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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"

27015 results found.

  1. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  2. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  3. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  4. GRB 050215b, BOOTES-1B optical limit
  5. GRB050215B: ROTSE-III optical observations
  6. GRB050215A: ROTSE-III Optical Observations
  7. GRB050209: REM optical observations
  8. GRB 050209 Optical observations
  9. GRB050209: P60 Optical Observations
  10. GRB 050209: Optical observation
  11. GRB050128,optical observations
  12. GRB 050124 I-band observation
  13. GRB050124,optical observation
  14. GRB050124: Refined BAT position, spectral and fluence information
  15. GRB050123,optical observation
  16. GRB 050123: KAIT observations
  17. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  18. GRB 050117, I-band observations
  19. SGR1806: Detection of a Sudden Ionospheric Disturbance
  20. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  21. The giant outburst from SGR 1806-20
  22. Swift-BAT Time History of GRB041219
  23. GRB041220: Swift-BAT burst
  24. Deep RAPTOR observations during GRB 041219
  25. GRB041219c: Third Burst in One Day from Swift-BAT
  26. GRB 041219 ,optical observation
  27. GRB 041218: R-band optical observations
  28. Swift-BAT detection of the bright long burst GRB041219
  29. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  30. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  31. GRB041211: Continued P60 Observations
  32. GRB041211: RAPTOR observations
  33. GRB041211, BVRcIc field calibration
  34. GRB041211,optical observation
  35. GRB 041211: Infrared Observations
  36. GRB 041211: KAIT observations
  37. Distribution of IBAS Alerts for NON-GRB sources
  38. GRB 041006: GETS Optical Afterglow Observation
  39. Summary of the recent bursts from SGR 1806-20
  40. GRB041015, optical observation in CrAO
  41. Bright bursts from SGR1806-20
  42. GRB 041016: BOOTES-2 simultaneous observation
  43. GRB041016,optical observation
  44. GRB 041016: Optical limits
  45. GRB 041016:Optical limit during first minute
  46. GRB041016: MASTER: Optical observations
  47. GRB041006: Near Infrared observations
  48. GRB 041016: Optical limit
  49. GRB 041015 R band observations
  50. GRB040924, BVRcIc field calibration
  51. GRB041015: MASTER: Optical observations
  52. GRB041015,optical observation
  53. GRB041006: MASTER optical observations
  54. GRB041006,optical observation
  55. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  56. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  57. GRB040929,optical observation
  58. GRB040924,optical observation
  59. GRB040924: KAIT observations
  60. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  61. GRB040924 (H3564): Optical afterglow candidate
  62. XRF040912, BVRcIc field calibration
  63. XRF040916, BVRcIc field calibration
  64. GRB040916: Optical observations
  65. GRB/XRF040912,optical observations
  66. GRB 040912, BVRI observations
  67. Optical observations of field of GRB040912
  68. HETE 3557: Optical observations
  69. GRB040825B, BVRcIc field photometry
  70. GRB040825A, BVRcIc field photometry
  71. GCN GRB OBSERBATION REPORT
  72. GRB 040825A,optical observations
  73. Increase of SGR 1806-20 activity
  74. GRB040825A: optical observations
  75. GRB040825B: optical observations
  76. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  77. GRB 040825A: Optical observations.
  78. MASTER: GRB040825b optical observation
  79. GRB040825B: Correction to GCN 2657
  80. GRB 040812: Second epoch CXO Observations
  81. GRB040823,optical observation
  82. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  83. CXO observation of GRB 040812
  84. Ongoing activity of SGR 1806-20
  85. GRB040709 J,H-band observations
  86. GRB040706:observation at University of Miyazaki
  87. GRB 040606: Optical observations
  88. MASTER: HETE Alert 3274 optical observation
  89. Activivty of SGR 1806-20
  90. GRB 040511: Optical limit
  91. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  92. GRB040511: Optical Observations
  93. GRB040511: Optical Observations
  94. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  95. GRB040422: optical observations at CrAO
  96. GRB 040423 (=H3175): A Long GRB Localized by HETE
  97. GRB040422, optical observations at Loiano
  98. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  99. GRB 040422,optical observation
  100. MASTER: HETE Alert 3163, 3167 technical optical observation

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