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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 101225A: Host galaxy
  2. GRB 101219A: Gemini-North host redshift
  3. GRB 110102A: Swift-XRT refined Analysis
  4. GRB 101219B: After 2 weeks still detected by Swift/UVOT
  5. Konus-Wind observation of GRB 110102A
  6. GRB110102A: Swift/UVOT observations
  7. GRB110102A: MITSuME Okayama Optical Observation
  8. GRB 110102A: Fermi GBM observation
  9. GRB 110102A: Swift-BAT refined analysis
  10. GRB 110102A: Enhanced Swift-XRT position
  11. GRB 110102A: Swift detection of a burst with an optical detection
  12. GRB 101225A: optical break from NOT observation
  13. GRB 101225A: MMT spectroscopy
  14. GRB 101225A: P60 Observations
  15. GRB 101225A: MAXI/GSC observations
  16. GRB 101225A Late-time emission observed by Swift-BAT
  17. GRB 101225: Optical follow-up of the Christmas burst
  18. GRB 101225A: WHT observations
  19. Tentative redshift of GRB101225A (Christmas's burst) from Swift-XRT data
  20. GRB 101225A, Swift-BAT refined analysis
  21. GRB 101225A: Swift/UVOT Detection
  22. GRB 101225A: Swift-XRT refined Analysis
  23. GRB 101225A: Enhanced Swift-XRT position
  24. Trigger 441015 / GRB 101225A: Further NOT optical observation
  25. Trigger 441015 / GRB 101225A: NOT optical afterglow candidate
  26. GRB 101225A (Swift trigger 441015): optical upper limit
  27. Trigger 441015: Swift detection of a possible burst or transient
  28. GRB 101224A: NOT optical observation
  29. GRB 101224A: Pre-event imaging from DeepSky; Detection of a source in the XRT error circle
  30. GRB 101224A: Swift/UVOT Upper Limits
  31. GRB 101224A: Fermi GBM observation
  32. GRB 101224A: Swift-XRT refined Analysis
  33. GRB101224A: MITSuME Okayama optical upper limits
  34. GRB 101224A, Swift-BAT refined analysis
  35. GRB 101224A - UVOT-enhanced XRT position
  36. GRB 101224A: Swift detection of a short burst
  37. GRB 101219A: Chandra Observations
  38. GRB 101219B: Swift/UVOT refined analysis
  39. GRB 101219B: Swift-XRT refined Analysis
  40. GRB 101219B: Enhanced Swift-XRT position
  41. GRB 101219A: MITSuME Ishigakijima Optical upper limits
  42. GRB 101219B: GROND Detection of the Optical/NIR Afterglow
  43. GRB 101219B: Fermi GBM observation
  44. GRB 101219A: IAC80 optical observations
  45. GRB 101219B: Swift-BAT refined analysis
  46. GRB 101219A: Swift-XRT refined Analysis
  47. GRB 101219B: Swift detection of a burst with an optical afterglow
  48. GRB 101219A: Swift/UVOT Upper Limits
  49. GRB 101219A: GROND Upper limits
  50. Konus-Wind observation of short hard GRB 101219A
  51. GRB 101219A: Magellan NIR observations
  52. GRB 101219A: Further Gemini-South Imaging
  53. GRB 101219A: Swift-BAT refined analysis
  54. GRB 101219A - NOT observation - upper limit
  55. GRB 101219A: SARA-N Upper Limit
  56. GRB 101219A: Gemini-South observations
  57. GRB 101219A: REM optical and NIR observations
  58. GRB 101219A: ROTSE-III Optical Limits
  59. GRB 101219A: Swift detection of a short hard burst
  60. Request for Supernova related data for GRB 101023A
  61. GRB 101213A : Suzaku WAM observation of the prompt emission
  62. Redshift solution(s) for GRB101213A from Swift-XRT data
  63. Konus-Wind observation of GRB 101213A
  64. XRF 101117A, RIMOTS optical upper limits
  65. GRB 101213A: Fermi GBM observation
  66. GRB 101213A, Swift-BAT refined analysis
  67. GRB 101213A: Swift-XRT refined Analysis
  68. GRB 101213A: Swift/UVOT Upper Limits
  69. GRB 101213A: Enhanced Swift-XRT position
  70. GRB 101213: object within the X-ray error circle
  71. GRB 101213A: Swift detection of a burst
  72. GRB101204A: Swift/UVOT observations
  73. GRB 101204A: Swift-XRT refined Analysis
  74. GRB101204A GROND Detection of the Optical/NIR Afterglow
  75. GRB 101204A Afterglow Candidate, VATT Observations
  76. GRB 101129A : Suzaku WAM observation of the prompt emission
  77. GRB 101204A Swift-XRT/UVOT afterglow candidate
  78. Konus-Wind observation of GRB 101130A
  79. GRB 101204A detected in ground analysis of BAT data
  80. Konus-Wind observation of GRB 101129A
  81. IPN Localization of GRB101130 (possible short duration burst)
  82. GRB 101129A SHB found by IPN and in ground analysis of BAT data
  83. GRB101030A
  84. GRB 101201A: Fermi GBM observation
  85. GRB 101201A: Swift-XRT refined Analysis
  86. GRB 101201A: Swift/UVOT Detection
  87. GRB 101201A: GROND Detection of the Optical/NIR Afterglow
  88. GRB 101201A detected in ground analysis of BAT data
  89. Swift detection of MAXIJ1409-619
  90. GRB 101123A: ROTSE optical observations
  91. GRB 101123A: MASTER prompt optical observations
  92. Konus-Wind observation of GRB 101123A
  93. IPN triangulation of bright GRB 101123A
  94. GRB 101123A: Fermi GBM detection
  95. Optical observation of GRB 101024A
  96. GRB 101117B: GROND Upper limits
  97. GRB 101117B: Swift/UVOT Observations of the Optical Afterglow
  98. GRB 101112A: OSN and BTA observations
  99. XRF 101117A: Palomar Transient Factory Observations
  100. GRB 101117B: Swift-XRT refined analysis

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