1. A proposal for additional Low Frequency Gravitational Wave Interferometric Detectors at LIGO Riccardo DeSalvo California Institute of Technology Globular Cluster 17 th October 2003 LIGO- xxx

2. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 2 Status of observations now and here!! TAMA has been running for >3 years –Steadily improving sensitivity >100 Hz –< factor of 10 from nominal sensitivity LIGO has been acquiring data for > 1 year (with GEO) –Steadily improving sensitivity ~100 Hz –< factor of 10 from nominal sensitivity Virgo commissioning –Taking data in ~< 1 year –> 20 Hz AdLIGO starting up –Foreseen for > 2007 –> 40 Hz Low Frequency Threshold defined as mirror thermal noise corner!

3. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 3 Why LF-GWIDs? Adv-LIGO will cover the detection of pulsars, NS-NS and low-mass BH inspirals, the coalescence phase, and other GW physics with its best sensitivity around100 Hz Can ground based GWIDs monitor even lower frequencies Is this useful to study globular clusters?

4. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 4 What is necessary for a LF-GWID? GW Interferometers can be optimized for LF with the following changes –Reduce beam power and different finesse (rad. Pressure) –Use longer suspensions (susp. TN) –Use Supersized, double weight, mirrors (coating TN, rad. Pr) –Use Fused Silica (instead of Sapphire) mirrors (bulk TN) – LF-tuning would divert AdLIGO from its original mission! Need operation of separate Low and High Frequency complementary interferometers

5. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 5 AdL LF-GWID complementarity Newtonian Noise limit

6. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 6 AdL LF-GWID complementarity End inspiral frequency First BH Kerr resonance Merger phase follow-up in the frequency mass area above the yellow line BH ring down in the frequency mass area above the purple line Triggered searches LF trigger HF strongly relativistic signal study Template Signal integration

7. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 7 AdL and LF-GWID Blue: Low seismic Day Purple: High seismic Day Green: Ad-LIGO 3.6 Gpc @37+37sm Seismic variability 1.15 Gpc @16+16 sm

8. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 8 Can we accommodate a LF interferometer next to Adv-LIGO? There seems to be space in the LIGO beam pipe just above and forwards of the Adv-LIGO mirrors Advanced LIGO nominal beam positions

9. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 9 And there appears to be space in the halls Virgo-like towers TAMA-like towers

10. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 10 Conclusions IMBH are important and compelling potential GW sources for a LF interferometer Optimized LF sensitivity would allow: –Increase quite significantly the explored volume in the Universe for heavier mass objects (3.6 Gpc, real cosmology reach). –Study of the genesis of the large galactic BH (believed to be central to the dynamics of galaxies) –Mapping the globular clusters in our neighborhood –Enhancement of the performance of both Virgo and LIGO They would be “triggered” by the LF detection and follow up studying final inspiral and merge signals Advanced LIGOs are freer to be narrow banded Splitting up the frequency range between two different interferometers eases lots of design constraints and allows better performance from both

11. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 11 LF-GWID proposal pointers Should all be in LIGO DCC, if not available LF-GWID Amaldi proceedings ( LIGO- P030047-00-D): www.ligo.caltech.edu/~desalvo/manuscript-Amaldi2003.doc LF-GWID Elba proceedings ( LIGO-P030040-00-D): www.ligo.caltech.edu/~desalvo/DESALVO_ELBA_manuscript.doc LF-GWID Amaldi power point presentation ( LIGO- G030332-00-R ): www.ligo.caltech.edu/~desalvo/desalvo_amaldi.ppt LF-GWID Elba power point presentation ( LIGO-G030292-00-R): www.ligo.caltech.edu/~desalvo/desalvo-elba.ppt

12. Globular Cluster Meeting State College, 17-21 October 2003 LIGO- xxx-00-R 12 Aspen GWDAW workshop winter 2004 The LIGO S. C. equivalent of this informal meeting is the Aspen meeting. February 15 to 21st 2004 Please consider participating. Input on what is relevant and important to make good astronomy is very important. You can help !!