1,203,612 research outputs found
Electron Scattering on 3He - a Playground to Test Nuclear Dynamics
The big spectrum of electron induced processes on 3He is illustrated by
several examples based on Faddeev calculations with modern nucleon-nucleon and
three-nucleon forces as well as exchange currents. The kinematical region is
restricted to a mostly nonrelativistic one where the three-nucleon c.m. energy
is below the pion production threshold and the three-momentum of the virtual
photon is sufficiently below the nucleon mass. Comparisons with available data
are shown and cases of agreement and disagreement are found. It is argued that
new and precise data are needed to systematically check the present day
dynamical ingredients.Comment: 27 pages, 24 figure
Evidence for binarity in the bipolar planetary nebulae A79, He2-428 and M1-91
We present low and high resolution long-slit spectra of three bipolar
planetary nebulae (PNe) with bright central cores: A79, He2-428 and M1-91.
He2-428 and M1-91 have high density (from 10^3.3 to 10^6.5 cm^-3) unresolved
nebular cores that indicate that strong mass loss/exchange phenomena are
occurring close to their central stars. An F0 star is found at the centre of
symmetry of A79; its reddening and distance are consistent with the association
of the star with the nebula. The spectrum of the core of He2-428 shows
indications of the presence of a hot star with red excess emission, probably
arising in a late-type companion. A79 is one of the richest PNe in N and He,
the abundances of M1-91 are at the lower end of the range spanned by bipolar
PNe, and He2-428 shows very low abundances, similar to those measured for halo
PNe. The extended nebulae of A79 and He2-428 have inclined equatorial rings
expanding at a velocity of approx. 15 km/s, with kinematical ages 10^4 yr. The
association of these aged, extended nebulae with a dense nebular core (He2-428)
or a relatively late type star (A79) is interpreted as evidence for the
binarity of their nuclei.Comment: 13 pages including 8 tables. A&A accepted; also available at
http://www.iac.es/publicaciones/preprints.htm
Buenas prácticas de transferencia del conocimiento en la Universidad de Córdoba
La recuperación y difusión de la capilla de San Bartolomé –declarado Monumento Histórico-Artístico el 3 de junio de 1931, que actualmente es Bien de Interés Cultural- es el motivo principal de la iniciativa. Para ello, el grupo de investigación HUM 428 de la Universidad de Córdoba presenta el trabajo que ha llevado a cabo y que parte de un minucioso estudio y análisis de las fuentes documentales para el que ha recopilado material gráfico y documental de las intervenciones que se han hecho en el monumento para dar la mejor información al público que visita el edificio a través de paneles divulgativos. El proyecto incluye también la señalización identificativa, tanto externa como interna, y la adaptación del espacio para la visita
Detection of the BL Lac Object H1426+428 at TeV Gamma Ray Energies
A very high energy (VHE) gamma-ray signal has been detected at the 5.4 sigma
level from H1426+428, an x-ray selected BL Lacertae object at a redshift of
0.129. The object was monitored from 1995 - 1998 with the Whipple 10m imaging
atmospheric Cherenkov telescope as part of a general blazar survey; the results
of these observations, although not statistically significant, were
consistently positive. X-ray observations of H1426+428 during 1999 with the
BeppoSAX instrument revealed that the peak of its synchrotron spectrum occurs
at > 100 keV, leading to the prediction of observable TeV emission from this
object. H1426+428 was monitored extensively at the Whipple Observatory during
the 1999, 2000, and 2001 observing seasons. The strongest TeV signals were
detected in 2000 and 2001. During 2001, an integral flux of 2.04 +/- 0.35
x10e-11 cm-2 s-1 above 280 GeV was recorded from H1426+428. The detection of
H1426+428 supports the idea that, as also seen in Markarian 501 and
1ES2344+514, BL Lacertae objects with extremely high synchrotron peak
frequencies produce gamma rays in the TeV range.Comment: 35 pages, 7 figures, accepted by ApJ Two upper limits in Table 3
(upper limits for 1995 and 1997) are different from the ApJ versio
Report on the Disabled Persons Loan Scheme of Project Ken/86/037
No142.pdf: 428 downloads, before Oct. 1, 2020
Marching Towards the American Dream: Illinois Immigrant Citizens Settle in Chicago Suburbs
While long a factor in "urban elections", immigrant populations are changing the political landscape in Illinois. Immigrant citizens and the U.S. born children of immigrants are fast becoming the critical voting blocks in Chicago's suburbs this November and beyond. A Research Brief, titled "Marching Toward the American Dream: Illinois Immigrant Citizens Settle in Chicago Suburbs" was released by the Illinois Coalition of Immigrant and Refugee Rights (ICIRR). It is based on the recently released U.S. Census figures for 2005 and reveals that over the past five years the number of immigrants in the state has increased by 177,000, a figure greater than the population of Aurora, Illinois's second largest city. Some key findings of the report: - Naturalized immigrants and their U.S. born children now represent 19% of all eligible voting age people in llinois. - The number of naturalized immigrants in suburban Chicago rose by 127,000 persons, or 38 percent, in the last five. - The number of immigrant citizens in the suburbs (460,000) dwarfs the number in the City of Chicago (229,000)
Very high-energy observations of the two high-frequency peaked BL Lac objects 1ES 1218+304 and H 1426+428
We present results of very-high-energy gamma-ray observations (E > 160 GeV)
of two high-frequency-peaked BL Lac (HBL) objects, 1ES 1218+304 and H 1426+428,
with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). Both
sources are very-high-energy gamma-ray emitters above 100 GeV, detected using
ground-based Cherenkov telescopes. STACEE observations of 1ES 1218+304 and H
1426+428 did not produce detections; we present 99% CL flux upper limits for
both sources, assuming spectral indices measured mostly at higher energies
The TeV spectrum of H1426+428
The BL Lac object H1426+428 was recently detected as a high energy gamma-ray
source by the VERITAS collaboration (Horan et al. 2002). We have reanalyzed the
2001 portion of the data used in the detection in order to examine the spectrum
of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with
a power law of the shape dF/dE = 10^(-7.31 +- 0.15(stat) +- 0.16(syst)) x
E^(-3.50 +- 0.35(stat) +- 0.05(syst)) m^(-2)s^(-1)TeV^(-1) The statistical
evidence from our data for emission above 2.5 TeV is 2.6 sigma. With 95% c.l.,
the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the
corresponding flux from the Crab Nebula. The spectrum is consistent with the
(non-contemporaneous) measurement by Aharonian et al. (2002) both in shape and
in normalization. Below 800 GeV, the data clearly favours a spectrum steeper
than that of any other TeV Blazar observed so far indicating a difference in
the processes involved either at the source or in the intervening space.Comment: LaTeX, 8 pages, 4 figures, accepted for publication in Ap
Blazar observations above 60 GeV: the Influence of CELESTE's Energy Scale on the Study of Flares and Spectra
The CELESTE atmospheric Cherenkov detector ran until June 2004. It has
observed the blazars Mrk 421, 1ES 1426+428 and Mrk 501. We significantly
improved our understanding of the atmosphere using a LIDAR, and of the optical
throughput of the detector using stellar photometry. The new data analysis
provides better background rejection. We present our light curve for Mrk 421
for the 2002-2004 season and a comparison with X-ray data and the 2004
observation of 1ES 1426+428. The new analysis will allow a more sensitive
search for a signal from Mrk 501.Comment: 7 pages, 7 figures, proc. of the 35th COSPAR Scientific Assembly held
in Paris, France, July 200
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