This file contains both the "A" and "B" bursts. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8000 SUBJECT: GRB 080723: Swift detection of a burst DATE: 08/07/23 04:40:07 GMT FROM: David Palmer at LANL M. Stamatikos (NASA/ORAU), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), S. T. Holland (CRESST/USRA/GSFC), S. D. Hunsberger (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 04:19:24 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080723 (trigger=317662). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 274.512, -6.923 which is RA(J2000) = 18h 18m 03s Dec(J2000) = -06d 55' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Because the BAT light curve has not been received, we cannot comment on the burst profile at this time. However, there is a strong 8.4 sigma excess detected in the scaled map image, which strongly suggests a real gamma-ray burst occurred. The XRT began observing the field at 04:20:50.2 UT, 85.8 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 274.48985, -6.89931 which is equivalent to: RA(J2000) = 18h 17m 57.56s Dec(J2000) = -06d 53' 57.5" with an uncertainty of 2.7 arcseconds (radius, 90% containment). This location is 116 arcseconds from the BAT onboard position, within the BAT error circle. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.94e+21 cm^-2, Kalberla et al. 2005), with an excess column of 5.7 (+6.36/-4.59) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 92 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 0% of the XRT error circle. The 8'x8' region for the list of sources generated on- board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large Galactic expected extinction corresponding to E(B-V) of 1.3 mag. Burst Advocate for this burst is M. Stamatikos (michael AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8001 SUBJECT: GRB 080723: Enhanced Swift-XRT position DATE: 08/07/23 10:42:19 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 5309 s of XRT Photon Counting mode data and 9 UVOT images for GRB 080723, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 274.49035, -6.89952 which is equivalent to: RA (J2000): 18h 17m 57.68s Dec (J2000): -06d 53' 58.3" with an uncertainty of 1.7 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8002 SUBJECT: GRB 080723B : a long GRB detected with INTEGRAL DATE: 08/07/23 14:28:26 GMT FROM: Diego Gotz at CEA D. Gotz (CEA-Saclay), A.Paizis, S.Mereghetti (IASF-Milano), V.Beckmann, M. Beck, A. Manousakis (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A bright GRB lasting about 105 s has been detected by IBAS in IBIS/ ISGRI data at 13:22:19 UT on July 23rd 2008. The refined position is R.A.: 176.8354 deg Dec.: -60.2452 deg with an uncertainty of 1.5 arcmin (90% c.l.). The burst is very bright and has saturated the available telemetry share. Hence the following preliminary spectral results are to be considered lower limits. The peak flux over 3 s in the 20-200 keV energy range is 6 ph/cmsq/s, and the fluence integrated over the whole burst duration is 1.3e-5 erg/cmsq. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8003 SUBJECT: GRB 080723B: Detection and Localization by SuperAGILE DATE: 08/07/23 14:47:13 GMT FROM: Marco Feroci at IASF/INAF E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, E. Costa, I. Lapshov, F. Lazzarotto, L. Pacciani, M. Rapisarda, P. Soffitta, (INAF/IASF Rome), A. Giuliani, S. Vercellone, A. Chen, S. Mereghetti, A. Pellizzoni, F. Perotti, F. Fornari, P. Caraveo (INAF/IASF Milan), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, V. Vittorini, A. Argan, A. Trois (INAF/IASF Rome), G. Barbiellini, F. Longo (INFN Trieste), P. Picozza, A. Morselli (INFN Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), and P. Giommi, C. Pittori, B. Preger, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, report: "SuperAGILE detected and localized a very bright gamma ray burst on July 23rd 2008, at 13:22:19 UT. The event was approximately 13 degrees off-axis. The observed duration in the 20-60 keV energy