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Unmanned Spaceflight.com _ Telescopic Observations _ Laser Interferometer Space Antenna

Posted by: ljk4-1 Feb 9 2006, 03:48 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0602033

From: Graham Woan [view email]

Date: Wed, 8 Feb 2006 18:04:22 GMT (57kb)

A principal component analysis for LISA -- the TDI connection

Authors: J. D. Romano, G. Woan

Comments: 7 pages, 3 figures, 1 table

Data from the Laser Interferometer Space Antenna (LISA) is expected to be dominated by frequency noise from its lasers. However the noise from any one laser appears more than once in the data and there are combinations of the data that are insensitive to this noise. These combinations, called time delay interferometry (TDI) variables, have received careful study, and point the way to how LISA data analysis may be performed. Here we approach the problem from the direction of statistical inference, and show that these variables are a direct consequence of a principal component analysis of the problem. We present a formal analysis for a simple LISA model and show that there are eigenvectors of the noise covariance matrix that do not depend on laser frequency noise. Importantly, these orthogonal basis vectors correspond to linear combinations of TDI variables. As a result we show that the likelihood function for source parameters using LISA data can be based on TDI combinations of the data without loss of information.

http://arxiv.org/abs/gr-qc/0602033

Posted by: ljk4-1 Feb 9 2006, 03:51 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0602019

From: Lee Samuel Finn [view email]

Date: Sun, 5 Feb 2006 22:37:25 GMT (7kb)

The Testbed for LISA Analysis Project

Authors: Lee Samuel Finn, Matthew J. Benacquista, Shane L. Larson, Louis J. Rubbo

Comments: 5 pages, no figures

Report-no: T06003

The Testbed for LISA Analysis (TLA) Project aims to facilitate the development, validation and comparison of different methods for LISA science data analysis, by the broad LISA Science Community, to meet the special challenges that LISA poses. It includes a well-defined Simulated LISA Data Product (SLDP), which provides a clean interface between the communities that have developed to model and to analyze the LISA science data stream; a web-based clearinghouse (at <this http URL>) providing SLDP software libraries, relevant software, papers and other documentation, and a repository for SLDP data sets; a set of mailing lists for communication between and among LISA simulators and LISA science analysts; a problem tracking system for SLDP support; and a program of workshops to allow the burgeoning LISA science community to further refine the SLDP definition, define specific LISA science analysis challenges, and report their results. This note describes the TLA Project, the resources it provides immediately, its future plans, and invites the participation of the broader community in the furtherance of its goals.

http://arxiv.org/abs/gr-qc/0602019

Posted by: ljk4-1 Feb 9 2006, 03:53 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0601096

From: J. Alberto Lobo [view email]

Date: Mon, 23 Jan 2006 15:45:26 GMT (21kb)

Theoretical foundations for on-ground tests of LISA PathFinder thermal diagnostics

Authors: Alberto Lobo, Miquel Nofrarias, Juan Ramos-Castro, Josep Sanjuan

Comments: 11 pages, 3 figures, LaTeX2e (compile with pdflatex), sumbitted to CQG

This paper reports on the methods and results of a theoretical analysis to design an insulator which must provide a thermally quiet environment to test on ground delicate temperature sensors and associated electronics. These will fly on board ESA's LISA PathFinder (LPF) mission as part of the thermal diagnostics subsystem of the LISA Test-flight Package (LTP). We evaluate the heat transfer function (in frequency domain) of a central body of good thermal conductivity surrounded by a layer of a very poorly conducting substrate. This is applied to assess the materials and dimensions necessary to meet temperature stability requirements in the metal core, where sensors will be implanted for test. The analysis is extended to evaluate the losses caused by heat leakage through connecting wires, linking the sensors with the electronics in a box outside the insulator. The results indicate that, in spite of the very demanding stability conditions, a sphere of outer diameter of the order one metre is sufficient.

http://arxiv.org/abs/gr-qc/0601096

Posted by: ljk4-1 Feb 9 2006, 03:55 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0601036

From: Neil J. Cornish [view email]

Date (v1): Tue, 10 Jan 2006 19:06:46 GMT (223kb)
Date (revised v2): Tue, 17 Jan 2006 23:20:17 GMT (221kb)

