//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2734 SUBJECT: GRB040924 (H3564): Optical afterglow candidate DATE: 04/09/24 13:04:49 GMT FROM: Derek Fox at CIT D.B. Fox and D.-S. Moon report on behalf of a larger collaboration: "We have imaged the localization region of GRB040924 (HETE Trigger 3564) with the robotic Palomar 60-inch telescope and CCD imager in the R-band. Comparison of a subset of these images to the digitized sky survey reveals the presence of a new, bright, stationary source that shows evidence of variability over the span of our observations. The coordinates of the source relative to the GSC-2.2 are: RA 02:06:22.45, Dec +16:06:48.72 (J2000) where the uncertainty in these coordinates is less than 2 arcsec. The source has R>~17 in our images." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2735 SUBJECT: GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE DATE: 04/09/24 15:19:21 GMT FROM: Roland Vanderspek at MIT GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE E. E. Fenimore, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; T. Donaghy, M. Galassi, C. Graziani, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki, T. Tamagawa, Y. Urata, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on behalf of the HETE WXM Team; N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; C. Barraud, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE FREGATE Team; report: The HETE Fregate and WXM instruments detected GRB 040924 (=H3564) at 11:52:11 UT (42731 SOD) on 24 September 2004. The WXM flight software localized the burst in real time, resulting in a GCN Notice 14 seconds after the burst trigger. The flight error region was a circle of 14 arcminutes radius (90% confidence) centered at RA = 02h 06m 40s, DEC = +16d 08' 10" (J2000). Ground analyses of the burst data allow the error region to be refined to a circle of 6.4 arcminutes radius (90% confidence) centered at RA = 02h 06m 19s, DEC = +16d 01' 26" (J2000). The burst is short, although not particularly hard: the burst durations, as measured by T50, are 1.2s, 1.0s, and 0.6s in the 7-30 keV, 7-80 keV, and 30-400 keV bands, respectively. Preliminary spectral analyses show GRB 040924 to have an Epeak of 42 +/- 6 keV. The 7-30 keV fluence is 1.6e-6 erg/cm2, and the 30-400 keV fluence is 2.6e-6 erg/cm2: the fluence ratio is 0.6, allowing us to classify GRB 040924 as an X-ray rich GRB. The empirical redshift indicator ("pseudo-z"; Atteia 2003) for GRB 040924 is 0.5. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2736 SUBJECT: IPN triangulation of GRB040924 (H3564) DATE: 04/09/24 16:59:51 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, HETE, and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, and E. E. Fenimore, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, S. Woosley, T. Donaghy, M. Galassi, C. Graziani, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki, T. Tamagawa, Y. Urata, T. Yamazaki, Y. Yamamoto, A. Yoshida, N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, G. Pizzichini, C. Barraud, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, report: This burst (H3564, GCN 2735) was observed by Mars Odyssey (HEND). Ulysses was off. We have triangulated it to a preliminary annulus centered RA, Decl. (2000)=359.188, -1.351 degrees, whose radius is 36.408 +/- 0.044 degrees (3 sigma). This annulus intersects the HETE WXM error circle at the following points: RA(2000) Decl.(2000) 31.630 +16.037 31.531 +16.236 31.528 +16.038 31.467 +16.159 The joint IPN/WXM error box has an area of ~70 sq. arcmin.; the candidate optical counterpart reported by Fox and Moon (GCN 2734) lies just at the outer edge of this error box. A map will be posted shortly at www.ssl.berkeley.edu/ipn3/040924. