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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"

20985 results found.

  1. GRB 100111A: Swift UVOT Refined Analysis
  2. GRB 100111A: NOT optical observations
  3. Swift/BAT Detects an Outburst from XTE J1901+014
  4. GRB 100103A: GROND Upper Limits
  5. GRB 100103A: Swift-XRT team refined analysis
  6. GRB 091231: GROND NIR observations
  7. GRB 091230: Swift/UVOT Observations
  8. GRB 091230: GROND optical/NIR afterglow candidate
  9. Swift Trigger 381434 is not a GRB
  10. GRB 091117: Swift-XRT late time observations
  11. GRB 091221: Swift/UVOT refined analysis
  12. GRB 091221, GROND observations
  13. GRB 091221: ROTSE-III Detection of Optical Counterpart
  14. Swift trigger 379449 (possible GRB) is not a burst
  15. GRB 091215: Faulkes Telescope North observations
  16. GRB 091208B: Xinglong TNT optical observation
  17. GRB 091208B: GAO 150cm telescope Optical Observation
  18. GRB 091208B: optical observations
  19. GRB 091208B: GROND observations
  20. GRB 091208A: Swift-XRT observations
  21. GRB091208B: NOT optical observations
  22. GRB091208B: Swift/UVOT refined analysis
  23. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  24. GRB 091208B: BOOTES-3 optical afterglow
  25. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  26. GRB 091127: GAO 150cm telescope Optical Observation
  27. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  28. GRB 091109A: GROND confirmation of redshift z = 3.5
  29. GRB091127: Continuing Swift/UVOT Observations
  30. GRB 091127, SMARTS optical/IR afterglow observations
  31. GRB091202: Swift-XRT refined analysis
  32. GRB 091202: Swift/UVOT Upper Limits
  33. GRB 091202: Liverpool Telescope observations
  34. GRB 091202: Optical and NIR observations
  35. GRB 091127: Zadko Telescope Observations
  36. GRB 091202: TAROT Calern observatory optical observations
  37. GRB 091202: Liverpool Telescope Observations
  38. GRB 091127: redshift confirmation with X-shooter
  39. GRB 091117: Chandra Observations
  40. GRB 091020: MASTER-Net optical polarization observations
  41. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  42. Short X-ray Transient Detection by MAXI/GSC
  43. GRB 091130A: Xinglong TNT upper limit
  44. GRB 091130B: Swift/UVOT Upper Limits
  45. GRB 091127: Skynet/PROMPT Observations of Fading
  46. Swift trigger 377436 (possible GRB 091130A) is not a burst
  47. GRB 091130B: MASTER observations
  48. GRB 091130: MASTER observations
  49. GRB 091130: Swift detection of a possible burst
  50. GRB 091127: Radio observations
  51. GRB 091127: TAROT La Silla observatory optical observations
  52. GRB 091127: optical observations
  53. GRB 091127: LABOCA/APEX submm observations
  54. GRB 091127: Further NOT optical observations
  55. GRB 091127: MASTER early optical transient polarimetry
  56. GRB 091127: Gemini-N redshift
  57. GRB 091127: TAROT La Silla observatory optical decay
  58. GRB 091127: Swift/UVOT observations
  59. GRB 091127: CAHA 1.23m I-band observations
  60. GRB 091127: NOT observations
  61. GRB 091127 : GROND observations
  62. GRB 091127: REM NIR afterglow detection
  63. GRB 091127: Liverpool Telescope afterglow candidate
  64. GRB 091117: TNG optical observations
  65. GRB 091117A: Swift/UVOT followup observations
  66. GRB 091117: 2nd epoch of Magellan optical observations
  67. GRB 091117: VLA radio observations
  68. GRB 091117: Swift-XRT observations
  69. GRB091117: Gemini South Observations
  70. GRB 091117: Swift XRT refined analysis
  71. GRB 091117: Gemini-North spectroscopy of DSS galaxy
  72. Konus-Wind observations of GRB 091117A
  73. GRB 091117: Magellan optical observations
  74. GRB 091117: XRT source coincident with a DSS galaxy
  75. GRB 091117: OSN I-band observations
  76. Konus-Wind and Konus-RF observations of GRB 091031
  77. GRB 091111: BOOTES-3 contemporaneous imaging
  78. GRB 091111: BOOTES-3 observations
  79. GRB 091109A: GROND and VLT observations
  80. GRB 091109B: Swift/UVOT Upper Limits
  81. GRB 091109B: VLT afterglow confirmation
  82. GRB 091109B: VLT observations
  83. GRB 091109b: Magellan Observations
  84. GRB 091109B: Optical limits from Watcher
  85. GRB 091109: BOOTES-3 observations
  86. GRB 091109: Swift/UVOT observations
  87. GRB 091109: Faulkes Telescope South observations
  88. GRB 091029: Observations from Stardome Observatory
  89. GRB 091104: Swift/UVOT Upper Limits
  90. GRB 091102: LABOCA/APEX submm observations
  91. Fermi LAT Upper Limits on GRB 091010
  92. GRB 091102: Swift/UVOT Upper Limits
  93. GRB 091102: GROND Upper Limits
  94. GRB 091102: BOOTES-3 observations
  95. GRB 091102: Swift/XRT localization
  96. GRB 091024: optical observations
  97. GRB 090926a, SMARTS optical/IR afterglow observations
  98. GRB 091018: Skynet/PROMPT Observations of Possible Host Galaxy
  99. GRB 091029, SMARTS optical/IR afterglow observations
  100. GRB 091018, SMARTS optical/IR afterglow observations

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