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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"

36066 results found.

  1. GRB 110106A: Swift-BAT refined analysis
  2. GRB 110106A: Enhanced Swift-XRT position
  3. GRB 110106B: Swift detection of a burst
  4. GRB 110106A: TNG optical observations and candidate counterparts
  5. GRB 110106A: MASTER optical observations
  6. GRB 101225A: Keck redshift
  7. GRB110106A: Xinglong TNT upper limit
  8. GRB 110106A: Swift detection of a burst
  9. GRB 101225A: Host galaxy
  10. GRB 101219A: Gemini-North host redshift
  11. GRB 110102A: Swift-XRT refined Analysis
  12. GRB 101219B: After 2 weeks still detected by Swift/UVOT
  13. Konus-Wind observation of GRB 110102A
  14. GRB110102A: Swift/UVOT observations
  15. GRB110102A: MITSuME Okayama Optical Observation
  16. GRB 110102A: Fermi GBM observation
  17. GRB 110102A: Swift-BAT refined analysis
  18. GRB 110102A: Enhanced Swift-XRT position
  19. GRB 110102A: Swift detection of a burst with an optical detection
  20. GRB 101225A: optical break from NOT observation
  21. GRB 101225A: MMT spectroscopy
  22. GRB 101225A: P60 Observations
  23. GRB 101225A: MAXI/GSC observations
  24. GRB 101225A Late-time emission observed by Swift-BAT
  25. GRB 101225: Optical follow-up of the Christmas burst
  26. GRB 101225A: WHT observations
  27. Tentative redshift of GRB101225A (Christmas's burst) from Swift-XRT data
  28. GRB 101225A, Swift-BAT refined analysis
  29. GRB 101225A: Swift/UVOT Detection
  30. GRB 101225A: Swift-XRT refined Analysis
  31. GRB 101225A: Enhanced Swift-XRT position
  32. Trigger 441015 / GRB 101225A: Further NOT optical observation
  33. Trigger 441015 / GRB 101225A: NOT optical afterglow candidate
  34. GRB 101225A (Swift trigger 441015): optical upper limit
  35. Trigger 441015: Swift detection of a possible burst or transient
  36. GRB 101224A: NOT optical observation
  37. GRB 101224A: Pre-event imaging from DeepSky; Detection of a source in the XRT error circle
  38. GRB 101224A: Swift/UVOT Upper Limits
  39. GRB 101224A: Fermi GBM observation
  40. GRB 101224A: Swift-XRT refined Analysis
  41. GRB101224A: MITSuME Okayama optical upper limits
  42. GRB 101224A, Swift-BAT refined analysis
  43. GRB 101224A - UVOT-enhanced XRT position
  44. GRB 101224A: Swift detection of a short burst
  45. GRB 101219A: Chandra Observations
  46. GRB 101219B: Swift/UVOT refined analysis
  47. GRB 101219B: Swift-XRT refined Analysis
  48. GRB 101219B: Enhanced Swift-XRT position
  49. GRB 101219A: MITSuME Ishigakijima Optical upper limits
  50. GRB 101219B: GROND Detection of the Optical/NIR Afterglow
  51. GRB 101219B: Fermi GBM observation
  52. GRB 101219A: IAC80 optical observations
  53. GRB 101219B: Swift-BAT refined analysis
  54. GRB 101219A: Swift-XRT refined Analysis
  55. GRB 101219B: Swift detection of a burst with an optical afterglow
  56. GRB 101219A: Swift/UVOT Upper Limits
  57. GRB 101219A: GROND Upper limits
  58. Konus-Wind observation of short hard GRB 101219A
  59. GRB 101219A: Magellan NIR observations
  60. GRB 101219A: Further Gemini-South Imaging
  61. GRB 101219A: Swift-BAT refined analysis
  62. GRB 101219A - NOT observation - upper limit
  63. GRB 101219A: SARA-N Upper Limit
  64. GRB 101219A: Gemini-South observations
  65. GRB 101219A: REM optical and NIR observations
  66. GRB 101219A: ROTSE-III Optical Limits
  67. GRB 101219A: Swift detection of a short hard burst
  68. Request for Supernova related data for GRB 101023A
  69. GRB 101213A : Suzaku WAM observation of the prompt emission
  70. Redshift solution(s) for GRB101213A from Swift-XRT data
  71. Konus-Wind observation of GRB 101213A
  72. GRB 101213A: Fermi GBM observation
  73. GRB 101213A, Swift-BAT refined analysis
  74. GRB 101213A: Swift-XRT refined Analysis
  75. GRB 101213A: Swift/UVOT Upper Limits
  76. GRB 101213A: Enhanced Swift-XRT position
  77. GRB 101213: object within the X-ray error circle
  78. GRB 101213A: Swift detection of a burst
  79. GRB101204A: Swift/UVOT observations
  80. GRB 101204A: Swift-XRT refined Analysis
  81. GRB101204A GROND Detection of the Optical/NIR Afterglow
  82. GRB 101204A Afterglow Candidate, VATT Observations
  83. GRB 101129A : Suzaku WAM observation of the prompt emission
  84. GRB 101204A Swift-XRT/UVOT afterglow candidate
  85. Konus-Wind observation of GRB 101130A
  86. GRB 101204A detected in ground analysis of BAT data
  87. Konus-Wind observation of GRB 101129A
  88. IPN Localization of GRB101130 (possible short duration burst)
  89. GRB 101129A SHB found by IPN and in ground analysis of BAT data
  90. GRB101030A
  91. GRB 101201A: Fermi GBM observation
  92. GRB 101201A: Swift-XRT refined Analysis
  93. GRB 101201A: Swift/UVOT Detection
  94. GRB 101201A: GROND Detection of the Optical/NIR Afterglow
  95. GRB 101201A detected in ground analysis of BAT data
  96. GRB 101123A: ROTSE optical observations
  97. GRB 101123A: MASTER prompt optical observations
  98. Konus-Wind observation of GRB 101123A
  99. IPN triangulation of bright GRB 101123A
  100. GRB 101123A: Fermi GBM detection

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