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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"

20523 results found.

  1. GRB 100213B: NOT optical observations
  2. GRB 100206A: Second epoch Gemini-north observations and afterglow limits
  3. Swift/UVOT observations of GRB100212A - correction of the name of the burst
  4. Swift/UVOT observations of GRB120212A
  5. GRB 100212A: candidate optical afterglow
  6. GRB 091127: Detection of a Supernova
  7. GRB 100205A: Keck limits on an underlying host galaxy
  8. GRB 100206A: GROND upper limits
  9. GRB 100206A: Gemini-North observations
  10. GRB 100206A: Swift/UVOT Upper Limits
  11. GRB 100131A: MASTER-Net optical alert observations
  12. GRB 100206A: YNAO-GMG observations
  13. GRB 100206A: MASTER-Net optical alert observations
  14. GRB 100206A: PAIRITEL Photometry of Host Candidate
  15. GRB 100206A - Keck/LRIS Spectroscopy
  16. GRB 100206A: NOT NIR observations
  17. GRB 100206A: WHT candidate afterglow
  18. GRB 100206A: optical observations from Southern Spain
  19. GRB 100205A: GROND upper limits
  20. GRB 100205A: Swift UVOT upper limits
  21. GRB 100205A: Swift XRT refined analysis
  22. GRB 100205A: Gemini-South Observations
  23. GRB 100205A: Super-LOTIS early observations
  24. GRB 100205A: NOT optical observations
  25. GRB 100122A: MASTER-Net optical observations
  26. GRB 100115A: Swift-XRT refined analysis
  27. GRB 100117A: candidate optical afterglow
  28. GRB 100119A: Swift detection of a burst
  29. GRB 100117A: Gemini North spectroscopy
  30. Swift/UVOT refined analysis of GRB100117A
  31. GRB 100117A: Optical object inside the revised XRT error circle
  32. GRB 100117A: Gemini-North upper limit
  33. GRB 100117A: Magellan IMACS imaging
  34. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  35. GRB100117A: Possible afterglow from NOT observation
  36. GRB 100115A: Gemini-N photometry
  37. GRB 100115A: SARA Afterglow Candidate
  38. GRB 100111A: PAIRITEL NIR Upper Limits
  39. GRB 100111A: Swift UVOT Refined Analysis
  40. GRB 100111A: NOT optical observations
  41. Swift/BAT Detects an Outburst from XTE J1901+014
  42. GRB 100103A: GROND Upper Limits
  43. GRB 100103A: Swift-XRT team refined analysis
  44. GRB 091231: GROND NIR observations
  45. GRB 091230: Swift/UVOT Observations
  46. GRB 091230: GROND optical/NIR afterglow candidate
  47. Swift Trigger 381434 is not a GRB
  48. GRB 091117: Swift-XRT late time observations
  49. GRB 091221: Swift/UVOT refined analysis
  50. GRB 091221, GROND observations
  51. GRB 091221: ROTSE-III Detection of Optical Counterpart
  52. Swift trigger 379449 (possible GRB) is not a burst
  53. GRB 091215: Faulkes Telescope North observations
  54. GRB 091208B: Xinglong TNT optical observation
  55. GRB 091208B: GAO 150cm telescope Optical Observation
  56. GRB 091208B: optical observations
  57. GRB 091208B: GROND observations
  58. GRB 091208A: Swift-XRT observations
  59. GRB091208B: NOT optical observations
  60. GRB091208B: Swift/UVOT refined analysis
  61. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  62. GRB 091208B: BOOTES-3 optical afterglow
  63. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  64. GRB 091127: GAO 150cm telescope Optical Observation
  65. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  66. GRB 091109A: GROND confirmation of redshift z = 3.5
  67. GRB091127: Continuing Swift/UVOT Observations
  68. GRB 091127, SMARTS optical/IR afterglow observations
  69. GRB091202: Swift-XRT refined analysis
  70. GRB 091202: Swift/UVOT Upper Limits
  71. GRB 091202: Liverpool Telescope observations
  72. GRB 091202: Optical and NIR observations
  73. GRB 091127: Zadko Telescope Observations
  74. GRB 091202: TAROT Calern observatory optical observations
  75. GRB 091202: Liverpool Telescope Observations
  76. GRB 091127: redshift confirmation with X-shooter
  77. GRB 091117: Chandra Observations
  78. GRB 091020: MASTER-Net optical polarization observations
  79. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  80. Short X-ray Transient Detection by MAXI/GSC
  81. GRB 091130A: Xinglong TNT upper limit
  82. GRB 091130B: Swift/UVOT Upper Limits
  83. GRB 091127: Skynet/PROMPT Observations of Fading
  84. Swift trigger 377436 (possible GRB 091130A) is not a burst
  85. GRB 091130B: MASTER observations
  86. GRB 091130: MASTER observations
  87. GRB 091130: Swift detection of a possible burst
  88. GRB 091127: Radio observations
  89. GRB 091127: TAROT La Silla observatory optical observations
  90. GRB 091127: optical observations
  91. GRB 091127: LABOCA/APEX submm observations
  92. GRB 091127: Further NOT optical observations
  93. GRB 091127: MASTER early optical transient polarimetry
  94. GRB 091127: Gemini-N redshift
  95. GRB 091127: TAROT La Silla observatory optical decay
  96. GRB 091127: Swift/UVOT observations
  97. GRB 091127: CAHA 1.23m I-band observations
  98. GRB 091127: NOT observations
  99. GRB 091127 : GROND observations
  100. GRB 091127: REM NIR afterglow detection

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