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2737 SUBJECT: GRB040924: MASTER Optical observations DATE: 04/09/24 18:06:17 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov, E.Gorbovskoy, N.Tyurina Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow At 5h 21m after HETE alert 3564 MASTER robotic telescope (http://observ.pereplet.ru) had imaging the corresponding area of the sky under the large zenit distance. The first image was started at 17h13m34s UT. Now we have 15 unfiltered images of the error box (45s exposition, 40 x 50 arcmin, 200 mm camera). Ther is no optical transient up to 17.5 m on all images and at position given Fox and Moon (GCN2734). Our unfiltred magnitude close to R filter. Sum FITS image are available at http://observ.pereplet.ru/images/GRB040924/ This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2738 SUBJECT: GRB040924: MASTER: OT decay DATE: 04/09/24 19:19:22 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov, E.Gorbovskoy, N.Tyurina Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow At 5h 21m after HETE alert 3564 MASTER robotic telescope (http://observ.pereplet.ru) had imaging the corresponding area of the sky under the large zenit distance (GCN 2737). The first image was started at 17h13m34s UT. Now we have 50 unfiltered images of the error box (45s exposition, 40 x 50 arcmin, 200 mm camera). Ther is no optical transient up to 18.5 m at position given Fox and Moon (GCN2734). Our unfiltered magnitude is close to R filter. So, we conclude that OT proposed by Fox and Moon can be real optical emission from GRB040929. Sum FITS image are available at http://observ.pereplet.ru/images/GRB040924/ This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2739 SUBJECT: GRB 040924, optical follow-up DATE: 04/09/24 21:47:19 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia D. Pérez-Ramírez (Univ. de Jaén), P. Tristram (Univ. of Canterbury), J. Gorosabel, M. Jelínek (IAA-CSIC, Granada), Ch. Okada (Nagoya Univ.), Ph. Yock (Univ. of Auckland), A. de Ugarte Postigo, S. Guziy and A. J. Castro-Tirado (IAA-CSIC) report: Following the detection by HETE-2 of the short/soft GRB 040924 (Fenimore et al. GCN Circ. 2735) we imaged the error box with the 0.6 m telescope at Mt. John Observatory (+ MOA camera) in the wide R-band filter. A 300-s single image was obtained through clouds starting on Sep 24, 13:53 UT (2.0 hr after the event). Additional images (3 x 300-s) were obtained at high airmass under clear sky conditions, about 5 hr after the GRB onset. At the position of the optical counterpart proposed by Fox and Moon (GCN Circ. 2734) we do not see any optical source down to about R = 19 and R = 20.5 at these two epochs. If this is the true optical counterpart, the fast decay would resemble the one of the proposed counterpart for the short/hard GRB 000313 as detected by BOOTES (Castro-Tirado et al. 2002, A&A 393, L55). A more in-depth analysis of the images is in progress. This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2740 SUBJECT: GRB 040924: RTT150 optical observations DATE: 04/09/25 00:24:06 GMT FROM: Irek Khamitov at TUG I. Khamitov, Z. Aslan (TUG), C. Yesilyaprak (AkUni), U. Kiziloglu (METU), A. Alpar (SabUni), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Bikmaev, N. Sakhibullin (KGU) report: We observed the error box of GRB 040924 (Fenimore et al., GCN 2735) with Russian-Turkish 1.5-m telescope (Bakyrlytepe, TUBITAK National Observatory, Turkey). We made a set of 300s exposures in R, starting at 20:50 UT, i.e. approximately 9 hours after the burst. Near the position of the OT given by Fox and Moon (GCN 2734) we detected a faint object, m_R=~22.1. Its coordinates: 02:06:22.56 +16:06:48.4 (2000.0) Astrometry was done using UCAC2 catalog, the accuracy is 0.1 arcsec. The object seems to be extended, therefore the host galaxy may contribute a significant fraction of the flux of this source. We will continue our observations in order to detect its possible fading behavior. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2741 SUBJECT: GRB040924: Optical afterglow properties DATE: 04/09/25 05:31:19 GMT FROM: Derek Fox at CIT D.B. Fox (Caltech) reports on behalf of a larger collaboration: "Further analysis of our Robotic P60 observations of the candidate optical afterglow of GRB040924 (GCNs 2734, 2735) reveals that the candidate afterglow fades by 0.87 +/- 0.08 mag from our first exposure (mean epoch 12:07:57 UT) to our last exposure (mean epoch 12:42:09 UT). Referenced to the time of the burst this corresponds to a decay with power-law index alpha approximately equal to -0.7. The coordinates of the candidate referenced to the GSC-2.2 are: RA 02:06:22.55, Dec +16:06:48.8 (J2000) with coordinate uncertainties of approximately 0.2". Photometric calibration of the data against the F-emulsion magnitudes of the GSC-2.2 yields an R-band magnitude of the candidate at our first epoch (945 sec after the burst) of R=18.0 mag. Images and a finding chart for the candidate may be found at: ." