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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"

35949 results found.

  1. GRB 050117, I-band observations
  2. GRB 050117: Optical observation
  3. GRB050117: Refined XRT position
  4. GRB050117: MASTER optical observations
  5. MASTER:GRB050117 SWIFT
  6. GRB050117: Swift-BAT detection of a long multi-peaked burst
  7. Triangulation of Short Hard GRB050112 (large error box)
  8. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  9. SGR 1806-20 and extragalactic short-duration GRBs
  10. SGR 1806-20: Temporal and Spectral behavior of radio transient
  11. SGR 1806-20, RHESSI observations of the 041227 giant flare
  12. SGR1806: Detection of a Sudden Ionospheric Disturbance
  13. GRB 041217: Optical observations
  14. GRB041219, early time observations
  15. IPN localization of giant flare from SGR1806-20
  16. GRB041219; RXTE ASM Observations
  17. NIR Observations of GRB 041219
  18. GRB041223: decay of the afterglow
  19. GRB 041224: near-infrared observations with REM
  20. GRB 041223: XRT afterglow spectrum and light curve
  21. GRB 041223 Fluence measured by Swift-BAT
  22. GRB041223: optical and NIR observations with REM
  23. GRB 041219: TAROT optical observations
  24. GRB 041218: TAROT optical observations
  25. GRB 041223: J-band observations of the afterglow
  26. GRB 041223: Detection of Optical Transient with LCO40
  27. GRB 041219c: PROMPT Observations
  28. GRB 041218: optical observations
  29. GRB 041219: Second Epoch WSRT Radio Observations
  30. GRB 041219: WSRT Radio Afterglow Detection
  31. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  32. GRB 041218: Optical observations
  33. GRB 041219 : optical follow-up observations
  34. Deep RAPTOR observations during GRB 041219
  35. GRB 041218 Optical Observations
  36. GRB 041219 Optical Observations
  37. GRB041219c: Third Burst in One Day from Swift-BAT
  38. GRB041219: Optical Afterglow Detection
  39. GRB041219: Continued NIR Observations
  40. GRB 041219 ,optical observation
  41. GRB 041219: Radio Afterglow Detection
  42. GRB 041218 : Radio Observations
  43. GRB 041218: R-band optical observations
  44. GRB041219: Confirmed NIR Afterglow
  45. GRB041218: Continued P60 Optical Observations
  46. GRB 041218: Optical Observation
  47. GRB 041219: Infrared Afterglow Candidate
  48. GRB041219, BVRcIc field calibration
  49. GRB 041219: Infrared Afterglow Candidate
  50. GRB041218, BVRcIc field calibration
  51. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  52. GRB041219: P60 Optical Observations
  53. GRB 041219 - A long GRB detected by INTEGRAL
  54. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  55. GRB 041217: PROMPT Observations
  56. GRB041218: optical observations
  57. GRB041217: optical limit 30 min after GRB
  58. GRB 041218; optical candidate
  59. GRB 041218: Optical observations
  60. GRB 041217: LCO40 Optical Observations and Possible Candidates
  61. GRB 041218 - A long GRB detected by integral
  62. GRB041217: Optical Observations
  63. GRB041217: P60 Optical Observations
  64. GRB041217: Infrared Observations
  65. GRB041217: The First GRB Located On-Board Swift
  66. GRB041211: Faulkes Telescope continued optical monitoring
  67. Optical Transient in Lynx not a GRB
  68. Optical transient (GRB?) in Lynx
  69. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  70. GRB041211: Continued P60 Observations
  71. GRB041211: RAPTOR observations
  72. GRB041211: Ashra Prototype optical observation
  73. GRB041211, Faulkes Telescope optical observation
  74. GRB041211, BVRcIc field calibration
  75. GRB 041211: Infrared Observations
  76. GRB 041211: KAIT observations
  77. GRB 041211: Optical follow-up in East Asian region
  78. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  79. GRB041211: P60 optical imaging
  80. GRB970815: Discovery of Optical Afterglow
  81. Distribution of IBAS Alerts for NON-GRB sources
  82. Triangulation of short GRB 041116 (large error box)
  83. GRB 040924: Afterglow Color
  84. GRB 041006: GETS Optical Afterglow Observation
  85. Summary of the recent bursts from SGR 1806-20
  86. GRB 041006: Optical Observations
  87. GRB041006, late-time optical photometry
  88. IBAS GRB Alert # 2034
  89. GRB041006: RTT150 Optical Observations
  90. Bright bursts from SGR1806-20
  91. GRB 041016: BOOTES-2 simultaneous observation
  92. GRB041006: RTT150 Optical Observations
  93. GRB 041016: Optical limits
  94. GRB 041016: Optical limits in V, R, I
  95. GRB 041016:Optical limit during first minute
  96. GRB041016: MASTER: Optical observations
  97. GRB 041015: Optical Observations at Rikubetsu
  98. GRB041006: Near Infrared observations
  99. GRB 041016: Optical limit
  100. GRB 041015 R band observations

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