//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12357 SUBJECT: IPN triangulation of GRB 110918A (long duration, extremely intense) DATE: 11/09/19 20:14:28 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Mars Odyssey and MESSENGER GRB teams, S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, A. von Kienlin, X. Zhang, V. Savchencko, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, and J. Goldsten, on behalf of the MESSENGER NS GRB team, report: The long-duration, extremely intense GRB110918A was observed by INTEGRAL (SPI-ACS), Konus-Wind, Mars Odyssey (HEND), and MESSENGER (GRNS) at 21:26:57 UT. Swift was in the SAA, and Fermi was Earth-occulted. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: ----------------------------------------------- RA(2000), deg Dec(2000), deg ----------------------------------------------- Center: 32.575 (02h 10m 18s) -27.281 (-27d 16' 51") Corners: 32.587 (02h 10m 21s) -27.114 (-27d 06' 51") 32.636 (02h 10m 33s) -27.237 (-27d 14' 14") 32.561 (02h 10m 15s) -27.447 (-27d 26' 48") 32.513 (02h 10m 03s) -27.324 (-27d 19' 27") ----------------------------------------------- The error box area is about 62 sq. arcmin., and its maximum dimension is about 20 arcmin. This localization can be improved. We note that this is the most intense burst observed in at least several years of IPN monitoring; details of the time history and energy spectrum will be given in a forthcoming GCN Circular. A Swift ToO observation has been scheduled. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12361 SUBJECT: GRB110918A: BOOTES-1 optical limit DATE: 11/09/20 11:10:50 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada M. Jelinek and A. J. Castro-Tirado (IAA-CSIC, Granada), on behalf of a larger collaboration, report: "We observed the error box of the extraordinarily intense GRB110918A detected by the IPN (Hurley et al. GCNC 12357) with the 0.3m BOOTES-1 robotic telescope in southern Spain. A 270x20s unfiltered coadded exposure taken under non-optimal conditions (low position in the sky, moonlight and fog) reached a limiting magnitude of ~17.0 at an exposure mean time of Sep 20, 1.09 UT (i.e. 27.65 hr after the onset of the high-energy emission). No new object is present within the entire IPN error box when compared to the DSS. Deeper optical/nIR observations are encouraged." This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12362 SUBJECT: Konus-Wind observation of GRB 110918A DATE: 11/09/20 11:18:01 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long exceptionally intense GRB 110918A (localized by IPN: Hurley et al., GCN 12357) triggered Konus-Wind at T0=77222.856s UT (21:27:02.856) The burst is the most intense long GRB event in the history of Konus-Wind observations since November, 1994. The light curve of event started with an extremely bright hard short pulse followed by three weaker partly overlapping peaks in the next 25 seconds. The emission during this part of the burst is seen up to ~12 MeV. A spectral lag between hard G3(1400-300 keV) and soft G1(25-90 keV) instrument's light curves of the initial bright phase of the event is estimated to a moderate value of ~0.090 s. A weak decaying emission in the soft energy channel G1(25-90 keV) continues till at least T0+250s when the measurements stopped. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110918_T77222/ As observed by Konus-Wind the burst had a fluence of 7.5(-0.2,+0.2)x10-4 erg/cm2, and a 16-ms peak flux, measured from T0+0.368 s, of 8.7(-0.4,+0.4)x10-4 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The best fit of the time-integrated spectrum of the burst (measured from T0 to T0+69.376 s) is achieved (in the 20 keV - 10 MeV range) with the GRB (Band) model, for which: the low-energy photon index alpha = -1.2 (-0.1, +0.1), the high energy photon index beta = -2.0 (-0.04, +0.03), the peak energy Ep = 150(-17, +20) keV, chi2 = 171/81 dof. The spectrum near the maximum count rate (measured from T0+0.256 to T0+0.512 s) is best fitted in the 20 keV - 10 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha = -0.34 (-0.02, +0.02), the high energy photon index beta = -2.5 (-0.1, +0.1), the peak energy Ep = 1150(-110, +120) keV, chi2 = 102/83 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12363 SUBJECT: GRB 110918A: pseudo-z= from prompt emission spectrum DATE: 11/09/20 13:31:38 GMT FROM: Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse J-L. Atteia (IRAP-UPS/CNRS)& A. Pelangeon report: We used the spectral parameters of GRB 110918A provided by Golenetskii et al. (GCNC 12362) to compute the spectral pseudo-redshift(**) of this burst localized by IPN (Pal'shin et al., GCNC 12358). We find a pseudo-redshift pz= 0.28 +/- .07 ** cf.http://cosmos.ast.obs-mip.fr/projet/v2/calculation_pz.html -- Jean-Luc Atteia atteia@ast.obs-mip.fr IRAP Observatoire Midi-Pyrenees Phone 0 561 332 884 14 Avenue E. Belin Internat. +33 561 332 884 31400 Toulouse - France Fax. 0 561 332 840 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12364 SUBJECT: GRB 110918A: Swift-XRT observations DATE: 11/09/20 13:32:36 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA), P. A. Evans (U Leicester), H. A. Krimm (GSFC/USRA) report on behalf of the Swift-XRT team: We have analysed 2.5 ks of XRT data for the IPN-detected burst: GRB 110918A (Hurley et al. et al. GCN Circ. 12357), from 107.4 ks to 113.6 ks after the IPN trigger. The data are entirely in Photon Counting (PC) mode. An new X-ray source is detected close to the edge of the XRT FoV. Using 2498 s of PC mode data and 6 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 32.53860, -27.10610 which is equivalent to: RA (J2000): 02h 10m 9.27s Dec(J2000): -27d 06' 22.0" with an uncertainty of 1.5 arcsec (radius, 90% confidence). This position is 640 arcsec from the IPN position, and outside the IPN error box. The light curve uses only the first 1.5 ks of data, since after this the source is too near the edge of the field of view for the light curve extraction tools to work. This light curve is consistent with a constant source of mean count rate 2.7e-01 ct/sec. A power-law fit gives an index of -1.320 (+3.525, -0.013). The source count rate is definitely above the 3 sigma upper limit of 0.08 ct/sec obtained from the analysis of RASS data. We believe that such a bright uncatalogued X-ray source close to the IPN error box is likely the afterglow of the GRB. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.12 (+0.28, -0.23). The best-fitting absorption column is 1.5 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 1.7 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.9 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.5 (+0.7, -0.6) x 10^21 cm^-2 Galactic foreground: 1.7 x 10^20 cm^-2 Excess significance: 3.9 sigma Photon index: 2.12 (+0.28, -0.23) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020186. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12365 SUBJECT: GRB 110918A: INT optical detection of Swift candidate afterglow DATE: 11/09/20 13:53:36 GMT FROM: Nial Tanvir at U.Leicester N.R. Tanvir, K. Wiersema (U. Leicester), A.J. Levan, S. Greiss,  B. Gaensicke (U. Warwick) report on behalf of a larger collaboration:  We observed the field of IPN burst GRB 110918A (Hurley et al. GCN 12357) with the Isaac Newton Telescope on La Palma, using the Wide Field Camera starting at 20-Sep-2011 02:22 UT, roughly 29 hours post-burst.  Close to the location of the X-ray source reported by Mangano et al. (GCN 12364) we detect a bright optical point-source which is not visible in the DSS2 images of the region. Very provisional calibration gives a magnitude R~19.0-19.5 (well above the DSS2 limit) and a position:  RA(2000)=02 10 09.39  dec(2000)=-27 06 19.6  accurate to ~0.5" in each coordinate.  We cannot yet assess variability. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12366 SUBJECT: GRB 110918A: GROND detection of the afterglow candidate DATE: 11/09/20 14:54:05 GMT FROM: Arne Rau at MPE J. Elliott (MPE Garching), T. Kruehler (DARK/NBI), S. Klose, D. A. Kann (both TLS Tautenburg), A. Rau and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of the IPN GRB 110918A (Hurley et al., GCN 12357) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile). Observations started at September 20, 2011, 02:37 which is roughly 29.2 hr after the trigger. They consisted of a dithered mosaic of 5 tiles covering the full IPN error box. The X-ray and optical afterglow candidate reported by Mangano et al. (GCN #12364) and Tanvir et al. (GCN #12365) however is only covered by the larger field of view of the NIR channels. We confirm the presence of a bright NIR source, and estimate a preliminary AB magnitude of J = 18.7 +/- 0.1 at a midtime of 08:04 UT, which has been derived by calibrating the field against stars from the 2MASS catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12367 SUBJECT: GRB 110918A: Afterglow