TITLE:   GCN CIRCULAR
NUMBER:  21575
SUBJECT: LIGO/Virgo G298048: Archival 2MASS and Spitzer non-detections of the potential LIGO EM counterpart SSS17a
DATE:    17/08/18 20:23:05 GMT
FROM:    Stephen Eikenberry at  U of Florida  <eiken@ufl.edu>

S. Eikenberry, K.Ackley, and S. Klimenko (U. Florida) report:

We have investigated archival 2MASS (28 Apr 1998) and Spitzer (12 Oct
2014) infrared observations of the field of SSS17a (Coulter et al. LVC GCN
21529). We find no evidence of a point-like source at this location. While
the presence of the host galaxy somewhat complicates sensitivity
estimates, in the case of 2MASS we have a preliminary estimate for a
3-sigma upper limit of J(Vega) ~ 17.6 +- 0.2 mag, which corresponds to
J(AB) ~ 18.5 +- 0.2 mag. This is a factor of ~2.5 fainter than the
J(AB)=17.5 mag detection of Tanvir et al. (LVC GCN 21544), indicating a
variable or transient nature for this source. More detailed analyses of
the upper limits for both 2MASS and Spitzer are forthcoming.

[GCN OPS NOTE(18aug17):  Per submitter's and author's request, the submitter
was changed from Singer to Eikenberry.  Singer submitted as Eikeberry's proxy,
because Eikenberry's GCN account was not yet activated.]