{
  "createdOn": 1777302106982,
  "body": "A. Moskvitin (SAO RAS), I. Zaznobin (IKI), M. Eselevich (ISTP),\nA. Volnova (IKI), N. Pankov (IKI), A. Pozanenko (IKI),\nreport on behalf of IKI-GRB-FuN:\n\nWe observed the optical counterpart of the fast X-ray transient\nEP260321a (Huang et al., GCN 44068; GCN 44075) identified early\nas SN 2026gzf (Lee et al., GCN 44070; Ma et al., GCN 44074;\nAguilar-Ruiz et al., GCN 44076; Aryan et al., GCN 44081;\nTanvir et al., GCN 44082; Moran et al., GCN 44083; Ahumada et al.,\nGCN 44084; Liu et al., GCN 44087; Sankar et al., GCN 44089;\nde Ugarte Postigo et al., GCN 44091; Xu et al., GCN 44092;\nPankov et al., GCN 44103; Corcoran et al., GCN 44105;\nRastinejad et al., GCN 44107; Gao et al., GCN 44110; Zhang et al.,\nGCN 44171; Li et al., GCN 44284; Gupta et al., GCN 44348;\nalso detected as NIR source: He et al., GCN 44117; Volnova et al.,\nGCN 44295) with AZT-33IK telescope (Mondy) equipped with the ADAM\nspectrograph (Afanasiev et al., Astrophysical Bulletin, 2015,\nVol. 71, Issue 4, p. 479; Burenin et al., Astronomy Letters, 2016,\nVol. 42, Issue 5, p. 295).\n\nWe obtained 4 x 900 sec spectra with VPHG600G grism\n(range 3600--7250AA, dispersion 3.6 A/pix) on 2026-04-13,\n15:02:08--16:02:47 UT(t_mid - T0 = 23.1265 days).\n\nIn the spectra we clearly detected host galaxy emission lines\nof Balmer series, [O III] 4959A, 5007A, 4363A, [O II] 3727A,\n[S II] 6717A and 6731A, He I 5876A at the redshift of z = 0.0343\nwhich is consistent with other reported measurements (Tanvir et al.,\nGCN 44082; Xu et al., GCN 44092; Corcoran et al., GCN 44105;\nRastinejad et al., GCN 44107).\n\nWe also detected broad lines of supernova SN 2026gzf which we\ninterpreted as Fe II and Si II with the velocity  of about 10000 km/s.\nComparison with the SNID (Blondin & Tonry, 2007, ApJ, 666, 1024)\nshowed best fit with SN 1997ef, SN 2006aj, SN 2002ap and SN 1998bw\nsupernovae.",
  "eventId": "EP260321a",
  "subject": "EP260321a/SN 2026gzf: spectroscopy at Mondy observatory",
  "submittedHow": "web",
  "circularId": 44412,
  "submitter": "Alexander Moskvitin at SAO RAS <mosk@sao.ru>",
  "format": "text/plain",
  "bibcode": "2026GCN.44412....1M"
}