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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 080303A: ROTSE-III Optical Limits
  2. GRB 080229: I-band observations from OSN
  3. GRB 080229: VLT NIR observations
  4. GRB080229: Swift XRT refined analysis
  5. GRB 080229: TNG NIR observations
  6. GRB 080229: Deep Gemini/GMOS optical observations
  7. GRB 080229: Enhanced Swift-XRT position
  8. GRB 080229: REM NIR observations
  9. GRB080229: Possible optical afterglow
  10. GRB 080229B: Gamma Ray Burst Localization by SuperAGILE
  11. UVOT analysis for GRB080229
  12. GRB 080229, Swift-BAT refined analysis
  13. GRB 080229: Faulkes Telescope South optical limit
  14. GRB 080229A: ROTSE-III Optical Limits
  15. GRB 080229: Swift detection of a bright burst
  16. Early optical shallow decay in GRB 071112C
  17. GRB080207: optical observations
  18. GRB080205: optical observations
  19. GRB080211: optical observations
  20. XRF 080109/SN2008D : GMRT upper limit at 1.28 GHz
  21. GRB 071010B : Early optical brightening detected by TAOS
  22. Swift-XRT improved positions, and new redshift limits.
  23. ESO optical and NIR observations of GRB 080218B
  24. GRB 080204: Suzaku WAM observation of the prompt emission
  25. GRB 080218B, Swift-BAT refined analysis
  26. GRB 080218B: Swift-XRT refined analysis
  27. Swift/UVOT observations of GRB080218B
  28. GRB 080218B: REM NIR early upper limits
  29. GRB 080212: Mount Abu NIR observations
  30. GRB 080218B: Enhanced Swift-XRT position
  31. GRB 080218B: GROND upper limits
  32. GRB 080218b, SMARTS optical/IR limits
  33. GRB 080218A, Swift-BAT refined analysis
  34. GRB080218B: Watcher prompt limit
  35. GRB 080211: Suzaku WAM observation of the prompt emission
  36. GRB 080218B: Swift detection of a burst
  37. GRB 080218: Swift detection of a burst
  38. Swift-XRT and UVOT observations of the IPN burst GRB 080211
  39. GRB 080212: VLT optical rapid decay
  40. GRB 080212: REM refined analysis
  41. Konus-Wind observation of GRB 080211
  42. VLA radio upper limit on GRB 080212
  43. Swift/UVOT refined analysis of GRB080212
  44. GRB 080212, Swift-BAT refined analysis
  45. GRB080212: Optical afterglow candidate observed by MITSuME Telescope
  46. GRB 080212: Gemini-South optical observations
  47. GRB 080212: GROND detects afterglow
  48. GRB 080212: REM NIR afterglow?
  49. GRB 080212: optical observations
  50. GRB 080212: Enhanced Swift-XRT position
  51. GRB 080212: Swift-XRT Team refined analysis
  52. GRB 080210: Keck photometry
  53. VLA non-detection of GRB 080210
  54. GRB 080212: Swift detection of a burst
  55. IPN localization of GRB 080211
  56. GRB 080212: DSS/2MASS Galaxy at XRT position
  57. GRB 080207: VLT NIR early upper limits
  58. GRB 080210: Swift/UVOT Refined Analysis
  59. GRB 080207: optical observations.
  60. GRB 080210: Hobby-Eberly Telescope Absorption Spectroscopy
  61. GRB 080210, Swift-BAT refined analysis
  62. GRB 080210: Super-LOTIS observations
  63. GRB 080210: Swift-XRT Refined Analysis
  64. GRB 080210: VLT redshift
  65. GRB 080210: Enhanced Swift-XRT position
  66. GRB 080210: Rapid PROMPT Detections
  67. GRB 080210: GOND detection in all bands and redshift upper limit
  68. GRB080210 - SDSS Pre-Burst Observations
  69. GRB 080210: Swift detection of a burst with optical afterglow
  70. GRB 080210: TAROT La Silla observatory optical detection
  71. GRB 080207: GROND upper limits
  72. GRB 080205: GAO 150cm telescope Optical limit
  73. GRB 080207, Swift-BAT refined analysis
  74. GRB 080207: Optical limits from Gemini-South
  75. GRB 080205: RTT150 optical observations
  76. Swift detection of AX J1749.1-2639
  77. GRB 080207: Super-LOTIS observations
  78. GRB 080207, Swift-BAT refined analysis
  79. Swift Trigger 302777 is not a GRB
  80. GRB080207: RTT150 Optical Observations
  81. GRB 080207: REM NIR observations
  82. GRB080207: Swift/UVOT refined analysis
  83. GRB 080207: TAROT Calern observatory optical observations
  84. GRB 080207: Swift-XRT Refined Analysis
  85. GRB 080207: Enhanced Swift-XRT position
  86. GRB 080207: Swift detection of a burst
  87. Konus-Wind observation of GRB 080204
  88. GRB 080205 optical upper limit
  89. GRB 080205: MASTER optical observation
  90. GRB 080205: optical observation
  91. VLA radio upper limit on GRB 080205
  92. INT+WFC R-band observations of GRB 080205
  93. GRB 080205, Swift-BAT refined analysis
  94. IPN localization of very hard GRB 080204
  95. GRB 080205: Swift XRT refined analysis
  96. GRB 080205: OA evolution from KAIT observations
  97. GRB 080205: Swift/UVOT observations
  98. GRB 080205: Enhanced Swift-XRT position
  99. GRB 080205: KAIT OA detection
  100. GRB 080205: Swift detection of a burst

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