{
  "version": 2,
  "body": "M. Huber (IfA, Univ. of Hawaii), K. W. Smith (QUB), K. Chambers, A.\nSchulz (IfA), S. Smartt, D. R. Young, O. McBrien, J. Gillanders. S.\nSrivastav, D. O'Neil, P. Clark, S. Sim (QUB), T. de Boer, J. Bulger,\nJ. Fairlamb, M. Huber, C.-C. Lin, T. Lowe, E. Magnier, R. J.\nWainscoat, M. Willman (IfA, Univ. of Hawaii), T.-W, Chen (MPE), A.\nRest (STScI), C. Stubbs (Harvard)\n\nWe report observations of the LALInference skymap of the NSBH event\nS190814bv (The LIGO Scientific Collaboration and the Virgo\nCollaboration, 25333, 25324) with the Pan-STARRS1 telescope (Chambers\net al. 2016, arXiv:1612.05560C). Images were taken in the PS1 i and z\nbands (Tonry et al. 2012, ApJ 750, 99).\n\nBeginning at 2019-08-15 12:40:37 UT (58710.5282) or 15.5hrs after the\ndetection of S190814bv, observations started in the i-band. We used\nthe updated LALInference.v1.fits.gz map for pointing coverage.\nObservations finished at 2019-08-15 15:13:38 UT.\n\nAt each pointing position a dithered sequence of 45 sec i-band and\nz-band images were taken. These were combined into a single night\nstack, covering the GPC1 camera chip gaps. These dithered sequences\nwere repeated, with overlaps, to map 18 square degrees of the\nLALInference.v1.gz map 90% credible region, corresponding to a summed\nprobability 89% of the skymap. We did not cover the smaller\nprobability blob to the south east at DEC=-32.\n\nConditions were somewhat affected by clouds, and moon, seeing was\naround 1.2 - 1.3 arcsec. 5-sigma limiting magnitudes were around i ~\n20.8 and z ~ 20.3.\n\nThe images were processed with the IPP (Magnier et al. 2016,\narXiv:1612.05240) and difference images were produced using the\nPan-STARRS1 Science Consortium 3Pi images as reference frames.\nTransient candidates were run through our standard filtering\nprocedures, combined with a machine learning algorithm (Wright et al.\n2015, MNRAS, 449, 451) were applied and all candidates were spatially\ncross-matched with known minor planets, and major star, galaxy, AGN\nand multi-wavelength catalogues (as described in Smartt et al. 2016,\nMNRAS, 462 4094), and already reported transients in the TNS before\nS190814by.\n\nAfter removing these, and requiring detections in BOTH i and z-band\nstacks, we were left with two transients. Both of which we discount as\npossible counterparts.\n\nName    | TNS Name  | RA (J2000)  | Dec (J2000) | Disc MJD |  i Mag err  | z Mag err\nPS19epf | AT2019noq | 00 48 47.88 | -25 18 23.4 | 58710.58 |  19.93 0.11 | 20.17 0.16\nPS19eph | AT2019nor | 00 49 51.99 | -24 16 17.7 | 58710.59 |  19.69 0.07 | 19.55 0.07 \n\nPS19epf is within the inner 20% contour. It is located 0.46\"S 3.96\"E\nfrom the centre of the galaxy PSO J012.1980-25.3064 (r = 18.3 Kron\nmag). The host has no measured photometric or spectroscopic redshift.\nHowever there are 4 separate, single night detections in the ZTF\npublic stream, from Lasair (Smith et al. 2019;\nhttps://lasair.roe.ac.uk/object/ZTF19abkhnce/), across the last 12\ndays. Hence it is most probably a SN exploding before the GW.\n\nPS19eph is within the inner 10% contour. However it is coincident with\nthe core of the B=18.67 galaxy 6dF J0049520-241618 at z = 0.436522\nfrom NED, and hence is not likely related to S190814bv.\n\nWe do not recover desgw-190814b (AT2019nme). Reported at i=19.33\nz=19.39, (58710.278) by Soares-Santos et al. GCN 25336. This is on the\nedge of our stack, but we estimate a 3-sigma limit of i~20.6 z~20.2.\nIf it is real, it implies a very fast fade in i-band of 1 mag in about\n8hrs. Deeper follow-up is required, and confirmation from the DECam\nteam if it is real.",
  "eventId": "LIGO/Virgo S190814bv",
  "email": "s.smartt@qub.ac.uk",
  "bibcode": "2019GCN.25356....1H",
  "subject": "LIGO/VIRGO S190814bv: No candidates from Pan-STARRS and non-detection of AT2019nme",
  "submitter": "Stephen Smartt at Queen's U/Belfast  <s.smartt@qub.ac.uk>",
  "circularId": 25356,
  "createdOn": 1565910905000,
  "editedOn": 1777052969821,
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>"
}