Prospects of continuous gravitational waves from Fermi LAT sources

Non-axisymmetric spinning Neutron Stars are expected to be sources of continuous gravitational waves. Only a small fraction of the total number of neutron stars believed to exist in the Galaxy is observed through their electromagnetic emission. This number steadily increasing recently, thanks to the Fermi Large Area Telescope and to radio surveys. The Fermi Large Area Telescope catalogue contains several potentially interesting sources for gravitational-wave searches, such as supernova remnants and the “unassociated” sources. In order to look for continuous gravitational signals the knowledge of the NS parameters, i.e. rotational frequency and position, is needed. Depending on the degree of accuracy with which these parameters are known, several types of searches can be performed. In this paper I will discuss the perspectives and considerations of continuous gravitational-wave searches for Fermi LAT sources

A new data analysis framework for the search of continuous gravitational wave signals

Continuous gravitational wave signals, like those expected by asymmetric spinning neutron stars, are among the most promising targets for LIGO and Virgo detectors. The development of fast and robust data analysis methods is crucial to increase the chances of a detection. We have developed a new and flexible general data analysis framework for the search of this kind of signals, which allows to reduce the computational cost of the analysis by about two orders of magnitude with respect to current procedures. This can correspond, at fixed computing cost, to a sensitivity gain of up to 10%-20%, depending on the search parameter space. Some possible applications are discussed, with a particular focus on a directed search for sources in the Galactic center. Validation through the injection of artificial signals in the data of Advanced LIGO first observational science run is also shown.Comment: 21 pages, 8 figure

An improved algorithm for narrow-band searches of continuous gravitational waves

Continuous gravitational waves signals, emitted by asymmetric spinning neutron stars, are among the main targets of current detectors like Advanced LIGO and Virgo. In the case of sources, like pulsars, which rotational parameters are measured through electromagnetic observations, typical searches assume that the gravitational wave frequency is at a given known fixed ratio with respect to the star rotational frequency. For instance, for a neutron star rotating around one of its principal axis of inertia the gravitational signal frequency would be exactly two times the rotational frequency of the star. It is possible, however, that this assumption is wrong. This is why search algorithms able to take into account a possible small mismatch between the gravitational waves frequency and the frequency inferred from electromagnetic observations have been developed. In this paper we present an improved pipeline to perform such narrow-band searches for continuous gravitational waves from neutron stars, about three orders of magnitude faster than previous implementations. The algorithm that we have developed is based on the {\it 5-vectors} framework and is able to perform a fully coherent search over a frequency band of width $\mathcal{O}$(Hertz) and for hundreds of spin-down values running a few hours on a standard workstation. This new algorithm opens the possibility of long coherence time searches for objects which rotational parameters are highly uncertain.Comment: 19 pages, 8 figures, 6 tables, submitted to CQ

A semi-coherent analysis method to search for continuous gravitational waves emitted by ultra-light boson clouds around spinning black holes

As a consequence of superradiant instability induced in Kerr black holes, ultra-light boson clouds can be a source of persistent gravitational waves, potentially detectable by current and future gravitational-wave detectors. These signals have been predicted to be nearly monochromatic, with a small steady frequency increase (spin-up), but given the several assumptions and simplifications done at theoretical level, it is wise to consider, from the data analysis point of view, a broader class of gravitational signals in which the phase (or the frequency) slightly wander in time. Also other types of sources, e.g. neutron stars in which a torque balance equilibrium exists between matter accretion and emission of persistent gravitational waves, would fit in this category. In this paper we present a robust and computationally cheap analysis pipeline devoted to the search of such kind of signals. We provide a full characterization of the method, through both a theoretical sensitivity estimation and through the analysis of syntethic data in which simulated signals have been injected. The search setup for both all-sky searches and higher sensitivity directed searches is discussed.Comment: 13 pages, 13 figure

Combining chirp mass, luminosity distance and sky localisation from gravitational wave events to detect the cosmic dipole

A key test of the isotropy of the Universe on large scales consists in comparing the dipole in the Cosmic Microwave Background (CMB) temperature with the dipole in the distribution of sources at low redshift. Current analyses find a dipole in the number counts of quasars and radio sources that is 2-5 times larger than expected from the CMB, leading to a tension reaching 5$\sigma$. In this paper, we derive a consistent framework to measure the dipole independently from gravitational wave (GW) detections. We exploit the fact that the observer velocity does not only change the distribution of events in the sky, but also the luminosity distance and redshifted chirp mass, that can be extracted from the GW waveform. We show that the estimator with higher signal-to-noise ratio is the dipole in the chirp mass measured from a population of binary neutron stars. Combining all estimators (accounting for their covariance) improves the detectability of the dipole by 30-50 percent compared to number counting of binary black holes alone. We find that a few $10^6$ events are necessary to detect a dipole consistent with the CMB one, whereas if the dipole is as large as predicted by radio sources, it will already be detectable with $10^5$ events, which would correspond to a single year of observation with next generation GW detectors. GW sources provide therefore a robust and independent way of testing the isotropy of the Universe.Comment: 17 pages, 11 figues, submitted to MNRA