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2742 SUBJECT: GRB 040924: Subaru NIR observation DATE: 04/09/25 05:47:26 GMT FROM: Nobuyuki Kawai at Tokyo Tech H. Terada and M. Akiyama (Subaru Telescope, NAOJ) report: "We observed the field of the optical afterglow candidate (Fox and Moon, GCN 2734) of GRB 040924 (=H3564, Fenimore et al., GCN 2735) in the K'-band with IRCS on the 8.2m Subaru Telescope at 14:12-14:23 UT on September 24 (2.4 hours after the burst). At the position of the OT candidate, we detected a source with magnitude K'= 17.5." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2743 SUBJECT: GRB040924 : Optical candidate observations at Lulin observatory DATE: 04/09/25 10:04:48 GMT FROM: Kuiyun Huang at IANCU This is a multi-part message in MIME format. ------=_NextPart_000_00D2_01C4A32A.2491DEF0 Content-Type: text/plain; charset="big5" Content-Transfer-Encoding: quoted-printable GRB040924 : Optical candidate observations at Lulin observatory J.H. Hu, H.C. Lin (NCU) K.Y. Huang, Y. Urata, W.H. Ip, T. Tamagawa=20 on behalf of Lulin GRB collaboration report: We have observed the optical candidate of GRB040924 reported by Fox et al. (GCN 2734) with 1-m telescope at Lulin Observatory ( National Central University, Taiwan). We made B, V, R and I-band imaging observations starting at 14.31 UT (2.3 hrs after the burst). =20 Based on our preliminary analysis, the optical candidate was detected. The position of the candidate referenced to the USNO-B1.0 are=20 RA =3D 02:06:22.52, Dec =3D 16:06:48.5 (J2000) with uncertainties of approximately 0.2".=20 The R-band magnitude at 18.67 UT (6.7 hrs after the burst) is 21.4 mag. compared with near USNO-B1.0 stars as photometric references. Further analysis are in progress." This message maybe cited. ------=_NextPart_000_00D2_01C4A32A.2491DEF0 Content-Type: text/html; charset="big5" Content-Transfer-Encoding: quoted-printable GRB040924 : Optical candidate observations at = Lulin=20 observatory

J.H. Hu, H.C. Lin (NCU)
K.Y. Huang, Y. Urata, W.H. = Ip, T.=20 Tamagawa
on behalf of Lulin GRB collaboration = report:

 We have=20 observed the optical candidate of GRB040924 reported by Fox
et al. = (GCN 2734)=20 with 1-m telescope at Lulin Observatory ( National
Central = University,=20 Taiwan). We made B, V, R and I-band imaging
observations starting at = 14.31 UT=20 (2.3 hrs after the burst). 
 Based on our preliminary = analysis,=20 the optical candidate was
detected. The position of the candidate = referenced=20 to the USNO-B1.0
are

 RA =3D 02:06:22.52, Dec =3D = 16:06:48.5=20 (J2000)

 with uncertainties of approximately 0.2". =

The=20 R-band magnitude at 18.67 UT (6.7 hrs after the burst) is 21.4
mag. = compared=20 with near USNO-B1.0 stars as photometric = references.

 Further=20 analysis are in progress."

This message maybe cited.
 
------=_NextPart_000_00D2_01C4A32A.2491DEF0-- //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2744 SUBJECT: GRB040924 : Optical candidate observations at Lulin observatory DATE: 04/09/25 10:26:17 GMT FROM: Kuiyun Huang at IANCU GRB040924 : Optical candidate observations at Lulin observatory J.H. Hu, H.C. Lin (NCU) K.Y. Huang, Y. Urata, W.H. Ip, T. Tamagawa on behalf of Lulin GRB collaboration report: We apologize to send multi-part mesage at last report (GCN 2743). We submit our report again. We have observed the optical candidate of GRB040924 reported by Fox et al. (GCN 2734) with 1-m telescope at Lulin Observatory ( National Central University, Taiwan). We made B, V, R and I-band imaging observations starting at 14.31 UT (2.3 hrs after the burst). Based on our preliminary analysis, the optical candidate was detected. The position of the candidate referenced to the USNO-B1.0 are RA = 02:06:22.52, Dec = 16:06:48.5 (J2000) with uncertainties of approximately 