{
  "body": "M. Lamoureux (UCLouvain), J.-G. Ducoin (IAP), Y.Tillayev (UBAI/NUUz), P. Hello (IJCLAB), R. Inasaridze, R. Natsvlishvili, N. Kochiashvili, S. Beradze, V. Aivazyan (AbAO), O. Burkhonov, Y. Rajabov (UBAI), S. Ehgamberdiev, T. Sadibekova (UBAI/CEA), R. Hainic, F. Rünger (UnP), I. Tosta e Melo (DFA/UNICT), L. Almeida, L. Fraga, W. Corradi, N. Sasaki (LNA), F. Navarete (NOIRLab/SOAR), F. Wang (THU/BJP), J. Zhu (BJP), L. Wang, X. Zeng, A. Iskandar (XAO), S. Antier, S. Gervasoni, S. Pormente (OCA), M. Coughlin (UMN), S. Karpov, A. Klotz (IRAP), T. Pradier (Univ. Stras.), D. Turpin (CEA), N. Leroy (IJCLAB), M. Masek (FZU), E. Gurbanov (ShAO) report on behalf of the GRANDMA collaboration:\n\n\nWe performed galaxy-targeted observations of the LIGO/Virgo S190627c event (GCN #34086) Abastumani-T70 telescope, UBAI-AZT-22, UBAI-NT60, UBAI-ST60, OST-CDK, NOWT, and OPD-60cm telescopes.\n\nThe target galaxies were selected from the list of potential host galaxies from the MANGROVE catalog [1] in the 90% credible area of the localization region of the LIGO/Virgo GW event (Bilby.multiorder.fits GCN #34087). Note that these galaxies are compatible within 3 sigma of the distance given by the GW event.\n\nA subset of the galaxies we observed is shown in the tables below. We report the center of each image. The field of view of each telescope is given in [2]. T-T0 is the time delay between the observation times and the GW trigger time. We did not detect any significant candidates and we report the upper limits of our images.\n\n\nRA,Dec          | Obser.         | T-T0 (day)| Filter   | Upp.Lim. (AB)\n________________________________________________________________________\n163.134,60.1863 | Abastumani-T70 | 0.69      | R        | 20.6 (3sig) \n162.6538,60.953 | Abastumani-T70 | 0.71      | R        | 20.2 (3sig)\n162.787,60.9992 | UBAI-AZT-22    | 0.60      | R        | 21.3 (3sig)\n162.754,61.5982 | UBAI-AZT-22    | 0.61      | R        | 21.3 (3sig)\n163.1923,60.0945| UBAI-NT60      | 0.60      | R        | 19.7 (3sig)\n163.326,60.8289 | UBAI-NT60      | 0.61      | R        | 19.7 (3sig)\n162.5432,63.2258| UBAI-ST60      | 0.58      | R        | 18.2 (3sig)\n165.6807,67.5331| UBAI-ST60      | 0.60      | R        | 20.5 (3sig)\n163.203,60.1212 | OST-CDK        | 0.88      | R        | 17.6 (5sig)\n163.322,60.5154 | OST-CDK        | 0.89      | R        | 17.4 (5sig)\n162.0689,58.8652| OST-CDK        | 0.90      | R        | 17.1 (5sig)\n162.763,60.9338 | OST-CDK        | 0.91      | R        | 17.1 (5sig)\n162.9998,61.5419| OST-CDK        | 0.92      | R        | 17.4 (5sig)\n163.9448,59.5613| OST-CDK        | 0.93      | R        | 17.0 (5sig)\n163.6954,64.0521| OST-CDK        | 0.94      | R        | 17.0 (5sig)\n162.6205,63.4638| OST-CDK        | 0.95      | R        | 16.3 (5sig)\n165.0186,66.4922| OST-CDK        | 0.96      | R        | 16.5 (5sig)\n153.8253,23.8459| OPD60          | 0.81      | R        | 18.7 (5sig)\n152.1807,20.2581| OPD60          | 0.82      | R        | 19.6 (5sig)\n157.2987,24.1633| OPD60          | 0.83      | R        | 19.6 (5sig)\n152.4550,21.9925| OPD60          | 0.84      | R        | 19.7 (5sig)             \n\nAbAO and UBAI observations have been calibrated using nearby stars from the Pan-STARRS catalog in sdss r, g, i and z, measured with STDpipe [3]. OST-CDK uses the APASS catalogs. OPD observations use Gaia/DR3 and RPmag for calibration.\n\nThe GRANDMA telescope network also observed the ZTF candidates (Anumarlapudi et al. GCN 34089). However, according to Fulton et al. GCN 34096, AT2023lxu and AT2023lxt are sources with an history prior to the GW alert. We report only our classification for AT2023lxx and AT2023lxs.\n\nAs time reference (T0), we choose: for AT 2023lxs 2023-06-27T04:38:47.999 UT (60122.19361110 MJD); for AT 2023lxx 2023-06-27T05:47:03 UT (60122.24100694 MJD) \n\nIn the following table, we report a subset of the preliminary photometry of our observations.\n\nZTF23aaptudb/AT2023lxs:\n\nT-T0 (day) |MJD   | Obser. |Exposure| Filter | Upp.Lim. (AB)\n________________________________________________________________________\n0.46  |60122.64983| NOWT    |4x200s | B      | 20.4 (5sig)\n\nZTF23aaptusa/AT2023lxx:\n\nT-T0 (day) |MJD   | Obser. |Exposure| Filter | Upp.Lim. (AB)\n________________________________________________________________________\n0.44  |60122.67498| NOWT   |4x200s  | B      | 20.6 (5sig)\n\nOur observations have been calibrated using nearby stars from the Pan-STARRS catalog in g and with color correction to convert it in B using STDPipe [3].\n\nThe galaxies of ZTF23aaptudb/AT2023lxs and ZTF23aaptusa/AT2023lxx in B-band are detected at a level consistent with catalogs and no clear decrease of the sources is detected. This is in agreement with data available at https://www.wis-tns.org/object/2023lxs, https://www.wis-tns.org/object/2023lxx, and Ahumada et al. #GCN 34100.\n\nGRANDMA is a worldwide coordinated telescope network (grandma.ijclab.in2p3.fr)  devoted to the observation of transients in the context of multi-messenger astrophysics [4]. Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).\n\n[1] Ducoin et al. 10.1093/mnras/staa114\n[2] Agayeva et al. 10.1117/12.2630240\n[3] Karpov: STDPipe software (https://ascl.net/2112.006)\n[4] Antier et al. 10.1093/mnras/staa1846",
  "bibcode": "2023GCN.34130....1L",
  "submitter": "Mathieu Lamoureux at UCLouvain <mathieu.lamoureux@uclouvain.be>",
  "subject": "LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates",
  "createdOn": 1688247827332,
  "circularId": 34130,
  "eventId": "LIGO/Virgo/KAGRA S230627c"
}