7,271 research outputs found
86 GHz SiO maser survey of late-type stars in the Inner Galaxy. IV. SiO emission and infrared data for sources in the Scutum and Sagittarius-Carina arms, 20 deg < l < 50 deg
We present an 86 GHz SiO (v = 1, J = 2 ---> 1) maser search toward late-type
stars located within |b|<0.5 deg and 20 deg < l < 50 deg. This search is an
extension at longer longitudes of a previously published work. We selected 135
stars from the MSX catalog using color and flux criteria and detected 92 (86
new detections). The detection rate is 68%, the same as in our previous study.
The last few decades have seen the publication of several catalogs of point
sources detected in infrared surveys (MSX, 2MASS, DENIS, ISOGAL, WISE, GLIMPSE,
AKARI, and MIPSGAL). We searched each catalog for data on the 444 targets of
our earlier survey and for the 135 in the survey reported here. We confirm
that, as anticipated, most of our targets have colors typical of oxygen-rich
asymptotic giant branch (AGB) stars. Only one target star may have already left
the AGB. Ten stars have colors typical of carbon-rich stars, meaning a
contamination of our sample with carbon stars <=1.7%.Comment: 13 pages, 6 Figures, A&A accepte
Measurements of vacuum magnetic birefringence using permanent dipole magnets: the PVLAS experiment
The PVLAS collaboration is presently assembling a new apparatus (at the INFN
section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB
is related to the structure of the QED vacuum and is predicted by the
Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by
measuring the ellipticity acquired by a linearly polarised light beam
propagating through a strong magnetic field. Using the very same optical
technique it is also possible to search for hypothetical low-mass particles
interacting with two photons, such as axion-like (ALP) or millicharged
particles (MCP). Here we report results of a scaled-down test setup and
describe the new PVLAS apparatus. This latter one is in construction and is
based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity
() and two 0.8 m long 2.5 T rotating permanent dipole magnets.
Measurements with the test setup have improved by a factor 2 the previous upper
bound on the parameter , which determines the strength of the nonlinear
terms in the QED Lagrangian: T
95% c.l. Furthermore, new laboratory limits have been put on the inverse
coupling constant of ALPs to two photons and confirmation of previous limits on
the fractional charge of millicharged particles is given
New PVLAS model independent limit for the axion coupling to for axion masses above 1meV
During 2014 the PVLAS experiment has started data taking with a new apparatus
installed at the INFN Section of Ferrara, Italy. The main target of the
experiment is the observation of magnetic birefringence of vacuum. According to
QED, the ellipticity generated by the magnetic birefringence of vacuum in the
experimental apparatus is expected to be . No ellipticity signal is present so far with a noise floor
after 210 hours of data taking.
The resulting ellipticity limit provides the best model independent upper limit
on the coupling of axions to for axion masses above eV
Measurement of the Cotton Mouton effect of water vapour
In this paper we report on a measurement of the Cotton Mouton effect of water
vapour. Measurement performed at room temperature ( K) with a wavelength
of 1064 nm gave the value for the
unit magnetic birefringence (1 T magnetic field and atmospheric pressure)
First results from the new PVLAS apparatus: a new limit on vacuum magnetic birefringence
Several groups are carrying out experiments to observe and measure vacuum
magnetic birefringence, predicted by Quantum Electrodynamics (QED). We have
started running the new PVLAS apparatus installed in Ferrara, Italy, and have
measured a noise floor value for the unitary field magnetic birefringence of
vacuum T (the error
represents a 1 deviation). This measurement is compatible with zero and
hence represents a new limit on vacuum magnetic birefringence deriving from non
linear electrodynamics. This result reduces to a factor 50 the gap to be
overcome to measure for the first time the value of predicted by QED:
~T. These birefringence measurements also yield improved
model-independent bounds on the coupling constant of axion-like particles to
two photons, for masses greater than 1 meV, along with a factor two improvement
of the fractional charge limit on millicharged particles (fermions and
scalars), including neutrinos
Open and / or laparoscopic surgical treatment of liver hydatic cysts
Hydatid disease is a severe parasitic disease with a widely ranging distribution. In the human being the liver is the most frequent organ affected. 1 The treatment should be individualized to the morphology, size, number and location of the cysts, that is why a variety of surgical operations have been advocated from complete resection like total pericystectomy or partial hepatectomy to laparoscopy to a minimally invasive procedures like percutaneous aspiration of cysts to conservative drug therapy. 3-4 This study compares laparoscopic versus open management of the hydatid cyst of liver the surgical approach to liver echinococcosis is still a controversial issue and shows our results of surgical treatment of liver hydatid cysts during a 3-years period
86 GHz SiO masers in Galactic Centre OH/IR stars
We present results on a search for 86.243 GHz SiO (J = 2 -- 1, v = 1) maser
emission toward 67 OH/IR stars located near the Galactic Centre. We detected 32
spectral peaks, of which 28 correspond to SiO maser lines arising from the
envelopes of these OH/IR stars. In OH/IR stars, we obtained an SiO maser
detection rate of about 40%. We serendipitously detected two other lines from
OH/IR stars at 86.18 GHz, which could be due to a CCS-molecule transition at
86.181 GHz or probably to an highly excited OH molecular transition at 86.178
GHz. The detection rate of 86 GHz maser emission is found to be about 60% for
sources with The Midcourse Space Experiment (MSX) A - E < 2.5 mag; but it drops
to 25% for the reddest OH/IR stars with MSX A - E > 2.5 mag. This supports the
hypothesis by Messineo et al. (2002) that the SiO masers are primarily found in
relatively thinner circumstellar material.Comment: 4 figures, 14 page
Explanatory Supplement of the ISOGAL-DENIS Point Source Catalogue
We present version 1.0 of the ISOGAL-DENIS Point Source Catalogue (PSC),
containing more than 100,000 point sources detected at 7 and/or 15 micron in
the ISOGAL survey of the inner Galaxy with the ISOCAM instrument on board the
Infrared Space Observatory (ISO). These sources are cross-identified, wherever
possible, with near-infrared (0.8-2.2 micron) data from the DENIS survey. The
overall surface covered by the ISOGAL survey is about 16 square degrees, mostly
(95%) distributed near the Galactic plane (|b| < 1 deg), where the source
extraction can become confusion limited and perturbed by the high background
emission. Therefore, special care has been taken aimed at limiting the
photometric error to ~0.2 magnitude down to a sensitivity limit of typically 10
mJy. The present paper gives a complete description of the entries and the
information which can be found in this catalogue, as well as a detailed
discussion of the data processing and the quality checks which have been
completed. The catalogue is available via the VizieR Service at the Centre de
Donn\'ees Astronomiques de Strasbourg (CDS,
http://vizier.u-strasbg.fr/viz-bin/VizieR/) and also via the server at the
Institut d'Astrophysique de Paris (http://www-isogal.iap.fr/). A more complete
version of this paper, including a detailed description of the data processing,
is available in electronic form through the ADS service.Comment: 21 pages, 7 figures. A&A in press. Full length version with 32
figures and detailed description of the data processing is available here:
http://www-isogal.iap.fr/Publications/ExplSupplFull.ps.g
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