range is about 110 seconds, with a multi-peaked structure. The burst position was reconstructed as (RA, Dec) (176.823 deg, -60.262 deg), which is: RA(J2000) = 11h 47m 17.42s Dec(J2000) = -60d 15' 43.7" with an uncertainty of 3' radius. The given uncertainty accounts for both the statistical and systematic errors. The same event was also localized and announced by INTEGRAL/ISGRI (BACODINE trigger n. 5311, and Gotz et al., GCN 8002). The SuperAGILE position lies at 1.1 arcmin from the one reported in the INTEGRAL off-line analysis. A SuperAGILE light curve of the event will shortly be posted on the AGILE Science Data Center website: http://agile.asdc.asi.it . An analysis of the AGILE Gamma Ray Imager (GRID) data is in progress." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8004 SUBJECT: GRB 080723A: Swift-XRT refined analysis DATE: 08/07/23 15:35:27 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore (U. Leicester) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift-XRT team : We have analysed the first two orbits of Swift-XRT data obtained from GRB 080723A (trigger 317662; Stamatikos et al., GCN Circ. 8000). The data were taken in photon counting mode and have an exposure of 2.83 ks, spanning 88 s to 7.44 ks after the trigger. The UVOT-enhanced XRT position was given by Beardmore et al. in GCN Circ. 8001. The light curve can be modelled by a doubly broken power-law, with an inital decay of alpha1 = 1.77 +0.34 -0.25 which flattens to a shallow decay of alpha2 = 0.05 +/- 0.24 at a time tbreak1 = 365 +68 -46 s. This is followed by a further steepening to alpha3 = 1.39 +/- 0.75 at a time tbreak2 = 3.4 +1.2 -1.8 ks. The spectrum of the photon counting mode data from the first two orbits can be fit with an absorbed power-law to give a photon index gamma = 2.39 +0.30 -0.28 and NH = (7.7 +2.5 -2.2)e21 cm^-2, in addition to the Galactic column of 3.9e+21 cm^-2 in the direction of the GRB. The observed 0.3-10 keV flux is (1.14 +0.10 -0.22)e-11 erg cm^-2 s^-1, which corresponds to an unabsorbed flux of 3.57e-11 erg cm^-2 s^-1. If the light curve continues to decay at the same rate we estimate the count rate will be 3.2e-2 count/s one day after the trigger, which corresponds to an observed flux of 1.9e-13 erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8005 SUBJECT: GRB 080723B : Planned XMM-Newton observation DATE: 08/07/23 17:30:53 GMT FROM: Norbert Schartel at XMM-Newton/ESA XMM-Newton will observe GRB 080723B at location (RA=11h 47m 20s, DEC=-60d 14' 41", J2000), starting at 18:30:00 UT, on July 23, 2008, for an exposure of 79800 seconds. XMM-Newton SOC //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8006 SUBJECT: GRB 080723B: AGILE GRID and MCAL results DATE: 08/07/23 18:38:49 GMT FROM: Sandro Mereghetti at IASF/CNR F. Fornari, S. Mereghetti, A. Giuliani, S. Vercellone, A. Chen, A. Pellizzoni, F. Perotti, P. Caraveo (INAF/IASF Milan), M. Marisaldi, F. Fuschino, A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, M. Galli (INAF/IASF Bologna), E. Moretti, F. Longo, G. Barbiellini (INFN Trieste), M. Tavani, G. Pucella, F. D'Ammando, V. Vittorini, A. Argan, A. Trois (INAF/IASF Rome), E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, E. Costa, I. Lapshov, F. Lazzarotto, L. Pacciani, M. Rapisarda, P. Soffitta (INAF/IASF Rome), P. Picozza, A. Morselli (INFN Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), P. Giommi, C. Pittori, B. Preger, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, report: Analysis of the AGILE Gamma Ray Imager Detector (GRID) data of the INTEGRAL GRB 080723B (Gotz et al. GCN 8002, Del Monte et al. GCN 8003) does not reveal significant high-energy emission during the time interval of the prompt emission. A preliminary estimate of the fluence, integrated over 100 s, gives a 99% c.l. upper limit of 0.03 photons/cm^2 for energy greater than 50 MeV. GRB 080723B has also triggered on-board the AGILE Mini-Calorimeter (MCAL) at 13:22:33 UT (=T0). Using the preliminary in-flight calibration and assuming a Crab-like spectrum we can estimate a fluence of (8 +/- 2)x10^-6 erg/cm^2 in the 350-700 keV energy range in the time interval between T0 and T0+48 s. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8007 SUBJECT: GRB 080723, Swift-BAT refined analysis DATE: 08/07/23 18:48:45 GMT FROM: Hans Krimm at NASA-GSFC M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080723 (trigger #317662) (Stamatikos, et al., GCN Circ. 8000). The BAT ground-calculated position is RA, Dec = 274.461, -6.910 deg which is RA(J2000) = 18h 17m 50.6s Dec(J2000) = -06d 54' 34.8" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The burst was in the fully coded part of the BAT field of view. The mask-weighted light curve showed a double-peaked structure, with the first peak extending from T-1 sec to T+4 sec, and the second smaller peak from T+6 sec to T+20 sec. T90 (15-350 keV) is 17.3 +- 3.0 sec (estimated error including systematics). The time-averaged spectrum from T-0.2 to T+18.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.77 +- 0.21. The fluence in the 15-150 keV band is 3.3 +- 0.4 x 10-7 erg/cm2. The 1-sec peak photon flux measured from T-0.13 sec in the 15-150 keV band is 0.9 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/317662/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8008 SUBJECT: GRB 080723B - Swift-XRT position DATE: 08/07/23 20:58:43 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team: Swift started observing the INTEGRAL- and Super-AGILE-detected GRB 080723B ~13.4 ks after the trigger (Gotz et al., GCN Circ. 8002; Del Monte et al., GCN Circ. 8003). In ~560 s of data, the XRT clearly detects a source within the error circles, at a position of RA, Dec = 176.83393, -60.2414, which is equivalent to RA(J2000) = 11 47 20.14 Dec(J2000) = -60 14 29.1 with an uncertainty of 3.9 arcsec (radius, 90% containment). Currently there are insufficient data to say whether the source is fading. An updated circular will be written when further data have been obtained. This is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8009 SUBJECT: GRB 080723B - Swift-XRT refined analysis DATE: 08/07/24 07:01:14 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team: The INTEGRAL/Super-AGILE-detected GRB 080723B has now been observed by the Swift-XRT for three orbits (a total of ~2.3 ks of Photon Counting mode data). The source reported in GCN Circ. 8008 can now be seen to be fading (alpha = 1.27 +/- 0.23), so is confirmed as the X-ray afterglow. A spectrum formed from the combined data (~1.3 - 30 ks after the triggers) can be fitted by a power-law of Gamma = 1.87 +/- 0.14, absorbed by the Galactic column in this direction, of 7.42x10^21 cm^-2. The average observed (unabsorbed) flux over this time is 1.49 (2.57) x 10^-9 erg cm^-2 s^-1, which provides an observed counts to flux conversion of 5.9x10^-9 erg cm^-2 count^-1. If the decay were to continue with alpha ~1.27, the count rate 24 hours after the trigger woule be 0.04 count s^-1 (corresponding to an observed flux of 2.4x10^-10 erg cm^-2 s^-1). The circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8010 SUBJECT: GRB 080723B - correction to flux conversion factor DATE: 08/07/24 08:15:47 GMT FROM: Kim Page at U.of Leicester K.L. Page and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team: The counts to flux conversion factor in GCN Circ. 8009 was inadvertantly mistyped. The actual conversion is 5.9x10^-11 erg cm^-2 count^-1 (a factor of 100 lower than that previously given). This implies that the predicted flux at 24 hours is 2.4x10^-12 erg cm^-2 s^-1. We apologise for the mistake and any inconvenience it may have caused. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8012 SUBJECT: GRB 080723A: Swift/UVOT Upper Limits DATE: 08/07/24 14:32:06 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and M. Stamatikos (NASA/ORAU) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 080723A starting 68 s after the BAT trigger (Stamatikos et al. 2008, GCN Circ. 8000). We do not find any source, in any of the UVOT observations, at the UVOT-enhanced XRT position of the afterglow (Beardmore 2008, GCN Circ. 8001). The 3-sigma upper limits for detecting a source at this location in the co-added images are: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ----------------------------------------------------------------- v 194 6260 1040 >20.1 b 674 7080 451 >20.6 u 649 6874 471 >20.4 uvw1 625 6670 469 >20.3 uvm2 600 6465 467 >20.1 uvw2 704 7468 430 >20.4 white 88 7284 628 >21.4 ----------------------------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 1.3 mag. All photometry is on the UVOT flight system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8013 SUBJECT: ATCA radio upper limit on GRB 080723B DATE: 08/07/25 02:06:42 GMT FROM: Poonam Chandra at U Virginia/NRAO Mark H. Wieringa (CSIRO), Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of a larger collaboration: "We observed a region centered on the bright INTEGRAL- and Super-AGILE-detected GRB 080723B (GCN 8002 and 8003) using the Australia Telescope Compact Array starting at July 23.97 UT and ending at July 24.13 UT. No radio emission was seen at 8 GHz frequency band within the XRT error circle (GCN 8008). The flux upper limit at XRT position is 170 uJy (rms 67 uJy). The Australia Telescope Compact Array is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8015 SUBJECT: Konus-Wind observation of GRB 080723B DATE: 08/07/25 11:33:12 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The bright GRB 080723B localized by IBIS/ISGRI (Gotz et al., GCN 8002) and SuperAGILE (Del Monte et al., GCN 8003) triggered Konus-Wind at T0=48143.773 s UT (13:22:23.773). The burst light curve shows multipeaked structure with a duration of ~100 s. As observed by Konus-Wind the burst had a fluence of 8.40(-0.56, +0.47)x10^-5 erg/cm2, and a 64-ms peak flux measured from T0+54.784 s of (1.11 +/- 0.15)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+87.808 s) is well fitted (in the 20 keV - 2 MeV range) by GRBM (Band) model for which: the low-energy photon index is alpha = -0.755 (-0.102, +0.103), the high energy photon index beta = -2.42(-0.40, +0.18), the peak energy Ep = 225(-21, +27) keV (chi2 = 64.2/58 dof). All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080723_T48143/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8017 SUBJECT: GRB080723B: Swift/UVOT Upper Limits DATE: 08/07/25 13:03:18 GMT FROM: Peter Brown at PSU P. J. Brown (Penn State) reports on behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 080723B (Gotz et al., GCN Circ. 8002) starting at 2008-07-23 17:05:44, 13.4 ks after the Integral detection. We do not find any source in the UVOT observations at the XRT position of the afterglow (Page, GCN Circ. 8008). The 3-sigma upper limits for detecting a source at this location in the co-added images are: Filter T_start(s) T_stop(s) Exp(s) Mag(3-sigma upper limit) v 13790 13836 45 >18.1 b 13551 35434 473 >20.3 u 13500 35220 661 >20.1 uvw1 13405 40586 1538 >20.4 uvm2 13841 13966 124 >18.8 uvw2 13603 35801 735 >20.1 The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). They have not been corrected for the expected high but uncertain Galactic extinction along the line of sight (Galactic latitude < 5 degrees). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8018 SUBJECT: GRB 080723A: optical upper limit DATE: 08/07/25 14:19:30 GMT FROM: Graziella Pizzichini at IASF/CNR,Bologna F. Munz (INAF/IASF Bologna), F. Terra (Second University of Roma "Tor Vergata"),,G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), G. Pizzichini (INAF/IASF Bologna), D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"), S. Galleti, R. Gualandi (Bologna Observatory) report: We observed the field of GRB 080723A (GCN 8000 Stamatikos et al.) with the 152 cm telescope located in Loiano under clear sky conditions (seeing~2.5"). In our 20 min exposure in the Rc filter at mean time 2008 July 23 20.62 UT we do not detect any afterglow candidate in the enhanced Swift-XRT position (GCN 8001, Beardmore et