0.2". The R-band magnitude at 18.67 UT (6.7 hrs after the burst) is 21.4 mag. compared with near USNO-B1.0 stars as photometric references. Further analysis are in progress." This message maybe cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2745 SUBJECT: GRB 040924: NIR finding chart DATE: 04/09/25 11:27:29 GMT FROM: Nobuyuki Kawai at Tokyo Tech H. Terada, M. Akiyama (Subaru Telescope, NAOJ) and N. Kawai (Tokyo Tech) report: "The finding chart based on the the K' band image of the Subaru IRCS observation (GCN 2742) is available at http://www.hp.phys.titech.ac.jp/nkawai/grb/040924/. The accuracy of the photometry (K'=17.5) is about 0.1 mag, as estimated from the scatter of photometric values for the OT in eight independent frames. " //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2746 SUBJECT: GRB 040924: WSRT Radio Observations DATE: 04/09/25 14:06:38 GMT FROM: Alexander van der Horst at U of Amsterdam A.J. van der Horst (University of Amsterdam), E. Rol (University of Leicester) and R.A.M.J. Wijers (University of Amsterdam) report on behalf of a larger collaboration: "We observed the position of the GRB 040924 afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at September 25, 0.41 - 7.36 UT, i.e. 12.54 - 19.49 hours after the burst (GCN 2735). We do not detect a radio source at the position of the optical afterglow (GCN 2734), with a 3 sigma upper limit of 0.12 mJy." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2747 SUBJECT: GRB040924: Afterglow magnitude at t=17.5hr DATE: 04/09/25 14:10:40 GMT FROM: Johan U. Fynbo at U.Copenhagen J. P. U. Fynbo (U. Copenhagen), A. Hornstrup (DSRI), J. Hjorth (U. Copenhagen), B. L. Jensen (U. Copenhagen), Michael I. Andersen (AIP) report on behalf or a larger collaboration: "We have observed the afterglow of GRB 040924 (Fenimore et al. GCN #2735; Fox et al. GCN #2734, GCN #2741) with the 2.56-m Nordic Optical Telescope on La Palma. By stacking 9 300sec exposures in the R-band with a mean epoch of Sep 25 5.25 UT we detect a source at the position of the candidate afterglow reported by Fox et al. Assuming a magnitude of R=19.1 for the nearby star U1050_00580520 we estimate that the afterglow flux is around R=22.1 17.5 hours after the burst. This implies the the lightcurve has become steeper than the slope of -0.7 during the first hour reported by Fox et al. (GCN #2741)." [GCN OPS NOTE: This circular was delayed 1.6 hr due to a change in the submiter's email domain.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2748 SUBJECT: GRB040924: KAIT observations DATE: 04/09/25 18:08:29 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li, A. V. Filippenko, R. Chornock, and S. Jha (University of California, Berkeley) report: "The Katzman Automatic Imaging Telescope (KAIT; see Li et al. 2003, PASP, 115, 844) at Lick Observatory robotically observed GRB 040924 (HETE Trigger #3564). Three batches of observations (a total of 34 images) were taken during the first 100 minutes after the burst. Our first exposure began at 11:52:55 UT, only 44 seconds after burst. Unfortunately, owing to the relatively small field of view of KAIT (6.7' x 6.7'), the OT reported by Fox and Moon (GCN 2734) was slightly outside our field of view in this image and in most of the subsequent images. The OT was detected only in two sets of images taken during our 2 x 2 mosaic procedure. From a 120 s unfiltered exposure that started at 12:18:21 UT, we measured a magnitude of 18.3 (USNO-A2.0 red mag calibrations) for the OT. The object declined to mag 19.2 in a 120 s image that started at 12:55:21 UT. Referenced to the time of the burst, this corresponds to a decay with power-law index alpha approximately equal to -1.0. We also obtained six 300 s KAIT unfiltered images (with the mean epoch at 8:50 UT) of GRB 040924 on Sep 25 UT. We did not detect the OT in the combined image, which has a 3-sigma limit of about mag 22.5." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2749 SUBJECT: GRB040924, RTT150 optical observation DATE: 04/09/25 18:40:55 GMT FROM: Irek Khamitov at TUG I. Khamitov, Z. Aslan (TUG), C. Yesilyaprak (Akdeniz Univ.), U. Kiziloglu (METU), E. Gogus, A. Alpar (Sabanci Univ.), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Bikmaev, N. Sakhibullin (KSU) report: We observed the error box of GRB 040924 (Fenimore et al., GCN 2735) with Russian-Turkish 1.5-m telescope (Bakyrlytepe, TUBITAK National Observatory, Turkey). During continuous observations of the afterdlow candidate from Sep. 24, 20:50UT to Sep. 25, 02:40UT (8.96--14.94 hours after the burst) weobtained 64x300s images in R. The observations were made under moderate atmospheric conditions. We found that the afterglow candidate (Fox and Moon, GCN 2734) faided by approximately 0.6 mag, from m_R=22.1 to 22.7, during our observations, which corresponds to power law decay with index -1.16. The absolute calibration was done according our mean photometric solutions. For comparison one can use star at 02:06:23.3 +16:07:13 wich has m_R=19.8 according to our solutions. Brighter magnitide, reported by Fynbo et al. (GCN 2747) most likely is due to the difference in absolute calibration. Our light curve can be found at: http://hea.iki.rssi.ru/~rodion/040924/lc_0924.jpg This message may be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2750 SUBJECT: GRB 040924: detection of possible host galaxy by Subaru DATE: 04/09/26 03:45:04 GMT FROM: Nobuyuki Kawai at Tokyo Tech H. Terada, M. Akiyama (Subaru Telescope, NAOJ) and N. Kawai (Tokyo Tech) report: "We have made the second epoch observation of the afterglow candidate (GCN 2734) of GRB 040924 (=H3564, GCN 2735) in the K'-band with IRCS on the 8.2m Subaru Telescope at 15:07-15:41 UT on September 25 (27.5 hours after the burst) for an integration time of 1200 seconds with an average seeing of 0.52 arcsec. At the position of the afterglow, we detected an extended source with magnitude K'=20.4 +/- 0.2. It is probably the afterglow of GRB 040924 with a significant contribution from its host galaxy. Comparison with the earlier flux (K'=17.5 at t=2.4 hr, Terada and Akiyama, GCN 2742) imply that the NIR afterglow decay index was steeper than -1. The image is available at http://www.hp.phys.titech.ac.jp/nkawai/grb/040924/." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2751 SUBJECT: GRB040924,optical observation DATE: 04/09/26 16:49:37 GMT FROM: Eri Sonoda at U of Miyazaki/Japan E.Sonoda,S.Maeno,Y.Matsuo,M.Yamauchi (University of Miyazaki) "We have observed the field covering the error box of GRB040924 (HETE trigger 3564; trigger time 11:52:11 UT) with unfiltered CCD camera on the 30-cm telescope at University of Miyazaki.The observation was started 15:53:50 UT on Sep.24. Observed field of view is 43 arcmin centerd on R.A.= 02h 06m 56.75s , Dec.= +16d 07m 27.5s,and include the position given by D.B.Fox and D.-S.Moon (GCN 2734). After co-adding a set of 3 images of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new sorce brighter than 16.6 mag." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2752 SUBJECT: GRB040924, RTT150 optical observation DATE: 04/09/26 21:01:40 GMT FROM: Irek Khamitov at TUG I. Khamitov, Z. Aslan (TUG), C. Yesilyaprak (Akdeniz Univ.), U. Kiziloglu (METU), E.Gogus, A. Alpar (Sabanci Univ.), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Bikmaev, N. Sakhibullin (KSU) report: We observed the afterglow of GRB 040924 (Fenimore et al. GCN 2735, Fox and Moon, GCN 2734) with Russian-Turkish 1.5-m telescope (Bakyrlytepe, TUBITAK National Observatory, Turkey). We made 33x300s images in R between Sep. 25, 23:45 UT, and Sep. 26, 2:45 UT. The observations were hampered by the bright-moon and bad seeing (1.7 arcsec). The object was clearly detected near the limit of the combined image. We estimate its magnitude to be m_R=23.7+/-0.2. This magnitude is consistent with power law decay with index -1.16, obtained in our previous observations (GCN 2749). The KAIT earlier measurements (GCN 2748) seem to be consistent with this power law as well. Therefore, to the first approximation, the whole light curve of the GRB 040924 afterglow can be described as a single power law with index -1.16. The combined light curve can be found at: http://hea.iki.rssi.ru/~rodion/040924/lc_all.jpg or http://www.tug.tubitak.gov.tr/~irekk/grb/grb040924/lc_all.jpeg The finding charts: http://hea.iki.rssi.ru/~rodion/040924/fcharts.html