GRB140408A

This page lists all entries on GRB140408A in GRBweb

Summary Fermi GBM IPN Swift GCN 16082 GCN 16084 GCN 16085 GCN 16086 GCN 16087 GCN 16088 GCN 16089 GCN 16090 GCN 16091 GCN 16093 GCN 16096 GCN 16341 GCN 24072

Summary table
Variable Value Source
GRB_name_Fermi GRB140408553
T0 13:15:54 UTC GCN_circulars,Swift Det
ra 290.7160° Swift
decl -12.5951° Swift
pos_error 2.33e-04° Swift
T90 7.68 s Fermi_GBM
T90_error 3.367 s Fermi_GBM
T90_start 13:15:54.218 UTC Fermi_GBM
fluence 6.57e-07 erg/cm² Fermi_GBM
fluence_error 5.42e-08 erg/cm² Fermi_GBM
redshift 4.0000 GCN_circulars,GROND
T100 7.898 s
GBM_located False
mjd 56755.552708333336 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB140408553
trigger_name bn140408553
ra 290.7158°
decl -12.5936°
pos_error 6.69e+00°
datum 2014-04-08
t_trigger 13:15:55.242 UTC
T90 7.68 s
T90_error 3.367 s
T90_start 13:15:54.218 UTC
fluence 6.57e-07 erg/cm²
fluence_error 5.42e-08 erg/cm²
flux_1024 2.39e+00 erg/cm²/s
flux_1024_error 2.50e-01 erg/cm²/s
flux_1024_time -3.20e-01 erg/cm²/s
flux_64 5.03e+00 erg/cm²/s
flux_64_error 1.54e+00 erg/cm²/s
IPN table
GRB_name GRB140408A
ra 290.6833°
decl -12.5833°
pos_error 5.00e-02°
Swift table
GRB_name GRB140408A
t_trigger 13:15:54 UTC
ra 290.7160°
decl -12.5951°
pos_error 2.33e-04°
T90 4.0 s
fluence 3.10e-07 erg/cm²
GCN 16082 table
GRB_name GRB140408A
GCN_number 16082
Detection_method Swift Det
t_trigger 13:15:54 UTC
ra 290.6850°
decl -12.5780°
Circular_text TITLE: GCN CIRCULAR NUMBER: 16082 SUBJECT: GRB 140408A: Swift detection of a burst DATE: 14/04/08 13:35:46 GMT FROM: Scott Barthelmy at NASA/GSFC V. D'Elia (ASDC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), R. L. C. Starling (U Leicester) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 13:15:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140408A (trigger=595141). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 290.685, -12.578 which is RA(J2000) = 19h 22m 44s Dec(J2000) = -12d 34' 40" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 10 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 13:17:40.2 UT, 105.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 290.71576, -12.59373 which is equivalent to: RA(J2000) = 19h 22m 51.78s Dec(J2000) = -12d 35' 37.4" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 122 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. No spectrum from the promptly downlinked event data is yet available to determine the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 109 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.19. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). 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.)
GCN 16084 table
GRB_name GRB140408A
GCN_number 16084
Detection_method Fermi GBM Det
t_trigger 13:15:55.240 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 16084 SUBJECT: GRB 140408A: Fermi GBM detection DATE: 14/04/08 20:34:47 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH), G. Fitzpatrick (UCD) reports on behalf of the Fermi GBM Team: "At 13:15:55.24 UT on April 8 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140408A (trigger 418655758/140408553), which was also detected by Swift (V. D'Elia et al. 2014, GCN 16082). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the Swift/BAT location. The angle of the burst direction to the Fermi LAT boresight is 90 degrees. The GBM light curve consists of one main peak with a duration (T90) of about 13 s (50-300 keV). The time-averaged spectrum from T0-4.1 s to T0+10.2s is well fit by a power law with an index of -1.61 +/- 0.07. The event fluence (10-1000 keV) in this time interval is (1.8 +/- 0.2)E-06 erg/cm^2. The 1.0-sec peak photon flux measured starting from T0+0.0 s in the 10-1000 keV band is 2.0 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 16085 table
GRB_name GRB140408A
GCN_number 16085
Detection_method Swift-XRT Det
ra 290.7159°
decl -12.5953°
Circular_text TITLE: GCN CIRCULAR NUMBER: 16085 SUBJECT: GRB 140408A: Enhanced Swift-XRT position DATE: 14/04/08 23:33:12 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 661 s of XRT Photon Counting mode data and 1 UVOT images for GRB 140408A, 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 = 290.71590, -12.59525 which is equivalent to: RA (J2000): 19h 22m 51.82s Dec (J2000): -12d 35' 42.9" with an uncertainty of 2.1 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) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 16086 table
GRB_name GRB140408A
GCN_number 16086
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 16086 SUBJECT: GRB 140408A: MITSuME Okayama upper limits DATE: 14/04/08 23:45:08 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME collaboration: We observed the field of GRB 140408A (D'Elia et al., GCNC 16082) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2014-04-08 17:47:44 UT (~4.5 h after the burst). We did not find any new point source within the enhanced XRT circle (Evans et al., GCNC 16085) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.21515 18:25:43 4200.0 >19.1 >18.9 >18.3 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]
GCN 16087 table
GRB_name GRB140408A
GCN_number 16087
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16087 SUBJECT: GRB 140408A: Swift-XRT refined Analysis DATE: 14/04/09 04:36:03 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), V. Mangano (PSU), M.C. Stroh (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB) and V. D'Elia report on behalf of the Swift-XRT team: We have analysed 8.7 ks of XRT data for GRB 140408A (D'Elia et al. GCN Circ. 16082), from 91 s to 29.8 ks after the BAT trigger. The data comprise 268 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 16085). The light curve can be modelled with a power-law decay with a decay index of alpha=0.77 (+0.10, -0.09). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2 (+80, -1). The best-fitting absorption column is 1.4 (+7.3, -1.2) x 10^22 cm^-2, consistent with the Galactic value of 1.8 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 1.5 x 10^-11 (6.9 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 1.4 (+7.3, -1.2) x 10^22 cm^-2 Galactic foreground: 1.8 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 2 (+80, -1) If the light curve continues to decay with a power-law decay index of 0.77, the count rate at T+24 hours will be 2.1 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.1 x 10^-14 (1.5 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00595141. This circular is an official product of the Swift-XRT team.
