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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"

15560 results found.

  1. GRB 070420: Faulkes Telescope South Observations
  2. GBR 070419A: Swift/XRT refined analysis
  3. GRB 070420: TAROT La Silla observatory optical observations
  4. GRB 070420: NIR and optical afterglow confirmed
  5. GRB 070420: Swift detection of a burst with optical afterglow
  6. GRB 070419A: MITSuME Okayama Observations
  7. GRB 070419A Swift-BAT Refined Analysis
  8. GRB070419B: Confirmation of Optical Transient
  9. GRB 070419A: RAPTOR Detection of Early Emission
  10. GRB 070419B: Swift XRT refined analysis
  11. GRB 070419: Keck/LRIS Absorption Redshift
  12. GRB 070419B: optical afterglow confirmation
  13. GRB 070419A, Optical observations
  14. GRB 070419A: NAYUTA Optical Observation
  15. GRB 070419A: Faulkes Telescope North Optical Observations
  16. GRB 070419B optical afterglow candidate
  17. GRB 070419A: Optical and IR observations with KANATA
  18. GRB 070419B: optical afterglow candidate
  19. GRB 070419A: Lulin Optical observation
  20. GRB070419A, optical observation
  21. GRB 070419A: Kiso Optical observation
  22. GRB070330: Correction to UVOT position
  23. GRB 070419: P60 Confirmation of Optical Afterglow
  24. GRB 070419 optical afterglow candidate
  25. GRB 070419A: ROTSE-III Optical Limits
  26. GRB 070418: Optical and IR observations with KANATA
  27. GRB 070318, SMARTS optical/IR afterglow observations
  28. GRB 070412 Liverpool Telescope optical limit
  29. GRB 070411: Optical photometry at Crni Vrh
  30. GRB 070412: Optical observations at Crni Vrh
  31. GRB 070411: OA redshift
  32. GRB 070412: Swift-XRT refined position
  33. GRB 070412: IAC80 optical afterglow candidate
  34. GRB 070411: IAC80 optical observations
  35. GRB 070411 : Liverpool Telescope Observations
  36. GRB 070411: Optical observations at Crni Vrh
  37. GRB 070411: ROTSE-III Detection of Optical Counterpart
  38. GRB 070411: Swift detection of a burst with optical afterglow
  39. GRB 070406: Swift XRT team further analysis
  40. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  41. GRB 070406: Correction to the optical candidate in GCN6253
  42. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  43. GRB 070406: Optical candidate
  44. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  45. GRB 070406: Xinglong TNT optical Upper Limit
  46. GRB 070311, deep optical photometry
  47. GRB 070330, SMARTS optical/IR observations
  48. GRB 070330: TAROT La Silla observatory optical observations
  49. GRB070220: optical observations
  50. GRB070208: optical observations
  51. GRB070223: confirmation of nIR and optical afterglow
  52. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  53. GRB 070311, deep optical photometry
  54. GRB 070318: Gemini + Magellan spectra
  55. GRB070318: Swift-XRT refined analysis
  56. GRB 070318: Swift/UVOT Continued Observations
  57. GRB 070318: Swift detection of a burst with an optical afterglow
  58. GRB 070311: Late Central Engine Activity Optical Flare??
  59. GRB 070311: MDM Optical Monitoring
  60. GRB 070311: Tautenburg sees afterglow fading
  61. GRB 070311: Optical observation.
  62. GRB 070311: Optical Brightening
  63. GRB 070311: MDM Optical Follow-up
  64. GRB 070311: RAPTOR Detection of Optical Emission
  65. GRB 070311: MDM Optical Detection
  66. GRB 070311: MITSuME Okayama Optical Observation
  67. GRB 070311: Swift-XRT refined analysis
  68. GRB 070311: REM candidate afterglow
  69. GRB060901: Candidate optical afterglow
  70. GRB 070125: Chandra X-ray Confirmation of Jet Break
  71. GRB 070306, optical observation
  72. GRB 070125: X-ray light curve analysis
  73. GRB 070306: ART-3 early optical and near infrared constraints
  74. GRB 070306: Optical and IR observations with KANATA
  75. GRB 070125, deep late-time optical observation
  76. GRB 070227: optical observations
  77. GRB 070223: Optical Observations
  78. GRB 070227: optical observations
  79. GRB 070227: TAROT La Silla observatory optical observations
  80. GRB 920925C: optical afterglow candidate
  81. GRB 070224: Optical afterglow confirmation
  82. GRB070224: Swift-XRT Astrometrically Corrected Position
  83. GRB 070224: optical afterglow candidate
  84. GRB 070223: Optical observations
  85. GRB 070223: Optical-IR observation with KANATA
  86. GRB 070223: Swift-XRT Refined Analysis
  87. GRB 070223: MDM Observations
  88. GRB 070220: MITSuME Okayama Optical Observation
  89. GRB 070220: ART-3 Optical and NIR limits
  90. GRB 070220: Observation with the KANATA 1.5m telescope
  91. GRB 070220 : Faulkes Telescope North optical limit
  92. GRB 070219: optical TNG observations
  93. GRB 070219: ROTSE-III Optical Limits
  94. GRB 070129: MDM I-band Detection
  95. GRB 070125: Break in Optical Decay
  96. GRB070208: optical observations
  97. GRB 070208: MARGE Optical Observations
  98. GRB 070208: RAPTOR detection of early afterglow onset
  99. GRB070208: Absorption and emission redshift from Gemini
  100. GRB 070208: MDM Optical Decay

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