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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"

26507 results found.

  1. GRB050315: Radio afterglow
  2. GRB 050315: Absorption redshift
  3. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  4. GRB 050315: Early Observations with Swift/UVOT
  5. Swift-BAT detection of GRB 050315
  6. GRB 050306: Radio Observations
  7. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  8. GRB 050306: optical afterglow
  9. GRB 050126: Redshift determination
  10. Swift-BAT trigger 107873: No Swift XRT counterpart
  11. GRB 050306: Confirmation of X-ray afterglow
  12. GRB 050306: further TAROT optical data
  13. GRB050309: Early optical limit from P60
  14. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  15. Swift 107873: P60 Optical Observations
  16. GRB 050306: R-band observations
  17. GRB 050306: REM optical-infrared observations
  18. GRB 050306: Possible X-ray Afterglow Position from the Swift
  19. GRB 050306: TAROT optical observations
  20. GRB 050306,optical observation
  21. GRB 050306: Swift-BAT detection of a long burst
  22. Ongoing activity of SGR 1806-20 after the giant flare
  23. GRB050215B: Late-Time Swift UVOT Observations
  24. PROMPT VRcIc Observations of GRB 050223
  25. XMM-Newton Images of GRB 050223
  26. GRB 050219b: candidate NIR afterglow
  27. Confirmed XRF nature for GRB050215b
  28. GRB 050223: optical observations
  29. GRB050223 XMM-Newton observation
  30. GRB050223: ROTSE-III Optical Observations
  31. GRB 050223 Swift/BAT detection of a burst
  32. GRB 050223: Swift XRT Position
  33. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  34. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  35. GRB 050219a: Optical observations from LCO
  36. GRB 050219b: Optical and near-IR observations from LCO
  37. GRB 050219b: Swift-BAT detection of a burst
  38. GRB 050219b: CORRECTION: Swift XRT Position
  39. GRB 050219b: Swift XRT Position
  40. GRB 050219a, optical observations
  41. GRB 050219: Swift-BAT detection of a burst
  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, BOOTES-2 simultaneous optical observations
  47. GRB 050215b, BOOTES-1B optical limit
  48. GRB050215A: ROTSE-III Optical Observations
  49. GRB050209: TAROT optical observations
  50. GRB 050209(=U11568): Duration and spectrum
  51. short/hard GRB 050202, optical observations
  52. GRB050209: REM optical observations
  53. GRB 050209 I-band observation
  54. GRB 050209 Optical observations
  55. GRB050209: P60 Optical Observations
  56. GRB 050128: Radio observations
  57. GRB 050202: Short burst detected by Swift-BAT
  58. GRB 050128 Optical observation with REM
  59. GRB050128: Faulkes Telescope South observations
  60. GRB 050124: Radio Observations
  61. GRB 050128: near-infrared observations with REM
  62. GRB050128,optical observations
  63. GRB050128 Swift-BAT observations
  64. GRB 050128: Swift XRT prompt afterglow position
  65. GRB050126: MASTER optical limit for KECK OT
  66. GRB050126: Burst Parameters Measured by BAT
  67. GRB050126: MASTER optical observations
  68. GRB 050117a: Radio Observations
  69. GRB 050124 I-band observation
  70. GRB050124,optical observation
  71. GRB050124: Updated Swift XRT Position and Fluxes
  72. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  73. GRB050124: Refined BAT position, spectral and fluence information
  74. GRB050123: optical limit 1.8h before GRB
  75. GRB050123,optical observation
  76. GRB 050123: KAIT observations
  77. CFHTLS optical transient unlikely to be a GRB
  78. Unusual optical transient (GRB ???)
  79. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  80. GRB050117b: Swift-BAT detection of a weak burst
  81. GRB 050117, I-band observations
  82. GRB050117: Refined XRT position
  83. GRB050117: MASTER optical observations
  84. MASTER:GRB050117 SWIFT
  85. GRB050117: Swift XRT Position
  86. Triangulation of Short Hard GRB050112 (large error box)
  87. SGR1806-20: Swift-BAT observations of two additional bursts
  88. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  89. SGR 1806-20 and extragalactic short-duration GRBs
  90. Further ATCA observations of SGR 1806-20
  91. Fourth Epoch VLA observations of SGR 1806-20
  92. ATCA observations of SGR 1806-20
  93. SGR 1806-20, RHESSI observations of the 041227 giant flare
  94. Third epoch observations of SGR 1806-20 with VLA
  95. Second Epoch VLA observations of SGR 1806-20
  96. Second-epoch VLA observations of SGR 1806-20
  97. GRB 041217: Optical observations
  98. Detection of the SGR 1806-20 giant outburst back-scattered by the
  99. GRB041228: Swift-BAT detection of a burst
  100. GRB041219; RXTE ASM Observations

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