Speaker
Description
Transient gravitational-wave (GW) signals have been discovered since 2015 by the LVK global network of giant, ground-based, interferometric detectors. It currently includes four instruments: the LIGO Hanford and LIGO Livingston detectors located in the USA, the Virgo detector in Italy – hosted by the European Gravitational Observatory (EGO) –, and the KAGRA detector in Japan. A key component of the search for GWs is the broadcast of a low-latency public alert to the astronomical community, each time a significant GW candidate is identified by the pipelines which jointly analyze in real time the data from all the running detectors.
These alerts require a quick, yet accurate, vetting of the quality of the corresponding data. The main input for such a decision – to confirm the alert or to retract it if the candidate is found not to be of astronomical origin – comes from the Data Quality Report (DQR), a set of predefined checks which is triggered automatically when a new candidate has been identified, and which runs on an HTCondor farm. In this contribution, we focus on the Virgo DQR framework which has been developed jointly by the Virgo Collaboration and the EGO IT department, following standards defined at the LIGO-Virgo Collaborations level in 2018-2019. It allows vetting the data acquired by the Virgo detector. After a short description of the EGO HTCondor farm and of the various software which run on it during a joint data-taking period of the LVK network, we will describe the Virgo DQR; the way a significant GW candidate leads to the generation of a global HTCondor DAG (running about 40 different checks in parallel, for a total of roughly 120 jobs); its main inputs and outputs; its performance; and finally the live monitoring system which has been developed to parse every minute the dag.dagman.out DAG log file. Similar but independent DQR frameworks are running at various LIGO computing centers to vet the LIGO Hanford and LIGO Livingston data.
| Desired slot length | 12+3 minutes should be enough, 20 minutes if there is space in the agenda |
|---|---|
| Speaker release | Yes |
