GCN Circular 24592
Subject
LIGO/Virgo S190426c: NICER X-ray Follow-Up of ZTF19aassfws
Date
2019-05-19T02:37:16Z (6 years ago)
From
Dheeraj R. Pasham at Mass. Inst. of Technology <dheeraj@space.mit.edu>
Dheeraj Pasham (MIT), Keith Gendreau (NASA/GSFC), Zaven Arzoumanian
(NASA/GSFC), Stephen Eikenberry (UFL), Wynn C.G. Ho (Haverford) report on
behalf of the NICER team:
The transient ZTF19aassfws (Perley et al., GCN#24331) fell in the
LIGO/Virgo error box of the trigger S190426c (LVC et al., GCN#24237), and
Cenko et al. (GCN#24430) found that its distance is consistent with that
inferred from the gravitational wave signal. NICER observed this target for
7 ks, approximately half of which was in especially low background/high
sensitivity conditions.
We do not detect any X-ray emission above the background from this region.
Assuming an X-ray spectrum with a power-law index of 1.7 (similar to
GW170817) at a redshift of 0.093 with an absorbing column of 8e20 cm**-2
(Milky Way column), we estimate an upper limit on the unabsorbed 0.35-11.5
keV X-ray flux of 1.3e-13 erg/s/cm**2.
NICER can carry out prompt follow-up observations of transients and is
planning to systematically follow up alerts from LIGO/Virgo and other X-ray
bright extra-galactic transients in the future.
NICER is a 0.2-12 keV X-ray telescope operating on the International Space
Station. The NICER mission and portions of the NICER science team
activities are funded by NASA.