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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"

34060 results found.

  1. GRB050117: MASTER optical observations
  2. MASTER:GRB050117 SWIFT
  3. GRB050117: Swift-BAT detection of a long multi-peaked burst
  4. Triangulation of Short Hard GRB050112 (large error box)
  5. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  6. SGR 1806-20 and extragalactic short-duration GRBs
  7. SGR 1806-20: Temporal and Spectral behavior of radio transient
  8. SGR 1806-20, RHESSI observations of the 041227 giant flare
  9. SGR1806: Detection of a Sudden Ionospheric Disturbance
  10. GRB 041217: Optical observations
  11. GRB041219, early time observations
  12. IPN localization of giant flare from SGR1806-20
  13. GRB041219; RXTE ASM Observations
  14. NIR Observations of GRB 041219
  15. GRB041223: decay of the afterglow
  16. GRB 041224: near-infrared observations with REM
  17. GRB 041223: XRT afterglow spectrum and light curve
  18. GRB 041223 Fluence measured by Swift-BAT
  19. GRB041223: optical and NIR observations with REM
  20. GRB 041219: TAROT optical observations
  21. GRB 041218: TAROT optical observations
  22. GRB 041223: J-band observations of the afterglow
  23. GRB 041223: Detection of Optical Transient with LCO40
  24. GRB 041219c: PROMPT Observations
  25. GRB 041218: optical observations
  26. GRB 041219: Second Epoch WSRT Radio Observations
  27. GRB 041219: WSRT Radio Afterglow Detection
  28. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  29. GRB 041218: Optical observations
  30. GRB 041219 : optical follow-up observations
  31. Deep RAPTOR observations during GRB 041219
  32. GRB 041218 Optical Observations
  33. GRB 041219 Optical Observations
  34. GRB041219c: Third Burst in One Day from Swift-BAT
  35. GRB041219: Optical Afterglow Detection
  36. GRB041219: Continued NIR Observations
  37. GRB 041219 ,optical observation
  38. GRB 041219: Radio Afterglow Detection
  39. GRB 041218 : Radio Observations
  40. GRB 041218: R-band optical observations
  41. GRB041219: Confirmed NIR Afterglow
  42. GRB041218: Continued P60 Optical Observations
  43. GRB 041218: Optical Observation
  44. GRB 041219: Infrared Afterglow Candidate
  45. GRB041219, BVRcIc field calibration
  46. GRB 041219: Infrared Afterglow Candidate
  47. GRB041218, BVRcIc field calibration
  48. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  49. GRB041219: P60 Optical Observations
  50. GRB 041219 - A long GRB detected by INTEGRAL
  51. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  52. GRB 041217: PROMPT Observations
  53. GRB041218: optical observations
  54. GRB041217: optical limit 30 min after GRB
  55. GRB 041218; optical candidate
  56. GRB 041218: Optical observations
  57. GRB 041217: LCO40 Optical Observations and Possible Candidates
  58. GRB 041218 - A long GRB detected by integral
  59. GRB041217: Optical Observations
  60. GRB041217: P60 Optical Observations
  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. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  67. GRB041211: Continued P60 Observations
  68. GRB041211: RAPTOR observations
  69. GRB041211: Ashra Prototype optical observation
  70. GRB041211, Faulkes Telescope optical observation
  71. GRB041211, BVRcIc field calibration
  72. GRB 041211: Infrared Observations
  73. GRB 041211: KAIT observations
  74. GRB 041211: Optical follow-up in East Asian region
  75. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  76. GRB041211: P60 optical imaging
  77. GRB970815: Discovery of Optical Afterglow
  78. Distribution of IBAS Alerts for NON-GRB sources
  79. Triangulation of short GRB 041116 (large error box)
  80. GRB 040924: Afterglow Color
  81. GRB 041006: GETS Optical Afterglow Observation
  82. Summary of the recent bursts from SGR 1806-20
  83. GRB 041006: Optical Observations
  84. GRB041006, late-time optical photometry
  85. IBAS GRB Alert # 2034
  86. GRB041006: RTT150 Optical Observations
  87. Bright bursts from SGR1806-20
  88. GRB 041016: BOOTES-2 simultaneous observation
  89. GRB041006: RTT150 Optical Observations
  90. GRB 041016: Optical limits
  91. GRB 041016: Optical limits in V, R, I
  92. GRB 041016:Optical limit during first minute
  93. GRB041016: MASTER: Optical observations
  94. GRB 041015: Optical Observations at Rikubetsu
  95. GRB041006: Near Infrared observations
  96. GRB 041016: Optical limit
  97. GRB 041015 R band observations
  98. GRB040924, BVRcIc field calibration
  99. GRB041015: MASTER: Optical observations
  100. GRB041015,optical observation

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