2026-09-23T15:03:44Zhttps://iris.unica.it/oai/requestoai:iris.unica.it:11584/2667962022-10-15T19:53:25Zcom_11584_207615com_11584_111066col_11584_265854
Multidisciplinary studies of pulsar data and applications to Pulsar Timinig Arrays
TIBURZI, CATERINA
detezioni
false
flase detections
gravitational waves
onde gravitazionali
polarization
polarizzazione
profili delle pulsar
pulsar
pulsar profiles
pulsar timing arrays
radioastronomia
radioastronomy
timing
Settore FIS/05 - Astronomia e Astrofisica
Pulsars are fast-rotating, highly-magnetized neutron stars, visible at radio
wavelenghts as pulsating obje
ts thanks to two beams of emission that are fo
ussed
on the magneti
poles and
o-rotate with the star, the rotational axis of whi
h is
not aligned with the magneti
one. The rotational stability and the possibility of
measuring the time-of-arrival of the "pulses" of emission with an extreme pre
ision
allows to
onstrain the physi
al parameters of these sour
es, and to undertake a
wide number of studies. In this PhD Thesis, we exploit this
hara
teristi
to explore
several aspe
ts of pulsar physi
s, mainly related with the "Pulsar Timing Array"
experiments.
The first aspe
t is pulsar polarization. Pulsars are among the most polarized obje
ts
of the radio sky ever known, however, the origin of pulsar polarization and of the
"modes" of polarization that
hara
terize pulsar emission is still obs
ure. Here we
present a
lassi
polarimetri
study of long-period pulsars dis
overed during the High
Time Resolution Universe survey and a new approa
h to
lassify the
ombination of
the polarized mode, along with a first appli
ation to the data.
The se
ond aspe
t dire
tly
on
erns the Pulsar Timing Array experiments, whose
main goal is a dire
t dete
tion of gravitational waves using pulsars. So far, no
dete
tion has been
laimed. However, given the in
reasing sensitivity of these
experiments, it is extremely important to develop solid sanity
he
ks on the data
to state if a future dete
tion is genuine or not. We present here a study about false
dete
tion indu
ed by
orrelated signals in Pulsar Timing Array experiments, along
with a sample of possible routines to mitigate these effe
ts.
The third aspe
t is the long term de
adal stability of millise
ond pulsar template
profiles in flux, that is one of the hypothesis of the pro
edures to obtain extreme
pre
isions in measuring the pulsar parameters. We study 10 millise
ond pulsars
using the longest and most uniform data set in the world. We also present the
surprising result that one of the sour
es in our sample seems to present a sistemati
profile variation along the years
overed by the data set.
2015-05-22
info:eu-repo/semantics/doctoralThesis
http://hdl.handle.net/11584/266796
eng
numberofpages:201
info:eu-repo/semantics/openAccess
Università degli Studi di Cagliari
license:Non specificato