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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"

45429 results found.

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

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