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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"

26001 results found.

  1. GRB060204a: Swift XRT Source is not GRB Afterglow
  2. GRB 060206: optical observations at Asiago
  3. GRB 060206: IR Detection of the Afterglow
  4. GRB 060206: Super-LOTIS observations
  5. GRB060204A: Swift/UVOT observations
  6. GRB 060206: Swift-BAT refined analysis
  7. GRB060206: SDSS Pre-Burst Observations
  8. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  9. GRB060206: Swift-BAT detection of a burst
  10. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  11. GRB060204C: optical observation
  12. GRB 060204A: Swift XRT upper limit
  13. GRB 060204A: FRAM optical observations
  14. GRB060204B: Swift/UVOT refined analysis
  15. GRB 060204C: optical observations
  16. Swift XRT Observation of GRB 060204C
  17. GRB 060204B: Swift-BAT refined analysis
  18. GRB 060204B: ART early limit
  19. GRB 060204b: Keck/LRIS Afterglow Confirmation
  20. GRB 060204C: Liverpool Telescopes optical limit
  21. GRB 060204C: Swift-BAT detection of a burst
  22. GRB 060204A: further INTEGRAL results
  23. GRB060204B, optical observation
  24. GRB060204B - SDSS pre-burst observations
  25. GRB 060203: Swift-BAT refined analysis
  26. GRB 060204B: Swift detection of a burst
  27. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  28. GRB 060203: RTT150 optical observations
  29. GRB 060203: IR Counterpart
  30. Possible GRB 060203: optical observations at Asiago
  31. GRB 060202: PROMPT Observations
  32. GRB 060202: GETS observation
  33. GRB 060202: Gemini-N J, H, K_s observations
  34. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  35. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  36. GRB 060202: Refined analysis of the Swift-BAT burst
  37. GRB060202, optical observation
  38. GRB 060202: Swift/UVOT upper limits
  39. GRB 060121: Gemini Late-time Observations
  40. GRB 060130: PROMPT Observations
  41. GRB060130: Further R-band imaging
  42. GRB 060130: Swift/XRT observation
  43. GRB 060123: Gemini spectroscopy of the putative host galaxy
  44. GRB060130: Optical imaging
  45. GRB060130: REM infrared observations
  46. GRB 060130, SMARTS optical observations
  47. GRB 060130: FRAM optical observations
  48. GRB 060130: further INTEGRAL IBIS results
  49. GRB 060121: Confirmation of NIR Afterglow
  50. GRB 060123: Swift refined analysis of an unusual GRB
  51. GRB060124, BVRcIc field calibration
  52. GRB 060121: Probable Detection of NIR Afterglow
  53. GRB 060116 HST observations
  54. GRB 060124: HETE detection and spectrum of the main peak
  55. GRB060124: detailed XRT analysis
  56. GRB 060124: ART optical limits during the burst
  57. GRB060123: Optical and IR Imaging
  58. GRB 060123: P200 Observations
  59. GRB 060124: XRT refined analysis
  60. GRB 060124: R band Observations
  61. GRB 060124 : Optical observation at Xinglong and Kiso
  62. GRB060124: optical observations at Asiago
  63. GRB060123: SDSS pre-burst observations
  64. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  65. GRB 060121: OHP optical limits
  66. GRB 060124: TAROT optical limits
  67. GRB060124, optical observation
  68. GRB 060124: Optical Observations at Tautenburg
  69. GRB 060117: Suzaku WAM observation of the prompt emission
  70. GRB 060111B: Suzaku WAM observation of the prompt emission
  71. GRB 060124: Swift-BAT detection of a burst
  72. GRB 060121: Liverpool Telescopes optical limits
  73. GRB 060121: Swift XRT refined analysis
  74. Konus-Wind observation of GRB 060121
  75. GRB 060121: candidate optical counterpart
  76. GRB 060121: Infrared Observations
  77. GRB 060121: optical observations
  78. GRB 060121: Optical imaging
  79. GRB060121 - SDSS pre-burst observations
  80. HETE Alert 4006: MASTER promt optical limit
  81. GRB060117 - ATCA 3/6cm radio limits - correction
  82. GRB060117 - ATCA 3/6cm radio limits
  83. GRB 060116: photometric redshift - the farthest GRB?
  84. Konus-Wind observation of GRB 060117
  85. GRB 060116: UKIRT IR Observations
  86. GRB 060117: Refined analysis of the Swift-BAT burst
  87. GRB 060117: FRAM optical afterglow candidate
  88. GRB 060117: nearby galaxy
  89. GRB 060116: VLT optical observations
  90. GRB 060116: Refined analysis of the Swift-BAT burst
  91. GRB 060116: XRT refined analysis
  92. GRB 060116: IR Candidate Afterglow
  93. GRB 060116: Swift/UVOT upper limits
  94. GRB060115: REM observations
  95. GRB 060110: XRT position and analysis
  96. GRB 060116 : Lulin optical limit
  97. GRB060116: Faulkes North observation
  98. GRB 060116: Swift-BAT detection of a burst
  99. GRB 060115: Refined analysis of the Swift-BAT burst
  100. GRB 060115: Swift/UVOT upper limits

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