ASTROD-GW: Overview and Progress

In this paper, we present an overview of ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity using Optical Devices] optimized for Gravitational Wave [GW] detection) mission concept and its studies. ASTROD-GW is an optimization of ASTROD which focuses on low frequency gravitational wave detection. The detection sensitivity is shifted by a factor of 260 (52) towards longer wavelengths compared with that of NGO/eLISA (LISA). The mission consists of three spacecraft, each of which orbits near one of the Sun-Earth Lagrange points (L3, L4 and L5), such that the array forms an almost equilateral triangle. The 3 spacecraft range interferometrically with one another with an arm length of about 260 million kilometers. The orbits have been optimized resulting in arm length changes of less than 0.00015 AU or, fractionally, less than 10^(-4) in twenty years, and relative Doppler velocities of the three spacecraft of less than 3 m/s. In this paper, we present an overview of the mission covering: the scientific aims, the sensitivity spectrum, the basic orbit configuration, the simulation and optimization of the spacecraft orbits, the deployment of ASTROD-GW formation, TDI (Time Delay Interferometry) and the payload. The science goals are the detection of GWs from (i) Supermassive Black Holes; (ii) Extreme-Mass-Ratio Black Hole Inspirals; (iii) Intermediate-Mass Black Holes; (iv) Galactic Compact Binaries and (v) Relic Gravitational Wave Background. For the purposes of primordial GW detection, a six spacecraft formation would be needed to enable the correlated detection of stochastic GWs. A brief discussion of the six spacecraft orbit optimization is also presented.

[1]  Astrod orbit simulation and accuracy of relativistic parameter determination , 2000 .

[2]  W. Ni,et al.  Numerical simulation of time delay interferometry for eLISA/NGO , 2012, 1204.2125.

[3]  COSMIC POLARIZATION ROTATION, COSMOLOGICAL MODELS, AND THE DETECTABILITY OF PRIMORDIAL GRAVITATIONAL WAVES , 2009, 0903.0756.

[4]  Deployment and Simulation of the Astrod-Gw Formation , 2012, 1212.1253.

[5]  Edward K. Porter,et al.  Massive black-hole binary inspirals: results from the LISA parameter estimation taskforce , 2008, 0811.1011.

[6]  Clive C. Speake,et al.  An interferometric sensor for satellite drag-free control , 2005 .

[7]  G. Wang,et al.  Time-delay Interferometry for ASTROD-GW☆ , 2012 .

[8]  Massimo Tinto,et al.  Time delay interferometry , 2003, Living Reviews in Relativity.

[9]  Shinji Tsujikawa,et al.  Dynamics of dark energy , 2006 .

[10]  B. Schutz Determining the Hubble constant from gravitational wave observations , 1986, Nature.

[11]  W. Ni Mini-ASTROD --- Mini-Astrodynamical Space Test of Relativity using Optical Devices , 2003 .

[12]  Bernard F. Schutz,et al.  Physics, Astrophysics and Cosmology with Gravitational Waves , 2009, Living reviews in relativity.

[13]  W. Ni,et al.  Progress in laboratory research for fundamental physics space missions using optical devices , 2003 .

[14]  C. Grimani IMPLICATIONS OF GALACTIC AND SOLAR PARTICLE MEASUREMENTS ON BOARD INTERFEROMETERS FOR GRAVITATIONAL WAVE DETECTION IN SPACE , 2013 .

[15]  Jonathan R. Gair,et al.  Reconstructing the massive black hole cosmic history through gravitational waves , 2010, 1011.5893.

[16]  H. Vocca,et al.  Solar And Cosmic Ray Physics And The Space Environment: Studies For And With LISA , 2006 .

[17]  A. Pai,et al.  TESTS OF GENERAL RELATIVITY AND ALTERNATIVE THEORIES OF GRAVITY USING GRAVITATIONAL WAVE OBSERVATIONS , 2013, 1302.2198.

[18]  R. Mcmillan,et al.  APOLLO: millimeter lunar laser ranging , 2012 .

[19]  W. Ni,et al.  Orbit optimization for ASTROD-GW and its time delay interferometry with two arms using CGC ephemeris , 2012, 1205.5175.

[20]  W. Ni Empirical Foundations of the Relativistic Gravity , 2005, gr-qc/0504116.

[21]  Asteroid Perturbations and Mass Determination for the ASTROD Space Mission , 2004, astro-ph/0407606.

