{
  "circularId": 34577,
  "bibcode": "2023GCN.34577....1R",
  "createdOn": 1693164258873,
  "submitter": "Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 <osservatorionastroverde@gmail.com>",
  "eventId": "GRB 230824A",
  "subject": " Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico \"Nastro Verde\" optical observations",
  "body": "Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy\nin a large collaboration with:\nM.G. Dainotti (National Astronomical Observatory of Japan), \nY. Niino (Tokyo University, Institute of Astronomy), \nK. Kalinowski (Aarhus University, Department of Physics and Astronomy),\nB. De Simone (Universita' degli Studi Di Salerno)\nreport: \nFollowing the Swift trigger no. 1186959 (GCN 34537), we pointed at the coordinates RA(J2000)=17h 27m 46s: Dec(J2000)=-16d 12' 53\" and started our observations with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy.\nMember of: \nAAVSO - American Association of Variable Star Observers.\nUAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.\nAstroCampania Associazione.\n\nThe observations started at 19:23 UT of 2023/08/24, after about 5,25 hours after the GRB trigger, at the end of twilight with clear skies, with principal telescope  SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME\nI took 9 image of 120 sec each in fotometric V and 13 in Rc . All images, calibrated with masterdark and masterflat have been measured with Maxim DL software\nWe have detected a clear visible source at the enhanced position reported by Swift Burst Alert Telescope (BAT) (Page et al., GCN 34537 ) and by other telescopes ( Jamie A. Kennea (PSU) et al GCN 34540., S. Dichiara (PSU) et al GCN 34542, 34547, 34554,34555., Mohammad Odeh et al GCN 34543, 34561., H. Negoro (Nihon U). et al GCN 34544., Brendan O'Connor et al GCN 34549.,Dylan Dutton et al GCN 34556., T. M. Parsotan et al GCN 34557., U.Quadri et al GCN 34562., Claudio Lopresti et al GCN 34566., S. Leonini et al GCN 34573) \nat following position\n\nRA (J2000.0)   17:27:43.32\nDec (J2000.0) -16:12:19\n\nwith the following photometry:\n\n    JD\t           Mag\t        Filter\n2460181.317\t13.69            V\n2460181.32\t13.74            V\n2460181.323\t13.66            V\n2460181.326\t13.59            V\n2460181.329\t13.63            V\n2460181.332\t13.55            V\n2460181.335\t13.54            V\n2460181.338\t13.62            V\n2460181.341\t13.55            V\n\t\n\n\nJD\t          Mag\t       Filter\n2460181.309\t13.49            Rc\n2460181.31\t13.51            Rc\n2460181.312\t13.54            Rc\n2460181.313\t13.45            Rc\n2460181.315\t13.47            Rc\n2460181.318\t13.48            Rc\n2460181.321\t13.50            Rc\n2460181.324\t13.52            Rc\n2460181.33\t13.45            Rc\n2460181.333\t13.46            Rc\n2460181.336\t13.50            Rc\n2460181.339\t13.50            Rc\n2460181.342\t13.50            Rc\n\n\n\nThe magnitudes are calibrated with stars of the PanSTARRS catalog, espressed in AB system and are not corrected for the expected Galactic extinction.\n\nThe peculiar transient ( detected by other observatories ) is confirmed in our observations. Further observations are encouraged.",
  "submittedHow": "web"
}