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We present high angular resolution observations, taken with the Very Large Array (VLA) and Multiple Element Radio Linked Interferometer Network (MERLIN) radio telescopes, at 7mm and 4.4cm respectively, of the prototype Class 0 protostar VLA1623. At 7mm we detect two sources (VLA1623A & B) coincident with the two previously detected components at the centre of this system. The separation between the two is 1.2arcsec, or ~170AU at an assumed distance of 139pc. The upper limit to the size of the source coincident with each component of VLA1623 is ~0.7arcsec, in agreement with previous findings. This corresponds to a diameter of ~100AU at an assumed distance of 139pc. Both components show the same general trend in their broadband continuum spectra, of a steeper dust continuum spectrum shortward of 7mm and a flatter spectrum longward of this. We estimate an upper limit to the VLA1623A disc mass of <0.13Msol and an upper limit to its radius of ~50AU. The longer wavelength data have a spectral index of alpha~0.6+/-0.3. This is too steep to be explained by optically thin free-free emission. It is most likely due to optically thick free-free emission. Alternatively, we speculate that it might be due to the formation of larger grains or planetesimals in the circumstellar disc. We estimate the mass of VLA1623B to be <0.15M$sol. We can place a lower limit to its size of ~30x7 AU, and an upper limit to its diameter of ~100AU. The longer wavelength data of VLA1623B also have a spectral index of alpha~0.6+/-0.3. The nature of VLA1623B remains a matter of debate. It could be a binary companion to the protostar, or a knot in the radio jet from VLA1623A.
Evaporation of water ice above 100 K in the inner few 100 AU of low-mass embedded protostars (the so-called hot core) should produce quiescent water vapor abundances of ~10^-4 relative to H2. Observational evidence so far points at abundances of only
We present 1.3-mm subarcsecond SMA observations of the prototypical Class 0 protostar VLA1623. We report the detection of 1.3-mm continuum emission both from the central protostellar component VLA1623 and two additional sources, Knot-A and Knot-B, wh
We present high-resolution sub/millimeter interferometric imaging of the Class 0 protostar L1527 IRS (IRAS 04368+2557) at 870 micron and 3.4 mm from the Submillimeter Array (SMA) and Combined Array for Research in Millimeter Astronomy (CARMA). We det
Context. The relationship between outflow launching and formation of accretion disks around young stellar objects is still not entirely understood, which is why spectrally and spatially resolved observations are needed. Recently, the Atacama Large Mi
Detecting and studying pulsars above a few GHz in the radio band is challenging due to the typical faintness of pulsar radio emission, their steep spectra, and the lack of observatories with sufficient sensitivity operating at high frequency ranges.