[22]  Etienne Samain,et al.  Astrodynamical Space Test of Relativity Using Optical Devices I (ASTROD I)—A class-M fundamental physics mission proposal for Cosmic Vision 2015–2025 , 2008, 0802.0582.

[23]  D. Wineland,et al.  Frequency comparison of two high-accuracy Al+ optical clocks. , 2009, Physical review letters.

[24]  W. Ni,et al.  Astrodynamical Space Test of Relativity Using Optical Devices i (astrod i) — Mission Overview , 2012, 1212.3645.

[25]  A. Vecchio,et al.  The stochastic gravitational-wave background from massive black hole binary systems: implications for observations with Pulsar Timing Arrays , 2008, 0804.4476.

[26]  Wei-Tou Ni,et al.  ASTROD–AN OVERVIEW , 2002 .

[27]  S. Dhurandhar,et al.  Time-delay interferometry for LISA with one arm dysfunctional , 2010, 1001.4911.

[28]  W. Ni,et al.  Progress in laboratory R & D for fundamental physics space missions - weak light phase-locking, fibre-linked heterodyne interferometry, fibre delay line and picometre real-time motion control , 1996 .

[29]  A. Vecchio,et al.  Gravitational waves from resolvable massive black hole binary systems and observations with Pulsar Timing Arrays , 2008, 0809.3412.

[30]  G. Wang,et al.  Design of ASTROD-GW Orbit☆☆☆ , 2010 .

[31]  F. T. Collaboration,et al.  Gravitational Wave Astronomy Using Pulsars: Massive Black Hole Mergers & the Early Universe , 2009, 0902.2968.

[32]  R. Manchester PULSAR SEARCHING AND TIMING , 2013 .

[33]  P. Guillemot,et al.  Status of the T2L2/Jason2 Experiment , 2010 .

[34]  B. C. Joshi PULSAR TIMING ARRAYS , 2013, 1301.5730.

[35]  W. Ni,et al.  ASTROD-GW Time Delay Interferometry , 2011 .

[36]  J. Primack Hidden Growth of Supermassive Black Holes in Galaxy Mergers , 2010, Science.

[37]  J. Armstrong,et al.  Time-Delay Interferometry for Space-based Gravitational Wave Searches , 1999 .

[38]  B. Paul ASTROSAT: Some Key Science Prospects , 2013, 1307.5637.

[39]  Wei-Tou Ni,et al.  ASTROD and ASTROD I -- Overview and Progress , 2007, 0712.2492.

[40]  P. Natarajan,et al.  Major Galaxy Mergers and the Growth of Supermassive Black Holes in Quasars , 2010, Science.

[41]  Wei-Tou Ni Dark energy, co-evolution of massive black holes with galaxies, and ASTROD-GW , 2010 .

[42]  Peter L. Bender LISA sensitivity below 0.1 mHz , 2003 .

[43]  K. G. Arun,et al.  Fifth ASTROD Symposium and Outlook of Direct Gravitational-Wave Detection , 2012 .

[44]  W. Ni,et al.  PICO-WATT AND FEMTO-WATT WEAK-LIGHT PHASE LOCKING , 2002 .

[45]  A. P. Patón Current Prospects for Astrod Inertial Sensor , 2007, 0704.3465.

[46]  Robert L. Byer,et al.  Advanced gravitational reference sensor for high precision space interferometers , 2005 .

[47]  Bernard F. Schutz,et al.  Low-frequency gravitational-wave science with eLISA/NGO , 2012, 1202.0839.

[48]  Gravitational waves, dark energy and inflation , 2010, 1003.3899.

[49]  C. Lämmerzahl,et al.  ASTROD optimized for Gravitational Wave detection: ASTROD-GW , 2010 .

[50]  A. Peters,et al.  OPTIS: a satellite-based test of special and general relativity , 2001, gr-qc/0104067.

[51]  W. Ni,et al.  ASTROD I: Mission Concept and Venus Flybys , 2006 .

[52]  K. Yagi,et al.  SCIENTIFIC POTENTIAL OF DECIGO PATHFINDER AND TESTING GR WITH SPACE-BORNE GRAVITATIONAL WAVE INTERFEROMETERS , 2013, 1302.2388.

[53]  Alison J. Farmer,et al.  The gravitational wave background from cosmological compact binaries , 2003, astro-ph/0304393.

[54]  E. Williams,et al.  The Apache Point Observatory Lunar Laser-ranging Operation: Instrument Description and First Detections , 2007, 0710.0890.

[55]  N. Cornish,et al.  Beyond LISA: Exploring future gravitational wave missions , 2005, gr-qc/0506015.