1,388 research outputs found
A program to develop a high-energy density primary battery with a minimum of 200 watt hours per pound of total battery weight Fifth quarterly report, 1 Jul. - 30 Sep. 1965
High energy density primary battery development - electrochemical half-cell screening of anode- electrolyte combinations, cell discharge, and potential studie
A program to develop a high-energy density primary battery with a minimum of 200 watt hours per pound of total battery weight Seventh quarterly report, Jan. 1 - Mar. 31, 1966
Cathodic materials for high energy density storage batter
A program to develop a high-energy density primary battery with a minimum of 200 watt hours per pound of total battery weight Eighth quarterly report, 1 Apr. - 30 Jun. 1966
Electrochemical characteristics of lithium in various electrolytes and magnesium in aluminum chloride-acetonitrile studied by voltammetric sweep metho
Radio Spectra of Giant Radio Galaxies from RATAN-600 Data
Measurements of the flux densities of the extended components of seven giant
radio galaxies obtained using the RATAN-600 radio telescope at wavelengths of
6.25 and 13 cm ar e presented. The spectra of components of these radio
galaxies are constructed using these new RA TAN-600 data together with data
from the WENSS, NVSS, and GB6 surveys. The spectral indices in the stu died
frequency range are calculated, and the need for detailed estimates of the
integrated contributi on of such objects to the background emission is
demonstrated.Comment: 7 pages, 2 figures, 5 table
Intermittent jet activity in the radio galaxy 4C29.30?
We present radio observations at frequencies ranging from 240 to 8460 MHz of
the radio galaxy 4C29.30 (J0840+2949) using the Giant Metrewave Radio Telescope
(GMRT), the Very Large Array (VLA) and the Effelsberg telescope. We report the
existence of weak extended emission with an angular size of 520 arcsec
(639 kpc) within which a compact edge-brightened double-lobed source with a
size of 29 arcsec (36 kpc) is embedded. We determine the spectrum of the inner
double from 240 to 8460 MHz and show that it has a single power-law spectrum
with a spectral index of 0.8. Its spectral age is estimated to be
\lapp33 Myr. The extended diffuse emission has a steep spectrum with a
spectral index of 1.3 and a break frequency \lapp240 MHz. The spectral
age is \gapp200 Myr, suggesting that the extended diffuse emission is due to
an earlier cycle of activity. We reanalyse archival x-ray data from Chandra and
suggest that the x-ray emission from the hotspots consists of a mixture of
nonthermal and thermal components, the latter being possibly due to gas which
is shock heated by the jets from the host galaxy.Comment: 14 pages, 11 figures, accepted for publication in MNRA
LOFAR discovery of a 700-kpc remnant radio galaxy at low redshift
Remnant radio galaxies represent the final dying phase of radio galaxy
evolution, in which the jets are no longer active. Due to their rarity in flux
limited samples and the difficulty of identification, this dying phase remains
poorly understood and the luminosity evolution largely unconstrained. Here we
present the discovery and detailed analysis of a large (700 kpc) remnant radio
galaxy with a low surface brightness that has been identified in LOFAR images
at 150 MHz. By combining LOFAR data with new follow-up Westerbork observations
and archival data at higher frequencies, we investigated the source morphology
and spectral properties from 116 to 4850 MHz. By modelling the radio spectrum
we probed characteristic timescales of the radio activity. The source has a
relatively smooth, diffuse, amorphous appearance together with a very weak
central compact core which is associated with the host galaxy located at
z=0.051. From our ageing and morphological analysis it is clear that the
nuclear engine is currently switched off or, at most, active at a very low
power state. The host galaxy is currently interacting with another galaxy
located at a projected separation of 15 kpc and a radial velocity offset of 300
km/s. This interaction may have played a role in the triggering and/or shut
down of the radio jets. The spectral shape of this remnant radio galaxy differs
from the majority of the previously identified remnant sources, which show
steep or curved spectra at low to intermediate frequencies. In light of this
finding and in preparation for new-generation deep low-frequency surveys, we
discuss the selection criteria to be used to select representative samples of
these sources.Comment: 10 pages, 6 figures, 5 tables, A&A accepte
Signatures of the disk-jet coupling in the Broad-line Radio Quasar 4C+74.26
Here we explore the disk-jet connection in the broad-line radio quasar
4C+74.26, utilizing the results of the multiwavelength monitoring of the
source. The target is unique in that its radiative output at radio wavelengths
is dominated by a moderately-beamed nuclear jet, at optical frequencies by the
accretion disk, and in the hard X-ray range by the disk corona. Our analysis
reveals a correlation (local and global significance of 96\% and 98\%,
respectively) between the optical and radio bands, with the disk lagging behind
the jet by days. We discuss the possible explanation for this,
speculating that the observed disk and the jet flux changes are generated by
magnetic fluctuations originating within the innermost parts of a truncated
disk, and that the lag is related to a delayed radiative response of the disk
when compared with the propagation timescale of magnetic perturbations along
relativistic outflow. This scenario is supported by the re-analysis of the
NuSTAR data, modelled in terms of a relativistic reflection from the disk
illuminated by the coronal emission, which returns the inner disk radius
. We discuss the global energetics in
the system, arguing that while the accretion proceeds at the Eddington rate,
with the accretion-related bolometric luminosity erg s , the jet total kinetic energy
erg s, inferred from the dynamical
modelling of the giant radio lobes in the source, constitutes only a small
fraction of the available accretion power.Comment: 9 pages and 6 figures, ApJ accepte
A multifrequency study of giant radio sources-II. Spectral ageing analysis of the lobes of selected sources
Multifrequency observations with the GMRT and the VLA are used to determine
the spectral breaks in consecutive strips along the lobes of a sample of
selected giant radio sources (GRSs) in order to estimate their spectral ages.
The maximum spectral ages estimated for the detected radio emission in the
lobes of our sources range from 6 to 36 Myr with a median value of
20 Myr using the classical equipartition fields. Using the magnetic field
estimates from the Beck & Krause formalism the spectral ages range from 5
to 38 Myr with a median value of 22 Myr. These ages are significantly
older than smaller sources. In all but one source (J1313+6937) the spectral age
gradually increases with distance from the hotspot regions, confirming that
acceleration of the particles mainly occurs in the hotspots. Most of the GRSs
do not exhibit zero spectral ages in the hotspots, as is the case in earlier
studies of smaller sources. This is likely to be largely due to contamination
by more extended emission due to relatively modest resolutions. The injection
spectral indices range from 0.55 to 0.88 with a median value of
0.6. We discuss these values in the light of theoretical expectations,
and show that the injection spectral index appears to be correlated with
luminosity and/or redshift as well as with linear size.Comment: 12 Pages, 13 Figures, 9 Tables, Accepted for publication in MNRA
The SST-1M camera for the Cherenkov Telescope Array
The prototype camera of the single-mirror Small Size Telescopes (SST-1M)
proposed for the Cherenkov Telescope Array (CTA) project has been designed to
be very compact and to deliver high performance over thirty years of operation.
The camera is composed of an hexagonal photo-detection plane made of custom
designed large area hexagonal silicon photomultipliers and a high throughput,
highly configurable, fully digital readout and trigger system (DigiCam). The
camera will be installed on the telescope structure at the H.
Niewodnicza{\'n}ski institute of Nuclear Physics in Krakow in fall 2015. In
this contribution, we review the steps that led to the development of the
innovative photo-detection plane and readout electronics, and we describe the
test and calibration strategy adopted.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.05894; Full consortium author list at http://cta-observatory.or
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