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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"

19543 results found.

  1. GRB061217: Swift/UVOT refined analysis.
  2. GRB 061217, Further Swift-BAT refined analysis of the short hard burst
  3. GRB 061217, Swift-BAT refined analysis
  4. GRB 061217: Magellan Observations
  5. GRB 061217: REM prompt observations
  6. GRB 061217: ROTSE-III Optical Limits
  7. GRB061210: Swift/UVOT observations
  8. GRB 061210: Swift XRT analysis - Possible counterparts
  9. GRB 061214(?): Swift detection of a possible burst
  10. GRB 061210: Gemini/GMOS Observations
  11. GRB 061126: Radio Observations
  12. GRB061210: Radio Observations
  13. Optical Afterglow observations of GRB 061126
  14. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  15. GRB 061202: TORTOREM optical upper limits
  16. GRB 061201: VLT optical decay
  17. GRB 061201: SOAR Confirmation of Candidate Afterglow
  18. GRB061202: FRAM early follow-up limit
  19. GRB061202 optical limit by "Pi of the Sky"
  20. GRB061202: optical/NIR observations with REM
  21. GRB061202: Swift/UVOT Upper Limits
  22. GRB 061202: Swift detection of a burst
  23. GRB 061201: VLT optical observations
  24. GRB 061201: Swift detection of a short hard burst
  25. INT+WFC observations of GRB 061126
  26. RHESSI Spectrum of GRB061126
  27. GRB061126: Optical afterglow observations from MIRO
  28. GRB061126: Optical afterglow observations from MIRO
  29. GRB 061126 : SDSS Pre-Burst Observations
  30. GRB 061126: Swift/UVOT Observations
  31. GRB 061126: Early Detection of the IR Afterglow
  32. GRB 061122: Candidate Optical Afterglow
  33. GRB061122: Swift/UVOT Optical Observations
  34. GRB061121: P60 Observations
  35. Radio detection of GRB 061121
  36. GRB061122: Swift-XRT position
  37. Konus-Wind observation of GRB 061122
  38. Swift-BAT trigger 239987 is not a GRB
  39. GRB 061121: Swift/UVOT Observations
  40. GRB061121, optical observation
  41. GRB 061121: Optical observation at the KANATA 1.5m telescope
  42. GRB061121: Spectroscopic Redshift
  43. GRB 061121: Swift detection of a bright burst with an optical counterpart
  44. GRB 060605: NIR Observations
  45. GRB 050915B: optical afterglow
  46. GRB061110A: Correction to GCN5817
  47. Swift/UVOT Upper Limits for GRB061110b
  48. Swift/UVOT Upper Limits for GRB061110a
  49. GRB061110B: Optical observations at Crni Vrh
  50. GRB 061110B: Swift-UVOT Initial Observation
  51. GRB 061110B: TAROT Calern observatory optical observations
  52. GRB 061110B: Swift detection of a burst
  53. GRB 061110: Candidate confirmed
  54. GRB 061110: ROTSE-III Optical Limits
  55. GRB 061110: Swift detection of a burst
  56. GRB061110A - Optical Non-detection
  57. GRB 061109: TAROT Calern observatory optical observations
  58. GRB 061027: TAROT La Silla observatory optical observations
  59. GRB 061028: Swift/XRT Astrometry Correction
  60. GRB 061102: Swift/UVOT Magnitude Upper Limits
  61. GRB061102B: Super-LOTIS observations
  62. GRB 061028: Optical R passband observations
  63. GRB 061102B: Swift detection of a possible burst
  64. GRB 061102: Swift detection of a burst
  65. GRB 061028: VLA Observation
  66. GRB 061004: Swift/XRT Astrometry Correction
  67. GRB 060801: Swift/XRT Astrometry Correction
  68. GRB 061028: Futher P200 Observations
  69. GRB 061028: P200 Observations
  70. GRB 061028: SARA upper limit
  71. GRB 061028: z band imaging
  72. GRB061028: XRT refined analysis
  73. GRB 061028: Swift/UVOT Observations
  74. GRB 061028: TAROT Calern observatory optical observations
  75. GRB 061028: Swift detection of a burst
  76. GRB 061027, Swift refined analysis of a possible burst
  77. GRB 061027: Swift detection of a possible burst
  78. GRB061025: Swift/UVOT observations
  79. GRB 061025: REM observations
  80. GRB 061025: ROTSE-III Optical Limits
  81. GRB 061021: Swift/UVOT Observation
  82. GRB 061021: Swift detection of a burst
  83. GRB 061019: SARA upper limit
  84. GRB 061019: Swift/UVOT upper limit
  85. GRB 061019: TAROT La Silla observatory optical observations
  86. GRB 061019: REM K-band candidate afterglow
  87. GRB 061006: astrometry-corrected XRT position
  88. GRB 061007: ATCA Radio Observations
  89. GRB061007: Swift UVOT followup observations
  90. GRB 061006: optical afterglow
  91. GRB 061007: OA fading and VLT redshift
  92. GRB 061007: Magellan Spectroscopy
  93. GRB 061006: Swift/UVOT optical observations
  94. GRB 061007: Swift detection of a burst with an optical counterpart
  95. GRB 061006: VLT observation
  96. GRB 060930: near-IR afterglow candidate retraction
  97. GRB 061006: Swift detection of a burst
  98. GRB 061004: Optical afterglow candidate and redshift
  99. GRB 061004, Swift BAT refined analysis
  100. GRB 061004: Swift detection of a burst

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