Darwin Meets Einstein: LISA Data Analysis Using Genetic Algorithms

Authors: Jeff Crowder, Neil J. Cornish, Lucas Reddinger

Comments: 8 pages, 12 figures

This work presents the first application of the method of Genetic Algorithms (GAs) to data analysis for the Laser Interferometer Space Antenna (LISA). In the low frequency regime of the LISA band there are expected to be tens of thousands galactic binary systems that will be emitting gravitational waves detectable by LISA. The challenge of parameter extraction of such a large number of sources in the LISA data stream requires a search method that can efficiently explore the large parameter spaces involved. As signals of many of these sources will overlap, a global search method is desired. GAs represent such a global search method for parameter extraction of multiple overlapping sources in the LISA data stream. We find that GAs are able to correctly extract source parameters for overlapping sources. Several optimizations of a basic GA are presented with results derived from applications of the GA searches to simulated LISA data.

http://arxiv.org/abs/gr-qc/0601036

Posted by: ljk4-1 Feb 9 2006, 03:57 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0512160

From: Emanuele Berti [view email]

Date: Thu, 29 Dec 2005 02:27:13 GMT (436kb)

On gravitational-wave spectroscopy of massive black holes with the space interferometer LISA

Authors: Emanuele Berti, Vitor Cardoso, Clifford M. Will

Comments: 44 pages, 21 figures, 10 tables

Newly formed black holes are expected to emit characteristic radiation in the form of quasi-normal modes, called ringdown waves, with discrete frequencies. LISA should be able to detect the ringdown waves emitted by oscillating supermassive black holes throughout the observable Universe. We develop a multi-mode formalism, applicable to any interferometric detectors, for detecting ringdown signals, for estimating black hole parameters from those signals, and for testing the no-hair theorem of general relativity. Focusing on LISA, we use current models of its sensitivity to compute the expected signal-to-noise ratio for ringdown events, the relative parameter estimation accuracy, and the resolvability of different modes. We also discuss the extent to which uncertainties on physical parameters, such as the black hole spin and the energy emitted in each mode, will affect our ability to do black hole spectroscopy.

http://arxiv.org/abs/gr-qc/0512160

Posted by: ljk4-1 Feb 9 2006, 03:59 PM

Astrophysics, abstract
astro-ph/0509813

From: Massimo Dotti [view email]

Date (v1): Tue, 27 Sep 2005 16:40:14 GMT (787kb)
Date (revised v2): Mon, 12 Dec 2005 17:01:15 GMT (358kb)

LISA double black holes: Dynamics in gaseous nuclear discs

Authors: M. Dotti, M. Colpi, F. Haardt

Comments: Minor changes, accepted to MNRAS (11 pags, 14 figs). Movies (.avi) are available at this http URL

We study the inspiral of double black holes, with masses in the LISA window of detectability, orbiting inside a massive circum-nuclear disc. Using high-resolution SPH simulations, we follow the black hole dynamics in the early phase when gas-dynamical friction acts on the black holes individually, and continue our simulation until they form a close binary. We find that in the early sinking the black holes lose memory of their initial orbital eccentricity if they co-rotate with the gaseous disc, forming a binary with a low eccentricity, consistent with zero within our numerical resolution limit. The cause of circularization resides in the rotation present in the gaseous background where dynamical friction operates. Circularization may hinder gravitational waves from taking over and leading the binary to coalescence. In the case of counter-rotating orbits the initial eccentricity does not decrease, and the black holes may bind forming an eccentric binary. When dynamical friction has subsided, for equal mass black holes and regardless their initial eccentricity, angular momentum loss, driven by the gravitational torque exerted on the binary by surrounding gas, is nevertheless observable down to the smallest scale probed. In the case of unequal masses, dynamical friction remains efficient down to our resolution limit, and there is no sign of formation of any ellipsoidal gas distribution that may further harden the binary. During inspiral, gravitational capture of gas by the black holes occurs mainly along circular orbits: eccentric orbits imply high relative velocities and weak gravitational focusing.

Thus, AGN activity may be excited during the black hole pairing process and double active nuclei may form when circularization is completed, on distance-scales of tens of pcs.

http://arxiv.org/abs/astro-ph/0509813

Posted by: ljk4-1 Feb 9 2006, 04:01 PM

Astrophysics, abstract
astro-ph/0509632

From: Alexander Stroeer [view email]

Date: Wed, 21 Sep 2005 14:41:48 GMT (11kb)

