1,498 research outputs found
ALMA observations of the Red Rectangle, a preliminary analysis
We aim to study equatorial disks in rotation and axial outflows in post-AGB
objects, as to disclose the formation and shaping mechanisms in planetary
nebulae. So far, both disks and outflows had not been observed simultaneously.
We have obtained high-quality ALMA observations of 12CO and 13CO J=3-2 and
12CO J=6-5 line emission in the Red Rectangle, the only post-AGB/protoplanetary
object in which a disk in rotation has been mapped up to date.
These observations provide an unprecedented description of the complex
structure of this source. Together with an equatorial disk in rotation, we find
a low-velocity outflow that occupies more or less the region placed between the
disk and the optical X-shaped nebula. From our observations and preliminary
modeling of the data, we confirm the previously known properties of the disk
and obtain a first description of the structure, dynamics, and physical
conditions of the outflow.Comment: 5 pages, 5 figure
Trigonometry of 'complex Hermitian' type homogeneous symmetric spaces
This paper contains a thorough study of the trigonometry of the homogeneous
symmetric spaces in the Cayley-Klein-Dickson family of spaces of 'complex
Hermitian' type and rank-one. The complex Hermitian elliptic CP^N and
hyperbolic CH^N spaces, their analogues with indefinite Hermitian metric and
some non-compact symmetric spaces associated to SL(N+1,R) are the generic
members in this family. The method encapsulates trigonometry for this whole
family of spaces into a single "basic trigonometric group equation", and has
'universality' and '(self)-duality' as its distinctive traits. All previously
known results on the trigonometry of CP^N and CH^N follow as particular cases
of our general equations. The physical Quantum Space of States of any quantum
system belongs, as the complex Hermitian space member, to this parametrised
family; hence its trigonometry appears as a rather particular case of the
equations we obtain.Comment: 46 pages, LaTe
A three-dimensional view of the remnant of Nova Persei 1901 (GK Per)
We present a kinematical study of the optical ejecta of GK Per. It is based
on proper motions measurements of 282 knots from ~20 images spanning 25 years.
Doppler-shifts are also computed for 217 knots. The combination of proper
motions and radial velocities allows a unique 3-D view of the ejecta to be
obtained. The main results are: (1) the outflow is a thick shell in which knots
expand with a significant range of velocities, mostly between 600 and 1000
km/s; (2) kinematical ages indicate that knots have suffered only a modest
deceleration since their ejection a century ago; (3) no evidence for anisotropy
in the expansion rate is found; (4) velocity vectors are generally aligned
along the radial direction but a symmetric pattern of non-radial velocities is
also observed at specific directions; (5) the total Halpha+[NII] flux has been
linearly decreasing at a rate of 2.6 % per year in the last decade. The Eastern
nebular side is fading at a slower rate than the Western one. Some of the knots
displayed a rapid change of brightness during the 2004-2011 period. Over a
longer timescale, a progressive circularization and homogenization of the
nebula is taking place; (6) a kinematic distance of 400+-30 pc is determined.
These results raise some problems to the previous interpretations of the
evolution of GK Per. In particular, the idea of a strong interaction of the
outflow with the surrounding medium in the Southwest quadrant is not supported
by our data.Comment: Accepted for publication in The Astrophysical Journal (19 pages, 17
figures). Higher resolution version of this article (2.5 MB) is available at
http://www.aai.ee/~sinope/ApJ89291_liimets.pd
K 3-22: a D-type symbiotic star
A goal of the IPHAS survey is to determine the frequency and nature of
emission-line sources in the Galactic plane. According to our selection
criteria, K 3-22 is a candidate symbiotic star, but it was previously
classified as a planetary nebula. To determine its nature, we acquired a
low-resolution optical spectrum of K 3-22. Our analysis of our spectroscopy
demonstrates that K 3-22 is indeed a D-type symbiotic star, because of its high
excitation nebular spectrum and the simultaneous presence of Raman-scattered O
VI emission at 6825 and 7082 angstrom, which is detected primarily in symbiotic
stars.Comment: 3 pages, 1 figure. Accepted for publication on Astronomy and
Astrophysic
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