or http://www.tug.tubitak.gov.tr/~irekk/grb/grb040924/fcharts.html This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2753 SUBJECT: GRB040924,optical observation DATE: 04/09/27 14:30:35 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Pavlenko, S. Sergeev, V.Rumyantsev (CrAO), A.Pozanenko (IKI) report: We observed the field of the optical afterglow candidate (Fox and Moon, GCN 2734) of GRB 040924 (=H3564, Fenimore et al., GCN 2735) in the R (Johnson) band with APOGEE 47 on the 38-cm Cassegrain telescope of the Crimean Astrophysical Observatory. The observations were started at Sep. 24, 20:21 UT (i.e. 8.48 hours after the burst) and continued up to Sep.24, 23.13 UT. The sum of the first 3 images (3x190-s) yield the limiting magnitude 19.7 +- 0.2. No optical counterpart at the position proposed by Fox and Moon was found. For the sum of last 7x240 images taken between Sep. 24 23:08 - 23:46 UT no counterpart fainter than 21.0 +- 0.2 was detected. The limiting magnitudes were estimated in comparison of the USNO-B1.0 stars as photometric sequences. The limits are in agreement with OT magnitude estimation in simultaneous observation of I.Khamitov et al. (GCN 2749). This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2754 SUBJECT: Konus-Wind and Helicon-Coronas-F observations of GRB040924 DATE: 04/09/28 13:47:10 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, report: A soft short GRB040924 (=H3564, GCN 2735) was detected by Konus-Wind at 11.52.15.280 UT and Helicon-Coronas-F at 11:52:12.691 UT. It had a duration of approximately 1.5s in the 20-300 keV band. As observed by Konus-Wind it had a 20-500 keV fluence of (2.73 +/- 0.12)E-6 erg/cm2, a 20-500 keV peak flux (3.33 +/- 0.35)E-6 erg/cm2 s over 0.064 s, and Epeak of the time-integrated spectrum of 67 +/- 6 keV. We have triangulated it to an annulus: RA(2000) = 339.625 deg, Decl(2000) = -5.584 deg, Radius = 56.049 +/- 1.038 degrees (3 sigma). This annulus encompasses the HETE WXM error circle reported in GCN 2735. The center of the annulus passes 0.29 deg (0.84 sigma) from the center of HETE error circle and 0.25 deg (0.7 sigma) from the position of the OT given by Fox and Moon (GCN 2734). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2758 SUBJECT: radio observations, GRB 040924 DATE: 04/09/30 21:16:19 GMT FROM: Dale A. Frail at NRAO D. A. Frail (NRAO) and A. M. Soderberg (Caltech) report on behalf of a larger collaboration: "On 2004 Sept. 30.28 UT we used the VLA to observe a field centered on the candidate optical afterglow (GCN 2734) of GRB040924 (GCN 2735). There are no radio sources at 8.46 GHz in the vicinity down to a 3-sigma limit of 147 microJy. Further observations are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2759 SUBJECT: GRB 040924: Second Epoch WSRT Radio Observations DATE: 04/10/01 12:49:59 GMT FROM: Alexander van der Horst at U of Amsterdam A.J. van der Horst (University of Amsterdam), E. Rol (University of Leicester) and R.A.M.J. Wijers (University of Amsterdam) report on behalf of a larger collaboration: "We reobserved the position of the GRB 040924 afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope from September 29 19.06 UT to September 30 6.81 UT, i.e. 5.30 - 5.79 days after the burst (GCN 2735). The rms noise in het map around that position is 30 microJy per beam. The formal flux measurement for a point source at the location of the optical afterglow (GCN 2734) is 11 +/- 30 microJy. In conclusion, we do not detect a source at the optical position, in agreement with our previous WSRT measurements (GCN 2746) and the VLA measurements (GCN 2758). No further observations are planned." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2800 SUBJECT: GRB 040924: VLT spectroscopy DATE: 04/10/13 14:54:11 GMT FROM: Rhaana Starling at GRACE/U of Amsterdam Klaas Wiersema (University of Amsterdam), Rhaana L.C. Starling (University of Amsterdam), Evert Rol (University of Leicester), Paul Vreeswijk (ESO), Ralph A.M.J. Wijers (University of Amsterdam) report on behalf of the GRACE collaboration: "We have obtained two spectra of the host galaxy of GRB 040924 (GCN #2735, 2734) with the FORS2 long slit spectrograph on the ESO VLT (Antu) on 10 October 2004, approx. 