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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"

28871 results found.

  1. GRB 050309, Early optical limits from RAPTOR
  2. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  3. GRB 050309 : Lulin R-band observation
  4. Swift 107873: P60 Optical Observations
  5. GRB 050306: CORRECTION to date of observation
  6. GRB 050306: No Swift UVOT Optical Counterpart Detected
  7. Swift trigger 107518: optical observation
  8. GRB 050306,optical observation
  9. Ongoing activity of SGR 1806-20 after the giant flare
  10. GRB 050219b: candidate NIR afterglow
  11. GRB050223: No Swift UVOT Detection of Afterglow Emission
  12. GRB050223: ROTSE-III Optical Observations
  13. GRB050219b: CORRECTION to time of UVOT observations
  14. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  15. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  16. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  17. GRB050215b: Swift UVOT Detection of Afterglow Emission
  18. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  19. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  20. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  21. GRB 050215b, BOOTES-1B optical limit
  22. GRB050215B: ROTSE-III optical observations
  23. GRB050215A: ROTSE-III Optical Observations
  24. GRB050209: REM optical observations
  25. GRB 050209 Optical observations
  26. GRB050209: P60 Optical Observations
  27. GRB 050209: Optical observation
  28. GRB050128,optical observations
  29. GRB 050124 I-band observation
  30. GRB050124,optical observation
  31. GRB050124: Refined BAT position, spectral and fluence information
  32. GRB050123,optical observation
  33. GRB 050123: KAIT observations
  34. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  35. GRB 050117, I-band observations
  36. The giant outburst from SGR 1806-20
  37. Swift-BAT Time History of GRB041219
  38. GRB041220: Swift-BAT burst
  39. Deep RAPTOR observations during GRB 041219
  40. GRB041219c: Third Burst in One Day from Swift-BAT
  41. GRB 041219 ,optical observation
  42. GRB 041218: R-band optical observations
  43. Swift-BAT detection of the bright long burst GRB041219
  44. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  45. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  46. GRB041211: RAPTOR observations
  47. GRB041211, BVRcIc field calibration
  48. GRB041211,optical observation
  49. GRB 041211: KAIT observations
  50. Distribution of IBAS Alerts for NON-GRB sources
  51. GRB 041006: GETS Optical Afterglow Observation
  52. Summary of the recent bursts from SGR 1806-20
  53. GRB041015, optical observation in CrAO
  54. Bright bursts from SGR1806-20
  55. GRB 041016: BOOTES-2 simultaneous observation
  56. GRB041016,optical observation
  57. GRB 041016: Optical limits
  58. GRB 041016:Optical limit during first minute
  59. GRB041016: MASTER: Optical observations
  60. GRB041006: Near Infrared observations
  61. GRB 041016: Optical limit
  62. GRB 041015 R band observations
  63. GRB040924, BVRcIc field calibration
  64. GRB041015: MASTER: Optical observations
  65. GRB041015,optical observation
  66. GRB041006: MASTER optical observations
  67. GRB041006,optical observation
  68. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  69. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  70. GRB040929,optical observation
  71. GRB040924,optical observation
  72. GRB040924: KAIT observations
  73. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  74. GRB040924 (H3564): Optical afterglow candidate
  75. XRF040912, BVRcIc field calibration
  76. XRF040916, BVRcIc field calibration
  77. GRB040916: Optical observations
  78. GRB/XRF040912,optical observations
  79. GRB 040912, BVRI observations
  80. Optical observations of field of GRB040912
  81. HETE 3557: Optical observations
  82. GRB040825B, BVRcIc field photometry
  83. GRB040825A, BVRcIc field photometry
  84. GCN GRB OBSERBATION REPORT
  85. GRB 040825A,optical observations
  86. Increase of SGR 1806-20 activity
  87. GRB040825A: optical observations
  88. GRB040825B: optical observations
  89. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  90. GRB 040825A: Optical observations.
  91. MASTER: GRB040825b optical observation
  92. GRB040825B: Correction to GCN 2657
  93. GRB 040812: Second epoch CXO Observations
  94. GRB040823,optical observation
  95. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  96. CXO observation of GRB 040812
  97. Ongoing activity of SGR 1806-20
  98. GRB040709 J,H-band observations
  99. GRB040706:observation at University of Miyazaki
  100. GRB 040606: Optical observations

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