LISA Data Analysis
Who we are
Round 4 - Data Sets
MDLC Round 4 consists
of a single, "whole enchilada" challenge that includes all the sources
of MLDCs 3.1-3.5 in the same dataset.
While the third round of the MLDCs was focused on increasing the
complexity and variety of GW sources, this iteration is devoted
to the global-fit problem of detecting and analyzing sources
of different types superposed in the LISA data.
All Round 3 sources are included, with larger numbers of
EMRIs and cosmic-string bursts and larger parameter ranges for
MBH binaries and EMRIs.
The waveform models are identical to those in Round 3 except for the
following changes: the spectra of the cosmic string bursts are
truncated below 1e-5 Hz; the stochastic background spectrum is
modified; and the MBH binary signals are truncated differently as
binary merges. See the 2009 Amadi proceedings article for more details
The deadline for Round 4 entries has been extended to 17 June 2011,
with preliminary results to be presented shortly thereafter.
The global-fit character of this challenge
encourages collaborative endeavors between groups that have developed
searches for different sources.
Note: The datasets were revised on Oct 18, 2010; The
correct datasets are in a subdirectory named "svn1159" with data stamps between Sep 29,
and Sep 30, 2010; do not use an earlier version.
A graphic representation of a Round 4 training dataset (not the "official" released training dataset). more
This particular realization includes 60+ million chirping Galactic
binaries, 4 MBH binaries, 9 EMRIs, 15 cosmic-string bursts, an
isotropic stochastic background, and of course instrument noise.
A two-year (15x2^22 s) dataset with signals of 4-6 MBH binaries,
approximately 6 EMRI's, approximately 20 cosmic-string bursts and an isotropic
stochastic background, as well as a galactic binary population of
~ 60 million binaries.
The signal parameters for various classes of sources are set as follows:
These signals are derived from a model of the galactic binary WD-WD population
(Nelemans, Yungelson and Portegies Zwart;
The population includes 34 million interacting systems and 26 million
detached binaries. For each, the gravitational wave frequency may be
linearly increasing or decreasing depending on the relative significance
of gravitational radiation power and mass transfer.
From 4 to 6 binaries with m1/MSun in [0.5,5e6], m1/m2 in [1,10],
a1/m1 in [0,1], a2/m2 in [0,1].
Coalescence times and SNRs are chosen as in Round 2 and Round 3,
for a set of BBH signals consisting of
(note that the SNR quoted here is only for the inspiral and assumes
coherent matched-filtering using 1 TDI observable):
The BBH signals will also include 2 of the following 4:
A loud (SNR ~ 2000) signal (with in-spiral in band, that is from f = 0.1 mHz, lasting about 1 week) and coalescing 60 to 120 days after the beginning of the observations
A moderate-to-low SNR (~ 20) signal with coalescence between 750 and 780 days from the beginning of the observations
A loud (SNR ~ 1000) signal coalescing between 180 and 720 days from beginning of observations
A loud (SNR ~ 200) signal coalescing between 180 and 720 days from beginning of observations
A loud (SNR ~ 100) signal with coalescence taking place between 495 and 585 days from the start of the observations
A low SNR (~ 10) signal with coalescence taking place between 810 and 840 days from the beginning of the observations
EMRI parameters are chosen from: mu/MSun in [9.5,10.5], S/M^2 in [0.5,0.7],
e_plunge in [0.05,0.25], t_plunge/(15 s) in [2^21,2^22], SNR in [25,50].
Central black hole masses are drawn as follows:
- Poisson(2) systems with M/(1e7 MSun) in [0.95,1.05]
- Poisson(2) systems with M/(1e6 MSun) in [4.75,5.25]
- Poisson(2) systems with M/(1e6 MSun) in [0.95,1.05]
Cosmic string bursts
Poisson(20) cosmic string bursts with parameters: log(fmax/mHz) in [0,2],
tc drawn uniformly over the duration of the dataset, and SNR in [10,100].
Isotropic stochastic background
The spectrum for the background is of the form, S_h = s x 1e-47 (f/Hz)^-3 / Hz,
with s in [0.7,1.3].
Several versions of the datasets are released:
data generated by
Synthetic LISA and
and equivalent-strain data generated by the
In contrast to MLDCs 3.4 and 3.5, all the LISA
instrument noises are set to symmetric, nominal levels,
and the LISA armlength are allowed to "breathe."
The data are provided at two cadences:
2^22 samples at 15 s sampling and "high-freq"
with 2^25 samples at 1.875 s sampling.
|Training data sets (key,
TDI directory with individual noiseless source signals
|Blind challenge data sets