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

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