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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"

32494 results found.

  1. GRB 090123: Swift-BAT refined analysis
  2. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  3. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  4. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  5. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  6. AXP 1E1547.0-5408: Fermi GBM observations
  7. Trigger 340734: Swift detection of a possible short burst
  8. GRB 090118: Subaru NIR Observation
  9. GRB 090118: KPNO 4m 2nd Epoch Observations
  10. GRB 090118 (BATSS): GRT Optical Observation
  11. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  12. GRB 090118: Swift-XRT observations
  13. GRB090118 Swift/UVOT upper limits
  14. GRB 090118: GROND Upper Limits
  15. GRB 090117: confirmation of the X-ray afterglow
  16. GRB 090117 - Fermi GBM Observations
  17. GRB 090117: GROND Upper Limits
  18. GRB090117 Swift/UVOT upper limits
  19. GRB 090112B: Suzaku WAM observation of the prompt emission
  20. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  21. GRB 090113: Swift UVOT upper limits
  22. GRB 090113: GROND Upper Limits
  23. GRB 090113: Swift-XRT refined analysis
  24. GRB 090113: Observations from NOT
  25. GRB 090113: Swift-BAT refined analysis
  26. GRB 090113: ROTSE-III Optical Limits
  27. GRB090113: XRT position
  28. GRB 090111, Swift-BAT refined analysis
  29. GRB 090111: Swift UVOT Upper Limits
  30. GRB 090111: Swift-XRT refined analysis
  31. GRB 090107B: Suzaku WAM observation of the prompt emission
  32. GRB090107B: Fermi GBM Detection
  33. GRB 090102: WSRT Radio Observations
  34. GRB 090107B: Swift XRT afterglow confirmation
  35. GRB 090107B: Swift/UVOT Observations
  36. GRB 090107B: Swift-XRT detection of possible afterglow
  37. GRB 090107B optical observations
  38. GRB 090107B: ROTSE-III Optical Limits
  39. Fermi/GBM detection of GRB 081226A
  40. GRB 090107: Swift-BAT refined analysis
  41. GRB 090102: optical decay
  42. VLA radio upper limit on GRB 090102
  43. GRB 090102: GRT Optical Observation
  44. Konus-Wind observation of GRB 090102
  45. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  46. GRB 090102: P60 Imaging and P200 Spectroscopy
  47. GRB 090102 Observations from IAC80
  48. GRB 090102: GROND observations of the optical afterglow
  49. Swift UVOT observations of GRB 090102
  50. GRB 090102: Swift-BAT refined analysis
  51. GRB 090102: Swift XRT refined analysis
  52. GRB 090102: NOT redshift
  53. GRB 090102: TAROT Calern observatory optical light curve
  54. GRB 090102: REM observations of a bright afterglow
  55. GRB 081230: GROND confirmation of the afterglow
  56. GRB 081230, Swift-BAT refined analysis
  57. GRB081230: Swift-XRT refined analysis
  58. GRB 081230 Swift/UVOT Observations
  59. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  60. GRB 081230: ROTSE-III Detection of Optical Counterpart
  61. GRB 081228: GROND confirmation of the optical/NIR afterglow
  62. GRB 081226B: Fermi GBM observation
  63. GRB 081228, Swift-BAT refined analysis
  64. VLA radio detection of GRB 081221
  65. GRB 081228: Swift/UVOT Upper Limits
  66. GRB 081228: Swift-XRT Team refined analysis
  67. GRB 081228: detection by GROND
  68. VLA radio observation of GRB 081221
  69. GRB 081226B: Swift XRT and UVOT upper limits
  70. GRB 081224: Suzaku WAM observation of the prompt emission
  71. GRB 081226: Swift-XRT refined analysis
  72. GRB 081226A: Swift UVOT Upper Limits
  73. GRB 081226: Second epoch of Gemini-South imaging
  74. GRB 081226A: Swift-BAT refined analysis
  75. GRB 081226: Gemini-South imaging
  76. GRB 081226: GROND afterglow candidate
  77. GRB 081226: ROTSE-III Optical Limits
  78. GRB 080810: optical observations
  79. GRB 081211B: optical observations
  80. GRB081224: LAT retraction
  81. GRB 081224: Swift-XRT observation
  82. GRB 081222: MITSuME optical observation
  83. GRB 080810: optical observations
  84. Konus-Wind observation of GRB 081222
  85. GRB 081221: GROND observations
  86. GRB 081222: Gemini-N confirmation of redshift z=2.77
  87. GRB 081222:Optical afterglow observation
  88. VLA radio upper limit on GRB 081222
  89. GRB 081222: Fermi GBM observation
  90. GRB 081222: Gemini-South absorption redshift
  91. GRB081222: Swift/UVOT further observations
  92. GRB 081221: Probable host galaxy in Keck imaging
  93. GRB 081222, Swift-BAT refined analysis
  94. GRB 081221, Swift-BAT refined analysis
  95. Konus-Wind observation of very bright GRB 081215A
  96. GRB 081222: Swift XRT refined analysis
  97. GRB081221: Fermi GBM observation
  98. Swift/UVOT observations of GRB 081221
  99. IPN triangulation of bright GRB 081215A
  100. GRB 081221: Swift-XRT Refined Analysis

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