# Data Challenge

### Data Challenge 1

The First IPTA Data Challenge was released on 23rd March 2012 and will close on 28th September 2012 Deadline extended to 19th October 2012.

The first data challenge is considered a “warm up”, reflecting the simple nature of the simulations. Although simple, this challenge intends to:

- Introduce people to the format and peculiarities of pulsar timing data.
- Aid agreement in definition of parameters and significance measurements.
- Be the first “blind” test of GW analysis pipelines.

It should be noted, however, that the simulated data for the first data challenge are much simpler than the real IPTA data sets (and future data challenges). More information can be found at “comparison between real data and data challenge 1″. To participate in the data challenge, download the data files and detailed description, then submit your results before the close of the data challenge.

Download the open and closed parts of the data challenge here:

```
* Information and downloads for the open part of IPTA data challenge 1
* Information and downloads for the closed part of IPTA data challenge 1
```

### Data Challenge 1: Closed Data Set Parameters

#### Dataset 1: Uniformly sampled data with a stochastic GW background and white noise

```
White Noise: 100 nano-seconds for each pulsar
GW Background: Characteristic strain spectrum is a power law with index -2/3. The amplitude of the strain spectrum at a frequency of 1 year-1 is 1 x 10-14
Cadence: Once every two weeks
Total Time Span: Five Years
```

Dataset 2: Non-uniformly sampled data with a stochastic GW background and white noise

```
White Noise: Different for all pulsars, consistent with measured values of residuals for IPTA pulsars. Click here to get the list of the white noise RMS for each pulsar.
GW Background: Characteristic strain spectrum is a power law with index -2/3. The amplitude of the strain spectrum at a frequency of 1 year -1 is 6 x 10 -14
Cadence: Randomly sampled. Average interval of two weeks, ±5 days. Same time base for all pulsars
Total Time Span: Five Years
```

Dataset 3: Non-uniformly sampled data with a stochastic GW background together with white and red noise

```
White Noise: Same as in dataset 2
Red Noise: Same power spectrum for all pulsars, different realization
```

Red Noise Power Spectrum is of the form: P(f) = A f -α where f is in Hz, A = 3.66 x 10-18 seconds1.8 and α= 1.2.

```
GW Background: Characteristic strain spectrum is a power law with index -2/3. The amplitude of the strain spectrum at a frequency of 1 year-1 is 5 x 10-15
Cadence: Randomly sampled. Average interval of two weeks, ±5 days. Same time base for all pulsars
Total Time Span: Five years
```