899 research outputs found
From Service to Experience: Understanding and Defining the Hospitality Business
Failure adequately to define or understand hospitality as a commercial phenomenon has created a fragmented academic environment and a schizophrenia in the industry that has the potential to limit its development as a global industry. This article suggests that, by redefining hospitality as behaviour and experience, a new perspective emerges that has exciting implications for the management of hospitality businesses. A framework to describe hospitality in the commercial domain is proposed. This framework suggests a focus on the hostâguest relationship, generosity, theatre and performance, âlots of little surprisesâ, and the security of strangers â a focus that provides guests with experiences that are personal, memorable and add value to their lives
Spectral Properties From Lyman-alpha to H-alpha For An Essentially Complete Sample of Quasars I: Data
We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of
23 quasars in the complete PG-X-ray sample with redshift, z<0.4, and M_B<-23.
The spectra cover rest-frame wavelengths from at least Lyman-alpha to H-alpha.
Here we provide a detailed description of the data, including careful
spectrophotometry and redshift determination. We also present direct
measurements of the continua, strong emission lines and features, including
Lyman-alpha, SiIV+OIV], CIV, CIII], SiIII], MgII, H-beta, [OIII],
He5876+NaI5890,5896, H-alpha, and blended iron emission in the UV and optical.
The widths, asymmetries and velocity shifts of profiles of strong emission
lines show that CIV and Lyman-alpha are very different from H-beta and H-alpha.
This suggests that the motion of the broad line region is related to the
ionization structure, but the data appears not agree with the radially
stratified ionization structure supported by reverberation mapping studies, and
therefore suggest that outflows contribute additional velocity components to
the broad emission line profiles.Comment: 42 pages, 10 figures, 13 tables. Accepted by AJ. Supplemental figures
not included. Full version available at
http://physics.uwyo.edu/~shang/pgxpaper/ShangPaper.pd
Red Quasars and Quasar Evolution: the Case of BALQSO FIRST J155633.8+351758
We present the first near-IR spectroscopy of the z=1.5 radio-loud BALQSO
FIRST J155633.8+351758. Both the Balmer decrement and the slope of the
rest-frame UV-optical continuum independently suggest a modest amount of
extinction along the line of sight to the BLR (E(B-V)~0.5 for SMC-type screen
extinction at the QSO redshift). The implied gas column density along the line
of sight is much less than is implied by the weak X-ray flux of the object,
suggesting that either the BLR and BAL region have a low dust-to-gas ratio, or
that the rest-frame optical light encounters significantly lower mean column
density lines of sight than the X-ray emission. From the rest-frame UV-optical
spectrum, we are able to constrain the stellar mass content of the system.
Comparing the maximal stellar mass with the black hole mass estimated from the
bolometric luminosity of the QSO, we find that the ratio of the black hole to
stellar mass may be comparable to the Magorrian value, which would imply that
the Magorrian relation is already in place at z=1.5. However, multiple factors
favor a much larger black hole to stellar mass ratio. This would imply that if
the Magorrian relation characterizes the late history of QSOs, and the
situation observed for F1556+3517 is typical of the early evolutionary history
of QSOs, central black hole masses develop more rapidly than bulge masses.
[ABRIDGED]Comment: 23 pages, 4 embedded postscript figures; Accepted for publication in
The Astronomical Journal, December 200
Do broad absorption line quasars live in different environments from ordinary quasars?
