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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. Swift-BAT detection of GRB 050315
  2. GRB050223: No XMM-Newton OM detection of afterglow emission
  3. GRB 050306: Radio Observations
  4. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  5. GRB050309: CONCAM pre-trigger and trigger coincident optical
  6. GRB 050306: optical afterglow
  7. GRB 050126: Redshift determination
  8. Swift-BAT trigger 107873: No Swift XRT counterpart
  9. GRB 050306: Confirmation of X-ray afterglow
  10. GRB 050309, Early optical limits from RAPTOR
  11. GRB 050306: further TAROT optical data
  12. GRB050309: Early optical limit from P60
  13. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  14. GRB 050309 : Lulin R-band observation
  15. Swift 107873: P60 Optical Observations
  16. GRB 050306: CORRECTION to date of observation
  17. GRB 050306: R-band observations
  18. GRB 050306: No Swift UVOT Optical Counterpart Detected
  19. GRB 050306: REM optical-infrared observations
  20. GRB 050306: Possible X-ray Afterglow Position from the Swift
  21. Swift trigger 107518: optical observation
  22. GRB 050306: TAROT optical observations
  23. GRB 050306,optical observation
  24. GRB 050306: Swift-BAT detection of a long burst
  25. Ongoing activity of SGR 1806-20 after the giant flare
  26. GRB050215B: Late-Time Swift UVOT Observations
  27. GRB 050126: Confirmation of the NIR afterglow candidate
  28. PROMPT VRcIc Observations of GRB 050223
  29. XRF/GRB 050215B: Radio Observations
  30. XMM-Newton Images of GRB 050223
  31. GRB 050219b: candidate NIR afterglow
  32. IBAS GRB Alert #2321
  33. Confirmed XRF nature for GRB050215b
  34. GRB 050223: optical observations
  35. GRB050223 XMM-Newton observation
  36. INTEGRAL detection of GRB 050223
  37. GRB 050223 : Planned XMM-Newton observation
  38. GRB050223: No Swift UVOT Detection of Afterglow Emission
  39. GRB050223: ROTSE-III Optical Observations
  40. GRB 050223 Swift/BAT detection of a burst
  41. GRB 050223: Swift XRT Position
  42. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  43. GRB050219b: CORRECTION to time of UVOT observations
  44. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  45. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  46. GRB 050219b: CORRECTION to refined XRT position
  47. GRB 050219a: Optical observations from LCO
  48. GRB 050219b: Optical and near-IR observations from LCO
  49. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  50. GRB 050219b: Refined XRT position
  51. GRB 050219b: Swift-BAT detection of a burst
  52. GRB 050219b: CORRECTION: Swift XRT Position
  53. GRB 050219b: Swift XRT Position
  54. GRB 050219a, optical observations
  55. GRB 050219a: Refined XRT position
  56. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  57. GRB 050219: Swift-BAT detection of a burst
  58. GRB050215b: Swift UVOT Detection of Afterglow Emission
  59. GRB 050219: Prompt X-ray position
  60. GRB 050215B: Radio Observations
  61. GRB 050215b: XRT confirmation of IR afterglow candidate
  62. GRB050215b: P60 Optical Observations
  63. GRB 050215b: Swift XRT Source Variability
  64. GRB 050215B: candidate afterglow
  65. GRB 050215b : Lulin follow-up observation
  66. GRB 050215b, BOOTES-2 simultaneous optical observations
  67. GRB 050215B: UKIRT K-band imaging
  68. GRB 050215b: Swift XRT Observations
  69. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  70. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  71. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  72. GRB 050215b, BOOTES-1B optical limit
  73. GRB050215B: ROTSE-III optical observations
  74. GRB050215A: ROTSE-III Optical Observations
  75. GRB050209: TAROT optical observations
  76. GRB 050209(=U11568): Duration and spectrum
  77. short/hard GRB 050202, optical observations
  78. GRB050209: REM optical observations
  79. GRB 050209 I-band observation
  80. GRB 050209 Optical observations
  81. GRB050209: P60 Optical Observations
  82. GRB050209 (=U11568): A Long GRB Detected by HETE
  83. GRB 050209: Optical observation
  84. GRB 050128: Radio observations
  85. Further analysis of the short Swift-BAT GRB 050202
  86. GRB 050202: Second epoch radio observations
  87. GRB 050129: Optical observations
  88. GRB050202: Radio Observations
  89. GRB 050202: Optical observations with LCO40
  90. GRB 050202: Short burst detected by Swift-BAT
  91. GRB 050128 Optical observation with REM
  92. GRB 050129: a weak long GRB detected with INTEGRAL
  93. SGR1806-20: Swift-BAT detection of a large normal burst
  94. GRB050128: Faulkes Telescope South observations
  95. GRB 050124: Radio Observations
  96. GRB 050128: near-infrared observations with REM
  97. GRB050128,optical observations
  98. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  99. GRB050126: Updated Swift XRT Position
  100. SGR 1806-20: GMRT results at 240 MHz band.

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