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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"
  1. GRB 050306: No Swift UVOT Optical Counterpart Detected
  2. GRB 050306: REM optical-infrared observations
  3. GRB 050306: Possible X-ray Afterglow Position from the Swift
  4. Swift trigger 107518: optical observation
  5. GRB 050306: TAROT optical observations
  6. GRB 050306,optical observation
  7. GRB 050306: Swift-BAT detection of a long burst
  8. Ongoing activity of SGR 1806-20 after the giant flare
  9. GRB050215B: Late-Time Swift UVOT Observations
  10. GRB 050126: Confirmation of the NIR afterglow candidate
  11. PROMPT VRcIc Observations of GRB 050223
  12. XRF/GRB 050215B: Radio Observations
  13. XMM-Newton Images of GRB 050223
  14. GRB 050219b: candidate NIR afterglow
  15. IBAS GRB Alert #2321
  16. Confirmed XRF nature for GRB050215b
  17. GRB 050223: optical observations
  18. GRB050223 XMM-Newton observation
  19. INTEGRAL detection of GRB 050223
  20. GRB 050223 : Planned XMM-Newton observation
  21. GRB050223: No Swift UVOT Detection of Afterglow Emission
  22. GRB050223: ROTSE-III Optical Observations
  23. GRB 050223 Swift/BAT detection of a burst
  24. GRB 050223: Swift XRT Position
  25. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  26. GRB050219b: CORRECTION to time of UVOT observations
  27. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  28. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  29. GRB 050219b: CORRECTION to refined XRT position
  30. GRB 050219a: Optical observations from LCO
  31. GRB 050219b: Optical and near-IR observations from LCO
  32. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  33. GRB 050219b: Refined XRT position
  34. GRB 050219b: Swift-BAT detection of a burst
  35. GRB 050219b: CORRECTION: Swift XRT Position
  36. GRB 050219b: Swift XRT Position
  37. GRB 050219a, optical observations
  38. GRB 050219a: Refined XRT position
  39. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  40. GRB 050219: Swift-BAT detection of a burst
  41. GRB050215b: Swift UVOT Detection of Afterglow Emission
  42. GRB 050219: Prompt X-ray position
  43. GRB 050215B: Radio Observations
  44. GRB 050215b: XRT confirmation of IR afterglow candidate
  45. GRB050215b: P60 Optical Observations
  46. GRB 050215b: Swift XRT Source Variability
  47. GRB 050215B: candidate afterglow
  48. GRB 050215b : Lulin follow-up observation
  49. GRB 050215b, BOOTES-2 simultaneous optical observations
  50. GRB 050215B: UKIRT K-band imaging
  51. GRB 050215b: Swift XRT Observations
  52. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  53. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  54. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  55. GRB 050215b, BOOTES-1B optical limit
  56. GRB050215B: ROTSE-III optical observations
  57. GRB050215A: ROTSE-III Optical Observations
  58. GRB050209: TAROT optical observations
  59. GRB 050209(=U11568): Duration and spectrum
  60. short/hard GRB 050202, optical observations
  61. GRB050209: REM optical observations
  62. GRB 050209 I-band observation
  63. GRB 050209 Optical observations
  64. GRB050209: P60 Optical Observations
  65. GRB050209 (=U11568): A Long GRB Detected by HETE
  66. GRB 050209: Optical observation
  67. GRB 050128: Radio observations
  68. Further analysis of the short Swift-BAT GRB 050202
  69. GRB 050202: Second epoch radio observations
  70. GRB 050129: Optical observations
  71. GRB050202: Radio Observations
  72. GRB 050202: Optical observations with LCO40
  73. GRB 050202: Short burst detected by Swift-BAT
  74. GRB 050128 Optical observation with REM
  75. GRB 050129: a weak long GRB detected with INTEGRAL
  76. SGR1806-20: Swift-BAT detection of a large normal burst
  77. GRB050128: Faulkes Telescope South observations
  78. GRB 050124: Radio Observations
  79. GRB 050128: near-infrared observations with REM
  80. GRB050128,optical observations
  81. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  82. GRB050126: Updated Swift XRT Position
  83. SGR 1806-20: GMRT results at 240 MHz band.
  84. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  85. GRB 050126: Radio Observations
  86. GRB050128 Swift-BAT observations
  87. GRB 050128: Swift XRT prompt afterglow position
  88. HETE #3667: P60 Observations
  89. GRB 050124: K-band afterglow observations
  90. GRB050126: MASTER optical limit for KECK OT
  91. GRB050126: Burst Parameters Measured by BAT
  92. GRB050126: MASTER optical observations
  93. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  94. GRB 050126: Prompt XRT detection and localization
  95. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  96. GRB050124: No Swift UVOT Detection of Afterglow Emission
  97. GRB 050124, SMARTS optical/IR observations
  98. GRB 050117a: Radio Observations
  99. GRB 050124 I-band observation
  100. GRB 050124: NIR Candidates from Keck/NIRC

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