Current status of Joint LIGO-TAMA Inspiral Analysis

In collaboration with: Patrick Brady, Nobuyuki Kanda, Hideyuki Tagoshi, Daisuke Tatsu

mi,the LIGO Scientific Collaboration and the TAMA Collaboration

Hirotaka Takahashi / Stephen Fairhurst (Osaka Univ. and Niigata Univ. / Univ. of Wisconsin-Milwaukee)

Introduction

• LIGO and TAMA300 performed a coincident observation between Feb. 14 and April 14, 2003.

The total amount of LIGO S2 science-mode data (one or more detectors) is 1218 hours.

The total amount of TAMA300 DT8 observation data is 1163 hours.

• We report on the current status of the coincidence analysis to search for gravitational waves from inspiraling compact binaries using LIGO (S2) and TAMA300 (DT8) data.

TAMA300 (T1) LIGO Hanford (H1 and H2) LIGO Livingston (L1)

Goals of the LIGO-TAMA search

• The ultimate goal of the search is a detection.

• We can place an upper limit on compact star inspiral rate in the Milky Way (if no detection).

• Sensitive to most of the Milky Way.

LIGO S2-TAMA DT8 coincidence data in 2003

650hours

513hours

135 hours

TAMA LIGO single site

• T1 : 1163 hours• (L1-nH1-nH2)+(nL1-H1-nH2)+(nL1-nH1-H2)+(nL1-H1-H2) : 785 hours • (L1-nH1-nH2-T1)+(nL1-H1-nH2-T1)+(nL1-nH1-H2-T1)+(nL1-H1-H2-T1) : 650 hours

nL1 : L1 was not operating

1. We determined our choice of coincidence parameters using the results of Galactic binary neutron star inspiral signals injection.

2. We performed time slide analysis to estimate the background.

3. We injected Galactic binary neutron star inspiral signals into both LIGO and TAMA data to evaluate efficiency.

In this talkWe focus on what has been learned from playground data.

To avoid statistical bias, Tuning of analysis parameters are decided. Test analysis is performed.

Playground data : 64 hours(not included upper limit calculation)

Tuning coincidence parameters• Time windows

TAMA-Hanford 24.97 msec

TAMA-Livingston 32.37 msec

• Timing accuracy ?Since we are planning to test for coincidence between LIGO and TAMA triggers using the time, we decided to check how accurately LIGO and TAMA can determine this quantity.

To do this, injected a set of Galactic binary neutron star signals into the LIGO-TAMA playground times.

TAMA-Hanford 7487 km

TAMA-Livingston 9703 km

The distance between LIGO and TAMA

Maximum time delay of the signal

Accuracy of coalescence time

The triggers of LIGO and TAMA are recorded within 1.5 msec of the injection

Detected-Injected End time (msec)

LIGO (455 injections)

Of the 455 injections into analyzed data,455 had triggers ( ) recordedwithin 3 ms of the end.

Of the 660 injections into analyzed data,516 had triggers ( ) recordedwithin 3 ms of the end.

Detected-Injected End time (msec)

TAMA (660 injections)

TAMA-Hanford 27 msec

TAMA-Livingston 35 msec

Time windows

Tuning coincidence parameters

• The accuracy of chirp mass

Detected-Injected chirp mass (Msol)Detected-Injected chirp mass (Msol)

LIGO (455 injections) TAMA (660 injections)

H1,H2 〜 0.005 Msol

L1 〜 0.005 Msol

TAMA 〜 0.05 Msol

Chirp mass window 　　　 0.05Msol

• Mass windows Chirp mass window? Reduced mass window? …

The accuracy of chirp mass

From TAMA-LISM coincidence, reduced mass did not give constraints in coincidence very much. Only the chirp mass was effective. Thus, to begin on chirp mass sounds reasonable.

The TAMA collaboration and the LISM collaboration: H.Takahashi et al.PRD 70 042003, (2004)