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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"

3360 results found.

  1. GRB 071028, Swift-BAT refined analysis
  2. GRB 071025: Kuiper Telescope Optical Observations
  3. GRB 060602A: host redshift
  4. GRB 071025a: PAIRITEL observations
  5. GRB 071020: Swift-XRT refined analysis
  6. GRB 071020: Swift detection of a bright burst
  7. GRB 071011: XRT afterglow detection
  8. VLA observation of GRB 070923
  9. GRB 070911: Swift detection of a burst
  10. GRB 070809: Swift detection of a short burst
  11. GRB 070808: ROTSE-III Optical Limits
  12. GRB 070808: Swift detection of a burst
  13. GRB 070805: Swift XRT initial analysis.
  14. Swift detection of a outburst from SAX J1810.8-2609
  15. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  16. GRB 070721A: optical observations
  17. GRB 070714B: Keck observations
  18. GRB 070721A: Swift/XRT refined analysis
  19. GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
  20. GRB 070714 ("Bastille"): Optical Pre-Imaging
  21. GRB 070714A, Swift-BAT refined analysis
  22. GRB 070714 : Liverpool Telescope optical counterpart ?
  23. GRB 070429B: NIR Observations
  24. GRB 070628: Watcher Observations
  25. OT20050728 was not an optical GRB afterglow
  26. GRB 070611, Swift-BAT refined analysis
  27. GRB 070529: Optical aterglow from MIRO
  28. GRB 070529: Swift detection of a burst with an optical aterglow
  29. GRB 070508: Optical afterglow detection
  30. GRB 070508: TAROT La Silla observatory optical observations
  31. GRB 070411 : Planned XMM-Newton observation
  32. GRB 070412: Swift detection of a burst
  33. GRB 070328 : Suzaku ToO follow up starts
  34. GRB070208: optical observations
  35. Short-Hard GRB 070209: PROMPT Observations
  36. GRB 070318: Swift detection of a burst with an optical afterglow
  37. GRB 070311: MDM Optical Detection
  38. GRB 070125: Chandra X-ray Confirmation of Jet Break
  39. GRB 070306: ART-3 early optical and near infrared constraints
  40. GRB 070306: IR observations and candidate afterglow
  41. GRB 070306, Swift-BAT refined analysis
  42. GRB 070306: XRT Team Refined Analysis
  43. GRB070306 - SDSS Pre-burst Observations
  44. GRB 070306: Swift detection of a burst
  45. GRB 070125, deep late-time optical observation
  46. VLA observation of GRB 070224
  47. GRB 070227: optical observations
  48. GRB 070227: optical observations
  49. GRB070227: possible X-ray afterglow detection
  50. GRB 070220 : Faulkes Telescope North optical limit
  51. GRB070208: optical observations
  52. GRB 070208: Early IR detection and afterglow astrometry
  53. GRB 070129: afterglow confirmation
  54. GRB 070125: further AAVSO optical observations
  55. GRB 070129: VLT observations
  56. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  57. GRB 070125: AAVSO optical observations
  58. GRB 070125: optical observations
  59. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  60. Retractions of previous Swift-BAT triggers
  61. GRB061222a: optical observations
  62. GRB 061222B: MITSuME Akeno optical upper limits
  63. GRB 061222: Swift detection of a burst
  64. INT+WFC observations of GRB 061126
  65. GRB 061126: Possible Jet Break
  66. GRB 061121: MDM Optical Decay
  67. RHESSI Spectrum of GRB061121
  68. GRB 061109: Swift detection of a possible burst
  69. GRB061019: second epoch CrAO observations
  70. GRB 061028: Swift/XRT Astrometry Correction
  71. GRB 061028: MDM Observations
  72. GRB 061028: P200 Observations
  73. GRB 061028: z band imaging
  74. GRB 061028: Swift/UVOT Observations
  75. GRB 061021, Swift-BAT Lag analysis
  76. GRB 060928: Swift observations
  77. GRB 060912, Swift-BAT refined analysis
  78. GRB 060904b: SMARTS optical/IR afterglow observations
  79. Two bright bursts from SGR 1806-20 detected with IBAS
  80. GRB060805 Liverpool Telescope observations
  81. GRB 060804: Swift-XRT Team Refined Analysis
  82. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  83. GRB 060728: Upper limits of the X-ray emission
  84. GRB 060719: Continued LCO optical observations
  85. GRB060717 - SDSS Pre-burst Observations
  86. Swift trigger 219136 is probably not a GRB
  87. GRB 050223: Magellan redshift
  88. GRB050223: Host Galaxy
  89. GRB 060605: RTT150 optical observations
  90. GRB 060522: PROMPT Optical Limits
  91. GRB 060605: RTT150 optical observations
  92. GRB 060605: ROTSE-III Detection of Optical Counterpart
  93. GRB 060604: Swift-XRT Team refined analysis
  94. GRB 060602B: XMM-Newton Survey Source
  95. GRB 060602B: Swift-XRT Refined Analysis
  96. GRB 060602B: RTT150 optical observations
  97. GRB 060602B: Swift detection of a burst
  98. GRB060602B: BOOTES-IR candidate afterglow
  99. GRB060526, optical observations
  100. GRB 060526: RTT150 optical observations

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