{ "bibcode": "2017GCN.20717....1F", "body": "R. Ferretti (OKC), R. Lunnan (Caltech), M. M. Kasliwal (Caltech), L. P.\nSinger (NASA/GSFC), S. B. Cenko (NASA/GSFC), D. Cook (Caltech), C. Cannella\n(Caltech), A. van Sistine (UWM), T. Barlow (Caltech), V. Bhalerao (IUCAA),\nJ. Rana (IUCAA), A. A. Miller (Northwestern/Adler), Y. Cao (UW)\n\nreport on behalf of the iPTF (intermediate Palomar Transient Factory) and\nGROWTH (Global Relay of Observatories Watching Transients Happen)\ncollaborations:-\n\nWe performed tiled observations of LIGO/Virgo G274296 (LVC, GCN 20689)\nusing the Palomar 48-inch Oschin telescope (P48) on the night of 2017-02-21\nUTC. We imaged 111 fields spanning 807 square degrees, with a 54% chance of\ncontaining the true location of the source. Of these, 69 fields (502 square\ndegrees; 42% probability) were imaged twice and searched for transient\ncandidates.\n\nDuring preliminary sifting through candidate variable sources using image\nsubtraction by our IPAC pipeline (Masci et al. 2016), and applying standard\niPTF vetting procedures, we flagged the following optical transient\ncandidates (60 total) for further follow-up:\n\nname RA Dec time mag\nz notes\n-------- ---------- ---------- ----- -----\n------ ---------\niPTF17bed 234.991732 +34.088243 2457806.0160 20.17\n0.138 photz; at edge of galaxy\niPTF17bec 232.665446 +33.928645 2457806.0160 19.90\n0.0482 specz; irregular galaxy; fading (0.34 mag intra-night)\niPTF17beb 235.828735 +32.682827 2457806.01757 19.03\n0.07 photz\niPTF17bdz 174.715936 +33.828372 2457805.90013 20.05\n0.0327 specz; nuclear edge-on\niPTF17bdy 178.129375 +35.456339 2457805.90162 20.30\n0.0943 specz; slightly off-center\niPTF17bdw 178.329915 +36.442293 2457805.90313 20.29\n0.18 photz\niPTF17bds 183.323594 +39.266026 2457805.9061 20.11\n0.13 photz; fading (0.40 mag intra-night)\niPTF17bdq 181.290430 +37.270222 2457805.90762 19.94\n0.0226 specz\niPTF17bdp 182.529730 +36.393440 2457805.90762 20.08\n0.2432 specz; nuclear (SDSS QSO)\niPTF17bdn 184.075520 +40.796273 2457805.93462 20.57\n0.136 photz\niPTF17bdl 183.608407 +42.063649 2457805.9346 19.65\n0.0231 specz; nuclear?\niPTF17bdk 186.611638 +40.726698 2457805.9346 20.55\n0.0699 specz; nuclear?\niPTF17bdj 185.368397 +42.208415 2457805.93462 19.51\n0.1206 specz\niPTF17bdf 188.315478 +36.824458 2457805.93763 19.68\n0.095 photz\niPTF17bde 187.281321 +36.457123 2457805.93763 19.58\n0.0714 specz; slightly off-center\niPTF17bdd 191.013043 +41.168996 2457805.93912 19.04\n0.0237 specz; nuclear?; rising (0.48 mag intra-night)\niPTF17bdc 192.553197 +36.464676 2457805.9421 20.49\n0.1448 specz; at edge of galaxy\niPTF17bda 193.915287 +39.855467 2457805.9436 19.21\n0.38 photz\niPTF17bcz 196.354965 +39.004452 2457805.9436 19.59\n0.0808 specz; off-center\niPTF17bcy 197.058084 +41.600850 2457805.9466 20.23\n0.0272 specz\niPTF17bcw 201.468624 +39.173964 2457805.94814 20.65\n0.0636 specz\niPTF17bcs 198.456906 +38.894402 2457805.94814 19.60\n0.0794 spez; nuclear\niPTF17bcr 200.757880 +40.201309 2457805.9481 20.35\n0.0640 specz\niPTF17bcn 201.030920 +42.445651 2457805.95116 19.99\n0.079 photz; nuclear\niPTF17bcl 207.110772 +41.975701 2457805.95416 20.44\n0.183 photz\niPTF17bck 208.258285 +40.302280 2457805.95715 19.85\n? no photz available\niPTF17bci 209.602490 +43.662936 2457805.95867 19.74\n0.065 specz; nuclear\niPTF17bch 209.362268 +44.387701 2457805.95867 19.65\n0.072 specz; nuclear?