10 research outputs found
Recommended from our members
Seeing is behaving : Frau Welt and the FĂĽrst der Welt, art and moral messages in the Rhineland ca. 1300
Frau Welt (Lady World) was a popular German allegory in the Middle Ages, which warned against the false nature of worldly things and desires through a uniquely deceptive appearance: her attractive front side concealed a horrid backside covered with toads, snakes, and worms. While the allegory remains uncommon in visual art, her male counterpart with a similar iconography and warning, the FĂĽrst der Welt (Prince of the World), survives in several sculptural examples. The two allegories, however, appear in very different contexts. While the Frau Welt allegory appears frequently in courtly literature and Minnesongs of the thirteenth and fourteenth centuries, it only appears once in monumental sculptural form, at Worms cathedral. Here the allegory appears with three other female personifications: Synagogue, Charity, and Faith. Surviving only in visual form, the FĂĽrst der Welt appears often with the Wise and Foolish Virgins. The best-known and earliest example of the FĂĽrst der Welt stands on the west facade of Strasbourg cathedral.
While previous scholarship has noted the similar iconographies of the two allegories, this dissertation will aim to contextualize the figures beyond iconography by posing larger, overarching questions: Why do these figures appear mainly nestled on cathedral facades along the Rhineland? And why is their popularity confined to the late thirteenth and early fourteenth centuries? I address these questions of geographic and temporal exclusivity by considering this artistic phenomenon against a changing theological and cultural backdrop.
I argue that the appearance of Frau Welt and the Fürst der Welt allegories in visual form is part of a growing interest in medieval society in visuality and moralizing themes. The Frau Welt and Fürst der Welt sculptures take these interests further through their “foolproof” iconography, which calls attention to their divided and deceptive nature. In short, the moral transparency of the sculptural representations of the Frau Welt and Fürst der Welt allegories takes the emerging interest in visuality to the extreme and makes it possible for the viewer to grasp the basic moral message or meaning without any prior conditioning to the allegories or their stories.Art Histor
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation IV: Background Simulations using GEANT-4 Toolkit
Hard X-ray detectors in space are prone to background signals due to the
ubiquitous cosmic rays and cosmic diffuse background radiation that
continuously bombards the satellites which carry the detectors. In general, the
background intensity depends on the space environment as well as the material
surrounding the detectors. Understanding the behavior of the background noise
in the detector is very important to extract the precise source information
from the detector data. In this paper, we carry out Monte Carlo simulations
using the GEANT-4 toolkit to estimate the prompt background noise measured with
the detectors of the RT-2 Experiment onboard the CORONAS-PHOTON satellite.Comment: 21 pages, 10 figures, Accepted for publication in Experimental
Astronomy (in press
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation V: Onboard software, Data Structure, Telemetry and Telecommand
The onboard software and data communication in the RT-2 Experiment onboard
the Coronas-Photon satellite is organized in a hierarchical way to effectively
handle and communicate asynchronous data generated by the X-ray detectors. A
flexible data handling system is organized in the X-ray detector packages
themselves and the processing electronic device, namely RT-2/E, has the
necessary intelligence to communicate with the 3 scientific payloads by issuing
commands and receiving data. It has direct interfacing with the Satellite
systems and issues commands to the detectors and processes the detector data
before sending to the satellite systems. The onboard software is configured
with several novel features like a) device independent communication scheme, b)
loss-less data compression and c) Digital Signal Processor. Functionality of
the onboard software along with the data structure, command structure, complex
processing scheme etc. are discussed in this paper.Comment: 24 pages, 2 figures, Accepted for publication in Experimental
Astronomy (in press
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation III: Coded Aperture Mask and Fresnel Zone Plates in RT-2/CZT Payload
Imaging in hard X-rays of any astrophysical source with high angular
resolution is a challenging job. Shadow-casting technique is one of the most
viable options for imaging in hard X-rays. We have used two different types of
shadow-casters, namely, Coded Aperture Mask (CAM) and Fresnel Zone Plate (FZP)
pair and two types of pixellated solid-state detectors, namely, CZT and CMOS in
RT-2/CZT payload, the hard X-ray imaging instrument onboard the CORONAS-PHOTON
satellite. In this paper, we present the results of simulations with different
combinations of coders (CAM & FZP) and detectors that are employed in the
