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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"

28860 results found.

  1. GRB050223: ROTSE-III Optical Observations
  2. GRB050219b: CORRECTION to time of UVOT observations
  3. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  4. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  5. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  6. GRB050215b: Swift UVOT Detection of Afterglow Emission
  7. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  8. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  9. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  10. GRB 050215b, BOOTES-1B optical limit
  11. GRB050215B: ROTSE-III optical observations
  12. GRB050215A: ROTSE-III Optical Observations
  13. GRB050209: REM optical observations
  14. GRB 050209 Optical observations
  15. GRB050209: P60 Optical Observations
  16. GRB 050209: Optical observation
  17. GRB050128,optical observations
  18. GRB 050124 I-band observation
  19. GRB050124,optical observation
  20. GRB050124: Refined BAT position, spectral and fluence information
  21. GRB050123,optical observation
  22. GRB 050123: KAIT observations
  23. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  24. GRB 050117, I-band observations
  25. The giant outburst from SGR 1806-20
  26. Swift-BAT Time History of GRB041219
  27. GRB041220: Swift-BAT burst
  28. Deep RAPTOR observations during GRB 041219
  29. GRB041219c: Third Burst in One Day from Swift-BAT
  30. GRB 041219 ,optical observation
  31. GRB 041218: R-band optical observations
  32. Swift-BAT detection of the bright long burst GRB041219
  33. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  34. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  35. GRB041211: RAPTOR observations
  36. GRB041211, BVRcIc field calibration
  37. GRB041211,optical observation
  38. GRB 041211: KAIT observations
  39. Distribution of IBAS Alerts for NON-GRB sources
  40. GRB 041006: GETS Optical Afterglow Observation
  41. Summary of the recent bursts from SGR 1806-20
  42. GRB041015, optical observation in CrAO
  43. Bright bursts from SGR1806-20
  44. GRB 041016: BOOTES-2 simultaneous observation
  45. GRB041016,optical observation
  46. GRB 041016: Optical limits
  47. GRB 041016:Optical limit during first minute
  48. GRB041016: MASTER: Optical observations
  49. GRB041006: Near Infrared observations
  50. GRB 041016: Optical limit
  51. GRB 041015 R band observations
  52. GRB040924, BVRcIc field calibration
  53. GRB041015: MASTER: Optical observations
  54. GRB041015,optical observation
  55. GRB041006: MASTER optical observations
  56. GRB041006,optical observation
  57. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  58. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  59. GRB040929,optical observation
  60. GRB040924,optical observation
  61. GRB040924: KAIT observations
  62. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  63. GRB040924 (H3564): Optical afterglow candidate
  64. XRF040912, BVRcIc field calibration
  65. XRF040916, BVRcIc field calibration
  66. GRB040916: Optical observations
  67. GRB/XRF040912,optical observations
  68. GRB 040912, BVRI observations
  69. Optical observations of field of GRB040912
  70. HETE 3557: Optical observations
  71. GRB040825B, BVRcIc field photometry
  72. GRB040825A, BVRcIc field photometry
  73. GCN GRB OBSERBATION REPORT
  74. GRB 040825A,optical observations
  75. Increase of SGR 1806-20 activity
  76. GRB040825A: optical observations
  77. GRB040825B: optical observations
  78. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  79. GRB 040825A: Optical observations.
  80. MASTER: GRB040825b optical observation
  81. GRB040825B: Correction to GCN 2657
  82. GRB 040812: Second epoch CXO Observations
  83. GRB040823,optical observation
  84. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  85. CXO observation of GRB 040812
  86. Ongoing activity of SGR 1806-20
  87. GRB040709 J,H-band observations
  88. GRB040706:observation at University of Miyazaki
  89. GRB 040606: Optical observations
  90. MASTER: HETE Alert 3274 optical observation
  91. Activivty of SGR 1806-20
  92. GRB 040511: Optical limit
  93. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  94. GRB040511: Optical Observations
  95. GRB040511: Optical Observations
  96. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  97. GRB040422: optical observations at CrAO
  98. GRB 040423 (=H3175): A Long GRB Localized by HETE
  99. GRB040422, optical observations at Loiano
  100. GRB 040422: ROTSE-IIIb Prompt Optical Limits

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