\niPTF17bcg 211.528986 +42.673631 2457805.96015 19.37\n0.088 specz\niPTF17bce 212.679949 +37.081015 2457805.96316 20.37\n0.224 photz\niPTF17bbv 174.674325 +36.232952 2457805.8986 18.27\n0.05996 specz\niPTF17bbu 167.125966 +31.440313 2457805.8911 19.70\n0.06 photz\niPTF17bbt 166.948991 +31.255977 2457805.8911 20.02\n0.087 photz\niPTF17bbs 166.950771 +31.311975 2457805.8911 19.95\n0.072 specz\niPTF17bbq 168.377846 +29.667545 2457805.8911 20.25\n0.0455 specz; =PS17bew (GCN 20699)\niPTF17bbp 166.537702 +30.246383 2457805.8911 19.95\n0.030 specz\niPTF17bbn 167.184990 +31.218324 2457805.8911 19.29\n0.073 specz; also detected 2017-02-17 (g=20.11); nuclear\niPTF17bbg 169.748759 +35.743451 2457805.89411 19.89\n0.104 specz\niPTF17bbf 170.901072 +34.765936 2457805.89411 19.60\n0.186 photz\niPTF17bbe 170.036330 +34.312810 2457805.89411 20.49\n0.037 specz; nuclear (SDSS AGN)\niPTF17bbb 170.475973 +33.961040 2457805.89411 20.11\n0.078 photz\niPTF17bba 170.464827 +33.845571 2457805.89411 19.88\n0.044 specz\niPTF17baz 170.427019 +34.363034 2457805.89411 19.05\n0.035 specz\niPTF17bav 168.441386 +37.278479 2457805.8956 19.61\n0.100 specz\niPTF17bat 171.393094 +40.511821 2457805.89712 20.01\n0.122 specz\niPTF17baq 134.698013 +01.842508 2457805.78102 19.70\n0.058 specz; nuclear?\niPTF17bap 134.438423 +00.933616 2457805.78102 19.80\n0.120 specz; nuclear\niPTF17bao 133.976313 +00.853143 2457805.78102 19.41\n0.053 specz; nuclear (SDSS AGN)\niPTF17bam 134.670596 +02.078209 2457805.78102 19.88\n0.125 specz; rising (0.35 mag intra-night)\niPTF17bal 138.036706 +06.780975 2457805.78255 19.72\n0.143 specz; nuclear\niPTF17bak 138.746540 +05.045414 2457805.78404 20.55\n0.143 specz; nuclear (SDSS AGN); rising (0.39 mag intra-night)\niPTF17bai 141.156805 +08.409091 2457805.78853 19.97\n0.129 specz; nuclear?\niPTF17bah 141.492784 +08.840897 2457805.78853 20.51\n0.107 specz; nuclear?; rising (0.59 mag intra-night)\niPTF17bag 137.893562 +06.774493 2457805.78255 20.20\n0.225 photz; nuclear\niPTF17bad 141.730214 +08.380390 2457805.78853 19.72\n0.122 specz; nuclear?\niPTF17baa 133.693265 +01.183738 2457805.78102 19.46\n0.066 photz\niPTF17aas 170.123758 +34.754070 2457805.89411 18.96\n0.042 specz; =SN2017aas=PTSS-17dib=PS17bey, known SNIa.\niPTF17mf 214.129450 +39.586295 2457805.96167 17.21\n0.0257 specz; =SN2017mf, known SNIa.\niPTF17jg 204.057109 +38.348005 2457805.94963 18.57\n0.014 specz; =ATLAS17aic, first discovered 2017-01-09\niPTF17hy 202.138887 +39.486881 2457805.94963 20.18\n0.064 specz; =Gaia17abk=PS17hc, first discovered 2017-01-12.\n\nPositions are stated in the ICRS. Times are in UTC. Magnitudes are based on\nimage subtraction; they are in the Mould R filter and in the AB system,\ncalibrated with respect to point sources in SDSS as described in Ofek et\nal. 2012.\n\nNone of the above transients show prior history of detection in iPTF\narchival images. All of the above transients coincide with a galaxy that is\nvisible in iPTF and/or SDSS images. Archival spectroscopic or photometric\nredshifts of the transients' likely host galaxies are given above.\n\nWe cross-matched this list to our ongoing effort to build a more complete\nCensus of the Local Universe (CLU; Cook et al. 2017) by identifying\nredshifted Halpha emitters out to 200 Mpc. The hosts of iPTF17bdq,\niPTF17bdl, iPTF17bcy, iPTF17bcn, iPTF17bbe, and iPTF17bbb, are viable\nemission line candidates.\n\nWe encourage spectroscopic classification of these candidates. In\nparticular, we highlight iPTF17bec, iPTF17bds, iPTF17bdd, iPTF17bam, and\niPTF17bah as fast-evolving by more than 0.3 mag in the same night. In\naddition, our local transients (d < 100 Mpc) are iPTF17jg, iPTF17bdq,\niPTF17bbp, iPTF17bdl, and iPTF17bdd, and our bright transients (R < 19 mag)\nare iPTF17bbv, iPTF17jg, iPTF17bdd, iPTF17baz, and iPTF17beb.", "circularId": 20717, "createdOn": 1487725893000, "email": "mansi@astro.caltech.edu", "subject": "LIGO/Virgo G274296: iPTF Optical Transient Candidates", "submitter": "Mansi M. Kasliwal at Caltech ", "eventId": "LIGO/Virgo G274296" }