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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"
  1. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  2. GRB 100628A: Chandra observations
  3. GRB 100628A: Swift XRT/UVOT refined analysis
  4. Tentative redshift of GRB100704A from Swift-XRT data
  5. Konus-Wind observation of GRB 100701B
  6. IPN triangulation of GRB 100701B
  7. Konus-Wind observation of GRB 100704A
  8. GRB 100703A: a short GRB detected by INTEGRAL
  9. GRB 100704A: Swift XRT refined analysis
  10. GRB 100704: Swift/UVOT Upper Limits
  11. GRB 100704A: Fermi GBM observation
  12. GRB 100704A: Swift-BAT refined analysis
  13. GRB100704A: MOA optical upper limit
  14. GRB 100704A: Enhanced Swift-XRT position
  15. GRB 100704A: Swift detection of a burst
  16. GRB 100615A: Additional Gemini/NIRI observations
  17. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  18. GRB 100702A, Swift-BAT refined analysis
  19. Fermi GBM trigger 299767472 (100702531) is not a GRB
  20. GRB 100702A: Swift XRT refined analysis
  21. Swift/UVOT observations of GRB100702A - correction
  22. Swift/UVOT observations of GRB100702A
  23. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  24. GRB 100701B: Fermi GBM detection
  25. GRB 100702A: Magellan near-IR observations
  26. GRB 100702A: VLT optical observations
  27. GRB 100702: ROTSE-III Optical Limits
  28. GRB 100702A: Swift detection of a short burst
  29. GRB 100615A: Chandra X-ray ToO Observation
  30. XRF 100701A : MAXI/GSC detection of a probable XRF
  31. GRB 100213B: Detection of Fading Optical Afterglow
  32. GRB 100625A: Fermi GBM detection
  33. GRB 100628A: Second epoch of Magellan near-IR observations
  34. GRB 100628A: GROND optical/NIR observations of the host candidate
  35. GRB 100628A: Gemini North Observations
  36. GRB 100628A: Coincidence of source "G1" with revised XRT error circle
  37. GRB 100628A: Swift XRT refined position
  38. GRB100625A: GROND confirmation of constant source
  39. GRB 100625A Gemini-South 2nd epoch imaging
  40. GRB100628A : MOA optical upper limit
  41. GRB 090709A: Host galaxy detection
  42. GRB 100628A: Magellan near-IR observations
  43. GRB 100628A: Swift/UVOT Upper Limits
  44. GRB100628A: RTT150 optical observations
  45. GRB 100628A: Swift XRT detection of a possible X-ray afterglow
  46. GRB 100628A: INTEGRAL SPI-ACS light curve
  47. GRB 100625A: Magellan near-IR Observations
  48. GRB 100628A: Swift-BAT refined analysis
  49. GRB 100628A: Swift detection of a short hard burst
  50. Swift-BAT trigger 426048 is not a burst
  51. GRB 100614A: CrAO optical limit
  52. GRB 100625A: Swift/UVOT Upper Limits
  53. GRB 100625A: Swift-BAT refined analysis
  54. Konus-Wind observation of GRB 100625A
  55. GRB 100625A : IRSF/SIRIUS NIR upper limit
  56. GRB 100625A: Swift-XRT Team refined analysis
  57. GRB 100625A: Gemini candidate afterglow
  58. GRB 100625A: Enhanced Swift-XRT position
  59. GRB100625A : MOA optical upper limit
  60. GRB 100625A: Swift detection of a short hard burst
  61. GRB 100418A: late time optical observations
  62. Konus-Wind observation of GRB 100621A
  63. GRB 100621A: IRSF/SIRIUS NIR Observation
  64. GRB 100621A MOA-II optical limit
  65. GRB 100619A: Correction to the Fermi GBM trigger time
  66. GRB 100621A: Swift/UVOT observations
  67. GRB 100621A: Swift XRT refined analysis
  68. GRB 100621A: VLT/X-shooter redshift
  69. GRB 100621A: Swift-BAT refined analysis
  70. GRB 100621A: GROND observation of bright NIR afterglow
  71. GRB 100621A: Enhanced Swift-XRT position
  72. GRB 100621A: Prompt enhanced Swift-XRT position
  73. GRB 100621A: ROTSE-III Optical Limits
  74. GRB 100621A: Swift detection of a burst
  75. GRB 100606A: Optical Limits
  76. GRB 100619A: Fermi GBM detection
  77. GRB 100619A: Swift/UVOT Upper Limits
  78. GRB 100619A: Swift-XRT refind analysis
  79. GRB 100619A: Enhanced Swift-XRT position
  80. GRB 100619A: Swift-BAT refined analysis
  81. GRB 100619A: Swift detection of a burst
  82. GRB 100614A: Gemini/NIRI Observations
  83. GRB 100615A: Gemini/NIRI Observations
  84. XRF 100616a : MAXI/GSC detection of a probable XRF
  85. Fermi GBM trigger 100612038 is not a GRB
  86. GRB 100615A: Swift/UVOT Upper Limits
  87. GRB 100614A: Swift/UVOT Upper Limits
  88. GRB 100614A: NOT optical upper limits
  89. GRB 100614A: MASTER-Net optical alert observations
  90. GRB 100614A: Swift-BAT refined analysis
  91. GRB 100615A: Fermi GBM detection
  92. GRB 100615A: Swift-BAT refined analysis
  93. GRB 100614A: Enhanced Swift-XRT position
  94. GRB 100615A: Enhanced Swift-XRT position
  95. GRB 100615A: Swift-XRT refined analysis
  96. GRB 100614A: Swift-XRT refined analysis
  97. GRB 100614 : XMM-Newton observation
  98. GRB 100615A: GROND observations, upper limits
  99. GRB 100615A: PAIRITEL NIR Upper Limits
  100. GRB 100615A: NTT/Ultracam imaging

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