TY  - JOUR
A1  - Bulla, Mattia
A1  - Coughlin, Michael W.
A1  - Dhawan, Suhail
A1  - Dietrich, Tim
T1  - Multi-messenger constraints on the Hubble constant through combination of gravitational waves, gamma-ray bursts and kilonovae from neutron star mergers
JF  - Universe : open access journal
N2  - The simultaneous detection of gravitational waves and light from the binary neutron star merger GW170817 led to independent measurements of distance and redshift, providing a direct estimate of the Hubble constant H-0 that does not rely on a cosmic distance ladder, nor assumes a specific cosmological model. 
By using gravitational waves as "standard sirens", this approach holds promise to arbitrate the existing tension between the H-0 value inferred from the cosmic microwave background and those obtained from local measurements.
However, the known degeneracy in the gravitational-wave analysis between distance and inclination of the source led to a H-0 value from GW170817 that was not precise enough to resolve the existing tension. 
In this review, we summarize recent works exploiting the viewing-angle dependence of the electromagnetic signal, namely the associated short gamma-ray burst and kilonova, to constrain the system inclination and improve on H-0. 
We outline the key ingredients of the different methods, summarize the results obtained in the aftermath of GW170817 and discuss the possible systematics introduced by each of these methods.
KW  - gravitational waves
KW  - stars: neutron
KW  - stars: binaries
KW  - cosmology: cosmological parameters
KW  - cosmology: distance scale
KW  - cosmology: cosmic background radiation
Y1  - 2022
U6  - https://doi.org/10.3390/universe8050289
SN  - 2218-1997
VL  - 8
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Kunert, Nina
A1  - Pang, Peter T. H.
A1  - Tews, Ingo
A1  - Coughlin, Michael W.
A1  - Dietrich, Tim
T1  - Quantifying modeling uncertainties when combining multiple gravitational-wave detections from binary neutron star sources
JF  - Physical review D
N2  - With the increasing sensitivity of gravitational-wave detectors, we expect to observe multiple binary neutron-star systems through gravitational waves in the near future. The combined analysis of these gravitational-wave signals offers the possibility to constrain the neutron-star radius and the equation of state of dense nuclear matter with unprecedented accuracy. However, it is crucial to ensure that uncertainties inherent in the gravitational-wave models will not lead to systematic biases when information from multiple detections is combined. To quantify waveform systematics, we perform an extensive simulation campaign of binary neutron-star sources and analyze them with a set of four different waveform models. For our analysis with 38 simulations, we find that statistical uncertainties in the neutron-star radius decrease to 1250 m (2% at 90% credible interval) but that systematic differences between currently employed waveform models can be twice as large. Hence, it will be essential to ensure that systematic biases will not become dominant in inferences of the neutron-star equation of state when capitalizing on future developments.
Y1  - 2022
U6  - https://doi.org/10.1103/PhysRevD.105.L061301
SN  - 2470-0010
SN  - 2470-0029
VL  - 105
IS  - 6
PB  - American Physical Society
CY  - College Park
ER  -