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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"

23417 results found.

  1. GRB 120612A: optical observations
  2. GRB 120612A: Swift/UVOT observations
  3. GRB 120612A: Enhanced Swift-XRT position
  4. GRB 120612A: BOOTES-3 optical upper limit
  5. GRB 120612A: Swift detection of a burst
  6. Konus-Wind observation of GRB 120603A
  7. IPN Triangulation of short GRB 120603A
  8. Konus-Wind observation of GRB 120528B
  9. GRB 120521C: EVLA 22 GHz Detection
  10. GRB120521B: SSO 2.3m upper limits
  11. IPN triangulation of GRB 120522A (long/intense)
  12. GRB 120521C: EVLA 22 GHz Upper Limit
  13. GRB 120521A: GROND Upper limits
  14. GRB 120521C: Keck Observations
  15. GRB 120521C: Swift/UVOT Upper Limits
  16. GRB 120521B: Swift/UVOT Upper Limits
  17. GRB 120521B: GROND Upper limits
  18. GRB 120521C: PAIRITEL NIR Upper Limits
  19. GRB 120521C: Enhanced Swift-XRT position
  20. GRB 120521C - NOT optical limits
  21. GRB 120521C: TAROT Calern observatory optical observations
  22. GRB 120521C: Swift detection of a burst
  23. Swift starts a new program to find fainter transients
  24. IPN Triangulation of GRB 120519A (short/hard)
  25. GRB 120521A: Swift/UVOT Upper Limits
  26. GRB 120521B: Enhanced Swift-XRT position
  27. GRB 120521B: TAROT La Silla observatory optical observations
  28. GRB 120521B: Swift detection of a burst
  29. GRB 120521A: Enhanced Swift-XRT position
  30. GRB 120521A: TAROT La Silla observatory optical observations
  31. GRB 120521A: Swift detection of a short burst
  32. Swift Trigger 522245 is a noise fluctuation near IGR J17091-3624
  33. GRB 120514A: GROND upper limits
  34. GRB 120514A: Swift/UVOT Upper Limits
  35. GRB 120514A: UKIRT IR observations
  36. Konus-Wind observation of GRB 120510A
  37. GRB 120514A: APEX observations of the submm counterpart
  38. GRB 120514A: Enhanced Swift-XRT position
  39. GRB 120514A: Swift-BAT refined analysis
  40. GRB 120514A: TAROT Calern observatory optical observations
  41. GRB 120514A: Swift detection of a burst
  42. GRB 120422A: Konkoly optical observations
  43. Fermi Trigger 358364818: BOOTES-4 observations
  44. GRB 120510B/Fermi Trigger 358364818: MASTER possible OT candidate
  45. GRB 120510A: Swift XRT and UVOT observations
  46. Fermi/GBM detection of a burst from the magnetar 1E 2259+5
  47. GRB 120422A: P200 NIR detection
  48. GRB 120422A: CARMA 3mm observations
  49. GRB 120422A: optical observations
  50. IPN Triangulation of GRB 120427A
  51. Swift detection of 4U 1630-47
  52. IPN Triangulation of bright GRB 120426A
  53. GRB 120422A: MITSuME Ishigakijima upper limit
  54. Swift Trigger 520928 is probably not a burst
  55. GRB 120422A: 272 GHz observations from SMA
  56. GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval
  57. GRB 120422A GROND observations
  58. GRB 120422A: Super-LOTIS early observations
  59. GRB 120422A: EVLA Detection
  60. GRB 120422A: NOT optical observations
  61. GRB 120422A: Zadko observatory - Gingin optical observations
  62. GRB 120422A: A Swift/UVOT Detection
  63. GRB 120422A: Enhanced Swift-XRT position
  64. GRB 120422A: Swift-BAT refined analysis
  65. GRB 120422A: Gemini observations
  66. GRB 120422A: Faulkes Telescope North observations
  67. GRB 120422A: Swift detection of a burst
  68. GRB 120419A: Swift-XRT and UVOT observations
  69. Swift Trigger 519874 is probably a noise event
  70. Trigger 519868: Swift detection of SGR1806-20
  71. GRB 120404A: optical observations in Mondy observatory
  72. GRB 120404A: optical observations
  73. GRB 120404A, Optical Observations
  74. GRB 120404A: EVLA Detection
  75. GRB 120404A: MASTER OT observations
  76. GRB120404A: GROND observations show steeply decaying afterglow
  77. GRB 120404A: Swift/UVOT Detection
  78. GRB 120404A: MITSuME Ishigakijima Optical Observation
  79. GRB 120404A: MITSuME Okayama Optical Observation
  80. GRB 120401A: GROND Detection of an optical/NIR afterglow candidate
  81. GRB 120404A: Enhanced Swift-XRT position
  82. GRB 120402B: MASTER early OT limit
  83. GRB 120403B: TAROT La Silla observatory optical observations
  84. GRB 120404A: Gemini-N Redshift
  85. GRB 120403B: AAT nIR observations
  86. GRB 120404A: Faulkes Telescope North afterglow confirmation
  87. GRB 120404A: Swift detection of a burst with an optical counterpart
  88. GRB 120403B: Swift/UVOT Upper Limits
  89. GRB 120403B: Enhanced Swift-XRT position
  90. GRB 120403B: Swift detection of a burst
  91. GRB 120402A: optical upper limit
  92. GRB 120320A: optical upper limit in Mondy observatory
  93. GRB 120320A: early optical upper limit
  94. GRB 120402B: Fermi GBM detection
  95. GRB 120328B: Pi of the Sky simultaneous upper limits
  96. GRB 120326A: Bassano Bresciano Observatory - correction for GCN Cir 13178
  97. GRB 120403A: Swift detection of a burst
  98. GRB 120402A: Swift detection of a possible burst or noise
  99. GRB 120326A: Cima Rest and Bassano Brescia
  100. GRB 120327A: SMARTS optical/IR afterglow observations

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