Results of S 3 pulsar injections Matt Pitkin

Results of S 3 pulsar injections Matt Pitkin for the CW search group University of Glasgow LIGO-G 040144 -00 -Z 2/24/2021 1

Contents Difference between S 2 and S 3 injections Recovering S 3 injections Calibration issues Results and recovered parameters Conclusions 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 2

Why perform pulsar injections? Pulsar injections allow us complete end-toend validation of our software pipelines Shows whether we would be able extract a signals parameters accurately Allows us to check phase and timing consistency between the detectors Have been shown to be very useful for all of the above 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 3

S 2 injections 2 pulsar signals injected into 10 hours of S 2 data n n n 2/24/2021 Signals had large SNR Frequencies were chosen specifically One signal had a spindown observable over the injection period, the other had no spin down LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 4

S 3 injections 10 signals injected solely into LIGO n n n n 2/24/2021 Frequency, spin-down, y, f 0 and i were chosen at random 5 pulsars to have publicly available parameters, 5 to be private h 0 chosen to have a variety of SNRs with two each at 3, 9, 27, 81 and 243 calculated by Graham Woan Signal were then calculated and injected by Bruce Allen and Peter Shawhan Injections were into ETMX All injections turned off for 3 weeks during the middle of the run 4 strongest pulsars were kept off and 1 signal was added to be coincident with GEO LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 5

Extracting the signals Bayesian time-domain method was used to extract the signals (see Rejean Dupuis’ talk) n n n 2/24/2021 Data heterodyned to remove time varying signal Signal parameters searched over using a mesh grid Each parameter can be estimated by marginalising over the other 3 parameters LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 6

Calibration issues (signal amplitudes) ETMX counts to give h 0 for each signal were calculated using E 10 calibrations The signals extracted using the S 3 V 1 calibrations and were seen to have amplitudes consistently off by of order 1015% This was due to the difference between the E 10 and S 3 V 1 actuation function magnitudes and can be corrected for using the ratio of the two 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 7

Calibration issues (signal phases) See Xavier Siemens talk Phases were extracted with at first seemingly random offsets from the supposed injected values Phases of the injected signals in H 1 and H 2 are now well understood and a coherent analysis between the two IFOs is possible L 1 phases are still to be resolved 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 8

H 1 pulsar pdfs pulsar 0 2/24/2021 pulsar 1 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 9

H 1 pulsar pdfs pulsar 3 2/24/2021 pulsar 5 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 10

H 1 pulsar pdfs pulsar 6 2/24/2021 pulsar 7 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 11

H 1 pulsar pdfs (pulsar 3) 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 12

H 1 pulsar pdfs (pulsar 4) 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 13

H 1 pulsar pdfs (pulsar 8) 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 14

H 1 pulsar pdfs (pulsar 9) 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 15

H 2 pdfs (strongest pulsar) 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 16

L 1 pdfs (strongest pulsar) 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 17

Conclusions Signals can be correctly injected and extracted from the IFOs (it is very impressive that such small strains can be injected and recovered from the instruments) We have coherent observations and are observing true phase (if observing an actual signal we would be able to tell the phase difference between EM and GW observations) It is very important have injections and to continue them in future runs to help us understand the signal phases and how the instruments respond 2/24/2021 LSC Meeting, LIGO Livingston Observatory LIGO-G 040144 -00 -Z 18