GCN Circular 15575
D. Denisenko (Sternberg Astronomical Institute at Moscow State University) reports: The position of the optical transient iPTF13ecv (Singer et al., GCN 15524) in the Fermi field of GRB 131127B (von Kienlin, GCN 15528) was observed in the past with the NEAT project (Teegarden et al., ApJ Vol. 589, pp. L51-L53, 2003). A total of 87 images were obtained on 33 different nights from 1998 July 19 to 2005 Sep. 08. Images can be downloaded from the SkyMorph website at http://skyview.gsfc.nasa.gov/skymorph/obs.html The object at the position of iPTF13ecv was detected in outburst on four last nights, namely on 2005 Aug. 21, Sep. 01, 07 and 08. It was below the detection limit (typically 19.5-20.0m) on the other nights. The following photometry was obtained from the unfiltered NEAT images using SDSS J203153.05+005858.4 as a reference star with r=16.40: 20050821.372 17.0 20050901.371 18.1 20050908.271 19.3 The coordinates of the object measured from the combination of three 2005-08-21 images are (J2000.0): 20 31 47.76 +00 59 23.8, consistent to 0.4" with the position reported by Singer et al. and to 1" with those by Quadri et al. (GCN 15543). Comparison of NEAT images of the variable object in outburst (2005 Aug. 21, Sep. 01 and 08) and at quiescence is uploaded to http://master.sai.msu.ru/static/OT/iPTF13ecv-NEAT-2005.jpg (5'x5' FOV centered at the variable). Reference star is marked on the bottom left (2005-09-01) panel as 16.4r. No object is detected at this position on the combination of 26 good quality NEAT images to the limit ~22.5m. No previous outbursts were found on 15 DSS plates. Combination of DSS plates and SDSS color image suggests that the object is fainter than 23m at quiescence. 2005 outburst amplitude about 6 mag and duration of at least about 20 days are typical for superoutbursts of SU UMa-type dwarf novae. Thus, the cataclysmic variable nature of iPTF13ecv already determined spectroscopically by Keck telescopes (Singer et al., GCN 15574) is independently confirmed by the archival light curve, once again showing the powerful capabilities of data mining methods. This message can be cited.