GCN Circular 20669

Sheng Yang (INAF-OAPd, UC Davis), Stefano Valenti(UC Davis), David
Sand (TTU), Leonardo Tartaglia (TTU, UC Davis), Enrico Cappellaro
(INAF-OAPd), Dan Reichart, Josh Haislip (UNC) report on behalf of the
Gravitational Wave Follow-Up by DLT40.

We report the observation of 25 galaxies within the LVC error region
for the GW trigger G270580 using the 'bayestar' GW localization map.
We selected 33 galaxies from the GWGC catalogue within 99% of the
trigger error region, within a distance of 20 Mpc, brighter
that -17.5 mag and at a Declination < 20 degree.
25 of those galaxies have been observed using the Prompt 5 telescope and are
part of the ongoing DLT40 search.
They represent the 1.33% of all galaxies within 20 Mpc
in the Glade catalogue within the LVC error region for the GW
trigger and contains 5% of all B band luminosity of those galaxies.
We started to observe these sample of galaxies on 2017-01-23 and
monitored them for 3 weeks after the GW trigger.
No interesting transients have been identified down to a limit magnitude of 19.2.


Below follow the list of galaxies observed:
Name           RA(J2000)  DEC(J2000) Dist(Mpc) BMAG KMAG
NGC0428     18.2317	0.9817         14.79        -19.12  -21.4648
NGC1249     47.505        -53.3359      14.19        -19.16  -21.4059
IC1954         52.8808       -51.9049     13.68        -18.98  -21.9344
NGC1546     63.6519      -56.0609      13.87        -18.21  -22.6574
IC2056         64.1022       -60.2068      15.0         -18.48  -21.7285
NGC1559     64.3989       -62.7836     12.59        -19.85  -22.4821
NGC1566     65.0016      -54.9378      6.55          -18.89  -22.1952
NGC1602     66.979        -55.0578      13.69       -18.48  -18.663
NGC1617     67.9156      -54.6019      13.87       -19.79  -23.6334
NGC1796     75.6777	 -61.1399     15.0         -18.28  -21.1815
NGC1947     81.6979	 -63.7613     13.87       -19.01  -23.2134
PGC018855 95.2321	 -8.4956       11.22       -18.39  -21.937
NGC2283     101.4718    -18.2122      9.86         -18.17  -19.8484
ESO494-026 121.546     -27.528        14.15       -19.86  -22.8778
NGC2640     129.3526    -55.1237      12.71       -20.17  -23.8057
NGC2784     138.0813    -24.1725      9.82         -19.42  -23.6386
NGC2835     139.4703    -22.3546      8.05         -19.03  -21.612
NGC3521     166.4524    -0.0358       11.22        -20.85  -24.467
NGC4123     182.0463    2.8782        14.86        -19.09  -22.0681
NGC4178     183.1929    10.8658      14.0          -19.37  -21.1556
NGC4192     183.4513    14.8993      13.61        -20.62  -23.7813
NGC4216     183.9762    13.15          14.13        -20.58  -24.2267
NGC4419     186.7357    15.047        13.49        -19.24  -22.9131
NGC4498     187.9144    16.852        14.06        -18.54  -21.0799
NGC4571     189.2349    14.2173      14.93        -19.12  -22.3523