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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 071021: Faulkes Telescope South optical candidate
  2. GRB 071021: Swift detection of a burst
  3. GRB 071010B: Independent Confirmation of Break
  4. GRB071020A: Xinglong TNT Optical afterglow observations
  5. GRB 071020: Swift-XRT refined analysis
  6. GRB 071020, Swift-BAT refined analysis
  7. GRB 071020A: IR Imaging with PAIRITEL
  8. GRB 071020: VLT spectroscopy
  9. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  10. GRB071020 - SDSS Pre-burst Observations
  11. GRB 071020: Swift detection of a bright burst
  12. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  13. GRB 071018: Mercator Telescope optical observations
  14. Swift autonomous slewing re-enabled
  15. GRB071010b: optical observations
  16. GRB 071018: SARA observations
  17. GRB 071018: Swift-XRT observation
  18. GRB 071017 - Swift XRT observations
  19. VLA radio observation of GRB 071018
  20. GRB071018: Correction to the GCN 6936
  21. GRB071018: Correction to the GCN 6936
  22. GRB071018: Correction to the GCN 6936
  23. GRB071018: Correction to the title of the GCN 6936
  24. GRB 071018: Possible OT from Xinglong TNT observation
  25. GRB 071010B: Light Curve Break Confirmed
  26. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  27. GRB 071018, Swift-BAT refined analysis
  28. GRB 071018?: Swift detection of a possible burst
  29. GRB 071010B: Suzaku WAM observation of the prompt emission
  30. GRB 071013: 3rd TLS Epoch - constraints on variability
  31. GRB 071013: TNT optical data refined analysis
  32. GRB 071010B: Keck/DEIMOS emission-line redshift
  33. GRB 071017: a SHORT GRB detected by INTEGRAL
  34. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  35. GRB071013: optical observations
  36. GRB 071010B: Optical observations of EST
  37. GRB 071010B: TLS 3rd Epoch - finally a break??
  38. GRB 071011: MITSuME Optical Observations
  39. GRB 070920A: deep optical observations at the NOT
  40. GRB 071010B: Photometry after 1.6 days
  41. GRB 071010B: Keck/LRIS Photometry
  42. GRB 071010B: TLS 2nd Epoch, refined analysis
  43. GRB 071013: TLS Upper Limit
  44. Correction to GCN circular no. # 6915 for GRB 071010B
  45. VLA detection of radio afterglow of GRB 071010B
  46. VLA non-detection of GRB 071011
  47. GRB 071013: Optical observations
  48. GRB 071013: optical observations at NOT
  49. GRB 071013, Swift-BAT refined analysis
  50. GRB071013: optical limit
  51. GRB071010B, BVRcIc field calibration
  52. GRB 20071013: Xinglong TNT optical Upper Limit
  53. GRB 071013: Swift detection of a burst
  54. GRB 071010C Swift-BAT detection of a burst
  55. GRB 071011: Optical Limit after 13.95hrs
  56. GRB 071011: Xinglong TNT Optical afterglow observations
  57. GRB 071010B correction to GCN 6892 optical observations
  58. GRB 071011: Swift-XRT refined analysis
  59. VLA non-detection of GRB 071010A
  60. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  61. GRB 071011, Optical afterglow
  62. GRB 071011: Confirmation of P60 optical afterglow
  63. GRB 071010B: Optical Detection
  64. GRB 071011: Kanazawa Optical limits
  65. GRB 071011: P60 Optical Afterglow Candidate
  66. GRB 071011: MARGE Optical Limits
  67. GRB 071010B: Super-LOTIS upper limit
  68. GRB 071010B optical photometry
  69. GRB 071011: XRT afterglow detection
  70. GRB 071010B: Keck/LRIS Spectroscopy
  71. GRB 071011, Swift-BAT refined analysis
  72. GRB 071010B: Gemini Spectroscopic Observations
  73. GRB 071011: Early Super-LOTIS Observations
  74. GRB 071011: NAYUTA Optical Observation
  75. GRB 071010A: Continued Keck Imaging
  76. GRB 071010B: Bright OT confirmed with TLS
  77. GRB 071011: Optical afterglow candidate
  78. GRB 071011: Swift detection of a burst
  79. Optical Observation: GRB 071010
  80. Optical observations: GRB 071010A
  81. Konus-Wind observation of GRB 071010B
  82. GRB071010B: Swift/XRT detection
  83. GRB 071010B, Swift-BAT refined analysis
  84. GRB 071010A: bright NIR afterglow
  85. GRB 071006, Swift-BAT refined analysis
  86. GRB071008: optical observations
  87. GRB 071010B possible optical transient
  88. GRB 071010A: Keck/LRIS Photometry
  89. GRB 071010B: Swift detection of a burst
  90. GRB 071010: Swift-XRT observation
  91. GRB 071008, Swift-BAT refined analysis
  92. GRB 071010, Swift-BAT refined analysis
  93. Konus-Wind observation of GRB 071006
  94. GRB071008: Swift-XRT observation
  95. GRB 071010 REM NIR observations
  96. GRB 071010: Keck/LRIS Spectroscopy
  97. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  98. GRB 071010: Rapid PROMPT Detections
  99. GRB 071010: Keck Observations of the Afterglow
  100. GRB 071010: TAROT La Silla observatory detection of the afterglow

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