was collecting the scattered radiation from the telescope mirror far away from the solar disk image, a class X5.3/3b flare erupted on the solar disk, on 25 August 2001. During the…
Identifying young gamma-ray burst fossils
Ramirez-Ruiz, Enrico
The recent reports of temporal and spectral peculiarities in the early stages of some afterglows suggest that we may be wrong in postulating a central engine that becomes dormant after the burst itself. A continually decreasing post-burst relativistic outflow, such as put out by a decaying magnetar, may continue to be emitted for periods of days o…
Theoretical Prediction of an Observed Solar g-Mode
Guzik, Joyce A.; Cox, Arthur N.
This Letter considers the weak but persistent radial velocity variations measured by the Global Oscillations at Low Frequencies instrument on the Solar and Heliospheric Observatory satellite at 75.55 minutes (220.6 µHz), which is very close to our new theoretical solar model period prediction of 75.15 minutes (221.8 µHz) for the angula…
Mass and Angular Momentum Transfer in the Massive Algol Binary RY Persei
Gies, D. R.; Peters, G. J.; Huang, W. +12 more
We present an investigation of the Hα emission-line variations observed in the massive Algol binary RY Per. We give new radial velocity data for the secondary based on our optical spectra and for the primary based on high-dispersion UV spectra. We present revised orbital elements and an estimate of the primary's projected rotational velocity (whic…
Temperature dependence of the Lyman α line wings in cool hydrogen-rich white dwarf atmospheres. Application to ZZ Ceti white dwarf spectra
Kielkopf, J. F.; Allard, N. F.; Loeillet, B.
Theoretical Lyman α absorption profiles show a significant dependence on temperature of the H2 satellite at 1600 Å, whereas the H2+ satellite at 1400 Å remains unchanged. The use of opacities calculated with different approximations concerning the electric dipole transition moment (constant, dependent on interatomi…
RX J1821.6+6827: A cool cluster at z = 0.81 from the ROSAT NEP survey
Böhringer, H.; Wolter, A.; Briel, U. G. +3 more
We present an analysis of the properties of the cluster of galaxies RX J1821.6+6827, or NEP 5281, at a redshift z= 0.816 ±0.001. RX J1821.6+6827 was discovered during the optical identification of the X-ray sources in the North Ecliptic Pole (NEP) region of the ROSAT All-Sky Survey and it is the highest redshift cluster of galaxies of the NEP surv…
Misleading results from low-resolution spectroscopy: From galaxy interstellar medium chemistry to cosmic star formation density
Flores, H.; Hammer, F.; Gruel, N. +2 more
Low resolution spectroscopy (R=150) from the Canada-France-Redshift Survey (CFRS) revealed intriguing properties for low redshift galaxies (z ≤0.3): nearly half of their spectra show prominent Hα emission lines, but no Hβ emission line and barely detected [O II] λ3727, and [O III] λ5007 lines. We call these objects ``CFRS Hα-single" galaxies and h…