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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 070509: objects inside XRT error circle
  2. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  3. GRB 070512: IPN localization and Konus spectrum of a bright burst
  4. GRB070419A: optical observations
  5. GRB 070419A, Deep LBT photometry
  6. GRB 070508: pseudo-z from 4 different spectral analyses
  7. GRB 070509: Swift/UVOT Upper Limits
  8. Konus-Wind and Konus-A observation of GRB 070508
  9. Swift-BAT trigger 278987 is not a GRB
  10. GRB 070510: Swift detection of a possible burst
  11. GRB070509: Swift-XRT Refined Analysis
  12. RHESSI Spectrum of GRB070508
  13. GRB 070508: OA fading and tentative redshift
  14. GRB 070509, Swift-BAT refined analysis
  15. GRB 070508: Suzaku/WAM observation of the prompt emission
  16. GRB 070509: REM observations
  17. GRB 070509: Swift detection of a burst
  18. GRB 070509: ROTSE-III Optical Limits
  19. GRB070508: Swift/UVOT Observations
  20. GRB 070508, SMARTS optical afterglow observation
  21. GRB 070508, Swift-BAT refined analysis
  22. GRB 070508: Multicolor optical observations and possible redshift limit
  23. GRB 070508: Swift-XRT refined analysis
  24. GRB 070508: Optical observation limiting magnitude
  25. GRB 070508: Optical afterglow detection
  26. GRB 070508: REM observations
  27. GRB 070508: TAROT La Silla observatory optical observations
  28. GRB 070508: Swift detection of an intense burst with an optical counterpart
  29. GRB070412: MAGIC telescope GeV observation
  30. Swift-BAT trigger 278809 is not a GRB
  31. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  32. GRB 070506: VLT redshift
  33. GRB070506: Swift/UVOT Observations
  34. GRB070506: Swift XRT refined analysis
  35. GRB 070506, Swift-BAT Refined Analysis
  36. GRB 070506: Swift detection of a burst with optical afterglow
  37. GRB 070412, deep LBT imaging
  38. GRB 070429A: Swift XRT further analysis
  39. GRB070429B: VLT observations
  40. GRB 070429A: optical observations
  41. GRB070429B: position correction
  42. GRB 070309: Swift-XRT afterglow confirmation
  43. GRB070429B: possible host galaxy detection
  44. VLA observation of GRB 070429B
  45. Swift/UVOT observations of GRB070429B
  46. GRB 070429B, Swift-BAT refined analysis
  47. Swift/UVOT observations of GRB070429A
  48. GRB 070429A: Swift XRT refined analysis
  49. GRB 070429A, Swift-BAT refined analysis
  50. GRB 070429A: optical and NIR observations
  51. GRB 070429B: Swift XRT refined analysis
  52. GRB 070429B: ROTSE-III Optical Limits
  53. GRB 070429B: Swift detection of a short burst
  54. GRB 070429: What's the temperature?
  55. GRB 070429: ROTSE-III Optical Limits
  56. GRB 070429: Swift detection of a burst
  57. GRB 070427, Swift-BAT Refined Analysis
  58. LT monitoring of GRB070412
  59. GRB 070427: Swift detection of a burst
  60. GRB 070411, further deep LBT photometry
  61. GRB 070411: Late-time Keck imaging
  62. GRB 070411 : Planned XMM-Newton observation
  63. GRB070419B: Suzaku WAM observation of the prompt emission
  64. GRB 070420, SMARTS optical/IR afterglow observations
  65. GRB 070411, deep LBT photometry
  66. GRB 070420: pseudo-z~1.56 from spectral parameters of the prompt
  67. Konus-Wind observation of GRB 070420
  68. GRB 070411: break in the optical light curve
  69. GRB 070420 Swift-BAT Refined Analysis
  70. GRB070419A: Kuiper Optical detection
  71. GRB070419a: Swift UVOT observations
  72. GRB 070419A: MARGE Observations
  73. GRB 070420: optical rebrightening observed at Mt. John
  74. GRB 070420: Swift XRT refined analysis
  75. GRB070420: Swift UVOT continuing observations
  76. GRB 070411: BART early limit
  77. GRB 070420: Faulkes Telescope South Observations
  78. GBR 070419A: Swift/XRT refined analysis
  79. GRB 070420: TAROT La Silla observatory optical observations
  80. GRB 070420: NIR and optical afterglow confirmed
  81. GRB 070420: Swift detection of a burst with optical afterglow
  82. GRB 070419A: MITSuME Okayama Observations
  83. GRB 070419A: Early Super-LOTIS Observations
  84. GRB 070419B, Swift-BAT refined analysis
  85. GRB 070419A Swift-BAT Refined Analysis
  86. GRB070419B: Confirmation of Optical Transient
  87. GRB 070419A: RAPTOR Detection of Early Emission
  88. GRB 070419B: Swift XRT refined analysis
  89. GRB 070419: Keck/LRIS Absorption Redshift
  90. GRB 070419B: optical afterglow confirmation
  91. GRB 070419A, Optical observations
  92. GRB 070411: Deep VLT detection
  93. GRB070419 - SDSS Pre-Burst Observations
  94. GRB 070419A: SARA observations
  95. GRB 070419A: NAYUTA Optical Observation
  96. GRB 070419A: Faulkes Telescope North Optical Observations
  97. GRB 070419B optical afterglow candidate
  98. GRB 070419A: Optical and IR observations with KANATA
  99. GRB 070419B: optical afterglow candidate
  100. GRB 070419A: Lulin Optical observation

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