797 research outputs found
Zoo-FISH in the European mole (Talpa europaea) detects all ancestral Boreo-Eutherian human homologous chromosome associations
Zoo-FISH with human whole-chromosome paint probes delineated syntenic association of human homologous chromosome segments 3-21, 14-15, 16-19, 4-8, 7-16 and 12-22 (twice) in the European mole (Talpa europaea, Talpidae, Eulipotyphla, Mammalia). These segment associations represent shared ancestral Boreo-Eutherian traits, half of which were previously not described for Eulipotyphla. The karyotype of the European mole acquired a minimum of 19 translocations and six inversions compared to the presumed Boreo-Eutherian ancestor. Copyright (c) 2006 S. Karger AG, Basel
The PLATO End-to-End CCD Simulator -- Modelling space-based ultra-high precision CCD photometry for the assessment study of the PLATO Mission
The PLATO satellite mission project is a next generation ESA Cosmic Vision
satellite project dedicated to the detection of exo-planets and to
asteroseismology of their host-stars using ultra-high precision photometry. The
main goal of the PLATO mission is to provide a full statistical analysis of
exo-planetary systems around stars that are bright and close enough for
detailed follow-up studies. Many aspects concerning the design trade-off of a
space-based instrument and its performance can best be tackled through
realistic simulations of the expected observations. The complex interplay of
various noise sources in the course of the observations made such simulations
an indispensable part of the assessment study of the PLATO Payload Consortium.
We created an end-to-end CCD simulation software-tool, dubbed PLATOSim, which
simulates photometric time-series of CCD images by including realistic models
of the CCD and its electronics, the telescope optics, the stellar field, the
pointing uncertainty of the satellite (or Attitude Control System [ACS]
jitter), and all important natural noise sources. The main questions that were
addressed with this simulator were the noise properties of different
photometric algorithms, the selection of the optical design, the allowable
jitter amplitude, and the expected noise budget of light-curves as a function
of the stellar magnitude for different parameter conditions. The results of our
simulations showed that the proposed multi-telescope concept of PLATO can
fulfil the defined scientific goal of measuring more than 20000 cool dwarfs
brighter than mV =11 with a precision better than 27 ppm/h which is essential
for the study of earth-like exo-planetary systems using the transit method.Comment: 5 pages, submitted for the Proceedings of the 4th HELAS International
Conference: Seismological Challenges for Stellar Structur
Higher Spins from Tensorial Charges and OSp(N|2n) Symmetry
It is shown that the quantization of a superparticle propagating in an N=1,
D=4 superspace extended with tensorial coordinates results in an infinite tower
of massless spin states satisfying the Vasiliev unfolded equations for free
higher spin fields in flat and AdS_4 N=1 superspace. The tensorial extension of
the AdS_4 superspace is proved to be a supergroup manifold OSp(1|4). The model
is manifestly invariant under an OSp(N|8) (N=1,2) superconformal symmetry. As a
byproduct, we find that the Cartan forms of arbitrary Sp(2n) and OSp(1|2n)
groups are GL(2n) flat, i.e. they are equivalent to flat Cartan forms up to a
GL(2n) rotation. This property is crucial for carrying out the quantization of
the particle model on OSp(1|4) and getting the higher spin field dynamics in
super AdS_4, which can be performed in a way analogous to the flat case.Comment: LaTeX, 21 page (JHEP style), misprints corrected, added comments on
the relation of results of hep-th/0106149 with hep-th/9904109 and
hep-th/9907113, references adde
A new method for the spectroscopic identification of stellar non-radial pulsation modes. II. Mode identification of the Delta Scuti star FG Virginis
We present a mode identification based on new high-resolution time-series
spectra of the non-radially pulsating Delta Scuti star FG~Vir (HD 106384, V =
6.57, A5V). From 2002 February to June a global Delta Scuti Network (DSN)
campaign, utilizing high-resolution spectroscopy and simultaneous photometry
has been conducted for FG~Vir in order to provide a theoretical pulsation
model. In this campaign we have acquired 969 Echelle spectra covering 147 hours
at six observatories. The mode identification was carried out by analyzing line
profile variations by means of the Fourier parameter fit method, where the
observational Fourier parameters across the line are fitted with theoretical
values. This method is especially well suited for determining the azimuthal
order m of non-radial pulsation modes and thus complementary with the method of
Daszynska-Daszkiewicz (2002) which does best at identifying the degree l. 15
frequencies between 9.2 and 33.5 c/d were detected spectroscopically. We
determined the azimuthal order m of 12 modes and constrained their harmonic
degree l. Only modes of low degree (l <= 4) were detected, most of them having
axisymmetric character mainly due to the relatively low projected rotational
