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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"

23440 results found.

  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. PROMPT VRcIc Observations of GRB 050223
  7. XRF/GRB 050215B: Radio Observations
  8. XMM-Newton Images of GRB 050223
  9. GRB 050219b: candidate NIR afterglow
  10. GRB050223 XMM-Newton observation
  11. INTEGRAL detection of GRB 050223
  12. GRB050223: ROTSE-III Optical Observations
  13. GRB 050223: Swift XRT Position
  14. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  15. GRB050219b: CORRECTION to time of UVOT observations
  16. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  17. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  18. GRB 050219a: Optical observations from LCO
  19. GRB 050219b: Optical and near-IR observations from LCO
  20. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  21. GRB 050219b: Refined XRT position
  22. GRB 050219b: CORRECTION: Swift XRT Position
  23. GRB 050219b: Swift XRT Position
  24. GRB 050219a, optical observations
  25. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  26. GRB 050215B: Radio Observations
  27. GRB 050215b: XRT confirmation of IR afterglow candidate
  28. GRB050215b: P60 Optical Observations
  29. GRB 050215b: Swift XRT Source Variability
  30. GRB 050215b : Lulin follow-up observation
  31. GRB 050215b, BOOTES-2 simultaneous optical observations
  32. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  33. GRB 050215b, BOOTES-1B optical limit
  34. GRB050215B: ROTSE-III optical observations
  35. GRB050215A: ROTSE-III Optical Observations
  36. GRB050209: TAROT optical observations
  37. GRB 050209(=U11568): Duration and spectrum
  38. short/hard GRB 050202, optical observations
  39. GRB050209: REM optical observations
  40. GRB 050209 I-band observation
  41. GRB 050209 Optical observations
  42. GRB050209: P60 Optical Observations
  43. GRB 050128: Radio observations
  44. GRB 050129: Optical observations
  45. GRB 050202: Short burst detected by Swift-BAT
  46. GRB 050128 Optical observation with REM
  47. GRB 050128: near-infrared observations with REM
  48. GRB050128,optical observations
  49. GRB050128 Swift-BAT observations
  50. GRB 050128: Swift XRT prompt afterglow position
  51. GRB050126: MASTER optical limit for KECK OT
  52. GRB050126: Burst Parameters Measured by BAT
  53. GRB050126: MASTER optical observations
  54. GRB050124: No Swift UVOT Detection of Afterglow Emission
  55. GRB 050124 I-band observation
  56. GRB050124,optical observation
  57. GRB050124: Updated Swift XRT Position and Fluxes
  58. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  59. GRB050124: Refined BAT position, spectral and fluence information
  60. GRB050124: Swift-BAT position of a double-peaked burst
  61. GRB 050123 : I-band follow-up observation
  62. GRB050123: optical limit 1.8h before GRB
  63. GRB050123,optical observation
  64. GRB 050123: KAIT observations
  65. CFHTLS optical transient unlikely to be a GRB
  66. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  67. GRB050117b: Swift-BAT detection of a weak burst
  68. GRB050117: MASTER optical observations
  69. MASTER:GRB050117 SWIFT
  70. GRB050117: Swift-BAT detection of a long multi-peaked burst
  71. GRB050117: Swift XRT Position
  72. Triangulation of Short Hard GRB050112 (large error box)
  73. SGR1806-20: Swift-BAT observations of two additional bursts
  74. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  75. Further VLA observations of SGR 1806-20
  76. SGR 1806-20 and extragalactic short-duration GRBs
  77. Further ATCA observations of SGR 1806-20
  78. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  79. SGR 1806-20, RHESSI observations of the 041227 giant flare
  80. Second-epoch VLA observations of SGR 1806-20
  81. SGR1806 VLA Observations
  82. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  83. GRB 041217: Optical observations
  84. GRB041228: ROTSE-III Optical Observations
  85. GRB041228: Swift-BAT detection of a burst
  86. GRB041219; RXTE ASM Observations
  87. GRB041226: ROTSE-III Optical Observations
  88. GRB041226: Swift-BAT detection of a burst
  89. GRB041223: decay of the afterglow
  90. GRB041224: ROTSE-III Optical Observations
  91. GRB 041224: near-infrared observations with REM
  92. GRB041224: Swift-BAT detection of a soft burst
  93. GRB041223: optical and NIR observations with REM
  94. GRB 041219: TAROT optical observations
  95. GRB 041218: TAROT optical observations
  96. GRB 041223: J-band observations of the afterglow
  97. GRB 041219c: PROMPT Observations
  98. GRB041223: ROTSE-III Optical Observations
  99. GRB041223: Swift-BAT detection of a bright long burst
  100. GRB 041218: optical observations

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