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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"

7415 results found.

  1. Swift triggers (#251863) on a possible burst
  2. GRB061217: Swift/UVOT refined analysis.
  3. GRB 061210: MDM Follow-up Observation
  4. GRB061210: Swift/UVOT observations
  5. GRB 061214(?): Swift detection of a possible burst
  6. GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
  7. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  8. GRB 061201: SOAR Confirmation of Candidate Afterglow
  9. GRB061202: Swift/UVOT Upper Limits
  10. GRB 061202: Swift detection of a burst
  11. GRB 061201: Swift detection of a short hard burst
  12. GRB 061126: Swift/UVOT Afterglow Detection
  13. GRB 061122: Candidate Optical Afterglow
  14. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  15. GRB 061121: Swift detection of a bright burst with an optical counterpart
  16. GRB 061110B: Swift/XRT position
  17. GRB 061110B: Swift-UVOT Initial Observation
  18. GRB 061110: Candidate confirmed
  19. GRB 061110 : Optical afterglow candidate
  20. GRB 061110: Swift detection of a burst
  21. GRB 061027: TAROT La Silla observatory optical observations
  22. GRB 061004: Further VLT/NTT observations
  23. GRB 061028: Optical R passband observations
  24. GRB 061102: Swift detection of a burst
  25. GRB 061028: Futher P200 Observations
  26. GRB 061028: P200 Observations
  27. GRB 061028: Swift detection of a burst
  28. GRB 061027, Swift refined analysis of a possible burst
  29. GRB 061027: Swift detection of a possible burst
  30. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  31. GRB 061025: REM observations
  32. GRB 061025: Gemini-S observations
  33. GRB 061021: Swift detection of a burst
  34. GRB 061019: SARA upper limit
  35. GRB061019: Swift XRT refined analysis
  36. GRB 061019: REM K-band candidate afterglow
  37. GRB 061006: astrometry-corrected XRT position
  38. GRB 061007: ROTSE-III Detection of Optical Counterpart
  39. GRB 060930: near-IR afterglow candidate retraction
  40. GRB 061004: Optical afterglow candidate and redshift
  41. GRB 061004: Swift detection of a burst
  42. GRB 060930: near-IR afterglow candidate
  43. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  44. GRB 061002: Swift detection of a burst
  45. GRB 060929: Swift detection of a burst
  46. GRB 060927: Swift XRT Team refined analysis
  47. GRB060927: Faulkes Telescope South observation
  48. GRB 060927: Swift detection of a burst
  49. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  50. GRB 060926: MASTER optical observation
  51. GRB 060926: Swift detection of a burst
  52. GRB 060923C: Gemini Observations and Afterglow Candidate
  53. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  54. GRB 060923A: Swift XRT refined analysis
  55. GRB 060923A: Keck and Gemini Observations
  56. GRB 060923C: optical observation
  57. GRB 060923B: Swift detection of a burst
  58. GRB 060923: UKIRT nIR observations - candidate afterglow
  59. GRB 060923: Swift detection of a burst
  60. GRB 060919: Swift detection of a burst
  61. GRB060912: optical observations
  62. GRB 060912: Swift detection of a burst with an optical afterglow
  63. GRB 060908: Swift detection of a burst with a bright optical counterpart
  64. GRB 060906: KAIT observations
  65. GRB 060906: Confirmation of P60 Optical Afterglow
  66. GRB 060906: observations with FRAM
  67. GRB 060906 (?): P60 Optical Afterglow Candidate
  68. GRB 060906: Swift detection of a probable burst
  69. GRB 060904B: Swift detection of a burst with optical counterpart
  70. GRB 060904: Swift detection of a bright burst
  71. GRB 060826(?): Swift detection of a possible burst
  72. GRB 060825: TAROT optical observations
  73. GRB 060825: Swift detection of a burst
  74. GRB060801: host galaxy redshift
  75. GRB 060814: Swift detection of a bright burst
  76. GRB 060813: Swift detection of a burst
  77. GRB 060807: K- and R-band observations
  78. GRB060807: optical afterglow candidate
  79. GRB060807: optical upper limit in white light
  80. GRB 060805B: Swift/UVOT Upper Limits
  81. GRB 060807: Swift detection of a burst
  82. GRB 060805: optical upper limit in R
  83. GRB 060805: Swift/UVOT Upper Limits
  84. GRB 060805: Swift detection of a burst
  85. GRB 060804: Swift UVOT observations
  86. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  87. GRB060801: optical upper limit in R
  88. GRB 060801: Swift detection of a short burst
  89. GRB060719: prompt NIR observations with REM
  90. GRB 060719: prompt PROMPT observations
  91. GRB 060719: Continued LCO optical observations
  92. GRB 060719: Swift detection of a burst
  93. GRB 060717 optical upper limit
  94. GRB 060714: REM infrared observations
  95. GRB 060717: Swift detection of a burst
  96. GRB 060714 : Liverpool Telescope Observations
  97. GRB 060714: OA redshift
  98. GRB 060708: VLT spectroscopy
  99. GRB060714: optical observations
  100. GRB 060714: Swift detection of a burst with an UVOT optical afterglow

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