15.75 days after burst. The first spectrum was taken at 05:10 UT using the 300V grism, with an exposure time of 1800 s; the second spectrum was taken at 05:48 UT using the 300I grism, again with an exposure time of 1800 s. We used a 1 arcsec slit. The total wavelength range is approx. 400 - 950 nm. We find weak emission lines in the spectra, which we identify with [OII] 3727, [NeIII] 3968.9, H gamma, H beta and [OIII] 4959,5007. All of these lines are consistent with a redshift z = 0.859. The presence of [NeIII] implies a galaxy with a significant population of massive stars. The isotropic energy of the burst is E_iso=1.48x10^52 erg, using the 25-100 keV fluence value from HETE and a cosmology with H_0=70 km/s/Mpc, Omega_matter=0.3 and Omega_lambda=0.7. As the lightcurve breaks fairly early on, the true energy is likely to be much lower. The presence of continuum features relating to a supernova can only be determined after further analysis: a SN1998bw-like bump would be expected to peak at approximately t_V~23.5 days, t_R~25 days and t_I~26 days with magnitudes V~25.4, R~24.6 and I~23.8. We acknowledge excellent support from the staff of Paranal Observatory and ESO's PSO and USG." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2811 SUBJECT: GRB040924, BVRcIc field calibration DATE: 04/10/16 02:36:15 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 (Fox and Moon, GCN 2734) for the HETE burst GRB040924 (trigger 3564; Fenimore et al., GCN 2735) with the USNOFS 1.0-m telescope on one photometric night. Stars brighter than V=14 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/grb040924.dat The astrometry in this file is based on linear plate solutions with respect to UCAC2. The external errors are less than 100mas. The estimated external photometric error is about 0.03mag and will be improved with additional calibration nights later this week, weather permitting. 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: 2833 SUBJECT: GRB 040924: Afterglow Color DATE: 04/11/08 17:34:49 GMT FROM: Matt Bayliss at UNC,Chapel Hill J. Silvey, D. Allen, M. Bayliss, M. Nysewander, T. Tilleman, A. Henden, M. Leake, A. Homewood, R. Canterna, D. Reichart, D. H. Hartmann, and M. Schwartz report on behalf of the U. Wyoming, U. North Carolina, USNO, and SARA GRB teams of the FUN GRB collaboration: We observed the afterglow location (Fox & Moon, GCN 2734) of the short/soft GRB 040924 (Fenimore et al., GCN 2735) in VRcIcH beginning 16.2 hours after the burst. Using the field calibrations of Henden (GCN 2811) and 2MASS, we report the following magnitudes: Start Mean Time Filter Exposure Magnitude Telescope Date Since GRB Time (sec) (1) (hours) x Exposures Sep 25.171 16.44 Rc 300 x 4 >18.9 0.9m SARA Sep 25.191 16.89 Ic 300 x 4 >20.6 0.9m SARA Sep 25.209 17.31 V 300 x 4 >19.6 0.9m SARA Sep 25.228 18.32 H 800 x 4 >19.5 1.55m NOFS Sep 25.328 21.18 Ic 300 x 24 >21.7 0.8m TII(2) Sep 25.391 21.86 Rc 300 x 3 22.68+/-0.07 2.3m WIRO Sep 25.395 21.96 V 300 x 3 23.06+/-0.07 2.3m WIRO (1) Limiting magnitudes are 2 sigma. (2) Tenagra II Compared to the R observations of Fox (GCN 2741) and Pavlenko et al. (GCN 2753), our Rc observation is generally consistent with a temporal index of approx. -1. Assuming a temporal index of -1.16 (Khamitov et al., GCN 2749) and using this index to scale our observations and the K' observation of Terada et al. (GCN 2750) to 21.9 hours after the burst, and correcting for Galactic extinction along the line of sight assuming that R_V = 3.1, yields a spectral index of -0.61 +/- 0.08: www.physics.unc.edu/~mbayliss/grbdata/grb040924spec.eps If source-frame extinction is negligible, this is consistent with either a constant-density or wind-swept medium with the cooling break blueward of the observed bands. It is inconsistent with either a constant-density or wind-swept medium with the cooling break redward of the observed bands (e.g., Sari, Piran & Narayan 1998, ApJ, 497, L17; Chevalier & Li 2000; ApJ, 536, 195). However, if source-frame extinction is non-negligible this is only consistent with a wind-swept medium with the cooling break blueward of the observed bands.