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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. GROND observations of GRB100316D/SN2010bh
  2. GRB 100325A: Fermi GBM detection
  3. GRB 100324A: GROND observations
  4. GRB 100324A found in ground analysis of BAT data
  5. Emerging Supernova in the Afterglow of GRB 100316D
  6. GRB 100322B or possible Galactic transient detected in ground analysis of BAT data
  7. GRB 100316D: Spectroscopic Discovery of a Supernova from Magellan
  8. SGR 1833-0832: Swift/UVOT Upper Limits
  9. GRB 100322A: Fermi GBM detection
  10. SGR 1833-0832: Archival Chandra Observations
  11. SGR 1833-0832 is pulsed at 7.56 seconds
  12. SGR 1833-0832 is pulsed at 7.56 seconds
  13. Possible pulsation period in SGR 1833-0832
  14. Discovery of the Spin Period of SGR 1833-0832
  15. GRB 100316D: ATCA radio observations
  16. GRB 100319A: correction to GCN 10527
  17. Probable SGR 1833-0832: Swift-XRT refined analysis
  18. Probable SGR 1833-0832: Enhanced Swift-XRT position
  19. Swift-XRT refined position of the probable new SGR 1833-0832
  20. Swift-BAT refined analysis of the probable new SGR 1833-0832
  21. GRB 100219A: MASTER-Net optical alert observations
  22. GRB 100319A: Swift detection of a burst; possible SGR
  23. GRB 100316D: Possible Supernova
  24. GRB 100316D: Pre-burst emission measured by BAT
  25. GRB 100316D: Further Gemini observations
  26. GRB 100219A: optical upper limit
  27. GRB 100316A: optical observations in CrAO
  28. GRB 100316D: Swift/UVOT Observations
  29. GRB 100316D: Swift XRT enhanced position and further refined analysis
  30. GRB 100316B: Swift-XRT refined analysis
  31. Tentative redshift of GRB100316D from X-ray data
  32. GRB 100316C: GROND Detection of a Optical/NIR Afterglow Candidate
  33. Trigger 416226 is probably not a GRB
  34. GRB 100316D: GROND Detection of the Optical/NIR Afterglow Candidate
  35. GRB 100316D: Gemini/GMOS and VLT/X-shooter observations
  36. GRB 100316D: VLT/X-shooter observations
  37. GRB 100316D: Swift-BAT refined analysis
  38. GRB100316C: Swift/UVOT Upper Limits
  39. GRB 100316C: Swift-BAT refined analysis
  40. GRB 100316B: Swift/UVOT observations
  41. GRB 100316C: Swift-XRT team refined analysis
  42. GRB 100316C: Enhanced Swift-XRT position
  43. GRB 100316D: Swift XRT refined analysis
  44. GRB 100316A: TAROT Calern observatory optical observations
  45. GRB 100316A: Swift-XRT refined analysis
  46. GRB 100316B: Enhanced Swift-XRT position
  47. GRB 100316A: Swift-BAT refined analysis
  48. GRB 100316B: Swift-BAT refined analysis
  49. GRB100316A: Swift/UVOT Upper Limits
  50. Trigger 416140 is almost certainly not a GRB
  51. GRB 100316C: BOOTES-3 observations
  52. GRB 100316D: Swift detection of a burst
  53. GRB 100316B: VLT/X-shooter redshift
  54. GRB 100316B: Skynet/PROMPT Observations of Fading
  55. GRB 100316B: GROND Detection of the Optical/NIR Afterglow Candidate
  56. XRF 100315A: MAXI/GSC detection of a short X-ray transient
  57. GRB 100316C: Swift detection of a burst
  58. GRB 100316A: Enhanced Swift-XRT position
  59. GRB 100316B: Swift detection of a burst with optical counterpart
  60. GRB 100316 optical candidate from 1.23m CAHA telescope
  61. GRB 100316 optical candidate from 1.23m CAHA telescope
  62. GRB 100316A: Swift/UVOT Observations
  63. GRB 100316A: Swift-XRT detection
  64. GRB 100316A: Swift detection of a burst
  65. IBAS Alert 5992 is not a GRB, but XTE J1855-026
  66. GRB100305A: Optical upper limits at IAO
  67. GRB 100305A: Super-LOTIS early observations
  68. GRB100302A : LOAO observations and Lulin afterglow analysis
  69. GRB 100305A, Swift-BAT refined analysis
  70. GRB 100305A: Gemini z'-band observation
  71. GRB 100305A: Swift/UVOT Upper Limits
  72. GRB 100305A: Swift-XRT refined analysis
  73. GRB 100305A Optical Observations
  74. GRB 100305A: Enhanced Swift-XRT position
  75. GRB 100305A: Gemini-N OT candidate
  76. GRB 100305A: PAIRITEL NIR Upper Limits
  77. GRB 100305A: P60 Observations
  78. GRB 100305A: Swift detection of a burst
  79. GRB 100302A: Ondrejov 65cm limit
  80. GRB 100302A: Swift/UVOT Upper Limits
  81. GRB 100302A: Swift-XRT refined analysis
  82. GRB 100302A: Gemini-North redshift
  83. GRB 100302A: Gemini-N OT confirmation
  84. GRB 100302A: Optical observations at Crni Vrh
  85. GRB 100302A: MASTER-Net optical alert observations
  86. GRB 100302A, Swift-BAT refined analysis
  87. GRB 1000302A : A possible afterglow candidate
  88. GRB 100302A: Enhanced Swift-XRT position
  89. GRB 100302A: Skynet/DAO Observations
  90. GRB 100302A: Swift detection of a burst
  91. GRB 100224B: Fermi GBM detection
  92. GRB 100206A: optical observations in CrAO
  93. GRB 100206A: optical observations in Terskol
  94. GRB 100213B: Mondy optical observations
  95. GRB 100219A: optical observations
  96. GRB 100219A: GAO 150cm telescope Optical Observation
  97. GRB 100224A SHB found in ground analysis of BAT data
  98. GRB 100225A: Fermi LAT detection
  99. GRB 100225A: Fermi GBM detection
  100. GRB 100223A: Fermi GBM detection

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