A 2D laser rangefinder scans dataset of standard EUR pallets

open5siopenIhab Mohamed, Alessio Capitanelli, Fulvio Mastrogiovanni, Stefano Rovetta, Renato ZaccariaMohamed, Ihab; Capitanelli, Alessio; Mastrogiovanni, Fulvio; Rovetta, Stefano; Zaccaria, RENATO UGO RAFFAEL

Aberration of gravitational waveforms by peculiar velocity

One key prediction of General Relativity is that gravitational waves areemitted with a pure spin-2 polarisation. Any extra polarisation mode, spin-1 orspin-0, is consequently considered a smoking gun for deviations from GeneralRelativity. In this paper, we show that the velocity of merging binaries withrespect to the observer gives rise to spin-1 polarisation in the observer frameeven in the context of General Relativity. These are pure projection effects,proportional to the plus and cross polarisations in the source frame, hencethey do not correspond to new degrees of freedom. We demonstrate that thespin-1 modes can always be rewritten as pure spin-2 modes coming from anaberrated direction. Since gravitational waves are not isotropically emittedaround binary systems, this aberration modifies the apparent orientation of thebinary system with respect to the observer: the system appears slightly rotateddue to the source velocity. Fortunately, this bias does not propagate to otherparameters of the system (and therefore does not spoil tests of GeneralRelativity), since the impact of the velocity can be fully reabsorbed into neworientation angles.<br

A mental health-informed, online health promotion programme targeting physical activity and healthy eating for adults aged 60+ years: study protocol for the MovingTogether randomised controlled trial

Background: The COVID-19 pandemic and associated social distancing regulations have led to an increased risk of social isolation and physical inactivity, particularly among older adults. The benefits of physical activity for reducing fall risk and improving mood and mental functioning have been well documented. The aim of this trial is to investigate the effect of the MovingTogether programme on psychological distress (primary outcome) and physical activity, social capital, cognition, concern about falling, loneliness, physical functioning, quality of life and physical activity enjoyment (secondary outcomes). Methods: A randomised controlled trial with a waitlist control will be conducted, recruiting 80 adults aged 60+ years with access to Facebook and a computer or tablet and not currently meeting the aerobic physical activity guidelines. Randomisation will be completed using REDCap. The intervention group (n = 40) will join a private Facebook group where allied health facilitators will provide targeted healthy lifestyle education throughout the 10-week programme with weekly telehealth group calls. Intervention participants will also be provided access to tailored strength and aerobic exercise guidance and an evidence-based eHealth balance exercise programme. Psychological distress and secondary outcomes will be assessed at baseline, 11 weeks (post-intervention) and 16 weeks (1-month follow-up). Linear mixed models will be applied for each outcome measure as per an intention-to-treat approach to determine the between-group differences. Secondary analyses are planned in people with greater adherence and those with higher psychological distress. Discussion: COVID-19 has highlighted the need for scalable, effective and novel methods to improve and protect the health of older adults. The integration of an evidence-based fall prevention programme with a mental health-informed online health promotion programme may help to improve mental and physical health outcomes among older adults. Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12621001322820p. Registered on 29 September 2021

Laboratory Diagnosis of Intrathecal Synthesis of Immunoglobulins: A Review about the Contribution of OCBs and K-index

the diagnosis of MS relies on a combination of imaging, clinical examinations, and biological analyses, including blood and cerebrospinal fluid (CSF) assessments. G-Oligoclonal bands (OCBs) are considered a "gold standard" for MS diagnosis due to their high sensitivity and specificity. recent advancements have involved the introduced of kappa free light chain (k-FLC) assay into cerebrospinal fluid (CSF) and serum (S), along with the albumin quotient, leading to the development of a novel biomarker known as the "K-index" or "k-FLC index". the use of the K-index has been recommended to decrease costs, increase laboratory efficiency, and to skip potential subjective operator-dependent risk that could happen during the identification of OCBs profiles. this review aims to provide a comprehensive overview and analysis of recent scientific articles, focusing on updated methods for MS diagnosis with an emphasis on the utility of the K-index. numerous studies indicate that the K-index demonstrates high sensitivity and specificity, often comparable to or surpassing the diagnostic accuracy of OCBs evaluation. the integration of the measure of the K-index with OCBs assessment emerges as a more precise method for MS diagnosis. this combined approach not only enhances diagnostic accuracy, but also offers a more efficient and cost-effective alternative