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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"

15722 results found.

  1. GRB050209: REM optical observations
  2. GRB 050209 Optical observations
  3. GRB050209: P60 Optical Observations
  4. GRB050209 (=U11568): A Long GRB Detected by HETE
  5. GRB 050209: Optical observation
  6. Further analysis of the short Swift-BAT GRB 050202
  7. GRB 050129: Optical observations
  8. GRB 050202: Optical observations with LCO40
  9. GRB 050128 Optical observation with REM
  10. GRB 050128: near-infrared observations with REM
  11. GRB050128,optical observations
  12. GRB 050128: Swift XRT prompt afterglow position
  13. GRB050126: MASTER optical limit for KECK OT
  14. GRB050126: MASTER optical observations
  15. GRB050124: No Swift UVOT Detection of Afterglow Emission
  16. GRB 050124, SMARTS optical/IR observations
  17. GRB050124,optical observation
  18. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  19. GRB050123: optical limit 1.8h before GRB
  20. GRB050123,optical observation
  21. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  22. CFHTLS optical transient unlikely to be a GRB
  23. Unusual optical transient (GRB ???)
  24. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  25. GRB050117: optical observation
  26. GRB 050117: Optical observation
  27. GRB050117: MASTER optical observations
  28. MASTER:GRB050117 SWIFT
  29. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  30. SGR 1806-20 and extragalactic short-duration GRBs
  31. GRB 041217: Optical observations
  32. GRB041219, early time observations
  33. GRB041228: ROTSE-III Optical Observations
  34. GRB041226: ROTSE-III Optical Observations
  35. GRB041223: decay of the afterglow
  36. GRB041224: ROTSE-III Optical Observations
  37. GRB 041224: near-infrared observations with REM
  38. GRB 041223: XRT afterglow spectrum and light curve
  39. GRB041223: optical and NIR observations with REM
  40. Swift-BAT Time History of GRB041219
  41. GRB 041219: TAROT optical observations
  42. GRB 041218: TAROT optical observations
  43. GRB 041223: Detection of Optical Transient with LCO40
  44. GRB041223: ROTSE-III Optical Observations
  45. GRB 041218: optical observations
  46. GRB 041218: Optical observations
  47. GRB 041219 : optical follow-up observations
  48. Deep RAPTOR observations during GRB 041219
  49. GRB 041218 Optical Observations
  50. GRB 041219 Optical Observations
  51. GRB041219: Optical Afterglow Detection
  52. GRB041219: Continued NIR Observations
  53. GRB 041219 ,optical observation
  54. GRB 041219: Radio Afterglow Detection
  55. GRB 041218 : Radio Observations
  56. GRB 041218: R-band optical observations
  57. GRB041218: Liverpool Telescope optical observations
  58. GRB041218: optical observations
  59. GRB041218: Continued P60 Optical Observations
  60. GRB 041218: Optical Observation
  61. GRB 041219: Infrared Afterglow Candidate
  62. GRB 041219: Infrared Afterglow Candidate
  63. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  64. GRB041219: P60 Optical Observations
  65. GRB041218: optical observations
  66. GRB041217: optical limit 30 min after GRB
  67. GRB 041218; optical candidate
  68. GRB 041218: Optical observations
  69. GRB 041217: LCO40 Optical Observations and Possible Candidates
  70. GRB041217: Optical Observations
  71. GRB041217: NIR and optical observations with REM
  72. GRB041217: P60 Optical Observations
  73. GRB041211: Faulkes Telescope continued optical monitoring
  74. Optical Transient in Lynx not a GRB
  75. Optical transient (GRB?) in Lynx
  76. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  77. GRB041211: Continued P60 Observations
  78. GRB041211: RAPTOR observations
  79. GRB041211: Ashra Prototype optical observation
  80. GRB041211, Faulkes Telescope optical observation
  81. GRB041211,optical observation
  82. GRB 041211: Optical follow-up in East Asian region
  83. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  84. GRB041211: P60 optical imaging
  85. GRB970815: Discovery of Optical Afterglow
  86. GRB 041006: GETS Optical Afterglow Observation
  87. GRB 041006: Optical Observations
  88. GRB041006, late-time optical photometry
  89. GRB041015, optical observation in CrAO
  90. GRB041006: RTT150 Optical Observations
  91. GRB041015 : Multi epoch optical observations
  92. GRB 041016: BOOTES-2 simultaneous observation
  93. GRB041006: RTT150 Optical Observations
  94. GRB041016,optical observation
  95. GRB 041016: Optical limits
  96. GRB 041016: Optical limits in V, R, I
  97. GRB 041016:Optical limit during first minute
  98. GRB041016: MASTER: Optical observations
  99. GRB 041015: Optical Observations at Rikubetsu
  100. GRB041006: Near Infrared observations

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