690 research outputs found
The tragic quality of contract guards: a discussion of the reach and theory of private security in the world today
The ERE of the "Red Rectangle" revisited
We present in this paper high signal-to-noise long-slit optical spectra of
the Extended Red Emission (ERE) in the "Red Rectangle" (RR) nebula. These
spectra, obtained at different positions in the nebula, reveal an extremely
complex emission pattern on top of the broad ERE continuum. It is well known
that three features converge at large distance from the central object, in
wavelength and profile to the diffuse interstellar bands (DIBs) at 5797, 5849.8
and 6614 ang., (e.g. Sarre et al., 1995). In this paper we give a detailed
inventory of all spectral subfeatures observed in the 5550--6850 ang. spectral
range. Thanks to our high S/N spectra, we propose 5 new features in the RR that
can be associated with DIBs. For the 5550--6200 ang. spectral range our slit
position was on top of the NE spike of the X shaped nebula. A detailed
description of the spatial profile-changes is given of the strongest features
revealing that even far out in the nebula at 24 arcsec from the central star,
there remains a small shift in wavelength of 1 respectively 2 ang between the
ERE subfeatures and the DIB wavelengths of 5797.11 and 5849.78 ang.Comment: 8 pages, 9 figures accepted by Astronomy and Astrophysic
Recommended from our members
Mediating punitiveness: understanding public attitudes towards work-related fatality cases
This paper concerns an empirical investigation into public attitudes towards work-related fatality cases, where organizational offenders cause the death of workers or members of the public. This issue is particularly relevant following the introduction of the Corporate Manslaughter and Corporate Homicide Act 2007 into UK law. Here, as elsewhere, the use of criminal law against companies reflects governmental concerns over public confidence in the law’s ability to regulate risk. The empirical findings demonstrate that high levels of public concern over these cases do not translate into punitive attitudes. Such cases are viewed rationally and constructively, and lead to instrumental rather than purely expressive enforcement preferences
Sequence structure emission in The Red Rectangle Bands
We report high resolution (R~37,000) integral field spectroscopy of the
central region (r<14arcsec) of the Red Rectangle nebula surrounding HD44179.
The observations focus on the 5800A emission feature, the bluest of the
yellow/red emission bands in the Red Rectangle. We propose that the emission
feature, widely believed to be a molecular emission band, is not a molecular
rotation contour, but a vibrational contour caused by overlapping sequence
bands from a molecule with an extended chromophore. We model the feature as
arising in a Polycyclic Aromatic Hydrocarbon (PAH) with 45-100 carbon atoms.Comment: 13 pages, 9 figures, accepted for publication in ApJ. A version of
the paper with full resolution figures is available at:
http://www.aao.gov.au/local/www/rgs/Sequence-Structure
A southern hemisphere survey of the 5780 and 6284 {\AA} diffuse interstellar bands: correlation with the extinction
We present a new database of 5780.5 and 6283.8 {\AA} DIB measurements and
also study their correlation with the reddening. The database is based on
high-resolution, high-quality spectra of early-type nearby stars located in the
southern hemisphere at an average distance of 300 pc. Equivalent widths of the
two DIBs were determined by means of a realistic continuum fitting and
synthetic atmospheric transmissions. For all stars that possess a precise
measurement of their color excess, we compare the DIBs and the extinction. We
find average linear relationships of the DIBS and the color excess that agree
well with those of a previous survey of northern hemisphere stars closer than
550 pc. This similarity shows that there is no significant spatial dependence
of the average relationship in the solar neighborhood within 600 pc. A
noticeably different result is our higher degree of correlation of the two DIBs
with the extinction. We demonstrate that it is simply due to the lower
temperature and intrinsic luminosity of our targets. Using cooler target stars
reduces the number of outliers, especially for nearby stars, confirming that
the radiation field of UV bright stars has a significant influence on the DIB
strength. We have used the cleanest data to compute updated DIB shapes.Comment: Astronomy & Astrophysics (in press
Centrosymmetric molecules as possible carriers of diffuse interstellar bands
In this paper, we present new data with interstellar C2 (Phillips bands A-X),
from observations made with the Ultraviolet-Visual Echelle Spectrograph of the
European Southern Observatory. We have determined the interstellar column
densities and excitation temperatures of C2 for nine Galactic lines. For seven
of these, C2 has never been observed before, so in this case the still small
sample of interstellar clouds (26 lines of sight), where a detailed analysis of
C2 excitation has been made, has increased significantly. This paper is a
continuation of previous works where interstellar molecules (C2 and diffuse
interstellar bands) have been analysed. Because the sample of interstellar
clouds with C2 has increased, we can show that the width and shape of the
profiles of some diffuse interstellar bands (6196 and 5797 A) apparently depend
on the gas kinetic and rotational temperatures of C2; the profiles are broader
because of the higher values of the gas kinetic and rotational temperatures of
C2. There are also diffuse interstellar bands (4964 and 5850 A) for which this
effect does not exist.Comment: 8 pages, 4 figures, accepted to MNRAS 201
- …
