776 research outputs found
Consistency Problems for Jump-Diffusion Models
In this paper consistency problems for multi-factor jump-diffusion models,
where the jump parts follow multivariate point processes are examined. First
the gap between jump-diffusion models and generalized Heath-Jarrow-Morton (HJM)
models is bridged. By applying the drift condition for a generalized
arbitrage-free HJM model, the consistency condition for jump-diffusion models
is derived. Then we consider a case in which the forward rate curve has a
separable structure, and obtain a specific version of the general consistency
condition. In particular, a necessary and sufficient condition for a
jump-diffusion model to be affine is provided. Finally the Nelson-Siegel type
of forward curve structures is discussed. It is demonstrated that under
regularity condition, there exists no jump-diffusion model consistent with the
Nelson-Siegel curves.Comment: To appear in Applied Mathematical Financ
Radio Detection of 18 Rass BL Lac Objects
We present the radio detection of 18 BL Lac objects from our survey of over
575 square degrees of sky. These 18 objects are located within 20 arcsec of the
X-ray position, of which 11 have a measured red-shift. All candidates are radio
emitters above ~1 mJy and fall within the range of existing samples on the two
colour, alpha_ro vs alpha_ox, diagram with a transitional population of three
(3) evident. Two unusual sources have been identified, a candidate radio quiet
BL Lac, RX J0140.9-4130, and an extreme HBL, RX J0109.9-4020, with
Log(nu_peak)~19.2. The BL Lac Log(N)-Log(S) relation is consistent with other
samples and indicates the ROSAT All Sky Survey (RASS) could contain (2000+-400)
BL Lac objects.Comment: 14 pages, 6 figures, accepted for publication in Serbian Astronomical
Journa
Radio Planetary Nebulae in the Magellanic Clouds
We present preliminary results of our deep Australia Telescope Compact Array
(ATCA) radio-continuum survey of the Magellanic Clouds Planetary Nebulae.Comment: 2 pages 1 figure, to appear in Planetary Nebulae an Eye to the Future
Proceedings IAU Symposium No. 28
Radio Continuum Study of Supernova Remnants in the Large Magellanic Cloud - SNR J0519-6926
We present the results of new high resolution ATCA observations of SNR
J0519-6926. We found that this SNR exhibits a typical "horseshoe" appearance
with alpha = -0.55 +- 0.08 and D=28+-1 pc. No polarization (or magnetic fields)
are detected to a level of 1%. This is probably due to a relatively poor
sampling of the uv plane caused be observing in "snap-shot" mode.Comment: 6 pages 4 figures, to be published in Serbian Astronomical Journa
Radio-Continuum Observations Of Small, Radially Polarised Supernova Remnant J0519-6902 In The Large Magellanic Cloud
We report on new Australian Telescope Compact Array (ATCA) observations of
SNR J0519-6902. The Supernova Remnant (SNR) is small in size (~8 pc) and
exhibits a typical SNR spectrum of alpha = -0.53 +- 0.07, with steeper spectral
indices found towards the northern limb of the remnant. SNR J0519-6902 contains
a low level of radially orientated polarisation at wavelengths of 3 & 6 cm,
which is characteristic of younger SNRs. A fairly strong magnetic field was
estimated of ~171 microG. The remnant appears to be the result of a typical
Type Ia supernovae, sharing many properties as another small and young Type Ia
LMC SNR, J0509-6731.Comment: 10 pages 7 figures, submitted to Serbian Astronomical Journa
Multifrequency Observations of One of the Largest Supernova Remnants in the Local Group of Galaxies, LMC - SNR J0450-709
We present the results of new Australia Telescope Compact Array (ATCA)
observations of one of the largest supernova remnants, SNR J0450-709, in the
Local Group of galaxies. We found that this Large Magellanic Cloud (LMC) ob
ject exhibits a typical morphology of an old supernova remnant (SNR) with
diameter D=102x75+-1 pc and radio spectral index alpha=-0.43+-0.06. Regions of
high polarisation were detected with peak value of ~40%.Comment: 7 pages, 4 figures, accepted for publication in Serbian Astronomical
Journa
Derivative pricing for a multi-curve extension of the Gaussian, exponentially quadratic short rate model
The recent financial crisis has led to so-called multi-curve models for the
term structure. Here we study a multi-curve extension of short rate models
where, in addition to the short rate itself, we introduce short rate spreads.
In particular, we consider a Gaussian factor model where the short rate and the
spreads are second order polynomials of Gaussian factor processes. This leads
to an exponentially quadratic model class that is less well known than the
exponentially affine class. In the latter class the factors enter linearly and
for positivity one considers square root factor processes. While the square
root factors in the affine class have more involved distributions, in the
quadratic class the factors remain Gaussian and this leads to various
advantages, in particular for derivative pricing. After some preliminaries on
martingale modeling in the multi-curve setup, we concentrate on pricing of
linear and optional derivatives. For linear derivatives, we exhibit an
adjustment factor that allows one to pass from pre-crisis single curve values
to the corresponding post-crisis multi-curve values
The ATLAS-SPT Radio Survey of Cluster Galaxies
Using a high-performance computing cluster to mosaic 4,787 pointings, we have
imaged the 100 sq. deg. South Pole Telescope (SPT) deep-field at 2.1 GHz using
the Australian Telescope Compact Array to an rms of 80 Jy and a resolution
of 8". Our goal is to generate an independent sample of radio-selected galaxy
clusters to study how the radio properties compare with cluster properties at
other wavelengths, over a wide range of redshifts in order to construct a
timeline of their evolution out to . A preliminary analysis of the
source catalogue suggests there is no spatial correlation between the clusters
identified in the SPT-SZ catalogue and our wide-angle tail galaxies.Comment: 9 pages, 4 figures. Submitted to Proceedings of Science for "The many
facets of extragalactic radio surveys: towards new scientific challenges",
Bologna, Italy 20-23 October 2015 (EXTRA-RADSUR2015
The Spatial Correlation of Bent-Tail Galaxies and Galaxy Clusters
We have completed a deep radio continuum survey covering 86 square degrees of
the Spitzer-South Pole Telescope deep field to test whether bent-tail galaxies
are associated with galaxy clusters. We present a new catalogue of 22 bent-tail
galaxies and a further 24 candidate bent-tail galaxies. Surprisingly, of the 8
bent-tail galaxies with photometric redshifts, only two are associated with
known clusters. While the absence of bent-tail sources in known clusters may be
explained by effects such as sensitivity, the absence of known clusters
associated with most bent-tail galaxies casts doubt upon current models of
bent-tail galaxies.Comment: Accepted by MNRA
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