//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2858 SUBJECT: GRB 041218 - A long GRB detected by integral DATE: 04/12/18 17:09:58 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti, D. Gotz, (IASF, Milano), S.Shaw, M. Beck, A. Paizis (ISDC, Versoix), J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A 60 s long GRB has been detected with the INTEGRAL Burst Alert System (IBAS) on December 18 at 15:45:25 UT. The GRB has been detected with IBIS/ISGRI in the 15-200 keV band (IBAS Alert # 2072). Its coordinates (J2000) are: R.A.: 24.7731 [degrees], DEC.: 71.3346 [degrees] with an uncertainty of 2.5 arcmin (90% c.l. radius) The preliminary peak flux in the 20-200 keV range is about 3 photons/cmsq/s (1.6E-7 erg/cmsq/s) (1 s integration time). This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2860 SUBJECT: GRB 041218: Optical observations DATE: 04/12/18 21:21:08 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka University) reports: The entire error region of GRB 041218 (Mereghetti, et al., GCN 2858) was observed with the 14-inch Automated Response Telescope at Osaka University in Toyonaka. The observation started at 2004 December 18 15:47:34 UT while the early data suffered from cloud passages. In a stacked image (60-s x 4 frames obtained between 15:58 UT and 16:09 UT), we do not identify a new object brighter than about 16.0 mag (USNO-A2.0 R). On the other hand, we note a low S/N afterglow candidate (R~16.5) at position (R.A., Dec.) = (01 39 7.6, +71 20 30) (J2000) (1.5" uncertainty) in the preliminary analysis. === //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2861 SUBJECT: GRB 041218; optical candidate DATE: 04/12/18 21:37:13 GMT FROM: Javier Gorosabel at LAEFF-INTA, Madrid J. Gorosabel, A. de Ugarte, A.J. Castro-Tirado, M.Jelinek (IAA-CSIC), S. Pedraz (CAHA), report "We have acquired multicolour optical observations with the 2.2m CAHA telescope (+BUSCA) starting at ~18:00 UT at the position of GRB 041218 (GCN 2858). Visual comparison reveals an object that shows a clear decay. The position is: RA(J2000)=01:39:07.7 DEC(J2009)=+71:20:28.8 Further observations are in progress. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2863 SUBJECT: GRB041218: optical observations DATE: 04/12/19 01:03:41 GMT FROM: Patrizia Ferrero at IASF/CNR,Bologna G. Greco, C. Bartolini, A. Guarnieri, and A. Piccioni (Universita' di Bologna), P. Ferrero (IASF/CNR/ Bologna/ Osservatorio e Universita' di Teramo), G. Pizzichini (IASF/CNR/ Bologna) and R.Gualandi (INAF/ Bologna Observatory) report: We observed the error region of GRB 041218 (Mereghetti,et al.,GCN 2858) with the 152 cm telescope in Loiano (Bologna University) in clear sky conditions (seeing ~2.5). The first observation started at 18h05m58s UT; the acquisition sequence was: R band 15x600 sec exposures; B band 1x1200 sec; V band 1X600 sec; R band 1x600 sec. We detect the candidate reported by Torii (GCN 2860) and Gorosabel et al. (GCN 2861). Our very preliminary estimate of the magnitude of the afterglow candidate in the first frame is R ~ 19.5. More precise analysis is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2869 SUBJECT: GRB041218, BVRcIc field calibration DATE: 04/12/19 04:27:29 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) reports on behalf of the USNO GRB team: We have acquired BVRcIc all-sky photometry for a 11x11 arcmin field centered on the afterglow coordinates for the INTEGRAL burst GRB041218 (Mereghetti et al., GCN 2858; Torii GCN 2860, Gorosabel et al. GCN 2861) with the USNOFS 1.0-m telescope on one marginally photometric night. Stars brighter than V=13.0 are saturated and should be used with care. We have placed the photometric data on our anonymous ftp