Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

Publicistiek en communicatiemodellen

Contains fulltext : mmubn000001_082217718.pdf (publisher's version ) (Open Access)Promotor : L. Schlichting180 p

Community communication and community media

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Individualiteit en engagement: religies en relaties in de hedendaagse cultuur.

0ntbrkt

Communicatoren op de pijnbank : een onderzoek naar de werkvisie en werkwijze van voorlichtings- en pr-functionarissen

The research project presented here displays a general profile of 72 leading pr and public information professionals regarding their basic views on communication, professional standards and ambitions in relation to their reported daily routine and practices. By far and away most of these top-practitioners claimed and often held a management or management-advisory position. Many of them would like to be called 'communication manager', and viewed their position in the organisation chiefly as a strategic one. However, with respect to what exactly it is they try to manage, their ideas are far from consistent. In some instances they seem to involve themselves in organizing the communication job itself. In other cases they appear to operate as an agent for the organisation and its objectives, and then again as an intermediary between the organisation and its environment. A consistent choice is not often made. Nor did an analysis of the communication managers reported daily routines, practices and working method show them up as real managers nor as agents or intermediaries, but mainly as 'producing messages'. The findings strongly suggest that the observed inconsistencies are connected with the top-practitioners' ideas on the effects of communication: the basic problem may very well be their conception of communication

Prospective assessment of pregnancy risk estimation models in women with congenital heart disease

Cardiolog