velocity of FG Vir. The detected non-axisymmetric modes have azimuthal orders
between -2 and 1. We derived an inclination of 19 degrees, which implies an
equatorial rotational rate of 66 km/s.Comment: 14 pages, 26 figure
Spectroscopic Pulsational Frequency Identification and Mode Determination of Gamma Doradus Star HD135825
We present the mode identification of frequencies found in spectroscopic
observations of the Gamma Doradus star HD135825. Four frequencies were
successfully identified: 1.3150 +/- 0.0003 1/d; 0.2902 +/- 0.0004 1/d; 1.4045
+/- 0.0005 1/d; and 1.8829 +/- 0.0005 1/d. These correspond to (l, m) modes of
(1,1), (2,-2), (4,0) and (1,1) respectively. Additional frequencies were found
but they were below the signal-to-noise limit of the Fourier spectrum and not
suitable for mode identification. The rotational axis inclination and vsini of
the star were determined to be 87 degrees (nearly edge-on) and 39.7 km/s
(moderate for Gamma Doradus stars) respectively. A simultaneous fit of these
four modes to the line profile variations in the data gives a reduced chi
square of 12.7. We confirm, based on the frequencies found, that HD135825 is a
bona fide Gamma Doradus star.Comment: Accepted to MNRAS 2012 March
Recommended from our members
In Defense of Neutrality
"In Defense of Neutrality" is a multi-media installation that depicts the recent re-militarization of the general public by the mass media. The installation has a very child-like, playground feeling since this conditioning begins at a very young age. I built the environment almost exclusively out of found objects in order to give it a sense of "history", as well as making the whole work feel false and trashy. By making the work a miniature golf course, I can trick viewers into participating in this celebration of war in order to point up the fact that we fill participate in "war games" at one time or another (whether consciously or otherwise), while challenging the traditional role of art as something that should be seen and not touched. I intentionally layer the work both physically (so that there are many objects to peek behind to discover little treasures), and metaphorically in order to give the work enough depth that a viewers will discover new things each time they view it. I've included painted canvases, sculpture, light and even (mock) video elements in order to stretch out personally as well as trying to promote a type of art-making that is about getting a message across rather than drawing distinctions between what is art, and what is everything else. </p
An asteroseismic study of the beta Cephei star 12 Lacertae: multisite spectroscopic observations, mode identification and seismic modelling
We present the results of a spectroscopic multisite campaign for the beta
Cephei star 12 (DD) Lacertae. Our study is based on more than thousand
high-resolution high S/N spectra gathered with 8 different telescopes in a time
span of 11 months. In addition we make use of numerous archival spectroscopic
measurements. We confirm 10 independent frequencies recently discovered from
photometry, as well as harmonics and combination frequencies. In particular,
the SPB-like g-mode with frequency 0.3428 1/d reported before is detected in
our spectroscopy. We identify the four main modes as (l1,m1) = (1, 1), (l2,m2)
= (0, 0), (l3,m3) = (1, 0) and (l4,m4) = (2, 1) for f1 = 5.178964 1/d, f2 =
5.334224 1/d, f3 = 5.066316 1/d and f4 = 5.490133 1/d, respectively. Our
seismic modelling shows that f2 is likely the radial first overtone and that
the core overshooting parameter alpha_ov is lower than 0.4 local pressure scale
heights.Comment: 16 pages, 11 figures, accepted in MNRA
New ground-based observational methods and instrumentation for asteroseismology
Space instrumentation like SOHO, MOST, CoRoT and Kepler has been and is being
built to attain very high precision data to be used for asteroseismic analysis.
Nonetheless, there is a very strong need for providing additional information,
especially on mode identification. With this contribution I will review the
efforts been put on new ground-based instrumentation and the methodology that
can be used to achieve this aim.Comment: 6 pages. Review contribution to be published in Astrophysics and
Space Science Proceedings series (ASSP), in the proceedings of "20th Stellar
Pulsation Conference Series: Impact of new instrumentation and new insights
in stellar pulsations", 5-9 September 2011, Granada, Spai
Various applications of multicolour photometry and radial velocity data for multimode Scuti stars
In addition to revealing spherical harmonic degrees, , of excited
modes, pulsational amplitudes and phases from multicolour photometry and radial
velocity data yield a valuable constraints on stellar atmospheric parameters
and on subphotospheric convection. Multiperiodic pulsators are of particular
interest because each mode yields independent constraints. We present an
analysis of data on twelve modes observed in FG Vir star.Comment: 7 pages, 5 figures, in the proceedings of IAU Symposium 224: "The
A-star Puzzle", eds. J. Zverko, W. W. Weiss, J. Ziznowsky, S. J. Adelma
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