LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
Abstract
Swift UVOT reobserved the field of Swift J221951-484240 (Oates et al., GCN Circ. 25901), a candidate transient found in the UVOT search results of the LVC event S190930t (LIGO/VIRGO Collaboration GCN Circ. 25876). A search of this source in various catalogs shows only a weak IR source, however Swift observed a blue source which maintained its brightness in the second observation suggesting that this is not a flaring M-dwarf. The second tranche of observations began at 2019-10-02 16:14:34 UT 179ks after the LVC trigger. Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are: Filter Exp(s) Mag v 79 > 18.7 b 79 19.68+-0.36 u 79 18.57+-0.21 w1 157 17.95+-0.16 m2 249 17.91+-0.15 w2 315 18.11+-0.13 In the combined 1.1 ks of data collected so far, no X-ray source is detected to a 3-sigma upper limit of 9.9e-3 count s^-1 (equivalent to an observed flux ~4e-13 erg cm^-2 s^-1, assuming a typical power-law spectrum). This new blue transient requires spectroscopy for further identification, and we encourage spectroscopic followup of this transient. This circular is an official product of the Swift team.
- Publication:
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GRB Coordinates Network
- Pub Date:
- October 2019
- Bibcode:
- 2019GCN.25939....1O