72,975 research outputs found
A wide field survey at the Northern Ecliptic Pole: II. Number counts and galaxy colours in B_j, R, and K
We present a medium deep survey carried out in the three filters B_j, R and
K. The survey covers homogeneously the central square degree around the
Northern Ecliptic Pole (NEP) down to a completeness limit of 24.25, 23.0 and
17.5mag in B_j, R and K, respectively. While the near infrared data have been
presented in the first paper of this series, here we concentrate on the optical
data and the results based on the combined B_jRK-data. The unique combination
of area and depth in our survey allows to perform a variety of investigations
based on homogeneous material covering more than ten magnitudes in apparent
brightness. We analyze the number counts for point-like and extended sources in
B_j and R to determine the slopes in dlogN/dm and to test for possible breaks
therein. While we can confirm the slopes found in previous works with a higher
statistical significance, the largest uncertainty remaining for the amplitudes
is galactic extinction. We determine the colour distributions of galaxies in
B_j-R and R-K down to B_j=24.0 and K=18.0mag, respectively. The distributions
in both colours are modeled using galaxy spectral evolution synthesis. We
demonstrate that the standard models of galaxy evolution are unable to
reproduce the steady reddening trend in R-K despite flawless fits to the colour
distributions in the optical (B_j-R). The B_jRK data collected over a large
area provides the opportunity to select rare objects like candidates for
high-redshift galaxies and extremely red objects (EROs, R-K>5.0) and to
determine their surface density. Our EROs are selected at an intermediate
magnitude range and contain contribution from both galactic as well as
extragalactic sources. At K<16.5mag, where a morphological classification is
possible, the stellar component dominates the sample.Comment: Accepted for A&A, 14 pages, 10 figure
Microfluidic detection and analysis by integration of evanescent wave sensing with thermocapillary actuation
An integrated system capable of microfluidic actuation, detection and sensing is described which combines evanescent wave sensing with thermocapillary manipulation. Liquid droplets or streams transported across the beam path of a planar thin film waveguide, which encapsulates the microheater array, induce attenuation of the propagating waveguide modes. The attenuated signal is used to monitor droplet location, dye concentration in aqueous solutions and reaction kinetics for enzymatic hydrolysis of the sugar X-galactose by beta-galactosidase
The complementarity of LEP, the Tevatron and the LHC in the search for a light MSSM Higgs boson
We study the properties of the Higgs boson sector in the MSSM, putting
special emphasis on radiative effects which can affect the discovery potential
of the LHC, Tevatron and/or LEP colliders. We concentrate on the V b b-bar
channel, with V=Z or W, and on the channels with diphoton final states, which
are the dominant ones for the search for a light Standard Model Higgs boson at
LEP/Tevatron and LHC, respectively. By analyzing the regions of parameter space
for which the searches in at least one of these colliders can be particularly
difficult, we demonstrate the complementarity of these three colliders in the
search for a light Higgs boson which couples in a relevant way to the W and Z
gauge bosons (and hence plays a relevant role in the mechanism of electroweak
symmetry breaking).Comment: 35 pages, including 11 Postscript figures, using JHEP.cl
Suggestions for Improved Benchmark Scenarios for Higgs-Boson Searches at LEP2
We suggest new benchmark scenarios for the Higgs-boson search at LEP2.
Keeping m_t and M_SUSY fixed, we improve on the definition of the maximal
mixing benchmark scenario defining precisely the values of all MSSM parameters
such that the new m_h^max benchmark scenario yields the parameters which
maximize the value of m_h for a given tan(beta). The corresponding scenario
with vanishing mixing in the scalar top sector is also considered. We propose a
further benchmark scenario with a relatively large value of |mu|, a moderate
value of M_SUSY, and moderate mixing parameters in the scalar top sector. While
the latter scenario yields m_h values that in principle allow to access the
complete M_A-tan(beta)-plane at LEP2, on the other hand it contains parameter
regions where the Higgs-boson detection can be difficult, because of a
suppression of the branching ratio of its decay into bottom quarks.Comment: 9 pages, no figures, Contribution to the Workshop on ``New
Theoretical Developments for Higgs Physics at LEP2'', CERN, October 199
Gravitational Harmonics from Shallow Resonant Orbits
Five gravitational constraints were derived for the GEOS 2 orbit (order 13, to 30th degree) whose principal resonant period is 6 days. The constraints explain the sinusoidal variation with argument of perigee of a lumped harmonic found from 41 6-day arcs of optical and laser data. The condition equations, derived from elementary perturbation theory are shown to account for almost all of the resonant information in the tracking data
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