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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"

26365 results found.

  1. GRB 050123: KAIT observations
  2. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  3. GRB050117: Refined XRT position
  4. GRB050117: MASTER optical observations
  5. MASTER:GRB050117 SWIFT
  6. GRB050117: Swift XRT Position
  7. Triangulation of Short Hard GRB050112 (large error box)
  8. SGR 1806-20: Further VLA Observations
  9. SGR1806-20: Swift-BAT observations of two additional bursts
  10. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  11. Further VLA observations of SGR 1806-20
  12. SGR 1806-20 and extragalactic short-duration GRBs
  13. Further ATCA observations of SGR 1806-20
  14. Fourth Epoch VLA observations of SGR 1806-20
  15. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  16. ATCA observations of SGR 1806-20
  17. SGR 1806-20, RHESSI observations of the 041227 giant flare
  18. Third epoch observations of SGR 1806-20 with VLA
  19. Second Epoch VLA observations of SGR 1806-20
  20. Second-epoch VLA observations of SGR 1806-20
  21. SGR1806 VLA Observations
  22. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  23. GRB 041217: Optical observations
  24. GRB041228: Swift-BAT detection of a burst
  25. GRB041219; RXTE ASM Observations
  26. NIR Observations of GRB 041219
  27. GRB041226: Swift-BAT detection of a burst
  28. GRB041223: decay of the afterglow
  29. GRB 041224: near-infrared observations with REM
  30. GRB 041223 Fluence measured by Swift-BAT
  31. GRB041223: optical and NIR observations with REM
  32. Swift-BAT Time History of GRB041219
  33. GRB 041219: TAROT optical observations
  34. GRB 041218: TAROT optical observations
  35. GRB 041223: J-band observations of the afterglow
  36. GRB 041219c: PROMPT Observations
  37. GRB041223: Swift-BAT detection of a bright long burst
  38. GRB 041218: optical observations
  39. GRB 041219 : optical follow-up observations
  40. Deep RAPTOR observations during GRB 041219
  41. GRB 041218 Optical Observations
  42. GRB041219: Continued NIR Observations
  43. GRB 041219 ,optical observation
  44. GRB 041219: Radio Afterglow Detection
  45. GRB 041218 : Radio Observations
  46. GRB 041218: R-band optical observations
  47. GRB041218: optical observations
  48. GRB041219: Confirmed NIR Afterglow
  49. Swift-BAT detection of the bright long burst GRB041219
  50. GRB 041219: Infrared Afterglow Candidate
  51. GRB041219, BVRcIc field calibration
  52. GRB 041219: Infrared Afterglow Candidate
  53. GRB041218, BVRcIc field calibration
  54. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  55. GRB 041219 - A long GRB detected by INTEGRAL
  56. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  57. GRB 041217: PROMPT Observations
  58. GRB 041217: LCO40 Optical Observations and Possible Candidates
  59. GRB 041218 - A long GRB detected by integral
  60. GRB041217: NIR and optical observations with REM
  61. GRB041217: Infrared Observations
  62. GRB041217: The First GRB Located On-Board Swift
  63. GRB041211: Faulkes Telescope continued optical monitoring
  64. Optical Transient in Lynx not a GRB
  65. Optical transient (GRB?) in Lynx
  66. GRB041211: RAPTOR observations
  67. GRB041211: Ashra Prototype optical observation
  68. GRB041211, BVRcIc field calibration
  69. GRB041211,optical observation
  70. GRB 041211: Infrared Observations
  71. GRB 041211: KAIT observations
  72. GRB 041211: Optical follow-up in East Asian region
  73. Triangulation of short GRB 041116 (large error box)
  74. GRB 040924: Afterglow Color
  75. GRB 041006: GETS Optical Afterglow Observation
  76. Summary of the recent bursts from SGR 1806-20
  77. GRB 041006: Optical Observations
  78. GRB041006, late-time optical photometry
  79. GRB041006: RTT150 Optical Observations
  80. HST Observations: XRF 040701 and 040812
  81. Bright bursts from SGR1806-20
  82. GRB 041016: BOOTES-2 simultaneous observation
  83. GRB041006: RTT150 Optical Observations
  84. GRB041016,optical observation
  85. GRB 041016: Optical limits
  86. GRB 041016:Optical limit during first minute
  87. GRB 041015: Optical Observations at Rikubetsu
  88. GRB 041016: Optical limit
  89. GRB 041015 R band observations
  90. GRB040924, BVRcIc field calibration
  91. GRB041015,optical observation
  92. GRB041006: Fading X-ray Afterglow Observed with Chandra
  93. GRB 041015 - A long GRB detected by INTEGRAL
  94. GRB041006: VLT observations of the afterglow and host galaxy
  95. GRB041006: Optical observations and Potential host galaxy
  96. GRB041006, BVRcIc field calibration
  97. GRB 040924: VLT spectroscopy
  98. GRB 041006: SARA afterglow observations
  99. GRB041006, optical observation in CrAO
  100. Search for SN light in XRF 040912 with MEGACAM

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