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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"

16155 results found.

  1. GRB 061019: SMARTS afterglow confirmation
  2. GRB 061019: TAROT La Silla observatory optical observations
  3. GRB 061019: REM K-band candidate afterglow
  4. GRB 060825: GORT Observations
  5. GRB 061007: Second Epoch ATCA Radio Observations
  6. GRB 061006: astrometry-corrected XRT position
  7. GRB 061007: ATCA Radio Observations
  8. GRB 061006: optical afterglow
  9. GRB 061007: OA fading and VLT redshift
  10. GRB 061006: Swift/UVOT optical observations
  11. GRB 061007 - FTS early brightening and power law decay
  12. GRB 061007: Swift detection of a burst with an optical counterpart
  13. GRB 061007: ROTSE-III Detection of Optical Counterpart
  14. GRB 061004: Optical afterglow candidate and redshift
  15. GRB 061004: Las Campanas Optical/NIR Observations
  16. GRB061004: Swift/UVOT optical observations
  17. GRB 060930: Xinglong TNT optical observations
  18. GRB 060929: Swift/UVOT Optical Observations
  19. GRB 060930: ROTSE-III Optical Limits
  20. GRB 060927 : GAO 150cm telescope optical observation
  21. GRB060929: Optical limit
  22. GRB 060929: BOOTES-IR & OSN observations
  23. GRB060908: optical observations
  24. GRB 060729: An update on the late-time Swift observations
  25. GRB060923C: optical limit
  26. GRB060927: optical observations
  27. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  28. GRB 060927: Swift/UVOT Optical Observations
  29. GRB 060927: Early color
  30. GRB 060927: Swift XRT Team refined analysis
  31. GRB 060927 optical limit
  32. GRB 060927: Xinglong TNT optical observations
  33. GRB 060927, optical observation
  34. GRB 060927 : Kiso optical observation
  35. GRB 060927: optical afterglow confirmation
  36. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  37. Swift XRT boresight
  38. GRB060926: VLT redshift
  39. GRB 060926: Swift-UVOT Detections
  40. GRB 060926: MASTER OT alert observation
  41. GRB 060926: BOOTES-IR observations
  42. GRB060926 OPTIMA-Burst optical observation
  43. GRB 060926: MASTER optical observation
  44. GRB060923C: AROMA optical obsevation
  45. GRB 060923C, optical observation
  46. GRB060923B: Swift/UVOT upper limits
  47. GRB 060923C: Keck Observations
  48. GRB 060923C: Xinglong TNT optical observations
  49. GRB060923C : Faulkes Telescope South optical limits
  50. GRB060923C: Faulkes Telescope North optical observations
  51. GRB 060923C: optical observation
  52. GRB060923: Faulkes Telescope North optical observations
  53. GRB060919: Swift/UVOT optical observations
  54. GRB 060919 : Faulkes South Telescope Observations
  55. GRB 060919: TAROT optical observations
  56. GRB 060912A: Probable Host Galaxy
  57. GRB 060912: Redshift of nearby 2MASS galaxy
  58. GRB060912: optical observations
  59. GRB060912: Swift/UVOT Observations
  60. GRB060912: OPTIMA-Burst optical observations
  61. GRB 060912: Correction to GCN 5559
  62. GRB 060912: Xinglong TNT optical observations
  63. GRB 060912: Swift detection of a burst with an optical afterglow
  64. GRB060906: Danish/DFOSC optical observations
  65. GRB 060908: Swift/UVOT Observations
  66. GRB 060908: Danish/DFOSC optical observations
  67. GRB 060904B: Kiso Optical observation
  68. GRB 060904A : Optical limit
  69. GRB 060908: REM optical prompt observation
  70. GRB 060908: Swift detection of a burst with a bright optical counterpart
  71. GRB060906 , optical observation
  72. GRB060904b optical detections (delayed report due to internet outage)
  73. GRB 060906: optical observation
  74. GRB 060906: Early RAPTOR optical limits
  75. GRB 060906: Swift/XRT Refined Analysis
  76. GRB 060906: Swift-UVOT observations
  77. VLT redshift of GRB 060906
  78. GRB 060906: KAIT observations
  79. GRB 060906: Confirmation of P60 Optical Afterglow
  80. GRB 060906 (?): P60 Optical Afterglow Candidate
  81. GRB060904b, optical observations
  82. GRB 060904b: SMARTS optical/IR afterglow observations
  83. GRB 060904B: RTT150 optical observations
  84. GRB060904A: Swift/UVOT optical observations
  85. GRB060904b: Optical observations with Swift/UVOT
  86. GRB 060904B: VLT redshift
  87. GRB 060904B: Optical observations at Crni Vrh
  88. GRB060904B: Watcher observations
  89. GRB 060904B BOOTES-IR and 1.5m OSN observations
  90. GRB 060904B: TAROT optical counterpart observations
  91. GRB 060904: TAROT optical observations
  92. GRB 060904B: Swift detection of a burst with optical counterpart
  93. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  94. GRB060901: Optical observations
  95. GRB 060901: SMARTS optical/IR observations update
  96. GRB 060901: SMARTS optical/IR observations
  97. GRB 060605, observations using an Integral Field Unit
  98. GRB 060826(?): Swift detection of a possible burst
  99. GRB060825: Liverpool Telescope optical observations
  100. GRB 060825: TNG optical observations

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