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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB040916 (= H3558): A Long XRF Localized by HETE
  2. GRB040912 (= H3557): Chandra Observations Scheduled
  3. GRB 040912: Optical Observations
  4. GRB/XRF040912,optical observations
  5. GRB 040912, BVRI observations
  6. Optical observations of GRB/XRF 040912 = HETE 3557
  7. An intense burst from SGR1806-20
  8. GRB040912 : Kiso Optical follow-up observation
  9. IBAS GRB Alerts 1978-1980
  10. Optical observations of field of GRB040912
  11. HETE 3557: Optical observations
  12. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  13. GRB 040827: XMM-Newton data
  14. GRB040903 - A XRF?
  15. GRB040827: analysis of the XMM-Newton observation
  16. GRB040903, REM near-IR observation
  17. GRB 040903 - INTEGRAL data analysis
  18. IBAS Alert 1974. Not a real GRB
  19. Very bright burst detected from SGR 1806-20
  20. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  21. Possible GRB 040903 - further analysis
  22. Possible GRB 040903 detected with INTEGRAL
  23. GRB 040827 - Radio Observations
  24. XMM-Newton Images of GRB 040827
  25. GRB040825A: Optical observations
  26. GRB040825A: Optical observations
  27. GRB 040827: optical and NIR observations at the VLT
  28. GRB 040827: UKIRT - 2nd epoch K-band imaging
  29. GRB 040827: 2nd epoch of Magellan K-band imaging
  30. GRB 040827: K imaging - no evidence of variability
  31. GRB 040827: Detection of NIR afterglow
  32. GRB 040827: Possible detection of optical afterglow
  33. GRB 040827: RTT150 optical observations
  34. GRB040827 XMM-Newton observation
  35. GRB040825A: optical limit before GRB
  36. MASTER: GRB040827 possible OT
  37. GRB 040825B: Optical observations
  38. GRB040827 optical observations
  39. GRB 040827 : Planned XMM-Newton observation
  40. GRB 040827 - Refined position
  41. GRB 040827 : peak flux
  42. GRB 040827 - A long GRB detected by INTEGRAL
  43. GRB040825B, BVRcIc field photometry
  44. GRB040825A, BVRcIc field photometry
  45. GCN GRB OBSERBATION REPORT
  46. GRB 040825A,optical observations
  47. Increase of SGR 1806-20 activity
  48. GRB040825A: optical observations
  49. GRB040825B: optical observations
  50. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  51. GRB 040825A: Optical observations.
  52. MASTER: GRB040825a optical observation
  53. MASTER: GRB040825b optical observation
  54. GRB040825B: Correction to GCN 2657
  55. GRB 040825: Optical observations
  56. XRF040812: possible afterglow second Chandra observation
  57. GRB 040812: Second epoch CXO Observations
  58. GRB040823,optical observation
  59. XRF040812: GMRT observations
  60. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  61. XRF 040812: optical observation at VLT
  62. GRB 040812: Optical counterparts of CXO sources
  63. XRF040812: possible afterglow
  64. CXO observation of GRB 040812
  65. Bursting activity from SGR 1806-20 detected with IBAS
  66. IPN/HETE localizations of GRB040810 (=H3489)
  67. GRB 040812: Keck and LCO optical observations
  68. GRB 040812: Keck and LCO observations
  69. GRB 040812: radio observations
  70. GRB040812, optical/IR observations
  71. Konus-Wind observation of GRB040810 (=H3489)
  72. GRB 040812: a long GRB detected by INTEGRAL
  73. GRB 040810: Optical observations of a limited region
  74. XRF040701: Optical Observations at ESO
  75. IPN/HETE triangulation of GRB040802 (=H3485)
  76. GRB 040730, infrared observations
  77. GRB 040730: Optical observations
  78. GRB 040730: a long GRB detected with INTEGRAL
  79. Ongoing activity of SGR 1806-20
  80. GRB040624: optical monitoring at TNG
  81. XRF 040701 - optical observations of the decaying Chandra source
  82. XRF040701: Second-Epoch Chandra Observations
  83. Cancellation of IBAS/INTEGRAL GRB alerts
  84. XRF040701: VLA Observations
  85. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  86. XRF040701: First-Epoch Chandra Observations
  87. IBAS Alert 1836: NOT a real GRB
  88. GRB040709 J,H-band observations
  89. GRB040624, optical observations
  90. GRB040706:observation at University of Miyazaki
  91. XRF 040701, optical observations
  92. XRF040701 (=U11548): a bright XRF detected by HETE
  93. GRB 040624: optical observations
  94. Optical Observations of GRB040624
  95. GRB 040624: optical observations at TNG and VLT
  96. MASTER: GRB 040624 optical observation after 0,48d
  97. GRB 040624: R-band observations
  98. GRB 040624, optical observations
  99. GRB 040624 - A long GRB detected with INTEGRAL
  100. GRB 030329: Rebrightening of hyperluminal ejecta.

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