# Gravitational Waves and Cosmic Microwave Background

As part of the Theoretical Particle Physics & Cosmology group at the Niels Bohr Institute, we conduct research in CMB science using data from the Planck satelite and the planned Deep Space experiment in Greenland. We also study gravitational waves using data from the LIGO observatories.
## Gravitational waves

Photographs courtesy Caltech/MIT/LIGO Laboratory

**Understanding the LIGO GW150914 event** (arxiv:1604.06211)

Identifying GW150914 in the LIGO data using cross-correlations with no assumptions about its origin

**Possible associated signal with GW150914 in the LIGO data** (arxiv:1609.08346)

Indications of an associated signal in the LIGO data with the same time lag as the GW150914 event

**On the time lags of the LIGO signals** (arxiv:1706.04191)

Correlations in the residuals at the time of LIGO events with the same time lag as the events themselves

Python script for computing correlations in residuals (uploaded June 27, 2017)

Comments on 'On the time lags of the LIGO signals'

uploaded June 27, 2017

**Published version of 'On the time lags of the LIGO signals'** (JCAP08(2017)013)

Comments on recent developments regarding 'On the time lags of the LIGO signals'

uploaded August 21, 2017

Our data files of cleaned 4096 seconds strain data around GW150914 (uploaded August 21, 2017)

The data is presented in two columns: The first shows the time-ordered, cleaned data for Hanford, the second shows that for Livingston. The sampling rate chosen is 16384 Hz. The GPS time marking the start of both files is 1126257414.

Alternatively, the Hanford and Livingston cleaned data can be downloaded in separate files:

Cleaned Hanford data, 4096 seconds, sampling rate 16384 Hz (uploaded August 22, 2017)

Cleaned Livingston data, 4096 seconds, sampling rate 16384 Hz (uploaded August 22, 2017)

Abnormal correlations in the LIGO data (AEI Hannover)

uploaded September 13, 2017

**A blind search for a common signal in gravitational wave detectors** (arxiv:1802.00340)

A blind method for extracting signals from strain data, without assumptions about the signal or noise properties

**Degeneracy of gravitational waveforms in the context of GW150914** (arxiv:1803.02350)

Demonstration of pronounced degeneracies in binary black hole parameters in cleaned data by the example of GW150914

## Cosmic microwave background

**Deep Space CMB observatory**

Measuring the CMB polarization from an observatory in Greenland

Project website