LISA astronomy of double white dwarf binary systems

Authors: A. Stroeer, A. Vecchio, G. Nelemans

Comments: accepted for publication in ApJLetters

Journal-ref: Astrophys.J. 633 (2005) L33-L36

The Laser Interferometer Space Antenna (LISA) will provide the largest observational sample of (interacting) double white dwarf binaries, whose evolution is driven by radiation reaction and other effects, such as tides and mass transfer. We show that, depending on the actual physical parameters of a source, LISA will be able to provide very different quality of information: for some systems LISA can test unambiguously the physical processes driving the binary evolution, for others it can simply detect a binary without allowing us to untangle the source parameters and therefore shed light on the physics at work. We also highlight that simultaneous surveys with GAIA and/or optical telescopes that are and will become available can radically improve the quality of the information that can be obtained.

http://arxiv.org/abs/astro-ph/0509632

Posted by: ljk4-1 Feb 9 2006, 04:03 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0509024

From: Kostas Glampedakis [view email]

Date: Wed, 7 Sep 2005 15:38:04 GMT (525kb)

Extreme Mass Ratio Inspirals: LISA's unique probe of black hole gravity

Authors: Kostas Glampedakis

Comments: Invited review article, 45 pages, 23 figures

Journal-ref: Class.Quant.Grav. 22 (2005) S605-S659

In this review article I attempt to summarise past and present-ongoing-work on the problem of the inspiral of a small body in the gravitational field of a much more massive Kerr black hole. Such extreme mass ratio systems, expected to occur in galactic nuclei, will constitute prime sources of gravitational radiation for the future LISA gravitational radiation detector. The article's main goal is to provide a survey of basic celestial mechanics in Kerr spacetime and calculations of gravitational waveforms and backreaction on the small body's orbital motion, based on the traditional `flux-balance' method and the Teukolsky black hole perturbation formalism.

http://arxiv.org/abs/gr-qc/0509024

Posted by: ljk4-1 Feb 9 2006, 04:12 PM

General Relativity and Quantum Cosmology, abstract
gr-qc/0507105

From: Rajesh Nayak K [view email]

Date: Mon, 25 Jul 2005 15:29:25 GMT (240kb)

Reducing the flexing of the arms of LISA

Authors: K. Rajesh Nayak, S. Koshti, S. V. Dhurandhar, J-Y. Vinet

The joint NASA-ESA mission LISA relies crucially on the stability of the three spacecraft constellation. All three spacecraft are on heliocentric and weakly eccentric orbits forming a stable triangle. It has been shown that for certain spacecraft orbits, the arms keep constant distances to the first order in the eccentricities. However, exact orbitography shows the so-called `breathing modes' of the arms where the arms slowly change their lengths over the time-scale of a year. In this paper we analyse the breathing modes (the flexing of the arms) with the help of the geodesic deviation equations to octupole order which are shown to be equivalent to higher order Clohessy-Wiltshire equations. We show that the flexing of the arms of LISA as given by the `exact' solution of Keplerian orbits, which gives constant armlengths to the first order in eccentricity and whose maximum flexing amplitude is $\sim 115,000$ km, can be improved, by tilting the plane of the LISA triangle slightly from the proposed orientation of $60^\circ$ with the ecliptic to obtain a maximum flexing amplitude of $\sim 48,000$ km, reducing it by a factor of $\sim 2.4$. The reduction factor is even larger if we consider the corresponding Doppler shifts, for which the reduction factor reaches almost a factor of 6. We solve the second order equations and obtain the general solution. We then use the general solution to establish the optimality of the solutions that we have found.

http://arxiv.org/abs/gr-qc/0507105

Posted by: ljk4-1 Feb 10 2006, 01:56 PM

Online from ESA Bulletin 119:

Gravitational Waves and Massive Black Holes?

The LISA and LISA Pathfinder Missions

http://www.esa.int/esapub/bulletin/bulletin119/bul119_chap1.pdf

Posted by: ljk4-1 Feb 22 2006, 10:32 PM

Astrophysics, abstract
astro-ph/0602445

From: Kelly Holley-Bockelmann [view email]

Date: Mon, 20 Feb 2006 21:04:39 GMT (28kb)

Event Rate for Extreme Mass Ratio Burst Signals in the LISA Band

Authors: Louis J. Rubbo, Kelly Holley-Bockelmann, Lee Samuel Finn

Comments: 4 pages, submitted to ApJ Letters

Stellar mass compact objects in short period orbits about a $10^{4.5}$--$10^{7.5}$ solar mass massive black hole (MBH) are thought to be a significant continuous-wave source of gravitational radiation for the ESA/NASA Laser Interferometer Space Antenna (LISA) gravitational wave detector. However, these extreme mass-ratio inspiral sources began in long-period, nearly parabolic orbits that have multiple close encounters with the MBH. The gravitational radiation emitted during these close encounters may be detectable by LISA as a gravitational wave burst if the characteristic passage timescale is less than $10^5$ seconds. Scaling a static, spherical model to the size and mass of the Milky Way bulge we estimate an event rate of ~ 15 per year for such burst signals, detectable by LISA with signal-to-noise greater than five, originating in our galaxy. When extended to include Virgo cluster galaxies our estimate increases to a gravitational wave burst rate of ~ 18. We conclude that these extreme mass-ratio burst sources may be a steady and significant source of gravitational radiation in the LISA data streams.