RT-2/CZT payload. We discuss the possibility of detecting transient Solar
flares with good angular resolution for various combinations. Simulated results
are compared with laboratory experiments to verify the consistency of the
designed configuration.Comment: 27 pages, 16 figures, Accepted for publication in Experimental
Astronomy (in press
RT-2 Detection of Quasi-Periodic Pulsations in the 2009 July 5 Solar Hard X-ray Flare
We present the results of an analysis of hard X-ray observations of the C2.7
solar flare detected by the RT-2 Experiment onboard the Coronas - Photon
satellite. We detect hard X-ray pulsations at periods of ~12 s and ~15 s. We
find a marginal evidence for a decrease in period with time. We have augmented
these results using the publicly available data from the RHESSI satellite. We
present a spectral analysis and measure the spectral parameters.Comment: 12 pages, 8 figures and 3 tables, accepted for publication in The
Astrophysical Journa
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation II: RT-2/CZT payload
Cadmium Zinc Telluride (CZT) detectors are high sensitivity and high
resolution devices for hard X-ray imaging and spectroscopic studies. The new
series of CZT detector modules (OMS40G256) manufactured by Orbotech Medical
Solutions (OMS), Israel, are used in the RT-2/CZT payload onboard the
CORONAS-PHOTON satellite. The CZT detectors, sensitive in the energy range of
20 keV to 150 keV, are used to image solar flares in hard X-rays. Since these
modules are essentially manufactured for commercial applications, we have
carried out a series of comprehensive tests on these modules so that they can
be confidently used in space-borne systems. These tests lead us to select the
best three pieces of the 'Gold' modules for the RT-2/CZT payload. This paper
presents the characterization of CZT modules and the criteria followed for
selecting the ones for the RT-2/CZT payload. The RT-2/CZT payload carries,
along with three CZT modules, a high spatial resolution CMOS detector for high
resolution imaging of transient X-ray events. Therefore, we discuss the
characterization of the CMOS detector as well.Comment: 26 pages, 19 figures, Accepted for publication in Experimental
Astronomy (in press
Indian payloads (RT-2 Experiment) onboard CORONAS-PHOTON mission
RT-2 Experiment (RT - Roentgen Telescope) is a low energy gamma-ray instrument which is designed and developed as a part of Indo-Russian collaborative project of CORONAS-PHOTON Mission to study the Solar flares in wide energy band of electromagnetic spectrum ranging from UV to high-energy Îł-rays (~ 2000 MeV). RT-2 instruments will cover the energy range of 15 keV to 150 keV extendable up to ~ 1 MeV. It consists of three detectors (two Phoswich detectors, namely, RT-2/S, RT-2/G and one solid-state imaging detector RT-2/CZT) and one processing electronic device (RT-2/E). Both Phoswich detectors will have time resolved spectrum, whereas the solid-state imaging detector will have high resolved image of the solar flares in hard X-rays. We have used Co-57 (122 keV) radio-active source for onboard calibration of all three detectors. In this paper, we briefly discuss the in-flight performance of RT-2 instruments and present initial flight data from the instruments. This mission was launched into polar LEO (Low Earth Orbit) (~ 550 km) on 30th January 2009 from Plesetsk Cosmodrome, Russia
Detection of GRB 090618 with RT-2 Experiment Onboard the Coronas-Photon Satellite
We present the results of an analysis of the prompt gamma-ray emission from
GRB 090618 using the RT-2 Experiment onboard the Coronas-Photon satellite. GRB
090618 shows multiple peaks and a detailed study of the temporal structure as a
function of energy is carried out. As the GRB was incident at an angle of 77
degree to the detector axis, we have generated appropriate response functions
of the detectors to derive the spectrum of this GRB. We have augmented these
results using the publicly available data from the Swift BAT detector and show
that a combined spectral analysis can measure the spectral parameters quite
accurately. We also attempt a spectral and timing analysis of individual peaks
and find evidence for a systematic change in the pulse emission characteristics
for the successive pulses. In particular, we find that the peak energy of the
spectrum, E_p, is found to monotonically decrease with time, for the successive
pulses of this GRB.Comment: 12 pages, 6 figures, 3 tables, Accepted for publication in The
Astrophysical Journa
Onboard performance of the RT-2 detectors
The RT-2 Experiment onboard the CORONAS-PHOTON satellite is designed to study the spectral, temporal, and spatial details of solar hard X-ray flares in the 15–150 keV range. Above this energy (and upto 1000 keV), it also acts as an omni-directional gamma-ray detector with a capability to study gamma-ray bursts (GRB), bright solar flares, and X-ray pulsars. With an ensemble of hard X-ray detectors with different fields of view and coding devices, it also has the capability to investigate the spectrum of Cosmic Diffuse X-ray Background. The performance of the detectors from 2009 February to November is described in this paper. Results obtained on a few GRBs and solar flares are also briefly discussed