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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"

3138 results found.

  1. GRB 091221: Skynet/PROMPT Detections
  2. GRB 091221 Swift-BAT refined analysis
  3. GRB 091221: Swift detection of a burst
  4. Trigger 379449: Swift detection of a possible burst
  5. GRB 091208: ROTSE-III Optical Limits
  6. GRB 091123: Suzaku WAM observation of the prompt emission
  7. GRB 091109A: GROND confirmation of redshift z = 3.5
  8. GRB 091128: Fermi GBM detection
  9. GRB 091117A: Suzaku WAM observation of the prompt emission
  10. GRB 091112: Swift detection of a possible burst
  11. GRB 091102: ROTSE-III Optical Limits
  12. GRB 091031: Fermi GBM detection
  13. Radio afterglow detection from GRB 091020
  14. GRB 091020: Early TLS Multicolor detections, red afterglow
  15. GRB 091024: Swift-BAT refined analysis
  16. GRB091020 Swift/UVOT observations
  17. GRB 091020: Swift detection of a burst with an optical afterglow
  18. Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
  19. GRB 090829B: Fermi GBM Detection
  20. GRB 090831B, RIMOTS optical upper limits
  21. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  22. IPN Triangulation and Konus-Wind observaions of GRB090727B
  23. GRB 090727: Swift detection of a burst
  24. GRB 090711: Fermi GBM detection
  25. GRB 090726: Swift detection of a burst
  26. GRB 090715B: Lick observations
  27. GRB 090709A, RIMOTS optical upper limits
  28. GRB 090709B: Swift detection of a burst
  29. GRB 090709: Swift detection of a bright burst
  30. GRB 090705: Swift detection of a possible burst
  31. GRB 090529: CrAO optical upper limit
  32. GRB 090703: Fermi GBM detection
  33. GRB 090701: Fermi GBM detection
  34. GRB090618: OAA-OAUV Optical observations
  35. GRB 090617: Fermi GBM detection
  36. GRB 090616: Fermi GBM detection
  37. RXTE Discovery of Pulsations from SGR 0418+5729
  38. GRB 090528B: Fermi GBM detection
  39. GRB 090520C: Fermi GBM detection
  40. GRB 090519B: Fermi GBM detection
  41. GRB 090518B: Fermi GBM detection
  42. GRB 090323: optical observations
  43. GRB 090424: YNAO-GMG observations
  44. GRB 090427B: Fermi GBM detection
  45. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  46. GRB 090417B: MITSuME Okayama optical upper limits
  47. GRB 090403: Fermi GBM detection
  48. GRB090401B, RIMOTS optical upper limits
  49. GRB 090330: Fermi GBM detection
  50. GRB 090323: Optical observation of xinglong TNT
  51. GRB 090323 TLS detection - still bright
  52. GRB 090323: UVOT Detection of Afterglow
  53. GRB 090323: Possible XRT Counterpart
  54. GRB090310: Fermi GBM detection
  55. IPN localization of GRB 090217
  56. SGR activity seen by BAT during ICSP Ionospheric Events
  57. GRB 090201: ROTSE-III Optical Limits
  58. Suzaku ToO Observation of AXP 1E 1547.0-5408
  59. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  60. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  61. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  62. Fermi/GBM detection of GRB 081225
  63. GRB 081226: Swift-XRT refined analysis
  64. GRB081203A: BTA observation
  65. GRB 081216 : Fermi GBM observation
  66. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  67. GRB 081207: Fermi GBM detection
  68. GRB 081211: Swift-BAT refined analysis
  69. GRB 081206: Fermi GBM detection
  70. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  71. GRB 081126: Confirmation of the Optical Afterglow
  72. GRB 081126: optical observations
  73. GRB 081126: Swift-BAT refined analysis
  74. GRB 081126: Enhanced Swift-XRT position
  75. GRB 081126: Swift detection of a burst
  76. GRB 081119: Fermi GBM detection
  77. GRB 081110: MASTER: first optical observations Fermi GRB
  78. GRB 081109A, Swift-BAT refined analysis
  79. GRB 081109A optical upper limit
  80. GRB 081109: REM NIR afterglow detection
  81. GRB 081109: Swift detection of a burst
  82. GRB 081107: Fermi GBM detection
  83. GRB 081104: Swift detection of a burst
  84. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
  85. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
  86. GRB 081024: KAIT Optical Limits
  87. Detection of flare star Algol in Swift-BAT slew data
  88. Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
  89. AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
  90. GRB 080925: Suzaku WAM observation of the prompt emission
  91. GRB081001: SuperAGILE Localization of a long GRB
  92. GRB 080919: Swift-XRT refined analysis
  93. GRB 080919: REM NIR observations
  94. INTEGRAL ToO observation of SGR0501+4516
  95. Swift trigger 322590: BAT detection of a possible burst
  96. SGR 0501+4516: Swift XRT measure of the spin period
  97. GRB080823: Fermi Gamma-ray Burst Monitor detection
  98. GRB080805 optical limit by "Pi of the Sky"
  99. GRB 080805: Swift detection of a burst
  100. GRB 080725, Swift-BAT refined analysis

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