TITLE: GCN CIRCULAR NUMBER: 39174 SUBJECT: LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume DATE: 25/02/06 21:55:45 GMT FROM: David Cook at Caltech/IPAC-NED dcook@ipac.caltech.edu

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 S250206dm-3-Initial 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 52020 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links:

Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250206dm/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250206dm/3/20

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 follow-up 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.

| objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J035607.76+573251.4| 59.03242| 57.54769| G| 410.56| null| null| null| 12.680| 0.123| 8.610| 0.006|5.19e-08| 6.11e-11| |WISEA J022843.33+542030.5| 37.18021| 54.34178| G| 408.50| null| null| null| 13.098| 0.150| 9.250| 0.006|9.06e-08| 5.22e-11| | MCG -01-57-002| 335.01662| -3.45381| G| 254.69| 0.65| null| null| null| null| 9.016| 0.006|1.75e-07| 4.70e-11| |WISEA J220219.95-113906.3| 330.58317| -11.65222| G| 302.43| null| 20.465| 0.149| 13.630| 0.229| 9.627| 0.006|1.87e-07| 4.02e-11| |WISEA J231640.26+192021.7| 349.16775| 19.33933| G| 508.89| null| null| null| 13.170| 0.139| 9.560| 0.006|5.70e-08| 3.72e-11| |WISEA J003646.96+403047.2| 9.19542| 40.51314| G| 463.14| 0.24| 20.697| 0.096| 13.700| 0.155| 9.758| 0.006|7.37e-08| 3.31e-11| |WISEA J215400.16-151308.9| 328.50075| -15.21903| G| 293.47| 1.21| 19.446| 0.077| 14.041| 0.269| 9.703| 0.006|1.64e-07| 3.10e-11| |WISEA J000430.95+335502.6| 1.12883| 33.91731| G| 495.19| null| null| null| 13.425| 0.157| 9.831| 0.006|6.26e-08| 3.00e-11| |WISEA J091707.96+104002.7| 139.28314| 10.66755| G| 245.27| 0.07| null| null| null| null| 9.503| 0.006|1.80e-07| 2.84e-11| |WISEA J235047.55+293551.6| 357.69817| 29.59772| G| 490.87| null| null| null| 12.766| 0.116| 9.929| 0.006|6.50e-08| 2.79e-11| |WISEA J090906.84+134338.0| 137.27863| 13.72719| G| 246.54| 0.03| 19.109| 0.048| null| null| 9.635| 0.006|1.91e-07| 2.71e-11| |WISEA J023348.85+553955.6| 38.45375| 55.66506| G| 554.10| null| null| null| 13.376| 0.194| 8.753| 0.005|1.44e-08| 2.47e-11| |WISEA J213220.13-230609.5| 323.08396| -23.10275| G| 152.92| 0.65| 20.276| 0.135| 12.046| 0.022| 9.287| 0.006|3.19e-07| 2.39e-11| | 3C 445| 335.95638| -2.10357| G| 250.91| 0.79| null| null| null| null| 9.765| 0.006|1.61e-07| 2.11e-11| | 2MFGC 07267| 140.43463| 7.28237| G| 239.49| null| null| null| 12.026| 0.087| 9.803| 0.006|1.77e-07| 2.03e-11| |WISEA J103204.15-302813.3| 158.01758| -30.47050| G| 526.75| 0.65| null| null| 12.749| 0.140| 9.417| 0.005|2.55e-08| 2.03e-11| |WISEA J111625.30-474423.2| 169.10533| -47.74000| G| 541.68| null| null| null| 13.677| 0.237| 9.277| 0.006|2.05e-08| 1.97e-11| |WISEA J004546.18+394932.4| 11.44258| 39.82569| G| 605.36| 0.24| 20.160| 0.035| 13.845| 0.185| 9.381| 0.005|1.82e-08| 1.97e-11| |WISEA J153057.77-694546.5| 232.74150| -69.76292| G| 373.52| null| null| null| 13.645| 0.271| 9.044| 0.006|3.31e-08| 1.87e-11| |WISEA J034501.09+571427.1| 56.25442| 57.24086| G| 395.20| null| null| null| 12.710| 0.124| 10.274| 0.007|7.34e-08| 1.75e-11|

Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S250206dm 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). Objtype is the object type of the galaxy candidate. 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).

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