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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"

26361 results found.

  1. MASTER:GRB050117 SWIFT
  2. GRB050117: Swift XRT Position
  3. Triangulation of Short Hard GRB050112 (large error box)
  4. SGR 1806-20: Further VLA Observations
  5. SGR1806-20: Swift-BAT observations of two additional bursts
  6. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  7. Further VLA observations of SGR 1806-20
  8. SGR 1806-20 and extragalactic short-duration GRBs
  9. Further ATCA observations of SGR 1806-20
  10. Fourth Epoch VLA observations of SGR 1806-20
  11. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  12. ATCA observations of SGR 1806-20
  13. SGR 1806-20, RHESSI observations of the 041227 giant flare
  14. Third epoch observations of SGR 1806-20 with VLA
  15. Second Epoch VLA observations of SGR 1806-20
  16. Second-epoch VLA observations of SGR 1806-20
  17. SGR1806 VLA Observations
  18. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  19. GRB 041217: Optical observations
  20. GRB041228: Swift-BAT detection of a burst
  21. GRB041219; RXTE ASM Observations
  22. NIR Observations of GRB 041219
  23. GRB041226: Swift-BAT detection of a burst
  24. GRB041223: decay of the afterglow
  25. GRB 041224: near-infrared observations with REM
  26. GRB 041223 Fluence measured by Swift-BAT
  27. GRB041223: optical and NIR observations with REM
  28. Swift-BAT Time History of GRB041219
  29. GRB 041219: TAROT optical observations
  30. GRB 041218: TAROT optical observations
  31. GRB 041223: J-band observations of the afterglow
  32. GRB 041219c: PROMPT Observations
  33. GRB041223: Swift-BAT detection of a bright long burst
  34. GRB 041218: optical observations
  35. GRB 041219 : optical follow-up observations
  36. Deep RAPTOR observations during GRB 041219
  37. GRB 041218 Optical Observations
  38. GRB041219: Continued NIR Observations
  39. GRB 041219 ,optical observation
  40. GRB 041219: Radio Afterglow Detection
  41. GRB 041218 : Radio Observations
  42. GRB 041218: R-band optical observations
  43. GRB041218: optical observations
  44. GRB041219: Confirmed NIR Afterglow
  45. Swift-BAT detection of the bright long burst GRB041219
  46. GRB 041219: Infrared Afterglow Candidate
  47. GRB041219, BVRcIc field calibration
  48. GRB 041219: Infrared Afterglow Candidate
  49. GRB041218, BVRcIc field calibration
  50. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  51. GRB 041219 - A long GRB detected by INTEGRAL
  52. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  53. GRB 041217: PROMPT Observations
  54. GRB 041217: LCO40 Optical Observations and Possible Candidates
  55. GRB 041218 - A long GRB detected by integral
  56. GRB041217: NIR and optical observations with REM
  57. GRB041217: Infrared Observations
  58. GRB041217: The First GRB Located On-Board Swift
  59. GRB041211: Faulkes Telescope continued optical monitoring
  60. Optical Transient in Lynx not a GRB
  61. Optical transient (GRB?) in Lynx
  62. GRB041211: RAPTOR observations
  63. GRB041211: Ashra Prototype optical observation
  64. GRB041211, BVRcIc field calibration
  65. GRB041211,optical observation
  66. GRB 041211: Infrared Observations
  67. GRB 041211: KAIT observations
  68. GRB 041211: Optical follow-up in East Asian region
  69. Triangulation of short GRB 041116 (large error box)
  70. GRB 040924: Afterglow Color
  71. GRB 041006: GETS Optical Afterglow Observation
  72. Summary of the recent bursts from SGR 1806-20
  73. GRB 041006: Optical Observations
  74. GRB041006, late-time optical photometry
  75. GRB041006: RTT150 Optical Observations
  76. HST Observations: XRF 040701 and 040812
  77. Bright bursts from SGR1806-20
  78. GRB 041016: BOOTES-2 simultaneous observation
  79. GRB041006: RTT150 Optical Observations
  80. GRB041016,optical observation
  81. GRB 041016: Optical limits
  82. GRB 041016:Optical limit during first minute
  83. GRB 041015: Optical Observations at Rikubetsu
  84. GRB 041016: Optical limit
  85. GRB 041015 R band observations
  86. GRB040924, BVRcIc field calibration
  87. GRB041015,optical observation
  88. GRB041006: Fading X-ray Afterglow Observed with Chandra
  89. GRB 041015 - A long GRB detected by INTEGRAL
  90. GRB041006: VLT observations of the afterglow and host galaxy
  91. GRB041006: Optical observations and Potential host galaxy
  92. GRB041006, BVRcIc field calibration
  93. GRB 040924: VLT spectroscopy
  94. GRB 041006: SARA afterglow observations
  95. GRB041006, optical observation in CrAO
  96. Search for SN light in XRF 040912 with MEGACAM
  97. GRB 041006: BR observations with VATT
  98. GRB 041006: Redshift confirmed
  99. GRB 041006: Radio Observations
  100. GRB 041006 : optical follow-up observation at Lulin Observatory

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