We select a sample of traditionally defined broad absorption line
quasars (BALQs) from the Fifth Data Release quasar catalog of the Sloan Digital
Sky Survey. For a statistically homogeneous quasar sample with , the BAL quasar fraction is and is almost constant with
redshift. We measure the auto-correlation of non-BAL quasars (nonBALQs) and the
cross-correlation of BALQs with nonBALQs using this statistically homogeneous
sample, both in redshift space and using the projected correlation function. We
find no significant difference between the clustering strengths of BALQs and
nonBALQs. Assuming a power-law model for the real space correlation function
, the correlation length for nonBALQs is ; for BALQs, the cross-correlation length is . Our clustering results suggest that BALQs live in similar
large-scale environments as do nonBALQs.Comment: accepted for publication in Ap
Origin of the complex radio structure in BAL QSO 1045+352
We present new more sensitive high-resolution radio observations of a compact
broad absorption line (BAL) quasar, 1045+352, made with the EVN+MERLIN at 5
GHz. They allowed us to trace the connection between the arcsecond structure
and the radio core of the quasar. The radio morphology of 1045+352 is dominated
by a knotty jet showing several bends. We discuss possible scenarios that could
explain such a complex morphology: galaxy merger, accretion disk instability,
precession of the jet and jet-cloud interactions. It is possible that we are
witnessing an ongoing jet precession in this source due to internal
instabilities within the jet flow, however, a dense environment detected in the
submillimeter band and an outflowing material suggested by the X-ray absorption
could strongly interact with the jet. It is difficult to establish the
orientation between the jet axis and the observer in 1045+352 because of the
complex structure. Nevertheless taking into account the most recent inner radio
structure we conclude that the radio jet is oriented close to the line of sight
which can mean that the opening angle of the accretion disk wind can be large
in this source. We also suggest that there is no direct correlation between the
jet-observer orientation and the possibility of observing BALs.Comment: 8 pages, 3 figures, accepted for publication in Ap
Associated Absorption Lines in the Radio-Loud Quasar 3C 351: Far-Ultraviolet Echelle Spectroscopy from the Hubble Space Telescope
As one of the most luminous radio-loud quasars showing intrinsic ultraviolet
(UV) and X-ray absorption, 3C 351 provides a laboratory for studying the
kinematics and physical conditions of such ionized absorbers. We present an
analysis of the intrinsic absorption lines in the high-resolution ( 7
km/s) far-UV spectrum which was obtained from observations with the Space
Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope
(HST). The spectrum spans wavelengths from 1150 \AA to 1710 \AA, and shows
strong emission lines from O VI and Ly. Associated absorption lines are
present on the blue wings of the high-ionization emission doublets O VI
1032,1038 and N V 1238,1242, as well as the
Lyman lines through Ly. These intrinsic absorption features are
resolved into several distinct kinematic components, covering rest-frame
velocities from -40 to -2800 km/s, with respect to the systemic redshift of
. For the majority of these absorption line regions, strong
evidence of partial covering of both the background continuum source and the
BELR is found, which supports the intrinsic absorption origin and rules out the
possibility that the absorption arises in some associated cluster of galaxies.
The relationship between the far-UV absorbers and X-ray `warm' absorbers are
studied with the assistance of photoionization models. Most of the UV
associated absorption components have low values of the ionization parameter
and total hydrogen column densities, which is inconsistent with previous claims
that the UV and X-ray absorption arises in the same material. Analysis of these
components supports a picture with a wide range of ionization parameters,
temperatures, and column densities in AGN outflows.Comment: 27 pages with 5 figures, accepted by Ap
Discovery of a Classic FR-II Broad Absorption Line Quasar from the FIRST Survey
We have discovered a remarkable quasar, FIRST J101614.3+520916, whose optical
spectrum shows unambiguous broad absorption features while its double-lobed
radio morphology and luminosity clearly indicate a classic Fanaroff-Riley Type
II radio source. Its radio luminosity places it at the extreme of the recently
established class of radio-loud broad absorption line quasars (Becker et al.
1997, 2000; Brotherton et al. 1998). Because of its hybrid nature, we speculate
that FIRST J101614.3+520916 is a typical FR-II quasar which has been
rejuvenated as a broad absorption line (BAL) quasar with a Compact Steep
Spectrum core. The direction of the jet axis of FIRST J101614.3+520916 can be
estimated from its radio structure and optical brightness, indicating that we
are viewing the system at a viewing angle of > 40 degrees. The position angles
of the radio jet and optical polarization are not well-aligned, differing by 20
to 30 degrees. When combined with the evidence presented by Becker et al.
(2000) for a sample of 29 BAL quasars showing that at least some BAL quasars
are viewed along the jet axis, the implication is that no preferred viewing
orientation is necessary to observe BAL systems in a quasar's spectrum. This,
and the probable young nature of compact steep spectrum sources, leads
naturally to the alternate hypothesis that BALs are an early stage in the lives
of quasars.Comment: 14 pages, 6 postscript figures; accepted for publication in the
Astrophysical Journa
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