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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"

15745 results found.

  1. GRB 100213B: GRT Optical Observation
  2. GRB 100213A: GRT Optical Observation
  3. GRB 100213B: Swift/UVOT Upper Limits
  4. GRB 100213A: Swift/UVOT Upper Limits
  5. GRB 100213B: NOT optical observations
  6. GRB 100206A: Second epoch Gemini-north observations and afterglow limits
  7. Swift/UVOT observations of GRB120212A
  8. GRB 100212A: candidate optical afterglow
  9. GRB 091127: Detection of a Supernova
  10. GRB 100205A: Keck limits on an underlying host galaxy
  11. GRB 100205A: BOAO/LOAO zYJK observation
  12. GRB 100206A: Gemini-North observations
  13. GRB 100206A: Swift/UVOT Upper Limits
  14. GRB 100131A: MASTER-Net optical alert observations
  15. GRB 100206A: MASTER-Net optical alert observations
  16. GRB 100206A: PAIRITEL Photometry of Host Candidate
  17. GRB100206: MITSuME optical upper limits
  18. GRB 100206A, RIMOTS optical upper limits
  19. GRB 100206A: optical observations from Southern Spain
  20. GRB 100206A: Optical limit
  21. GRB 100205A: Super-LOTIS early observations
  22. GRB 100205A: NOT optical observations
  23. GRB 100122A: MASTER-Net optical observations
  24. GRB091109A: VLT/FORS2 spectroscopic redshift
  25. GRB 100117A: candidate optical afterglow
  26. GRB 100117A: Optical object inside the revised XRT error circle
  27. GRB100117A: Possible afterglow from NOT observation
  28. NOT observation of GRB100115A localization
  29. GRB 100111A: PAIRITEL NIR Upper Limits
  30. GRB 100111A: NOT optical observations
  31. GRB 100111A: Swift detection of a burst with an optical afterglow
  32. Swift/BAT Detects an Outburst from XTE J1901+014
  33. GRB 100103A: Swift/UVOT Upper Limits
  34. GRB 091230: Swift-XRT observation
  35. GRB 091230: GROND optical/NIR afterglow candidate
  36. Swift Trigger 381434 is not a GRB
  37. GRB 091221: Swift/UVOT refined analysis
  38. GRB 091221: UVOT Confirmation of an Optical Afterglow
  39. GRB 091221: ROTSE-III Detection of Optical Counterpart
  40. GRB 091215: Faulkes Telescope North observations
  41. GRB 091208B: Xinglong TNT optical observation
  42. GRB 091208A: GAO 150cm telescope Optical Observation
  43. GRB 091208B: GAO 150cm telescope Optical Observation
  44. GRB 091208B: optical observations
  45. GRB091208B: NOT optical observations
  46. GRB091208B: Swift/UVOT refined analysis
  47. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  48. GRB 091208A, RIMOTS optical upper limits
  49. GRB 091208B: MITSuME Akeno Optical Observation
  50. GRB 091208B: MITSuME Okayama Optical Observation
  51. GRB 091208B, RIMOTS optical upper limits
  52. GRB 091208B: Swift detection of a burst with an optical afterglow
  53. GRB 091208B: BOOTES-3 optical afterglow
  54. GRB 091208: ROTSE-III Optical Limits
  55. Short X-ray Transient, RIMOTS optical upper limits
  56. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  57. GRB 091127: GAO 150cm telescope Optical Observation
  58. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  59. GRB 091109A: GROND confirmation of redshift z = 3.5
  60. GRB091127: Continuing Swift/UVOT Observations
  61. GRB 091127, SMARTS optical/IR afterglow observations
  62. GRB 091202: Optical and NIR observations
  63. GRB 091127: Zadko Telescope Observations
  64. GRB 091202: TAROT Calern observatory optical observations
  65. GRB 091117: Chandra Observations
  66. GRB 091020: MASTER-Net optical polarization observations
  67. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  68. GRB 091130A: Xinglong TNT upper limit
  69. GRB 091127: Skynet/PROMPT Observations of Fading
  70. GRB 091130B: MASTER observations
  71. GRB 091130: MASTER observations
  72. GRB 091127: Radio observations
  73. GRB 091127: TAROT La Silla observatory optical observations
  74. GRB 091127: optical observations
  75. GRB 091127: LABOCA/APEX submm observations
  76. GRB 091127: Further NOT optical observations
  77. GRB 091127: MASTER early optical transient polarimetry
  78. GRB 091127: Swift-XRT afterglow detection and analysis
  79. GRB 091127: TAROT La Silla observatory optical decay
  80. GRB 091127: Swift/UVOT observations
  81. GRB 091127: CAHA 1.23m I-band observations
  82. GRB 091127: NOT observations
  83. GRB 091127: REM NIR afterglow detection
  84. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  85. GRB 091117: TNG optical observations
  86. GRB 091117: 2nd epoch of Magellan optical observations
  87. GRB 091117: Magellan optical observations
  88. GRB 091117: XRT source coincident with a DSS galaxy
  89. GRB 091109A: GROND and VLT observations
  90. GRB 091109b: Magellan Observations
  91. GRB 091109B: Optical limits from Watcher
  92. GRB 091109B: ROTSE-III Optical Limits
  93. GRB 091109: Swift/UVOT observations
  94. GRB 091109: Faulkes Telescope South observations
  95. GRB 091109: Swift detection of a burst with optical afterglow
  96. GRB 091104: Swift/UVOT Upper Limits
  97. GRB091102 : MOA optical upper limit
  98. GRB 091102: ROTSE-III Optical Limits
  99. GRB 091024: optical observations
  100. GRB 090926a, SMARTS optical/IR afterglow observations

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