LIGO-Virgo S190426c
GCN Circular 24245
Subject
LIGO-Virgo S190426c: AGILE MCAL observation
Date
2019-04-26T18:52:06Z (6 years ago)
From
Martina Cardillo at INAF-IAPS <martina.cardillo@inaf.it>
M.Cardillo , G.Piano, A. Ursi (INAF/IAPS), F. Verrecchia� (SSDC, and
INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C.
Casentini, (INAF/IAPS), F. Lucarelli, C. Pittori,� (SSDC, and INAF/OAR),
A. Bulgarelli, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia
(INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report
on behalf of the AGILE Team:
In response to the LIGO-Virgo GW event S190426c at T0 =
2019-04-26T15:21:55.337 (UT), a preliminary analysis of the AGILE
minicalorimeter (MCAL)� data found no event candidates within a time
interval covering +/- 100 sec from the LIGO-Virgo T0.
Three-sigma upper limits (ULs) are obtained for a 1 s integration time
at different celestial positions within the accessible S190426c� 90%
c.l. localization region (that one which includes the Celestial North
Pole),� from a minimum of 1.27e-6 erg cm^-2 to a maximum of 2.16e-6 erg
cm^-2� (assuming as spectral model a single power law with photon index
1.5).
The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in
the energy range 0.4-100 MeV. Additional analysis of AGILE data is in
progress.
GCN Circular 24458
Subject
LIGO-Virgo S190426c: Pan-STARRS non-detection of ZTF19aassfws
Date
2019-05-10T17:55:38Z (6 years ago)
From
Stephen Smartt at Queen's U/Belfast <s.smartt@qub.ac.uk>
M. Huber, (IfA), S. J. Smartt (QUB), K. Chamber (IfA) K. W. Smith, D. R. Young, O. McBrien, J. Gillanders. S. Srivastav, S. J. Smartt, D. O'Neil, P. Clark, S. Sim (QUB), T. de Boer, J. Bulger, J. Fairlamb, C.-C. Lin, T. Lowe, E. Magnier A. Schultz, R. J. Wainscoat,
M. Willman (IfA, University of Hawaii)
We imaged ZTF19aassfws (Fremling et al. GCN 24433, Cenko et al. GCN 24430, Perley et al. GCN 24331, Coughlin et al. GCN 24283) with Pan-STARRS1 on UT 2019-05-09. This is the ZTF candidate within the skymap and distance range of s190426c
(the possible NS-BH candidate), which was detected at r=21.41.
A set of 6x300s exposures in i and z band filters were taken and stacked together. A custom made reference image in each filter was constructed (deeper than the public 3Pi stack of Chambers et al. 2016, arXiv:1612.05560) and subtracted this from the night stacks. The image quality was 0.75 arcseconds in the stacked frames.
We find no clear detection of significant excess flux at the positon of ZTF19aassfws, or at the core of the host galaxy in either band. There is some residual positive flux coincident with the galaxy core in each filter but this is not PSF in shape and is almost certainly a minor residual from the convolution and subtraction. Forcing photometry at the positon we find i =23.5 +/- 0.5 and z=22.5 +/- 0.3. We do not consider either to be significant detections and conclude there is no transient flux above these estimates.