TITLE: GCN CIRCULAR NUMBER: 21860 SUBJECT: LIGO/Virgo G297595: Las Cumbres Observatory Optical Follow-Up DATE: 17/09/12 00:48:45 GMT FROM: Griffin Hosseinzadeh at Las Cumbres Observatory G. Hosseinzadeh, I. Arcavi (Las Cumbres Obs./UCSB), M. Zalzman, D. Poznanski (TAU), L. P. Singer (NASA/GSFC), D. A. Howell, C. McCully, S. Vasylyev (Las Cumbres Obs./UCSB), S. Valenti (UC Davis), T. Piran (HUJI), D. Kasen, and J. Barnes (UC Berkeley) report optical follow-up observations of GW170814 (GCN 21474) using Las Cumbres Observatory's 2-meter telescopes at Haleakala Observatory (HO), Hawai'i, and Siding Spring Observatory (SSO), Australia. We observed 16 nearby galaxies from the GLADE catalog (Dalya et al. 2016, http://aquarius.elte.hu/glade/) prioritized by their position in the localization region, their mass, and inversely with their distance. A total of 49 images were obtained in the g, r, and i filters using 300-second exposures (full list below). We calculated 3-sigma limiting magnitudes by calibrating to nearby stars in the APASS catalog (Henden et al. 2009, AAS, 214, 407.02). Further analysis is ongoing. GLADE ID R.A. Dec. Dist. Date Time Site Filter Limit (deg) (deg) (Mpc) (UT) (UT) (mag) 723415 40.523499 -45.337452 433 2017-08-14 16:46:38 SSO g 21.5 723415 40.523499 -45.337452 433 2017-08-14 16:52:10 SSO r 21.2 723415 40.523499 -45.337452 433 2017-08-14 16:57:41 SSO i 20.4 721389 42.015915 -44.111561 476 2017-08-14 16:00:52 SSO g 21.3 721389 42.015915 -44.111561 476 2017-08-14 16:08:39 SSO r 21.4 721389 42.015915 -44.111561 476 2017-08-14 16:14:12 SSO i 21.7 787654 40.731670 -44.360573 443 2017-08-14 17:06:51 SSO g 20.8 787654 40.731670 -44.360573 443 2017-08-14 17:12:22 SSO r 18.9 787654 40.731670 -44.360573 443 2017-08-14 17:17:53 SSO i 21.6 556821 41.190659 -45.095711 441 2017-08-14 18:20:21 SSO g 20.2 556821 41.190659 -45.095711 441 2017-08-14 18:26:34 SSO r 19.0 556821 41.190659 -45.095711 441 2017-08-14 18:32:06 SSO i 17.4 625999 41.654194 -42.367088 308 2017-08-15 14:28:10 HO g 21.8 625999 41.654194 -42.367088 308 2017-08-15 15:08:26 HO g 21.4 625999 41.654194 -42.367088 308 2017-08-15 14:34:20 HO r 22.0 625999 41.654194 -42.367088 308 2017-08-15 14:39:52 HO i 21.8 706152 40.122471 -45.386868 494 2017-08-15 13:30:24 SSO g 20.4 706152 40.122471 -45.386868 494 2017-08-15 13:35:57 SSO r 20.5 706152 40.122471 -45.386868 494 2017-08-15 13:41:28 SSO i 20.2 752527 42.434814 -42.327412 322 2017-08-15 14:47:23 HO g * 752527 42.434814 -42.327412 322 2017-08-15 14:52:54 HO r * 752527 42.434814 -42.327412 322 2017-08-15 14:58:25 HO i * 1066576 41.292435 -46.597050 399 2017-08-14 17:27:53 SSO g 21.4 1066576 41.292435 -46.597050 399 2017-08-14 17:33:24 SSO r 21.5 1066576 41.292435 -46.597050 399 2017-08-14 17:38:56 SSO i 21.5 1005823 42.079330 -44.054893 451 2017-08-15 14:10:58 SSO g 20.5 1005823 42.079330 -44.054893 451 2017-08-15 14:16:30 SSO r 20.6 1005823 42.079330 -44.054893 451 2017-08-15 14:22:02 SSO i 20.3 1031304 41.217548 -46.500435 402 2017-08-15 14:53:00 SSO g 20.9 1031304 41.217548 -46.500435 402 2017-08-15 14:58:31 SSO r 20.8 1031304 41.217548 -46.500435 402 2017-08-15 15:04:03 SSO i 20.6 622864 41.392635 -44.539589 316 2017-08-14 19:12:39 SSO g 20.4 622864 41.392635 -44.539589 316 2017-08-14 19:18:10 SSO r 20.2 622864 41.392635 -44.539589 316 2017-08-14 19:23:41 SSO i 19.9 1415752 42.418404 -44.226032 422 2017-08-15 13:49:58 SSO g 20.4 1415752 42.418404 -44.226032 422 2017-08-15 13:55:31 SSO r 20.6 1415752 42.418404 -44.226032 422 2017-08-15 14:01:02 SSO i 20.3 1181112 41.086727 -43.939903 452 2017-08-15 14:32:00 SSO g 20.8 1181112 41.086727 -43.939903 452 2017-08-15 14:37:31 SSO r 20.7 1181112 41.086727 -43.939903 452 2017-08-15 14:43:03 SSO i 20.6 806902 42.062664 -45.159618 447 2017-08-14 16:25:24 SSO g 20.8 806902 42.062664 -45.159618 447 2017-08-14 16:30:55 SSO r 18.4 806902 42.062664 -45.159618 447 2017-08-14 16:36:27 SSO i 20.7 1647694 42.000800 -46.319860 382 2017-08-14 18:52:50 SSO g 21.5 1647694 42.000800 -46.319860 382 2017-08-14 18:59:02 SSO r 21.5 1647694 42.000800 -46.319860 382 2017-08-14 19:04:33 SSO i 20.5 62667 41.574863 -44.984894 488 2017-08-15 15:14:03 SSO g 20.8 62667 41.574863 -44.984894 488 2017-08-15 15:19:34 SSO r 20.9 62667 41.574863 -44.984894 488 2017-08-15 15:25:06 SSO i 20.5 *A limiting magnitude was not calculated for fields with very few APASS stars visible.