GCN Circular 34092

David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC)
On behalf of the NASA/IPAC Extragalactic Database (NED) Team.

We spatially cross-matched the LVK S230627c-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 2531 galaxies within the 90% containment volume, and we list here the top 20 galaxies located in the 90% volume sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full list of galaxies in the 90% volume go to the NED Gravitational Wave Followup service (https://ned.ipac.caltech.edu/uri/NED::GWF/). 

The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic followup observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D*P_SFR; and specific star formation rate, P_3D*P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume.

Galaxy                                                          RA                    Dec                Dist       m_NUV mErr   m_Ks   mErr   m_W1  mErr    P_3D         P_3D_LumW1
                                                                       (Deg)               (Deg)            (Mpc)    (AB)       (mag)  (Vega)  (mag) (Vega)  (mag)  (Prob)       (Prob)
--------------------------------------------- ---------------- -------------- ---------- --------- --------- --------- -------- --------  --------  ------------ -------------          
     WISEA J102356.11+283710.630 |  155.98380 |  28.61961 |  249.69 | 19.76 |    0.09 | 11.75 |   0.06 | 10.19 |   0.01 | 8.89e-01 | 3.83e-03 
     WISEA J102356.11+283710.630 |  155.98380 |  28.61961 |  249.69 | 19.76 |    0.09 | 11.75 |   0.06 | 10.19 |   0.01 | 8.89e-01 | 3.83e-03 
     WISEA J103543.86+373517.630 |  158.93274 |  37.58823 |  247.97 |   nan |     nan | 12.46 |   0.08 | 10.53 |   0.01 | 7.89e-01 | 2.44e-03 
     WISEA J110213.02+645925.030 |  165.55424 |  64.99022 |  353.66 | 20.05 |    0.14 | 12.55 |   0.08 | 11.59 |   0.01 | 8.75e-01 | 2.09e-03 
     WISEA J105943.56+650406.730 |  164.93154 |  65.06841 |  382.69 |   nan |     nan | 13.16 |   0.13 | 11.84 |   0.01 | 8.96e-01 | 1.98e-03 
     WISEA J103213.97+401616.630 |  158.05814 |  40.27125 |  353.93 |   nan |     nan | 11.25 |   0.09 | 11.41 |   0.01 | 6.77e-01 | 1.91e-03 
     WISEA J105410.27+544851.830 |  163.54295 |  54.81439 |  321.95 | 19.72 |    0.14 | 13.25 |   0.05 | 11.46 |   0.01 | 7.72e-01 | 1.71e-03 
                              MCG +09-18-04530 |  163.34551 |  56.31446 |  348.07 |   nan |     nan | 12.61 |   0.02 | 11.43 |   0.01 | 6.13e-01 | 1.63e-03 
     WISEA J103906.07+444224.430 |  159.77528 |  44.70674 |  424.01 | 21.04 |    0.12 | 12.33 |   0.09 | 12.29 |   0.01 | 8.99e-01 | 1.62e-03 
     WISEA J103626.50+444349.830 |  159.11038 |  44.73046 |  423.33 |   nan |     nan | 13.20 |   0.11 | 12.34 |   0.01 | 8.94e-01 | 1.53e-03 
     WISEA J103228.87+400854.330 |  158.12024 |  40.14840 |  302.94 |   nan |     nan | 12.42 |   0.09 | 10.73 |   0.01 | 3.95e-01 | 1.52e-03 
                              MCG +10-15-12330 |  160.89709 |  58.10631 |  324.40 |   nan |     nan | 11.54 |   0.10 | 11.69 |   0.01 | 8.32e-01 | 1.52e-03 
     WISEA J110213.05+661002.630 |  165.55419 |  66.16735 |  353.71 |   nan |     nan | 12.15 |   0.09 | 11.98 |   0.01 | 8.70e-01 | 1.45e-03 
     WISEA J103141.11+360123.930 |  157.92133 |  36.02338 |  390.76 |   nan |     nan | 12.80 |   0.05 | 12.22 |   0.01 | 8.70e-01 | 1.42e-03 
     WISEA J103151.38+355744.630 |  157.96421 |  35.96247 |  398.10 |   nan |     nan | 12.79 |   0.13 | 12.31 |   0.01 | 8.88e-01 | 1.38e-03 
     WISEA J105404.26+544941.130 |  163.51771 |  54.82815 |  335.96 |   nan |     nan | 12.30 |   0.08 | 11.82 |   0.01 | 7.94e-01 | 1.38e-03 
     WISEA J103626.60+444407.830 |  159.11067 |  44.73547 |  414.76 | 20.71 |    0.08 | 13.01 |   0.09 | 12.37 |   0.01 | 8.62e-01 | 1.38e-03 
     WISEA J105336.54+545204.630 |  163.40236 |  54.86795 |  325.02 |   nan |     nan | 11.84 |   0.08 | 11.75 |   0.01 | 7.76e-01 | 1.35e-03 
     WISEA J103407.92+424833.130 |  158.53304 |  42.80921 |  402.87 |   nan |     nan | 12.61 |   0.09 | 12.33 |   0.01 | 8.60e-01 | 1.34e-03 
                              MCG +09-18-04130 |  162.94749 |  55.38566 |  336.20 |   nan |     nan | 11.39 |   0.07 | 11.42 |   0.01 | 5.14e-01 | 1.29e-03 
     WISEA J103747.36+394846.030 |  159.44730 |  39.81275 |  311.18 | 20.64 |    0.09 | 11.55 |   0.08 | 11.63 |   0.01 | 6.81e-01 | 1.21e-03 

Table: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S230627c sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D*P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1).