{
  "bibcode": "2019GCN.24331....1P",
  "body": "Daniel A. Perley (LJMU), Ariel Goobar (OKC), Mansi M. Kasliwal \n(Caltech), Michael W. Coughlin (Caltech), Adam A. Miller (Northwestern), \nTomas Ahumada (UMD), Jacob Jencson (Caltech), Harsh Kumar (IITB), David \nKaplan (UWM), Shreya Anand (Caltech),  Leo P. Singer (NASA GSFC), Igor \nAndreoni (Caltech), Varun Bhalerao (IITB), Danny Goldstein (Caltech), \nDmitry Duev (Caltech), S. Bradley Cenko (NASA GSFC),  Eric C. Bellm \n(UW), Kishalay De (Caltech),  Rahul Biswas (OKC), Kishalay De (Caltech), \nand Joshua Bloom (UCB) report on behalf of the Zwicky Transient Facility \n(ZTF) and Global Relay of Observatories Watching Transients Happen \n(GROWTH) collaborations:\n\nWe continued observations of the gravitational wave trigger S190426c \n(LVC et al. GCN 24237) with ZTF on UT 2019-04-28. We covered 1150 sq deg \nin g-band and r-band with over 54% of the enclosed probability targeted \nbased on the latest sky map (LALInference1.fits.gz, GCN 24277). Each \nexposure on the second night was 300s, with a typical depth of 22 mag. \nIn total, over both nights, we have covered 4420 sq deg, enclosing 56% \nof the the total probability. See details in Coughlin et al. (GCN 24283) \nfor additional details on data processing.\n\nAdditional candidates with no detections prior to merger, inside the 90% \nlocalization area of the LALInference sky map, and not consistent with \nthe locations of known AGN or other variable objects, are:\n\n------------------------------------------------------------------------------------------------\nZTF Name     | RA (deg)    | DEC (deg)  | Filt.| Mag.  | Magerr | Notes\n------------------------------------------------------------------------------------------------\nZTF19aasmftm | 325.9004479 | 77.8315634 |    g | 21.16 | 0.12   | [rising]\nZTF19aaslvwn | 299.059846  | 46.463559  |    g | 20.83 | 0.12   | [lowb]\nZTF19aasmdir | 300.2360007 |  9.504002  |    g | 20.35 | 0.09   | [lowb] \n[nuc] [agn?]\nZTF19aaslzjf | 320.6262982 | 65.8134516 |    r | 20.54 | 0.09   | [lowb]\nZTF19aassfws | 298.6678611 | 61.2400121 |    r | 21.41 | 0.20   | \nphotz~0.07 +/- 0.03 [nuc]\nZTF19aasmddt | 299.25055   |  9.7016748 |    g | 20.00 | 0.08   | \nphotz~0.08 +/- 0.04 [lowb]\nZTF19aaslszp | 301.3434628 | 53.3990477 |    g | 20.84 | 0.11   | \nphotz~0.062 [lowb] [nuc?]\nZTF19aasmekb | 300.6013987 | 14.2873159 |    g | 18.29 | 0.03   | [lowb] \n[hostless] [fading]\nZTF19aaslolf | 288.7838539 | 79.4357187 |    g | 21.33 | 0.19   | \nphotz~0.42+/-0.20 [nuc] [agn?]\nZTF19aaslphi | 297.3809977 | 61.9605925 |    g | 21.24 | 0.17   | \nphotz~0.16+/-0.02\nZTF19aaslpds | 306.2625186 |  61.521461 |    r | 20.99 | 0.13   | [lowb]\nZTF19aaslozu | 306.3144981 | 65.1093759 |    r | 20.87 | 0.16   |\nZTF19aasshpf | 315.4768651 | 70.2055771 |    r | 21.42 | 0.18   |\nZTF19aasmzee | 296.8366485 |  5.1534971 |    r | 20.33 | 0.09   | [lowb]\nZTF19aasmzqf | 353.5204911 | 78.9577781 |    g | 20.53 | 0.09   |\n----------------------------------------------------------------------------------------------\nNotes:\n[rising] : Rising light curve\n[lowb] : Galactic latitude less than 15 degrees\n[agn?] : WISE colors consistent within an AGN within 1\" of the transient.\n[hostless] : No discernable host galaxy or other counterpart.\n[nuc] : Close to the host nucleus.\n[fading] : Clear fading is observed over the past two nights, with no \nprior rise.  This may indicate a CV / dwarf nova.\n\nThree candidates (ZTF19aassfws, ZTF19aasmddt, ZTF19aaslszp) are \ninteresting given that their photometric redshifts are consistent with \nthe LVC error volume.  ZTF19aaslzjf is also in a galaxy that is likely \nnearby, although no redshift estimate is available.  ZTF19aasmftm is \ninteresting given a (probable) rising light curve that suggests a young \nobject, although its galaxy counterpart is very faint (r=21.2 in PS1). \nDeep upper limits preceding the detections are not available for any of \nthese sources, and they could be unrelated SNe.\n\nAdditional follow-up and analysis is ongoing.\n\nZTF and GROWTH are worldwide collaborations comprising Caltech, USA; \nIPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; \nDESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, \nJapan; IIT-B, India; IIA, India; LJMU, UK; TTU USA and USyd, Australia. \nZTF acknowledges the generous support of the NSF under AST MSIP Grant No \n1440341. GROWTH acknowledges generous support of the NSF under PIRE \nGrant No 1545949. Alert distribution service provided by DIRAC@UW \n(Patterson et al. 2019). Alert filtering and follow-up co-ordination is \nbeing undertaken by the GROWTH marshal system (Kasliwal et al. 2019).\n\n\n\n\n\n\n\n\n\n\n\n\n\nDisclaimerNone",
  "circularId": 24331,
  "createdOn": 1556469041000,
  "email": "d.a.perley@ljmu.ac.uk",
  "subject": "LIGO/Virgo S190426c: Additional Candidates from the Zwicky Transient Facility",
  "submitter": "Daniel Perley at Liverpool JMU  <d.a.perley@ljmu.ac.uk>",
  "eventId": "LIGO/Virgo S190426c"
}