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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"

16162 results found.

  1. GRB 121017A: BOOTES-2/TELMA observations
  2. GRB 121011A: WSRT radio observation
  3. GRB 121011A: optical observations
  4. GRB 121011A: NOT optical observations
  5. GRB 121011A: optical observations
  6. GRB 121011A: TNG optical observations
  7. GRB 121011A: MASTER-Net early OT light curve
  8. GRB121011A : Xinglong TNT optical observation
  9. GRB 121011A: MITSuME Okayama Optical Observation
  10. GRB 121011A: Swift detection of a burst with optical afterglow
  11. GRB 120927A: optical upper limit
  12. GRB 121001A: GROND Afterglow Confirmation
  13. GRB 121001A: Swift/UVOT Upper Limits
  14. Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA.
  15. GRB 121001A: MASTER optical observations
  16. GRB 121001A: possible optical counterpart
  17. Swift Trigger 535026: ROTSE-III Optical Limits
  18. GRB 120927A: Swift/UVOT Upper Limits
  19. GRB 120923A: optical upper limit
  20. GRB 120923A: RAPTOR Early Afterglow Limits
  21. GRB 120923A: MITSuME Okayama Optical upper limits
  22. GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval
  23. GRB 120922A: GROND photometric redshift
  24. GRB 120922A: Swift/UVOT Detection
  25. GRB 120923A: Swift/UVOT Upper Limit
  26. GRB 120923A: Gemini afterglow detection, high-z candidate
  27. GRB 120922A: TAROT La Silla observatory optical observations
  28. GRB 120923A: TAROT La Silla observatory optical observations
  29. GRB 120923A: ROTSE-III Optical Limits
  30. GRB 120919B: MASTER prompt optical observations
  31. GRB 120919A: Swift/UVOT Upper Limits
  32. GRB 120913B: FRAM early follow up and detection
  33. GRB 120913B: REM NIR early time detection
  34. Continued Skynet/PROMPT observations of GRB120913B
  35. GRB 120913B: TAROT La Silla observatory optical photometry
  36. GRB 120913B: TAROT La Silla observatory optical detection
  37. GRB 120907A: optical observations of ISON-Kislovodsk
  38. GRB 120911A: optical upper limit CrAO
  39. GRB 120911A: optical upper limit ISON-NM
  40. GRB120911A: MITSuME Okayama Optical upper limits
  41. GRB 120911A: Swift/UVOT Upper Limits
  42. GRB 120911A: ROTSE-III Optical Limits
  43. GRB 120908A: Swift Observations
  44. GRB 120909A: TAROT La Silla observatory optical observations
  45. GRB 120909A: Swift/UVOT Detection
  46. GRB 120909A: X-Shooter redshift 3.93
  47. GRB 120907A: EVLA observations
  48. GRB 120907A: NOT optical observations
  49. GRB 120907A MASTER optical observations
  50. GRB 120907A: ROTSE-III Optical Limits
  51. GRB 120907A: Swift detection of a burst with optical counterpart
  52. GRB 120819A: optical upper limit
  53. GRB 120802A: optical observations in CrAO
  54. GRB 120830A: early MASTER optical limit
  55. Fermi trigger 368003226 : MASTER optical observations
  56. GRB 120819A: Swift/UVOT Upper Limits
  57. GRB 120817A: Swift/UVOT Upper Limits
  58. GRB 120817B: Deep limit on the optical afterglow from du Pont and Magellan observations
  59. GRB 120821A: Swift/UVOT Upper Limits
  60. GRB 120811C: optical observations
  61. GRB 120819A: Bassano Bresciano Observatory optical observations
  62. GRB 120819A: MITSuME Ishigakijima upper limits
  63. GRB 120819A: MITSuME Okayama Optical upper limits
  64. GRB 120819A: MASTER optical observations
  65. GRB 120811C: optical observations
  66. GRB 120816A: Swift/UVOT Detection of the Optical Afterglow
  67. GRB 120815A: MASTER-ICATE observations
  68. GRB 120817B: LCO Optical Observations
  69. GRB 120816A: optical upper limit
  70. GRB 120815A: Swift/UVOT Detection of the Optical Afterglow
  71. GRB 120816A: Bassano Bresciano Observatory optical observations
  72. GRB 120816A: BOOTES-2 observations
  73. GRB120816A: OPTIMA discovery of optical counterpart
  74. GRB 120816A: TAROT Calern observatory optical observations
  75. GRB 120816A: ROTSE-III Optical Limits
  76. GRB 120805A: Liverpool Telescope optical candidate detection
  77. GRB 120815A: TAROT La Silla observatory optical observations
  78. GRB 120811A: Swift/XRT-UVOT Obseravations
  79. GRB 120805A: optical afterglow confirmation from the NOT
  80. GRB 120805A: Enhanced Swift-XRT position
  81. GRB 120811C: EVLA Observations
  82. GRB 120811C: RTT150 optical observations
  83. GRB 120811C: MASTER-Tunka OT observations
  84. GRB 120811C: NOT redshift
  85. GRB 120811C: Bassano Bresciano Observatory optical observations
  86. GRB 120811C: RTT150 optical observations
  87. GRB 120811C: TAROT Calern observatory optical observations
  88. GRB 120811C: MASTER-Amur observations of fading OT
  89. GRB 120811C: Swift detection of a burst with an optical counterpart
  90. GRB 120803A: optical upper limit
  91. GRB 120807A: Swift/UVOT Upper Limits
  92. GRB 120714B: GROND/FORS2 detection of a supernova
  93. GRB 120802A: optical observations
  94. GRB 120804A: Gemini-North detection of an optical afterglow and putative host galaxy
  95. GRB 120807A: TAROT La Silla observatory optical observations
  96. GRB 120805A: Swift/UVOT Upper Limits
  97. GRB 120805A: 1.23m CAHA observations
  98. GRB 120805A: TAROT Calern observatory optical observations
  99. GRB 120804A: MITSuME Okayama Optical upper limits
  100. GRB 120804A: Swift/UVOT Upper Limits

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