http://arxiv.org/abs/astro-ph/0602445

Astrophysics, abstract
astro-ph/0602470

From: Emanuele Berti [view email]

Date: Tue, 21 Feb 2006 19:03:13 GMT (37kb)

LISA observations of massive black hole mergers: event rates and issues in waveform modelling

Authors: Emanuele Berti

Comments: 13 pages, 2 figures. To appear in the proceedings of 10th Annual Gravitational Wave Data Analysis Workshop (GWDAW 10), Brownsville, Texas, 14-17 Dec 2005

The observability of gravitational waves from supermassive and intermediate-mass black holes by the forecoming Laser Interferometer Space Antenna (LISA), and the physics we can learn from the observations, will depend on two basic factors: the event rates for massive black hole mergers occurring in the LISA best sensitivity window, and our theoretical knowledge of the gravitational waveforms. We first provide a concise review of the literature on LISA event rates for massive black hole mergers, as predicted by different formation scenarios. Then we discuss what (in our view) are the most urgent issues to address in terms of waveform modelling. For massive black hole binary inspiral these include spin precession, eccentricity, the effect of high-order Post-Newtonian terms in the amplitude and phase, and an accurate prediction of the transition from inspiral to plunge. For black hole ringdown, numerical relativity will ultimately be required to determine the relative quasinormal mode excitation, and to reduce the dimensionality of the template space in matched filtering.

http://arxiv.org/abs/astro-ph/0602470

Posted by: GravityWaves Mar 29 2006, 08:15 PM

What can I say about the budget cuts for this mission....

I suppose that Dawn came back means there is still some hope left for our favorite 'gravity-wave' observatory

Posted by: ljk4-1 May 2 2006, 02:26 PM

We study the limits on how accurately LISA will be able to estimate the parameters of low-mass compact binaries, comprising white dwarfs (WDs), neutron stars (NSs) or black holes (BHs), while battling the amplitude, frequency, and phase modulations of their signals.

http://arxiv.org/abs/astro-ph/0605034

Posted by: PaulM Feb 12 2013, 05:36 PM

The following link suggests that the micro-propulsion system for the Lisa Pathfinder mission may change from Field Emission
Electric Propulsion to one of the listed alternative propulsion systems:

http://agenda.infn.it/getFile.py/access?contribId=9&resId=0&materialId=slides&confId=3807

Here is another interesting link describing recent developments in the Lisa Pathfinder mission:

http://www.rssd.esa.int/SP/LISAPATHFINDER/docs/Data_Analysis/DA_20/LISA%20Pathfinder%20status.pdf

Posted by: PaulM Jan 27 2016, 06:40 PM

The LISA Pathfinder spacecraft is on station and is ready to begin its scientific mission:

http://spaceflightnow.com/2016/01/25/lisa-pathfinder-on-station-a-million-miles-from-earth/

Posted by: scalbers Jan 28 2016, 01:09 AM

I can note that this (LPF) is a Pathfinder for the next generation spacecraft, called eLISA.

https://www.elisascience.org/

(not to be confused with aLIGO )

Posted by: PaulM Feb 14 2016, 10:15 AM

The first of two sets of locks holding Lisa Pathfinder's test cubes in place have been released. The cubes will be fully released on the 15th of February which will allow science operations to begin on the 1st of March.

http://sci.esa.int/lisa-pathfinder/57290-first-locks-released-from-lisa-pathfinders-cubes/

Posted by: Paolo Jun 7 2016, 04:17 PM

http://www.esa.int/Our_Activities/Space_Science/LISA_Pathfinder_exceeds_expectations

and the Physical Review Letters paper (pdf in open access):
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.231101

Posted by: Explorer1 Jul 3 2017, 09:22 PM

Good summary of the mission and its technology (with applications for many other spacecraft, not just gravity wave observing) http://sci.esa.int/lisa-pathfinder/59238-lisa-pathfinder-to-conclude-trailblazing-mission/

Last data taken on June 30th, EOM July 18, and a maneuver into a parking orbit around the Sun.