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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"

21772 results found.

  1. GRB050124: Updated Swift XRT Position and Fluxes
  2. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  3. GRB050123,optical observation
  4. GRB 050123: KAIT observations
  5. GRB050117a: Refined analysis
  6. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  7. GRB050117: optical observation
  8. GRB050117: MASTER optical observations
  9. MASTER:GRB050117 SWIFT
  10. GRB050117: Swift XRT Position
  11. Triangulation of Short Hard GRB050112 (large error box)
  12. SGR1806-20: Swift-BAT observations of two additional bursts
  13. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  14. Further VLA observations of SGR 1806-20
  15. ATCA observations of SGR 1806-20
  16. SGR 1806-20, RHESSI observations of the 041227 giant flare
  17. Third epoch observations of SGR 1806-20 with VLA
  18. Second Epoch VLA observations of SGR 1806-20
  19. Second-epoch VLA observations of SGR 1806-20
  20. GRB 041217: Optical observations
  21. The giant outburst from SGR 1806-20
  22. GRB041228: Swift-BAT detection of a burst
  23. GRB041219; RXTE ASM Observations
  24. NIR Observations of GRB 041219
  25. GRB041226: ROTSE-III Optical Observations
  26. GRB041223: decay of the afterglow
  27. GRB041224: ROTSE-III Optical Observations
  28. GRB 041224: near-infrared observations with REM
  29. GRB 041223 Fluence measured by Swift-BAT
  30. GRB041223: optical and NIR observations with REM
  31. GRB 041219: TAROT optical observations
  32. GRB 041218: TAROT optical observations
  33. GRB 041223: J-band observations of the afterglow
  34. GRB 041219c: PROMPT Observations
  35. GRB041223: ROTSE-III Optical Observations
  36. GRB041223: Swift-BAT detection of a bright long burst
  37. Very high activity of SGR 1806-20
  38. GRB 041218 Optical Observations
  39. GRB041219: Continued NIR Observations
  40. GRB041219b: A Swift-BAT burst
  41. GRB 041219 ,optical observation
  42. GRB 041219: Radio Afterglow Detection
  43. GRB 041218 : Radio Observations
  44. GRB 041218: R-band optical observations
  45. GRB041218: optical observations
  46. GRB041219: Confirmed NIR Afterglow
  47. Swift-BAT detection of the bright long burst GRB041219
  48. GRB 041219: Infrared Afterglow Candidate
  49. GRB041219, BVRcIc field calibration
  50. GRB 041219: Infrared Afterglow Candidate
  51. GRB041218, BVRcIc field calibration
  52. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  53. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  54. GRB 041217: PROMPT Observations
  55. GRB041217: NIR and optical observations with REM
  56. GRB041217: Infrared Observations
  57. GRB041217: The First GRB Located On-Board Swift
  58. GRB041211: Faulkes Telescope continued optical monitoring
  59. Optical transient (GRB?) in Lynx
  60. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  61. GRB041211: RAPTOR observations
  62. GRB041211: Ashra Prototype optical observation
  63. GRB041211, BVRcIc field calibration
  64. GRB041211,optical observation
  65. GRB 041211: Infrared Observations
  66. GRB 041211: KAIT observations
  67. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  68. GRB041015: Near-Infrared observations
  69. GRB 040924: Afterglow Color
  70. GRB 041006: GETS Optical Afterglow Observation
  71. Summary of the recent bursts from SGR 1806-20
  72. GRB 041006: Optical Observations
  73. GRB041006, late-time optical photometry
  74. GRB041006: RTT150 Optical Observations
  75. Bright bursts from SGR1806-20
  76. GRB 041016: BOOTES-2 simultaneous observation
  77. GRB041006: RTT150 Optical Observations
  78. GRB041016,optical observation
  79. GRB 041016: Optical limits
  80. GRB 041016:Optical limit during first minute
  81. GRB 041016: Optical limit
  82. GRB 041015 R band observations
  83. GRB040924, BVRcIc field calibration
  84. GRB041015,optical observation
  85. GRB041006: Fading X-ray Afterglow Observed with Chandra
  86. GRB041006: Optical observations and Potential host galaxy
  87. GRB041006, BVRcIc field calibration
  88. GRB 041006: SARA afterglow observations
  89. GRB041006, optical observation in CrAO
  90. Search for SN light in XRF 040912 with MEGACAM
  91. GRB 041006: BR observations with VATT
  92. GRB041006 (= H3570): Chandra Observations In Progress
  93. GRB041006, optical I observation
  94. ROTSE-IIIa Observations of GRB 041006
  95. GRB041006: MASTER optical observations
  96. GRB041006,optical observation
  97. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  98. GRB041006: Fading of optical afterglow candidate
  99. GRB 041006: Optical afterglow candidate
  100. Bursts from SGR 1806-20: Preliminary INTEGRAL results

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