GLADE: A Galaxy Catalogue for Multi-Messenger Searches in the Advanced Gravitational-Wave Detector Era (1804.05709v2)

Abstract: We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localised electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA and SDSS-DR12Q. GLADE is complete up to $d_L = 37^{+3}_{-4}$ Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance $d_L$, and contains all of the brightest galaxies giving half of the total B-band luminosity up to $d_L = 91$ Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local universe.

GLADE: A Galaxy Catalogue for Multi-Messenger Astronomy

The paper "GLADE: A Galaxy Catalogue for Multi-Messenger Searches in the Advanced Gravitational-Wave Detector Era" presents a comprehensive and value-added full-sky catalogue of galaxies intended for the advanced gravitational-wave (GW) detection era. The Galaxy List for the Advanced Detector Era (GLADE) serves multiple purposes in the emergent field of multi-messenger astronomy, particularly facilitating the identification of host candidates for transient GW events, supporting electromagnetic (EM) follow-up observations, and aiding cosmological simulations.

Construction and Composition of GLADE

GLADE is curated by meticulously cross-matching data from five significant astronomical catalogues: the Gravitational Wave Galaxy Catalog (GWGC), 2MASS Photometric Redshift Catalog (2MPZ), 2MASS XSC, HyperLEDA, and the SDSS-DR12Q. This effort results in a catalogue comprising over 2.97 million galaxies, as well as quasars and globular clusters. The cross-matching minimizes redundancy by effectively eliminating duplicates using a robust k-dimensional tree method, enhancing the reliability of spatial and parametric data.

Crucially, GLADE includes comprehensive data such as right ascension, declination, luminosity distance, redshift, and magnitudes across several photometric bands (e.g., $B$, $J$, $H$, $K_s$). This breadth of data ensures its applicability to various research areas, notably the paper of the local universe's matter distribution.

Completeness and Statistical Validation

The completeness of GLADE is rigorously evaluated using two distinct methodologies. The first compares the integrated $B$-band luminosity of GLADE galaxies within certain distance limits with a reference value expected for a complete sample of galaxies in a homogeneously distributed universe. This approach illustrates that GLADE is complete up to about 37 Mpc based on cumulative $B$-band luminosities. Beyond this radius, the catalogue maintains significant completeness levels, with robustness demonstrated up to approximately 91 Mpc for the brightest galaxies.

A secondary method leverages the Schechter function, analyzing luminosity distributions in discrete distance shells to compare GLADE's content against theoretical expectations of galaxy distributions. The results indicate that while GLADE excels in cataloguing brighter galaxies, as distance increases, completeness for fainter galaxies diminishes, consistent with observational constraints.

Applications and Implications

GLADE supports various applications aligned with multi-messenger astronomy objectives. Notably, it aids in identifying host galaxy candidates for both detected GW events and poorly localized EM transients such as GRBs. This identification process is paramount in optimizing follow-up strategies, effectively enhancing the probability of capturing EM counterparts to GW detections.

The catalogue's integration into multi-messenger efforts was exemplified following the binary neutron star merger event GW170817, where astronomers were able to pinpoint the EM counterpart using GLADE. This integration underscores GLADE's critical role in advancing the detection capabilities and scientific insights achievable within the multimodal observational framework.

Future Developments

The authors articulate a commitment to enhancing GLADE's utility through continuous updates and expansions, including the incorporation of data from forthcoming surveys such as WISE and Pan-STARRS. There is also an ambition to integrate additional parameters like stellar mass estimates and binary neutron star (BNS) formation rates to enrich the catalogue's applicability to a broader spectrum of astrophysical research endeavors.

GLADE is poised to remain an important tool for upcoming gravitational-wave observational campaigns as GW detector sensitivities improve, cementing its role in the facilitation and advancement of multi-messenger astrophysics.

In conclusion, the paper documents a crucial resource for the astronomical community, noting both its current contributions and potential future impact in furthering our understanding of the universe through the complementary strengths of gravitational-wave and electromagnetic observations.