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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"

19570 results found.

  1. GRB 061028: TAROT Calern observatory optical observations
  2. GRB 061028: Swift detection of a burst
  3. GRB 061027, Swift refined analysis of a possible burst
  4. GRB 061027: Swift detection of a possible burst
  5. GRB061025: Swift/UVOT observations
  6. GRB 061025: REM observations
  7. GRB 061025: ROTSE-III Optical Limits
  8. GRB 061021: Swift/UVOT Observation
  9. GRB 061021: Swift detection of a burst
  10. GRB 061019: SARA upper limit
  11. GRB 061019: Swift/UVOT upper limit
  12. GRB 061019: TAROT La Silla observatory optical observations
  13. GRB 061019: REM K-band candidate afterglow
  14. GRB 061006: astrometry-corrected XRT position
  15. GRB 061007: ATCA Radio Observations
  16. GRB061007: Swift UVOT followup observations
  17. GRB 061006: optical afterglow
  18. GRB 061007: OA fading and VLT redshift
  19. GRB 061007: Magellan Spectroscopy
  20. GRB 061006: Swift/UVOT optical observations
  21. GRB 061007: Swift detection of a burst with an optical counterpart
  22. GRB 061006: VLT observation
  23. GRB 060930: near-IR afterglow candidate retraction
  24. GRB 061006: Swift detection of a burst
  25. GRB 061004: Optical afterglow candidate and redshift
  26. GRB 061004, Swift BAT refined analysis
  27. GRB 061004: Swift detection of a burst
  28. Konus-Wind observation of GRB 060928
  29. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  30. GRB 060928: Swift observations
  31. IPN triangulation of GRB060928 (long, exceptionally bright)
  32. GRB 060930: near-IR afterglow candidate
  33. VLA observations of GRB 060926
  34. GRB061002 - SDSS Pre-Burst Observations
  35. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  36. GRB 061002: Swift detection of a burst
  37. GRB 060908: Detection of a possible host
  38. GRB 060807: Detection of a possible host galaxy
  39. GRB 060923A: VLA K-band Observations
  40. GRB 060930: Xinglong TNT optical observations
  41. GRB 060929: Swift/UVOT Optical Observations
  42. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  43. GRB 060929: TNG K-band observations
  44. GRB060929: Optical limit
  45. Liverpool Telescope observations of GRB 060929
  46. GRB060908: optical observations
  47. GRB 060927: Swift/UVOT Optical Observations
  48. GRB 060927: Swift XRT Team refined analysis
  49. GRB 060927 optical limit
  50. GRB 060927: Xinglong TNT optical observations
  51. GRB 060927, optical observation
  52. GRB060927 - SDSS Pre-Burst Observations
  53. GRB060926: VLT redshift
  54. GRB 060926: Swift-UVOT Detections
  55. GRB 060923A: Radio Observations
  56. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  57. GRB 060923C: VLA Observation
  58. GRB 060923C: NIR afterglow confirmed
  59. GRB060923C: AROMA optical obsevation
  60. GRB 060923C, optical observation
  61. GRB 060923C: VLT J-band observations
  62. GRB 060923A: Keck and Gemini Observations
  63. GRB 060923C: Xinglong TNT optical observations
  64. GRB 060923C: Swift detection of a burst
  65. GRB 060923B: Swift detection of a burst
  66. GRB 060923: UKIRT nIR observations - candidate afterglow
  67. GRB060923 - SDSS Pre-Burst Observations
  68. GRB 060923: Swift detection of a burst
  69. GRB 060919 : Faulkes South Telescope Observations
  70. GRB 060919: TAROT optical observations
  71. GRB 060919: Swift detection of a burst
  72. GRB 060912A: VLA Observation
  73. GRB 060912A: Probable Host Galaxy
  74. Konus-Wind observation of GRB 060912
  75. GRB 060912: Correction to GCN 5559
  76. GRB060906: Danish/DFOSC optical observations
  77. VLA observations of GRB 060908
  78. GRB 060908 - SDSS Pre-burst Observations
  79. GRB 060908: REM optical prompt observation
  80. GRB 060908: Swift detection of a burst with a bright optical counterpart
  81. GRB060906 , optical observation
  82. GRB 060906: Early RAPTOR optical limits
  83. GRB 060906, Swift-BAT refined spectral analysis
  84. GRB 060906: Confirmation of P60 Optical Afterglow
  85. GRB 060906 (?): P60 Optical Afterglow Candidate
  86. GRB 060906: Swift detection of a probable burst
  87. GRB060904b, optical observations
  88. GRB 060904B: RTT150 optical observations
  89. GRB060904A: Swift/UVOT optical observations
  90. GRB 060904A: Subaru NIR observation
  91. GRB 060904A: Refined analysis of the Swift-BAT burst
  92. GRB 060904A: Suzaku-XIS and -HXD observation plan
  93. GRB 060904A: P60 Observations
  94. GRB 060904B: TAROT optical counterpart observations
  95. GRB060904B - SDSS Pre-Burst Observations
  96. GRB 060904: TAROT optical observations
  97. GRB 060904B: Swift detection of a burst with optical counterpart
  98. GRB060904 - SDSS Pre-Burst Observations
  99. GRB 060904: Swift detection of a bright burst
  100. GRB060901: Optical observations

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