Phil A. Evans (U. Leicester), Jamie A. Kennea (PSU), Scott Barthelmy
(NASA/GSFC), Dave Burrows (PSU), Sergio Campana (INAF-OAB), Brad Cenko
(NASA/GSFC), Neil Gehrels (NASA/GSFC), Paolo Giommi (ASI), Frank
Marshall (NASA/GSFC), John Nousek (PSU), Paul O'Brien (U. Leicester),
Julian Osborne (U. Leicester), David Palmer (LANL), Matteo Perri
(ASDC), Judy Racusin (NASA/GSFC), Mike Siegel (PSU), Gianpiero
Tagliaferri (INAF-OAB) on behalf of the Swift team:
P. D'Avanzo (INAF-OAB), S. Piranomonte (INAF-OAR), E. Cappellaro
(INAF-OAPd), M. Branchesi (Urbino University/INFN Pisa), E. Brocato
(INAF-OAR) on behalf of the INAF-GW collaboration:
Alessandra Corsi (Texas Tech), Shri Kulkarni (Caltech), Mansi Kasliwal
(Caltech), Dale Frail (NRAO) Avishay Gal-Yam (Weizmann Institute) on
behalf of the iPTF team:
Swift has observed the location of iPTF15dld (Singer at al., LVC Circ.
18497), which may be a type Ic supernova (Benetti et al., LVC Circ.
18563). The observations were gathered from 15.4 d to 15.9 d after the
aLIGO trigger, for a total of 10 ks observing time.
No X-ray emission is detected from iPTF15dld, with a 3-sigma upper limit
of 9.8e-4 ct/sec; this corresponds to an approximate 0.3-10 keV flux
limit of 4.9e-14 erg cm^-2 s^-1.
Swift-UVOT detected a bright source with a magnitude of 17.51 +/- 0.10
in the uvw1 filter, however this lies within the host galaxy, whose uvw1
magnitude is not known, thus the above magnitude is a combination of
host+source. Once the transient has faded, we will perform repeat
observations to measure the host flux and determine the correct
These Swift observations were performed in part through the Swift-GI
program 1114155 (PI: Corsi).
This circular is an official product of the Swift GW follow-up team.