GCN 16088 table
GRB_name GRB140408A
GCN_number 16088
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16088 SUBJECT: GRB 140408A: Swift/UVOT Upper Limits DATE: 14/04/09 07:42:56 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140408A 109 s after the BAT trigger (D'Elia et al., GCN Circ. 16082). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 16085,) and with the non-detection reported by Kuroda et al. (GCN Circ. 16086), is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 109 259 147 >20.9 u_FC 321 571 246 >20.5 white 109 1025 334 >21.2 v 652 4403 236 >20.0 b 577 769 39 >18.7 u 321 745 265 >20.5 w1 701 720 19 >18.1 m2 676 4572 201 >19.9 w2 627 1046 54 >20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.19 in the direction of the burst (Schlegel et al. 1998).
GCN 16089 table
GRB_name GRB140408A
GCN_number 16089
Detection_method GROND
redshift 4.0000
Circular_text TITLE: GCN CIRCULAR NUMBER: 16089 SUBJECT: GRB 140408A: GROND Detection of an Afterglow Candidate DATE: 14/04/09 12:58:38 GMT FROM: Jochen Greiner at MPI GRB 140408A: GROND Detection of an Afterglow Candidate K. Varela, C. Delvaux (both MPE Garching), D.A. Kann (TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 140408A (Swift trigger 595141; d'Elia et al., GCN #16082) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at La Silla Observatory (Chile). Observations started at 06:16:31 UT on 8th April 2014, 0.709 days after the GRB trigger. They were performed at an average seeing of 0".9 and at an average airmass of 1.6. We find a single point source within the 2".2 Swift-XRT error circle reported by Evans et al. (GCN #16085) at RA (J2000) = 19h 22m 51.78s Dec. (J2000) = -12d 35' 40.9" with an uncertainty of 0".4 in each coordinate. Based on a 7380 s exposure on g'r'i'z' , and a 6000 s exposure in JHK, we estimate preliminary magnitudes (all in AB system) of g' = 25.6 +- 0.3 mag, r' = 23.7 +- 0.2 mag, i' = 22.7 +- 0.2 mag, z' = 22.8 +- 0.3 mag, J > 22.0 mag, H > 21.5 mag, and K > 20.0 mag. We propose this source to be a candidate afterglow for GRB 140408A. At the moment, fading can not be established. If it is the afterglow, the SED suggests a redshift of z ~ 4. Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.16 mag in the direction of the burst (Schlafly & Finkbeiner 2011). [GCN OPS NOTE(10apr14): The missing minus sign on the Declination value in the 3rd paragraph was added. Acknowledgement to F.Marshall.]
