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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
  1. An intense burst from SGR1806-20
  2. GRB040912 : Kiso Optical follow-up observation
  3. IBAS GRB Alerts 1978-1980
  4. Optical observations of field of GRB040912
  5. HETE 3557: Optical observations
  6. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  7. GRB 040827: XMM-Newton data
  8. GRB040903 - A XRF?
  9. GRB040827: analysis of the XMM-Newton observation
  10. GRB040903, REM near-IR observation
  11. GRB 040903 - INTEGRAL data analysis
  12. IBAS Alert 1974. Not a real GRB
  13. Very bright burst detected from SGR 1806-20
  14. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  15. Possible GRB 040903 - further analysis
  16. Possible GRB 040903 detected with INTEGRAL
  17. GRB 040827 - Radio Observations
  18. XMM-Newton Images of GRB 040827
  19. GRB040825A: Optical observations
  20. GRB040825A: Optical observations
  21. GRB 040827: optical and NIR observations at the VLT
  22. GRB 040827: UKIRT - 2nd epoch K-band imaging
  23. GRB 040827: 2nd epoch of Magellan K-band imaging
  24. GRB 040827: K imaging - no evidence of variability
  25. GRB 040827: Detection of NIR afterglow
  26. GRB 040827: Possible detection of optical afterglow
  27. GRB 040827: RTT150 optical observations
  28. GRB040827 XMM-Newton observation
  29. GRB040825A: optical limit before GRB
  30. MASTER: GRB040827 possible OT
  31. GRB 040825B: Optical observations
  32. GRB040827 optical observations
  33. GRB 040827 : Planned XMM-Newton observation
  34. GRB 040827 - Refined position
  35. GRB 040827 : peak flux
  36. GRB 040827 - A long GRB detected by INTEGRAL
  37. GRB040825B, BVRcIc field photometry
  38. GRB040825A, BVRcIc field photometry
  39. GCN GRB OBSERBATION REPORT
  40. GRB 040825A,optical observations
  41. Increase of SGR 1806-20 activity
  42. GRB040825A: optical observations
  43. GRB040825B: optical observations
  44. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  45. GRB 040825A: Optical observations.
  46. MASTER: GRB040825a optical observation
  47. MASTER: GRB040825b optical observation
  48. GRB040825B: Correction to GCN 2657
  49. GRB 040825: Optical observations
  50. XRF040812: possible afterglow second Chandra observation
  51. GRB 040812: Second epoch CXO Observations
  52. GRB040823,optical observation
  53. XRF040812: GMRT observations
  54. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  55. XRF 040812: optical observation at VLT
  56. GRB 040812: Optical counterparts of CXO sources
  57. XRF040812: possible afterglow
  58. CXO observation of GRB 040812
  59. Bursting activity from SGR 1806-20 detected with IBAS
  60. IPN/HETE localizations of GRB040810 (=H3489)
  61. GRB 040812: Keck and LCO optical observations
  62. GRB 040812: Keck and LCO observations
  63. GRB 040812: radio observations
  64. GRB040812, optical/IR observations
  65. Konus-Wind observation of GRB040810 (=H3489)
  66. GRB 040812: a long GRB detected by INTEGRAL
  67. GRB 040810: Optical observations of a limited region
  68. XRF040701: Optical Observations at ESO
  69. IPN/HETE triangulation of GRB040802 (=H3485)
  70. GRB 040730, infrared observations
  71. GRB 040730: Optical observations
  72. GRB 040730: a long GRB detected with INTEGRAL
  73. Ongoing activity of SGR 1806-20
  74. GRB040624: optical monitoring at TNG
  75. XRF 040701 - optical observations of the decaying Chandra source
  76. XRF040701: Second-Epoch Chandra Observations
  77. Cancellation of IBAS/INTEGRAL GRB alerts
  78. XRF040701: VLA Observations
  79. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  80. XRF040701: First-Epoch Chandra Observations
  81. IBAS Alert 1836: NOT a real GRB
  82. GRB040709 J,H-band observations
  83. Subject: GRB040624, optical observations
  84. GRB040706:observation at University of Miyazaki
  85. XRF 040701, optical observations
  86. XRF040701 (=U11548): a bright XRF detected by HETE
  87. GRB 040624: optical observations
  88. Optical Observations of GRB040624
  89. GRB 040624: optical observations at TNG and VLT
  90. MASTER: GRB 040624 optical observation after 0,48d
  91. GRB 040624: R-band observations
  92. GRB 040624, optical observations
  93. GRB 040624 - A long GRB detected with INTEGRAL
  94. GRB 030329: Rebrightening of hyperluminal ejecta.
  95. IPN Summary of SGR1806-20 Activity in 2004
  96. GRB040511: Retraction of redshift identification
  97. SGR 1806-20: no IR variability of the proposed counterparts
  98. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  99. SGR 1806-20, potential NIR counterpart
  100. GRB 040606: Optical observations

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