Confirmation from PTF DATE: 11/09/20 15:08:34 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley), N. R. Tanvir (Leicester), E. O. Ofek (Caltech / Weizmann Institute), K. Wiersema (Leicester), A. J. Levan (Warwick), and P. E. Nugent (LBNL): As part of the Palomar Transient Factory (PTF), we have imaged the location of the afterglow candidate (GCN 12364, GCN 12365) of the IPN GRB 110918A (GCN 12357) with the robotic Palomar 48 inch telescope. Images began at 8:49 UT (dt ~ 35.4 hours after the burst trigger time) in the PTF R-band. Comparing our images with those obtained by the INT approximately six hours earlier (GCN 12365), we find the optical candidate has faded by 0.45 +/- 0.13 mag. The observed variability thus confirms that this object is the afterglow of GRB 110918A. Though with large uncertainties, the inferred power-law decay slope (alpha ~ 2.1) is quite steep for this period after the trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12368 SUBJECT: GRB 110918A: Gemini-N redshift DATE: 11/09/20 15:30:29 GMT FROM: Nial Tanvir at U.Leicester A.J. Levan (U. Warwick), N.R. Tanvir, K. Wiersema (U. Leicester), E. Berger (Harvard), D. Fox (Penn State) report on behalf of a larger collaboration: We observed the candidate optical afterglow of GRB 110918A reported by Tanvir et al. (GCN12365) with the GMOS-N spectrograph on Gemini-N, Mauna Kea.  Observations began at 20-Sep-2011 12:51 UT.  The trace is well detected and consistent with being a power-law continuum, confirming that this source is very likely the afterglow of the burst detected by the IPN (Hurley et al. GCN12357, see also Cenko et al. GCN12367).  We identify absorption features of MgII (2796A/2804A), MgI (2853A) and CaII (3935A/3970A) at a common redshift of z=0.982 (based on a provisional wavelength calibration). We thank the Gemini staff, particularly Jen Holt, for obtaining these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12369 SUBJECT: GRB 110918A optical observation DATE: 11/09/20 16:36:08 GMT FROM: AAVSO GRB Network at AAVSO Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland), Caisey Harlingten (Harlingten Observatory, San Pedro de Atacama, Chile), Bradley Schaefer (LSU), and Matthew Templeton (AAVSO) report the following follow-up optical observation of the error box of GRB 110918A (Hurley et al., GCN Circ. #12357): A. Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports an observation of the error box of the intense, long GRB 110918A (Hurley et al., GCNC #12357; Golonetskii, et al., GCNC #12362) using the Harlingten Observatory 0.5-m Planewave telescope with Apogee Alta-U42D9 CCD located in San Pedro de Atacama, Chile. Ten, 60-second unfiltered observations of the field containing the GRB error box were made; the coadded image has a midpoint time of 2011 Sep 20 07:33 UT (JD 2455824.8146), approximately 34 hours post burst. We find the point source detected by Mangano et al. (GCNC #12364) and Tanvir et al. (GCNC #12365) at a preliminary magnitude of R=19.0 measured relative to the nearby USNO-A2.0 star 0600-00854967 (B=18.8,R=17.7). Coadded images of the field are available at the following links: FITS: http://pilvi.dyndns.org/arto/GRB110918A_median.fit JPEG: http://pilvi.dyndns.org/arto/GRB110918A_median.jpg The AAVSO International High Energy Network was made possible through grants from the Charles Curry Foundation and from NASA, and is supported through the AAVSO Endowment. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12370 SUBJECT: GRB 110918A: rest-frame energetics in gamma-gays DATE: 11/09/20 17:43:34 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks and V.Pal'shin on behalf of the Konus-WIND team, report: Basing on the Konus-Wind detection of GRB 110918A (Hurley et al., GCN 12357; Golenetskii et al. GCN 12362), assuming Gemini-N redshift z=0.982 (Levan et al., GCN 12368), and a standard cosmology model (H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda = 0.73), we estimate the following rest-frame parameters of the prompt gamma-ray emission: the isotropic equivalent energy release is E_iso ~1.9x10^54 erg, the peak luminosity is L_iso_max ~ 4.4x10^54 erg/s, and the peak energy of the time-integrated spectrum is Ep_rest ~300 keV. This estimation of L_iso_max makes GRB 110918A the most luminous gamma-ray burst (with known redshift) ever observed by Konus-Wind. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12371 SUBJECT: GRB 110918A: Swift/UVOT Detection of the Optical Counterpart DATE: 11/09/21 03:56:54 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU), F. E. Marshall (NASA/GSFC), M. De Pasquale (UNLV), and H. A. Krimm (GSFC/USRA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110918A 153272 s after the IPN Trigger. A source consistent with the XRT position (Mangano et al., GCN 12364) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 02:10:09.33 = 32.53887 (deg.) Dec (J2000) = -27:06:19.6 = -27.10545 (deg.) with an estimated uncertainty of 0.55 arc sec. (radius, 90% confidence). Over approximately 18 ks of observation, we do not detect any statistically significant fading. Additional Swift/UVOT observations are planned. Preliminary detections using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 153272 154107 791 20.36+-0.13 white 158468 159889 1373 20.16+-0.08 white 163169 165670 2419 20.12+-0.05 white 168950 171166 2178 20.21+-0.06 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12375 SUBJECT: GRB 110918A: Spectroscopy from GTC DATE: 11/09/21 15:46:02 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (DARK/NBI), J. Gorosabel, A.J. Castro-Tirado and C.C. Thoene (IAA-CSIC) report on behalf of a larger collaboration: We have obtained spectroscopy of the afterglow of GRB 110918A (Hurley et al., GCN 12357, Mangano et al. GCN 12364, Tanvir et al., GCN 12365) using OSIRIS at the 10.4m GTC telescope at Roque de los Muchachos Observatory (Spain). Our data consisted of 3x900s exposures with the R500B grism, with a resolution of ~500 obtained with an average epoch of Sep. 21.106 UT (53.09 hr after the burst). In a preliminary reduction we detect absorption features of ZnII, FeII, MnII, MgII, MgI and CaII at a common redshift of 0.984+/-0.001, similar to the one derived by Levan et al. (GCN 12368). We acknowledge the excellent support of the GTC staff, in particular J.M. Gonzalez Perez, A. Cabrera Lavers and B. Gerken. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12376 SUBJECT: GRB 110918A: Swift-XRT refined Analysis DATE: 11/09/21 16:04:56 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA), P. A. Evans (U Leicester), H. A. Krimm (GSFC/USRA) report on behalf of the Swift-XRT team: We have analysed 13.1 ks of XRT data for GRB 110918A, from 107.4 ks to 211.3 ks after the IPN trigger (Hurley et al. GCN Circ. 12357). The data are in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Mangano et al. (GCN Circ. 12364). The light curve can now be modeled with a single power-law decay with index alpha=1.49 (+0.24, -0.25). This confirms the XRT source is the afterglow of the GRB. The PC mode spectrum has a photon index of 2.11 (+0.21, -0.19) and a best-fitting absorption column at redshift z=0.982 (Levan et al. GCN Circ. 12368) of 6.3 (+2.8, -2.1) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.0 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020186. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12381 SUBJECT: GRB 110918A: submm observations from APEX DATE: 11/09/21 21:30:55 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (DARK/NBI), C. De Breuck (ESO), A. Lundgren (ALMA/ESO) and M. Dumke (APEX/ESO) report on behalf of a larger collaboration: We have observed the afterglow candidate (Tanvir et al., GCN 12365) of the bright IPN GRB110918A (Hurley et al., GCN 12357) using APEX/LABOCA at Chajnantor (Chile). Observations where performed at 345GHz, using the photometric mode, with mean epoch Sep. 21.184 UT (54.97 hr after the burst) under good weather conditions (PWV ~ 0.25 mm). No flux is detected at the position of the afterglow, with a 3-sigma upper limit of 15mJy. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12382 SUBJECT: GRB 110918A: Liverpool Telescope optical observations DATE: 11/09/21 22:18:29 GMT FROM: Drejc Kopac at Math Phys U,Slovenia C. Guidorzi (U. Ferrara), D. Kopac (U. Ljubljana) and N. R. Tanvir (U. Leicester), on behalf of a large collaboration report: We observed the optical afterglow of GRB 110918A (Cenko et al., GCN 12367) with the 2-m Liverpool Telescope, starting at 01:07 UT on 2011 September 21. We took 6 images in R band with exposure time 300s and we clearly detect the optical afterglow. Our preliminary photometry yields: Mid time from Exp Filter Magnitude trigger (days) (sec) ------------------------------------------- 2.16 1800 R 19.7 +- 0.1 ------------------------------------------- The magnitude is calibrated against nearby USNO-B1.0 stars and is not corrected