NOAO < NEWS < Gravitational waves detected 100 years after Einstein’s prediction

Gravitational waves detected 100 years after Einstein’s prediction

Credit: SXS, LIGO Laboratory and T. Abbot & NOAO/AURA/NSF

Ripples in the fabric of spacetime produced by two merging black holes were detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO; top inset). The announcement comes 100 years after Albert Einstein’s prediction of the existence of gravitational waves and signals the opening of the gravitational wave Universe. The wide-field imaging capability of DECam at CTIO (bottom inset) was used to search for the optical counterpart of the gravitational wave event.

Detecting light from a gravitational wave event illuminates its underlying physics and astrophysical context. While LIGO is extremely sensitive to gravitational waves, it can only determine the direction of the event to within 100s of square degrees. The wide field-of-view of DECam is well suited to the need for timely follow up of these events.

DECam observations were used to search for an “optical counterpart” to GW150914, i.e., transient optical light associated with the gravitational wave event. No candidate counterparts were identified (Soares-Santos et al. 2016). The DECam observations were also used to investigate the possibility that the gravitational waves were caused by the core collapse of a luminous red supergiant rather than a merger of two black holes. The DECam observations, which included an area centered on the Large Magellanic Cloud (LMC), recovered all known LMC red supergiants: none of them had disappeared in the gravitational wave event (Annis et al. 2016).

These results are consistent with the interpretation that GW150914 was caused by a binary black hole merger.

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