al.). Our 3-sigma limiting magnitude is R~20 (based on Nomad1 catalogue). In this area there is a strong galactic extinction, A_lambda ~ 4 mag in R from the NASA/IPAC extragalactic data base. The image has been posted in our public directory from where it can be retrieved by sftp using hostname: ermione.bo.astro.it username: publicGRB password: GRB_bo directory: GRB080723A //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8078 SUBJECT: GRB 080723B: XMM-Newton observation DATE: 08/08/08 20:16:55 GMT FROM: Jochen Greiner at MPI G. Sala, J. Greiner, S. McBreen, T. Kruehler, P.M. Esquej (all MPE Garching, Germany) report: XMM-Newton observed GRB 080723B detected by INTEGRAL (Gotz et al. 2008, #GCN 8002) and AGILE (Del Monte et al. 2008, GCN #8003), starting at 18:47:41 UT, on July 23, 2008, for an exposure of 62.5 ks (Schartel 2008, GCN 8005). The observation was affected by background radiation flaring, reducing the good exposure time to 54 ks. GRB 080723B is detected with an average count rate of 0.9, 0.3 and 0.01 cts/s in the EPIC-pn, MOS1/2 and RGS instruments, respectively. Here we report on a refined position and the X-ray spectrum of the afterglow of GRB 080723B. By identifying four X-ray sources in the FOV of the EPIC camera with counterparts from the 2MASS catalogue, we are able to register the X-ray coordinate system, and obtain a best-fit X-ray position of the afterglow of GRB 080723B of RA = 176.83317, Decl. = -60.24096, equivalent to RA (2000.0) = 11 47 20.09 Dec (2000.0) = -60 14 28.6 with an uncertainty of 2.0 arcsec. This coincides perfectly with the X-ray position reported by Swift/XRT (Page 2008, GCN #8008), but reduces the error circle by nearly a factor of two. The X-ray flux during the XMM-Newton observation decays gradually, with no noticable deviations from a power law of slope 1.50 +/-0.05, compatible within the error with the flatter Swift/XRT decay (Page 2008, GCN #8009). The spectrum averaged over the full observation (25.7 - 65.7 ks after the GRB trigger) can be fitted by an absorbed power-law with photon index Gamma = 1.79 +/-0.02, and an equivalent hydrogen column of 1.22(+/-0.02)*10^22 cm^-2, in excess of the catalogued Galactic column in this direction, 7.4*10^21 cm^-2 (Kalberla et al. 2005, AA 440, 775; Dickey & Lockman 1990, ARAA 28, 215). Being at a Galactic latitude of 1.6 deg, this difference may be due to clumpiness of foreground material relative to the spacing of the above HI surveys, rather than necessarily due to intrinsic extinction in the GRB host galaxy. The observed 0.3-10 keV flux during the XMM-Newton observation decreases from about 1*10^-11 erg/cm^2/s (26 ks after burst trigger) to 2.5*10^-12 erg/cm^2/s (65 ks post-burst). We thank Ignacio de la Calle, Nora Loiseau and Norbert Schartel from the XMM-Newton SOC (Villafranca, Spain) for scheduling and executing this observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8079 SUBJECT: GRB 080723B: GROND upper limits DATE: 08/08/08 20:19:08 GMT FROM: Jochen Greiner at MPI T. Kruehler, J. Greiner, F. Schrey, G. Sala, C. Clemens (all MPE Garching) report on behalf of the GROND team: We observed the field of the INTEGRAL GRB 080723B (Gotz et al. 2008, GCN #8002) on two epochs, simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). First observations started at 2008-07-24 23:46 UT, 36.4 h after the burst, with total exposures of 50 min in g'r'i'z' and 40 min in JHK. A second set of images was obtained starting at 2008-07-31 23:39 UT with effective exposures of 100 min (g'r'i'z') and 80 min (JHK). We do not detect a fading source in neither the XRT (Page 2008, GCN #8008) nor XMM (Sala et al. 2008, GCN #8078) error circle down to limiting magnitudes of: g' > 23.4 r' > 23.6 i' > 22.7 z' > 22.7 J > 20.6 H > 19.5 K > 18.5 calibrated against USNO-B1 and 2MASS field stars. At longer wavelength, these limits are compromised by the high density of foreground stars. The reported upper limits are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 1.3 (Schlegel et al. 1998).