GCN 16090 table
GRB_name GRB140408A
GCN_number 16090
Detection_method Swift-BAT Det
ra 290.7230°
decl -12.5850°
Circular_text TITLE: GCN CIRCULAR NUMBER: 16090 SUBJECT: GRB 140408A: Swift-BAT refined analysis DATE: 14/04/09 14:31:03 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), (i.e. the Swift-BAT team): Using the data set from T-180 to T+902 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140408A (trigger #595141) (D'Elia, et al., GCN Circ. 16082). The BAT ground-calculated position is RA, Dec = 290.723, -12.585 deg which is RA(J2000) = 19h 22m 53.5s Dec(J2000) = -12d 35' 07.7" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 40%. The mask-weighted light curve shows a single-pulse structure starts at ~T-1 sec, peaks at ~ T+1 sec, and ends at ~T+4 sec. T90 (15-350 keV) is 4.00 +- 1.41 sec (estimated error including systematics). The time-averaged spectrum from T-0.66 to T+3.34 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.49 +- 0.25. The fluence in the 15-150 keV band is 3.1 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.34 sec in the 15-150 keV band is 1.2 +- 0.3 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/595141/BA/
GCN 16091 table
GRB_name GRB140408A
GCN_number 16091
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 16091 SUBJECT: GRB 140408A: RATIR Optical Upper Limits DATE: 14/04/09 23:48:05 GMT FROM: Owen Littlejohns at Az State U Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 140408A (D'Elia, et al., GCN 16082) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on Sierra San Pedro Mrtir from 2014/04 9.41 to 2014/04 9.48 UTC (20.52 to 22.37 hours after the BAT trigger), obtaining a total of 1.42 hours exposure in the r and i bands. For a source within the Swift-XRT error circle we obtain the following upper limits (3-sigma): r > 22.84 i > 22.53 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. These upper limits are consistent with the previously reported GROND afterglow candidate (Varela, et al., GCN 16089). We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 16093 table
GRB_name GRB140408A
GCN_number 16093
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 16093 SUBJECT: GRB 140408A: MITSuME Akeno Optical observation DATE: 14/04/10 05:21:39 GMT FROM: Taketoshi Yoshii at Tokyo Tech H. Ohuchi, T. Yoshii, Y. Saito, Y. Tachibana, S. Kurita, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 140408A (V. D'Elia et al., GCN Circular #16082) with the optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2014-04-08 17:03:08.6 UT ( 3.8h after the burst). We did not find any new point source within the enhanced XRT circle (Evans et al., GCNC 16085) in all the three bands. The measured magnitudes were listed below. T0+[sec] MID-UT T-EXP[sec] g' Rc Ic $B!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=(B- 17105 18:00:59 6300 >20.1 >19.6 >19.1 $B!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=!=(B- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration.
GCN 16096 table
GRB_name GRB140408A
GCN_number 16096
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 16096 SUBJECT: GRB 140408A: 1.5m OSN optical upper limit DATE: 14/04/10 18:34:22 GMT FROM: Soomin Jeong at CSIC S. Jeong, S. R. Oates, J. C. Tello, J. Gorosabel, A. Sota and A. J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report: "Following the detection of GRB140408A by Swift (D'Elia et al., GCNC 16082), we observed the field of GRB 140408A with the 1.5 m OSN telescope at Observatorio de Sierra Nevada in the R and I-bands. The observation started on Apr 9, 04:01:16 UT (i.e. ~0.62 d post burst). No optical afterglow is found at the position of the optical candidate reported by Varela et al. (GCNC 16089) in the median combined images (6 x 300s) down to 21.7 mag (I band) and 22.5 mag (R band) (3-sigma upper limits, with all magnitudes in Vega system and no correction for the Galaxy reddening)."
GCN 16341 table
GRB_name GRB140408A
GCN_number 16341
Detection_method GROND
Circular_text TITLE: GCN CIRCULAR NUMBER: 16341 SUBJECT: GRB 140408A: Withdrawal of afterglow candidate DATE: 14/05/30 06:57:16 GMT FROM: Fabian Knust at MPE/GROND GRB 140408A: Withdrawal of afterglow candidate F. Knust, K. Varela, C. Delvaux (all MPE Garching), D.A. Kann (TLS Tautenburg) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the GRB 140408A field again on further three epochs, simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). The afterglow candidate reported in Varela et al. (GCN #16089) remained constant, thus this source is a fore- or background source and not the afterglow of GRB 140408A. For the first epoch as reported in Varela et al. (GCN #16089), no other source is seen in the 1".8 Swift-XRT refined error circle (http://www.swift.ac.uk/xrt_positions/00595141/) down to limiting magnitudes (all in the AB system) of g' > 25.8 mag, r' > 25.6 mag, i' > 25.0 mag, z' > 25.0 mag, J > 22.1 mag, H > 21.5 mag, and K > 20.0 mag. The given limits are based on calibrating the images against GROND zeropoints and 2MASS field stars, and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.16 in the direction of the burst (Schlegel et al. 1998).
GCN 24072 table
GRB_name GRB140408A
GCN_number 24072
Detection_method MAXI Det
ra 47.3420°
decl 1.7580°
Circular_text TITLE: GCN CIRCULAR NUMBER: 24072 SUBJECT: GRB 140408A: MAXI/GSC detection DATE: 19/04/09 01:14:21 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. S. Sugita (AGU), H. Negoro, M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, T. Mihara, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at UT 2019/04/08 18:06:19. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (47.342 deg, 1.758 deg) = (03 09 22, +01 45 28) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.52 deg and 0.22 deg, respectively. The roll angle of long axis from the north direction is 145.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 189 +- 35 mCrab (2.0-4.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (R.A., Dec) = (46.050, 1.531) deg = (03 04 11, +01 31 51) (J2000) (R.A., Dec) = (46.579, 0.646) deg = (03 06 18, +00 38 45) (J2000) (R.A., Dec) = (48.900, 2.032) deg = (03 15 35, +02 01 55) (J2000) (R.A., Dec) = (48.371, 2.917) deg = (03 13 29, +02 55 01) (J2000) There was no significant excess flux in the previous transit at UT 16:33 and in the next transit at UT 19:39 with an upper limit of 20 mCrab for each.