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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"

35947 results found.

  1. GRB050117: Refined XRT position
  2. GRB050117: MASTER optical observations
  3. MASTER:GRB050117 SWIFT
  4. GRB050117: Swift-BAT detection of a long multi-peaked burst
  5. Triangulation of Short Hard GRB050112 (large error box)
  6. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  7. SGR 1806-20 and extragalactic short-duration GRBs
  8. SGR 1806-20: Temporal and Spectral behavior of radio transient
  9. SGR 1806-20, RHESSI observations of the 041227 giant flare
  10. SGR1806: Detection of a Sudden Ionospheric Disturbance
  11. GRB 041217: Optical observations
  12. GRB041219, early time observations
  13. IPN localization of giant flare from SGR1806-20
  14. GRB041219; RXTE ASM Observations
  15. NIR Observations of GRB 041219
  16. GRB041223: decay of the afterglow
  17. GRB 041224: near-infrared observations with REM
  18. GRB 041223: XRT afterglow spectrum and light curve
  19. GRB 041223 Fluence measured by Swift-BAT
  20. GRB041223: optical and NIR observations with REM
  21. GRB 041219: TAROT optical observations
  22. GRB 041218: TAROT optical observations
  23. GRB 041223: J-band observations of the afterglow
  24. GRB 041223: Detection of Optical Transient with LCO40
  25. GRB 041219c: PROMPT Observations
  26. GRB 041218: optical observations
  27. GRB 041219: Second Epoch WSRT Radio Observations
  28. GRB 041219: WSRT Radio Afterglow Detection
  29. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  30. GRB 041218: Optical observations
  31. GRB 041219 : optical follow-up observations
  32. Deep RAPTOR observations during GRB 041219
  33. GRB 041218 Optical Observations
  34. GRB 041219 Optical Observations
  35. GRB041219c: Third Burst in One Day from Swift-BAT
  36. GRB041219: Optical Afterglow Detection
  37. GRB041219: Continued NIR Observations
  38. GRB 041219 ,optical observation
  39. GRB 041219: Radio Afterglow Detection
  40. GRB 041218 : Radio Observations
  41. GRB 041218: R-band optical observations
  42. GRB041219: Confirmed NIR Afterglow
  43. GRB041218: Continued P60 Optical Observations
  44. GRB 041218: Optical Observation
  45. GRB 041219: Infrared Afterglow Candidate
  46. GRB041219, BVRcIc field calibration
  47. GRB 041219: Infrared Afterglow Candidate
  48. GRB041218, BVRcIc field calibration
  49. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  50. GRB041219: P60 Optical Observations
  51. GRB 041219 - A long GRB detected by INTEGRAL
  52. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  53. GRB 041217: PROMPT Observations
  54. GRB041218: optical observations
  55. GRB041217: optical limit 30 min after GRB
  56. GRB 041218; optical candidate
  57. GRB 041218: Optical observations
  58. GRB 041217: LCO40 Optical Observations and Possible Candidates
  59. GRB 041218 - A long GRB detected by integral
  60. GRB041217: Optical Observations
  61. GRB041217: P60 Optical Observations
  62. GRB041217: Infrared Observations
  63. GRB041217: The First GRB Located On-Board Swift
  64. GRB041211: Faulkes Telescope continued optical monitoring
  65. Optical Transient in Lynx not a GRB
  66. Optical transient (GRB?) in Lynx
  67. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  68. GRB041211: Continued P60 Observations
  69. GRB041211: RAPTOR observations
  70. GRB041211: Ashra Prototype optical observation
  71. GRB041211, Faulkes Telescope optical observation
  72. GRB041211, BVRcIc field calibration
  73. GRB 041211: Infrared Observations
  74. GRB 041211: KAIT observations
  75. GRB 041211: Optical follow-up in East Asian region
  76. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  77. GRB041211: P60 optical imaging
  78. GRB970815: Discovery of Optical Afterglow
  79. Distribution of IBAS Alerts for NON-GRB sources
  80. Triangulation of short GRB 041116 (large error box)
  81. GRB 040924: Afterglow Color
  82. GRB 041006: GETS Optical Afterglow Observation
  83. Summary of the recent bursts from SGR 1806-20
  84. GRB 041006: Optical Observations
  85. GRB041006, late-time optical photometry
  86. IBAS GRB Alert # 2034
  87. GRB041006: RTT150 Optical Observations
  88. Bright bursts from SGR1806-20
  89. GRB 041016: BOOTES-2 simultaneous observation
  90. GRB041006: RTT150 Optical Observations
  91. GRB 041016: Optical limits
  92. GRB 041016: Optical limits in V, R, I
  93. GRB 041016:Optical limit during first minute
  94. GRB041016: MASTER: Optical observations
  95. GRB 041015: Optical Observations at Rikubetsu
  96. GRB041006: Near Infrared observations
  97. GRB 041016: Optical limit
  98. GRB 041015 R band observations
  99. GRB040924, BVRcIc field calibration
  100. GRB041015: MASTER: Optical observations

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