for the Galactic extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12388 SUBJECT: GRB110918A: Lick Observations DATE: 11/09/23 01:36:34 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley (Caltech), M. Ganeshalingam, P. Blanchard, and M. Mason (UC Berkeley) report: We observed the location of bright IPN GRB 110918A (Hurley et al, GCN 12357) starting at UT 2011-09-22 03:04:29 UT using the Nickel 40-inch telescope at Lick Observatory, under good seeing conditions at high airmass. A series of five 180-second exposures in R-band were acquired in total. The optical afterglow (Tanvir et al., GCN 12365) is well-detected in the combined stack. Using five nearby USNOB1.0 stars, we calculate the following photometry: R = 20.68 +/- 0.13 (t_mid = 3.2406 day) The uncertainty estimate does not include the uncertainty of the calibration to USNO (for convenience, our calibration stars are listed below). The measurement indicates a decay slope of approximately alpha=2.2 since the report of Guidorzi et al. (GCN 12382) and may suggest a very early jet break for this burst (see also Cenko et al., GCN 12367). USNO calibration stars: RA dec R2 032.546809 -27.104117 19.38 032.549492 -27.121698 19.29 032.555214 -27.117650 19.38 032.558045 -27.100853 19.39 032.569403 -27.106270 19.40 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12458 SUBJECT: GRB 110918A: Optical light curve for days 1.4 to 16.3 DATE: 11/10/19 12:14:28 GMT FROM: AAVSO GRB Network at AAVSO Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland), Bradley Schaefer (LSU), Caisey Harlingten (Harlingten Observatory, San Pedro de Atacama, Chile), and Matthew Templeton (AAVSO) report the following observations of GRB 110918A (Hurley et al., GCN Circ. #12357): A. Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports observations of the optical transient associated with the intense, long GRB 110918A at z=0.982 (Hurley et al., GCNC #12357; Golonetskii, et al., GCNC #12362; Mangano et al. GCN 12364; Levan et al. GCN 12368) using the Harlingten Observatory 0.5-m Planewave telescope with Apogee Alta-U42D9 CCD located in San Pedro de Atacama, Chile. The observations were made on 15 nights from 1.417 to 16.325 days after the burst, all without a filter so that the color sensitivity is like that of a broad R-band filter. We have calibrated the optical transient magnitude with the five comparison stars used by Perley et al. (GCN 12388) for which they quote the R-band magnitudes from the USNO catalog. Our magnitudes (plus two taken from the GCNs) are given in the following table: JD R(GRB) T-T0 (days) 2455824.8105 19.18 ± 0.04 1.417 2455825.5537 19.70 ± 0.10 2.160 (Guidorzi et al. GCN 12382) 2455825.7625 19.97 ± 0.05 2.369 2455826.6343 20.68 ± 0.13 3.241 (Perley et al. GCN 12388) 2455826.7059 20.51 ± 0.06 3.312 2455827.7137 20.85 ± 0.07 4.320 2455828.7067 21.14 ± 0.09 5.313 2455829.7193 21.26 ± 0.09 6.326 2455830.7107 21.56 ± 0.12 7.317 2455831.7025 21.34 ± 0.09 8.309 2455832.7116 21.62 ± 0.11 9.318 2455833.6930 21.90 ± 0.12 10.299 2455834.7065 21.76 ± 0.12 11.313 2455835.6894 21.58 ± 0.10 12.296 2455836.7208 21.67 ± 0.11 13.327 2455837.7159 21.94 ± 0.12 14.322 2455839.7185 21.99 ± 0.13 16.325 The flux up to 10 days after the burst is well fit by a power law with an index of -1.24. After 10 days after the burst, the light curve appears to flatten (i.e., the opposite of a jet break), for which we expect that the underlying galaxy is appearing in the light curve. There is certainly no jet break in the time interval from 1.417 to roughly 10-16 days after the burst. The index over this time interval is typical for the interval before the jet break, which implies that the jet break is at a time of greater than 10 days after the burst. The previous suggestion of an early jet break was simply due to one group looking at only two magnitudes with relatively large uncertainty (not counting inconsistencies in the two calibrations) and closely spaced in time and seeing an apparently steep slope. With our long interval with consistent magnitudes with small statistical uncertainty, we can be certain that the index is shallow and no jet break is present. The light curve of this GRB may be viewed at the following URL: http://www.aavso.org/sites/default/files/images/110918A_Oksanen.png The AAVSO International High Energy Network was made possible through grants from the Charles Curry Foundation and from NASA, and is supported through the AAVSO Endowment.