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

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