José María Torrelles

Learn More
The kinematics and physical conditions of the bipolar planetary nebula M 2-48 are analysed from high and low dispersion long-slit spectra. Previous CCD narrow-band optical observations have suggested that this nebula is mainly formed by a pair of symmetric bowshocks, an off-center semi-circular shell, and an internal bipolar structure. The bipolar outflow(More)
Synchrotron emission is commonly found in relativistic jets from active galactic nuclei (AGNs) and microquasars, but so far its presence in jets from young stellar objects (YSOs) has not been proved. Here, we present evidence of polarized synchrotron emission arising from the jet of a YSO. The apparent magnetic field, with strength of ~0.2 milligauss, is(More)
We present linear and circular polarization observations of the H2O masers in 4 distinct regions spread over 1 × 2 arcseconds around the HW2 high-mass young stellar object in the Cepheus A star-forming region. We find magnetic fields between 100–500 mG in the central maser region, which has been argued to trace a circumstellar disk. The masers further from(More)
A star like the Sun becomes a planetary nebula towards the end of its life, when the envelope ejected during the earlier giant phase becomes photoionized as the surface of the remnant star reaches a temperature of approximately 30,000 K. The spherical symmetry of the giant phase is lost in the transition to a planetary nebula, when non-spherical shells and(More)
The processes leading to the birth of low-mass stars such as our Sun have been well studied, but the formation of high-mass (over eight times the Sun's mass, M(o)) stars remains poorly understood. Recent studies suggest that high-mass stars may form through accretion of material from a circumstellar disk, in essentially the same way as low-mass stars form,(More)
The young stellar object SVS 13 has been proposed as the powering source of the HH 7-11 objects. Recent observations have revealed that in the radio continuum (3.6-cm) the source is a binary separated by about 0~/3 in the east-west direction. We present Very Large Array observations, made in the highest angular resolution A configuration, of H20 maser(More)
The exact processes by which interstellar matter condenses to form young stars are of great interest, in part because they bear on the formation of planets like our own from the material that fails to become part of the star. Theoretical models suggest that ejection of gas during early phases of stellar evolution is a key mechanism for removing excess(More)
We present Hα, [NII] and [OIII] ground-based and HST archive images, VLA–A 3.6 cm continuum and H92α emission line data and high resolution long-slit [NII] spectra of the planetary nebula Hu 2-1. A large number of structural components are identified in the nebula: an outer bipolar and an inner shell, two pairs of collimated bipolar structures at different(More)
We have studied the kinematics traced by the water masers located at the centre of the planetary nebula (PN) K3-35, using data from previous Very Large Array (VLA) observations. An analysis of the spatial distribution and line-of-sight velocities of the maser spots allows us to identify typical patterns of a rotating and expanding ring in the(More)