GW TDR Docs Web Runner

Intro

GW targeted detectability range

The targeted detectability range (TDR) tool computes the gravitational wave (GW) range (D90) targeted on a given external astronomical trigger, under the assumption that it is associated with a binary neutron star (BNS) or black hole-neutron star merger (NSBH). The TDR leverages the trigger time and sky localization of the transient and computes the GW detection probability using the sensitivity of each interferometer online at the time of the trigger.

How TDR is computed

The targeted range D90 is defined as the distance at which 90% of simulated signals are detected above a chosen SNR threshold, accounting for detector sensitivity and source sky position.

The tool computes the detection probability using localization through RA/DEC or HEALPix FITS sky maps. In order to compute the noise power spectral density of each GW interferometer online at the trigger time, the tool makes use of the strain data publicly available on GWOSC. For BNS (NSBH) signals, the TaylorF2 (IMRPhenomNSBH) waveform is adopted. By default, injections are done for the following mass combinations:

  • BNS: m1, m2 = 1.0 - 1.0 M☉, 1.4 - 1.4 M☉, 2.0 - 2.0 M☉
  • NSBH: m1, m2 = 5.0 - 1.0 M☉, 10 - 1.4 M☉, 20 - 2.0 M☉

For NSBH signals, the tidal deformability is computed using the SFHo and DD2 equations of state, and the reported TDR is the average of the two results. Users can choose the range of the binary inclination angle ι. By default, the tool assumes the ranges 0° ≤ ι ≤ 45° and 0° ≤ ι ≤ 90°. Detection probability is computed using both optimal SNR and matched-filter SNR, and the TDR can be derived from either metric.

Workflow

  1. Identify the GW observing run from trigger time t0.
  2. Check GWOSC data availability for H1/L1/V1.
  3. Download a 256 s strain segment around the trigger from GWOSC.
  4. Estimate PSDs for available detectors.
  5. Generate BNS and NSBH injections with PyCBC, for a set of component masses and inclination angle ι.
  6. Compute SNRs and D90 targeted range values.
  7. Produce plots, sky maps, and JSON result files.

Main outputs

  • targ_range.log: run log with detector and processing details.
  • ifos_used.txt and ifos_used.json: detector availability and usage.
  • psd_plot.pdf: PSD curves used by the analysis.
  • bns_targeted_range.pdf and nsbh_targeted_range.pdf: detection fraction curves.
  • results_bns.json and results_nsbh.json: final D90 summaries.
  • range_map_bns_m1_1.4_m2_1.4.fits: fits map of the TDR along with the related PDF map output.

Detector/network behavior

  • If GWOSC is temporarily unreachable, the run is marked incomplete and can be retried later.
  • If a downloaded file is already in cache and valid, it is reused instead of downloaded again.