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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"
  1. GRB 070311: RAPTOR Detection of Optical Emission
  2. GRB070311: FRAM early follow-up limit
  3. GRB 070311: P60 Observations
  4. GRB 070311: MDM Optical Detection
  5. GRB 070311: Swift/UVOT Upper Limits
  6. GRB 070311: MITSuME Okayama Optical Observation
  7. GRB 070311: Swift-XRT refined analysis
  8. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  9. GRB 070311: REM candidate afterglow
  10. GRB 070311: a long GRB detected by INTEGRAL
  11. GRB060901: Candidate optical afterglow
  12. GRB070309: Swift/XRT possible afterglow detection
  13. GRB 070125: Chandra X-ray Confirmation of Jet Break
  14. GRB 070309: Swift/UVOT Upper Limits
  15. GRB 070306, optical observation
  16. Swift UVOT Finding Charts for GRB 070309
  17. GRB 070309: A long GRB detected by INTEGRAL
  18. GRB 070125: X-ray light curve analysis
  19. VLA observation of GRB 070306
  20. IBAS Alert 4162: Not a GRB
  21. GRB 070306: NOT observations
  22. GRB 070306 Swift/UVOT refined analysis
  23. GRB070306: confirmation of near infrared afterglow
  24. GRB 070306: ART-3 early optical and near infrared constraints
  25. GRB 070306: IR observations and candidate afterglow
  26. GRB 070306, Swift-BAT refined analysis
  27. GRB 070306: XRT Team Refined Analysis
  28. GRB 070306: Optical and IR observations with KANATA
  29. GRB070306 - SDSS Pre-burst Observations
  30. GRB 070306: Swift detection of a burst
  31. GRB 070223: NIR observations at WHT
  32. GRB070227: Swift-XRT refined analysis
  33. GRB 060605 new redshift
  34. GRB 070125, deep late-time optical observation
  35. VLA observation of GRB 070224
  36. GRB 070227: optical observations
  37. GRB 070223: Optical Observations
  38. GRB 070227: optical observations
  39. GRB 070227: Swift/UVOT Upper Limits
  40. GRB 070227: TAROT La Silla observatory optical observations
  41. GRB 070227, Swift-BAT refined analysis
  42. GRB070227: possible X-ray afterglow detection
  43. GRB 070227: Swift detection of a burst in ground analysis
  44. GRB 920925C: optical afterglow candidate
  45. GRB 070224: Optical afterglow confirmation
  46. IBAS Alert n. 4144: not a GRB
  47. GRB 070224: Swift/UVOT Upper Limits
  48. GRB070224: Swift-XRT Astrometrically Corrected Position
  49. VLA observation of GRB 070223
  50. VLA observation of GRB 070220
  51. GRB070224: Magellan Imaging Observations
  52. GRB 070224: WHT K-band imaging
  53. GRB 070224: MDM Observations
  54. GRB070224: Gemini Imaging Observations
  55. GRB 070224: SARA upper limit
  56. GRB070224: Swift-XRT Refined Analysis
  57. GRB 070224: optical afterglow candidate
  58. GRB 070224, Swift-BAT refined analysis
  59. GRB 070224: MASTER-Net refind analysis
  60. GRB 070224: MASTER-VWF-Kislovodsk observations
  61. GRB 070224: MASTER observations
  62. GRB 070224: Swift detection of a burst
  63. GRB 070223: Optical observations
  64. RHESSI Spectrum of GRB070220
  65. GRB070223: Swift/UVOT refined analysis
  66. GRB 070223: Optical-IR observation with KANATA
  67. GRB 070223, Swift-BAT refined analysis
  68. GRB070223: MASTER-VWF-Kislovodsk observations
  69. GRB 070223: Swift-XRT Refined Analysis
  70. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  71. GRB070223 - SDSS Pre-Burst Observations
  72. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  73. GRB 070223: MDM Observations
  74. GRB070223: Swift burst
  75. Konus-Wind and Konus-A observations of GRB 070220
  76. GRB 070220: MITSuME Okayama Optical Observation
  77. GRB 070220: ART-3 Optical and NIR limits
  78. GRB 070220 Swift-BAT Refined Analysis
  79. Swift/UVOT refined analysis of GRB070220
  80. GRB 070209: Swift XRT refined analysis
  81. GRB 070220: Swift-XRT Refined Analysis
  82. GRB 070220: Observation with the KANATA 1.5m telescope
  83. GRB 070219: Gemini Observations
  84. GRB 070220 : Faulkes Telescope North optical limit
  85. GRB 070220: Swift detection of a burst
  86. GRB070219: MASTER-VWF-Kislovodsk observations
  87. GRB 070219: XRT Refined Analysis
  88. GRB 070219: Swift/UVOT Upper limits
  89. GRB 070219: I-band observations
  90. GRB 070219, Swift-BAT refined analysis
  91. GRB 070219: optical TNG observations
  92. GRB 070219: Liverpool Telescope Observations
  93. GRB 070219: ROTSE-III Optical Limits
  94. GRB070219 - SDSS Pre-Burst Observations
  95. GRB 070219: Swift detection of a burst
  96. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  97. GRB 070125 observations with the GMRT
  98. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  99. Swift-BAT trigger 260304 is NOT a burst or transient
  100. GRB 060927: PROMPT Observations

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