site: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb041218.dat The astrometry in this file is based on linear plate solutions with respect to USNOA2. The external errors are less than 300mas. The estimated external photometric error is about 0.04mag due to the poor seeing, and will be improved with additional calibration nights after Christmas. As always, you should check the dates on the .dat file prior to final publication to get the latest photometry. There is a README file on the ftp directory to give you information about the procedures used to calibrate these fields. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2873 SUBJECT: GRB 041218: Optical Observation DATE: 04/12/19 06:14:51 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern and S. Tuttle (Columbia U.) report for the erstwhile MDM Observatory GRB follow-up team: "We observed INTEGRAL GRB 041218 (Mereghetti et al. GCN #2858) in the R-band using the MDM 1.3m telescope under conditions of poor seeing. A total of 50 minutes of exposure centered at Dec. 19, 05:03 UT, or 13.3 hours after the burst showed a faint object of R = 22.15 +/- 0.25 at the position of the OT reported by Torii et al (GCN #2860), Gorosabel et al. (GCN #2861), and Greco et al. (GCN #2863). We use for comparison the USNO B1.0 star 1613-0027268 located at R.A. = 01h39m04s.17, Decl. = +71o21'06".0 (J2000) for which Henden (GCN #2869) gives Rc = 16.65. We note that there is considerable Galactic extinction in this direction, E(B-V)=0.63 corresponding to A_R=1.67 (Schlegel et al. 1998)." An image is posted at: http://www.astro.columbia.edu/~jules/grb/041218/ This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2875 SUBJECT: GRB041218: Continued P60 Optical Observations DATE: 04/12/19 09:32:31 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko reports on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We have continued to image the afterglow candidate of the Integral GRB041218 (GCNs 2858, 2860, 2861) with the robotic Palomar 60-inch telescope. We have obtained 9 x 180-second images in Johnson B and V, Kron R and I, and Gunn z filters. Extremely poor weather conditions (2 - 4 arcsecond seeing) have greatly limited our sensitivity. We were unable to detect the afterglow in any of our observed bands. The mean observing time and limiting magnitudes of our observations are outlined below: Filter UT (Dec. 19) Limiting Magnitude ---------------------------------------------------------------------- B 04:47 20.5 V 05:01 20.3 R 05:17 20.1 I 05:38 19.7 z 05:53 19.4 No further observations at the Palomar 60-inch are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2877 SUBJECT: GRB041218: optical observations DATE: 04/12/19 18:03:25 GMT FROM: Arto Oksanen at Nyrola Obs., Finland O. Trondal (otrondal@online.no) Oslo, Norway reports: "I observed the error region of GRB041218 for the INTEGRAL burst GRB041218 (Mereghetti et al., GCN 2858) with my 25cm Schmidt-Cassegrain telescope and unfiltered CCD (MX916) under clear sky conditions. I took 8 unfilterd 60 s images. The afterglow reported by Torii (GCN 2860) and Gorosabel et. al. (GCN 2861) is visible in the co-added image at RA 01:39:07.57 Dec +71:20:28.5 (2000.0, USNOA2.0 reference, average residual 0.4 arc secs), at magnitude V=18.6 +/- 0.2 using the field calibration by Henden (GCN 2896). The observation started 16:07:04 UT and ended 16:15:51 UT on December 18, 2004. Here is image and animation with DSS1 : http://www.geocities.com/Odd_Trondal/grb041218.htm" //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2878 SUBJECT: GRB041218: Liverpool Telescope optical observations DATE: 04/12/19 21:01:44 GMT FROM: Alessandro Monfardini at JMU/Liverpool Robotic Tele A. Monfardini (Liverpool), C. Mottram (Liverpool), C. Guidorzi (Liverpool), E. Rol (Leicester), C. Mundell (Liverpool), I. Steele (Liverpool), R. Smith (Liverpool), A. Gomboc (Ljubljana) report: "We observed the afterglow of GRB041218 with the 2.0m Liverpool Telescope on La Palma. We obtained RI imaging commencing 4.3 hours after the burst under poor seeing conditions. We report R and I estimates: I = 20.1 +/- 0.2 mag at Dec 18.840 (exposure time = 2x120s) R = 20.6 +/- 0.2 mag at Dec 18.837 (exposure time = 2x120s) These values were derived using Henden calibration (GCN 2869)" This message can be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2879 SUBJECT: GRB 041218: R-band optical observations DATE: 04/12/19 21:27:17 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy Paolo D'Avanzo, Stefano Ciroi, Daniele Malesani, Stefano Covino, Vincenzo Testa, and Angelo Antonelli, report on behalf of a larger Italian collaboration: "We observed the field of GRB041218 (Mereghetti et al., GCN 2858) starting about 6 hours after the trigger. Observations were performed with the 182cm Copernicus telescope equipped with the AFOSC instrument, at the Asiago Observatory (Northern Italy). Weather conditions were not optimal, with a seeing of 3". We detected the optical afterglow in the R filter (Torii, GCN 2860; Gorosabel et al., GCN 2861), with the following magnitudes (based on the calibration provided by Henden, GCN 2869): UT (mean) t-t0* mag error ------------------------------- Dec 18.912 6.1 h 21.37 0.15 Dec 19.061 9.7 h 22.41 0.46 t0 = Dec 18.6565 UT (burst explosion time). In the last epoch, the object is barely visible, but clearly faded since the first epoch. Our results are consistent with those reported by Greco et al. (GCN 2863), Halpern & Tuttle (GCN 2873) and Monfardini et al. (GCN 2878). Using all the available data, the decay index is alpha ~ 1.4 (F=K*t^-alpha) from ~2 to ~13 hours after the GRB. When comparing with the earliest measurement from Torii (GCN 2860), a steepening in the light curve is apparent. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2880 SUBJECT: GRB 041218 : Radio Observations DATE: 04/12/20 00:44:10 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) reports on behalf of the Caltech/NRAO/Carnegie GRB Collaboration: "We observed the field of GRB 041218 (GCN #2858) with the VLA at 8.5 GHz on 2004 Dec 19.21 UT (t ~ 0.55 days). We do not detect a radio counterpart to the optical afterglow reported by Gorosabel (GCN #2861) and place an upper limit of 0.07 mJy at the optical afterglow position." ----------------------------------------------------------------- Alicia M. Soderberg Office: 626.395.4095 Caltech Astronomy Mobile: 626.676.4723 MS 105-24 FAX: 626.568-9352 1201 E. California Blvd. Email: ams@astro.caltech.edu Pasadena, CA 91125 http://www.astro.caltech.edu/~ams ----------------------------------------------------------------- //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2888 SUBJECT: GRB 041218 Optical Observations DATE: 04/12/20 19:26:04 GMT FROM: Shashi Bhushan Pandey at State Obs.Nainital,India Kuntal Misra and S. B. Pandey (ARIES NainiTal), on behalf of larger Indian GRB collaboration We observed INTEGRAL GRB 041218 localization by Mereghetti et al. (GCN 2858) using 1.04m telescope at ARIES NainiTal, starting from Dec 19.66 UT. Several R_c band frames were observed in thin cloudy conditions. In a 300sec x 5 averaged frame, we put an upper limit of ~ 21 mag around 1.0 day after the burst at the OT position by Torii K. (GCN 2860), in comparison to the nearby stars using the field photometry by Henden (GCN 2869). This massage may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2892 SUBJECT: GRB 041218: Optical observations DATE: 04/12/21 07:15:34 GMT FROM: Daisuke Yonetoku at Kanazawa U D.Yonetoku, T.Murakami, H.Masui and Kanazawa GRB follow-up team report: We observed the INTEGRAL GRB 041218 (Mereghetti et al. GCN #2858) using the ISAS-Kanazawa automated 1.3m telescope at the roof top of the Institute of Space and Astronautical Science (ISAS) in Sagamihara city. The first observation started at 16:06:54 UT in a poor condition. The stacked image of 30sx20 revealed a faint object with Rc=17.6 with an error of 0.5 at the position reported by Torii and Gorosabel et al. (GCNs # 2860, 2861). This was the first detection of this system with a capability of R, J, H, K bands. Further analysis in progress. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2897 SUBJECT: GRB 041218: optical observations DATE: 04/12/23 17:25:42 GMT FROM: Graziella Pizzichini at IASF/CNR,Bologna P. Ferrero (IASF/CNR- Bologna/ Osservatorio e Universita' di Teramo), G. Pizzichini (IASF/CNR- Bologna), G. Greco, C. Bartolini, A. Guarnieri, and A. Piccioni(Universita' di Bologna), and R.Gualandi (INAF/ Bologna Observatory) report: We observed the optical afterglow of INTEGRAL GRB 041218 (Mereghetti et al.,GCN 2858) detected by Torii (GCN 2860) and Gorosabel et al. (GCN 2861), using the 152 cm telescope in Loiano (Bologna University) on December, 18 (Greco et al., GCN 2863) in clear sky conditions and strong winds (seeing ~3). Our photometric analysis of the images gives the following results: ---------------------------------------------------- Filter UT mean magOT exp ---------------------------------------------------- Rc Dec 18.758 19.74 +- 0.07 600s Rc Dec 18.765 19.74 +- 0.06 600s Rc Dec 18.781 20.04 +- 0.07 600s Rc Dec 18.792 20.27 +- 0.07 600s Rc Dec 18.800 20.58 +- 0.09 600s Rc Dec 18.807 20.45 +- 0.09 600s Rc Dec 18.814 20.64 +- 0.09 600s Rc Dec 18.824 20.63 +- 0.09 600s Rc Dec 18.840 20.81 +- 0.08 2x600s Rc Dec 18.854 20.90 +- 0.10 2x600s Rc Dec 18.872 20.75 +- 0.09 3x600s V Dec 18.906 >19.1 (1 sigma) 600s Rc Dec 18.913 >21 (1 sigma) 600s B Dec 18.895 >20.4 600s ---------------------------------------------------- In the time interval of our observations we find the same decay index alpha = 1.4 given by D'Avanzo et al., GCN 2879, with the possible exception of the Rc magnitude at UT 18.872, which is however still within 3 sigmas of the extrapolation from the other points. The following stars have been used: R.A.: 24.853910 Decl.:+71.385923 R.A.: 24.801607 Decl.:+71.360825 R.A.: 24.831858 Decl.:+71.343547 for Rc photometry; R.A.: 24.909680 Decl.:+71.278967 for V upper limit (Henden, GCN 2869); R.A.: 24.903450 Decl.:+71.379872 for B upper limit (USNOA.2). This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2904 SUBJECT: GRB 041218: TAROT optical observations DATE: 04/12/24 13:58:37 GMT FROM: Michel Boer at Obs Haute Prov. GRB 041218: Optical observations Klotz, A., Boer M. (OHP), Atteia, J.L., and G. Stratta (LATT) report: The field of GRB 041218 (Mereghetti, et al., GCNC 2858) was observed with the TAROT 25 cm robotic telescope at Calern, France. The unfiltered observations started at 2004 December 18 17:12 UT (beginning of the night). Due to a technical problem images were slightly defocused. We co-added 129 frames of 30s from 17:12 to 18:50 UT. The associated OT described by Torii (GCNC 2860) is detected 0.5 mag fainter than the nearby star USNO-B1 1613-0027278. Hence, we estimate its magnitude, R = 19.4 +/- 0.2. We analyzed the 2MASS catalogue to extract the galactic extinction through the line of sight of GRB041218. We used the method described in Klotz et al. (A&A 2004, vol 425, p427). From Earth to a distance modulus of about 8, the visual extinction is Av=1.45. The 2MASS data doesn't allow probing farer distances. This message can be cited.