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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"

21264 results found.

  1. MASTER:GRB050117 SWIFT
  2. GRB050117: Swift XRT Position
  3. Triangulation of Short Hard GRB050112 (large error box)
  4. SGR1806-20: Swift-BAT observations of two additional bursts
  5. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  6. Further VLA observations of SGR 1806-20
  7. ATCA observations of SGR 1806-20
  8. SGR 1806-20, RHESSI observations of the 041227 giant flare
  9. Third epoch observations of SGR 1806-20 with VLA
  10. Second Epoch VLA observations of SGR 1806-20
  11. Second-epoch VLA observations of SGR 1806-20
  12. GRB 041217: Optical observations
  13. The giant outburst from SGR 1806-20
  14. GRB041228: Swift-BAT detection of a burst
  15. GRB041219; RXTE ASM Observations
  16. NIR Observations of GRB 041219
  17. GRB041226: ROTSE-III Optical Observations
  18. GRB041223: decay of the afterglow
  19. GRB041224: ROTSE-III Optical Observations
  20. GRB 041224: near-infrared observations with REM
  21. GRB 041223 Fluence measured by Swift-BAT
  22. GRB041223: optical and NIR observations with REM
  23. GRB 041219: TAROT optical observations
  24. GRB 041218: TAROT optical observations
  25. GRB 041223: J-band observations of the afterglow
  26. GRB 041219c: PROMPT Observations
  27. GRB041223: ROTSE-III Optical Observations
  28. GRB041223: Swift-BAT detection of a bright long burst
  29. Very high activity of SGR 1806-20
  30. GRB 041218 Optical Observations
  31. GRB041219: Continued NIR Observations
  32. GRB041219b: A Swift-BAT burst
  33. GRB 041219 ,optical observation
  34. GRB 041219: Radio Afterglow Detection
  35. GRB 041218 : Radio Observations
  36. GRB 041218: R-band optical observations
  37. GRB041218: optical observations
  38. GRB041219: Confirmed NIR Afterglow
  39. Swift-BAT detection of the bright long burst GRB041219
  40. GRB 041219: Infrared Afterglow Candidate
  41. GRB041219, BVRcIc field calibration
  42. GRB 041219: Infrared Afterglow Candidate
  43. GRB041218, BVRcIc field calibration
  44. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  45. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  46. GRB 041217: PROMPT Observations
  47. GRB041217: NIR and optical observations with REM
  48. GRB041217: Infrared Observations
  49. GRB041217: The First GRB Located On-Board Swift
  50. GRB041211: Faulkes Telescope continued optical monitoring
  51. Optical transient (GRB?) in Lynx
  52. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  53. GRB041211: RAPTOR observations
  54. GRB041211: Ashra Prototype optical observation
  55. GRB041211, BVRcIc field calibration
  56. GRB041211,optical observation
  57. GRB 041211: Infrared Observations
  58. GRB 041211: KAIT observations
  59. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  60. GRB041015: Near-Infrared observations
  61. GRB 040924: Afterglow Color
  62. GRB 041006: GETS Optical Afterglow Observation
  63. Summary of the recent bursts from SGR 1806-20
  64. GRB 041006: Optical Observations
  65. GRB041006, late-time optical photometry
  66. GRB041006: RTT150 Optical Observations
  67. Bright bursts from SGR1806-20
  68. GRB 041016: BOOTES-2 simultaneous observation
  69. GRB041006: RTT150 Optical Observations
  70. GRB041016,optical observation
  71. GRB 041016: Optical limits
  72. GRB 041016:Optical limit during first minute
  73. GRB 041016: Optical limit
  74. GRB 041015 R band observations
  75. GRB040924, BVRcIc field calibration
  76. GRB041015,optical observation
  77. GRB041006: Fading X-ray Afterglow Observed with Chandra
  78. GRB041006: Optical observations and Potential host galaxy
  79. GRB041006, BVRcIc field calibration
  80. GRB 041006: SARA afterglow observations
  81. GRB041006, optical observation in CrAO
  82. Search for SN light in XRF 040912 with MEGACAM
  83. GRB 041006: BR observations with VATT
  84. GRB041006 (= H3570): Chandra Observations In Progress
  85. GRB041006, optical I observation
  86. ROTSE-IIIa Observations of GRB 041006
  87. GRB041006: MASTER optical observations
  88. GRB041006,optical observation
  89. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  90. GRB041006: Fading of optical afterglow candidate
  91. GRB 041006: Optical afterglow candidate
  92. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  93. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  94. radio observations, GRB 040924
  95. GRB040929,optical observation
  96. GRB040924,optical observation
  97. GRB040924,optical observation
  98. GRB040924: KAIT observations
  99. GRB 040924: Subaru NIR observation
  100. GRB 040924, optical follow-up

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