Publications by authors named "H Wittel"
In the manufacturing process of electrical devices, ensuring the cleanliness of technical surfaces, such as direct bonded copper substrates, is crucial. An in-line monitoring system for quality checking must provide sufficiently resolved lateral data in a short time. UV hyperspectral imaging is a promising in-line method for rapid, contactless, and large-scale detection of contamination; thus, UV hyperspectral imaging (225-400 nm) was utilized to characterize the cleanliness of direct bonded copper in a non-destructive way.
View Article and Find Full Text PDFThe nature of dark matter remains unknown to date, although several candidate particles are being considered in a dynamically changing research landscape. Scalar field dark matter is a prominent option that is being explored with precision instruments, such as atomic clocks and optical cavities. Here we describe a direct search for scalar field dark matter using a gravitational-wave detector, which operates beyond the quantum shot-noise limit.
View Article and Find Full Text PDFWe present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems.
View Article and Find Full Text PDFArticle Synopsis
- On May 21, 2019, Advanced LIGO and Virgo detected a significant gravitational-wave signal known as GW190521, indicating a high probability event with a low chance of false alarms.
- The signal suggests it resulted from the merger of two black holes, one around 85 solar masses and the other about 66 solar masses, with the primary black hole likely being an intermediate mass black hole.
- The source of the merger is estimated to be about 5.3 billion light-years away, and the rate of similar black hole mergers is estimated to be about 0.13 mergers per billion cubic parsecs per year.
Article Synopsis
- The study investigates the existence of subsolar mass ultracompact objects by analyzing data from Advanced LIGO's second observing run and includes the impact of spin on gravitational waves.
- No suitable gravitational-wave candidates were found for binaries with at least one component between 0.2 and 1.0 solar masses, leading to significant constraints on their binary merger rates.
- The findings suggest that such ultracompact objects likely do not form through conventional stellar evolution, and they outline how these constraints on merger rates can be applied to different black hole population models that predict subsolar mass binaries.