{
  "subject": "LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart",
  "eventId": "LIGO/Virgo S190425z",
  "bibcode": "2019GCN.24305....1T",
  "createdOn": 1556402162000,
  "circularId": 24305,
  "submitter": "Aaron Tohuvavohu at PSU/Swift  <auc444@psu.edu>",
  "email": "auc444@psu.edu",
  "body": "Aaron Tohuvavohu (PSU), Phil Evans (U. Leicester), Mike Siegel (PSU),\nFrank Marshall (NASA GSFC), Brad Cenko (NASA GSFC) and Jamie Kennea\n(PSU) report on behalf of the Swift Gravitational Wave Galaxy Survey\n(SGWGS) team\n\nThe position of the potential Swift/UVOT counterpart (Breeveld et\nal. GCN. 24296) to the LIGO/Virgo S190425z trigger (LIGO/Virgo\nCollaboration GCN. 24168)  was imaged by the Neil Gehrels Swift\nObservatory on 2018, October 21/22 UT with the Swift\nUltraviolet/Optical Telescope in the u and uvw1 filters for a total\n1.2 ks of exposure as part of the Swift Gravitational Wave Galaxy\nSurvey (PI Tohuvavohu). Examining the image we do not detect any\nsource at the position of the counterpart candidate to a 5-sigma\nlimiting magnitude of ~21 mag in U-band, corresponding to  ~ -14 mag\nat the distance of the associated host galaxies (~100 Mpc).  These\nmagnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the event.\n\nThe Swift Gravitational Wave Galaxy Survey is a 5 Million second\npre-imaging survey of the ~14,000 most likely host galaxies for BNS\nmergers within ~100 Mpc. It is performed in the  u and uvw1 bands and\nwith XRT in the Photon Counting mode. It is currently ~43%\ncomplete. When complete it will cover 41.2% of the integrated B-band\nluminosity within 100 Mpc down to ~21 mag in u and uvw1 and\n~5 �� 10 ���13 erg cm ���2 s ���1 in the X-rays (0.3 - 10 keV)."
}