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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. GRB100725B: MITSuME optical upper limits
  2. GRB 100724B: AGILE/GRID analysis
  3. GRB 100724B: Suzaku WAM observation of the prompt emission
  4. GRB 100724B: gamma-ray detection by AGILE
  5. GRB 100725B: Swift-BAT refined analysis
  6. GRB 100725B: refined XRT analysis
  7. GRB 100725A: GROND upper limits
  8. GRB 100725B: Swift/UVOT Upper Limits
  9. GRB 100725A: Swift/UVOT Upper Limits
  10. GRB 100725A: Swift-BAT refined analysis
  11. GRB 100725A: Swift XRT refined analysis
  12. GRB 100725B: Enhanced Swift-XRT position
  13. GRB 100725A: Enhanced Swift-XRT position
  14. GRB100725B: Faulkes Telescope North observations
  15. GRB 100725B: Swift detection of a burst
  16. GRB100725A Faulkes Telescope South observations
  17. Konus-Wind observation of GRB 100724B
  18. GRB 100725A: Prompt enhanced Swift-XRT position
  19. GRB 100725A: Swift detection of a burst
  20. GRB 100724B: Fermi LAT and GBM analysis
  21. GRB 100724B: Fermi GBM detection
  22. GRB 100724A: Swift/BAT spectral lag results
  23. GRB 100724A: Swift XRT refined analysis
  24. GRB 100724A: Enhanced Swift-XRT position
  25. GRB 100724A: Swift/UVOT observations
  26. GRB 100724A: Swift-BAT refined analysis
  27. GRB 100724A: X-shooter redshift
  28. GRB 100724A: fading afterglow seen with GROND
  29. GRB 100724A, GROND detection of an afterglow candidate
  30. GRB 100724A: Swift detection of a burst
  31. GRB 100614A: 10.4-m GTC deep-optical limit
  32. GRB 100722A: Fermi GBM detection
  33. GRB 100718A: MASTER-Net optical prompt and alert observations
  34. GRB 100719A: Swift-BAT refined analysis
  35. GRB 100719A: Swift detection of a burst
  36. GRB 100713A: optical observation in Maidanak
  37. GRB 100713A: further inspection of TNG images
  38. GRB 100713A: Swift XRT refined analysis
  39. GRB 100713A : IRSF/SIRIUS NIR upper limits
  40. Fermi GBM trigger 300794561 (100714419) is not a GRB
  41. GRB100713A: Swift/UVOT observations
  42. GRB 100713A: GROND upper limits
  43. GRB 100713A: optical upper limit
  44. GRB 100713A: TNG optical observations
  45. GRB 100713A: TELMA and 1.5m OSN optical observations
  46. GRB100713A: Swift X-ray afterglow detection
  47. GRB 100713A: a long GRB detected by INTEGRAL
  48. GRB 100707A: Suzaku WAM observation of the prompt emission
  49. Fermi GBM trigger 300370702 (100709513) is not a GRB
  50. Konus-Wind observation of GRB 100707A
  51. IPN triangulation of GRB 100707A
  52. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  53. GRB 100707A: Fermi LAT detection
  54. GRB 100707A: Fermi GBM detection
  55. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  56. GRB 100628A: Chandra observations
  57. GRB 100628A: Swift XRT/UVOT refined analysis
  58. Tentative redshift of GRB100704A from Swift-XRT data
  59. Konus-Wind observation of GRB 100701B
  60. IPN triangulation of GRB 100701B
  61. Konus-Wind observation of GRB 100704A
  62. GRB 100703A: a short GRB detected by INTEGRAL
  63. GRB 100704A: Swift XRT refined analysis
  64. GRB 100704: Swift/UVOT Upper Limits
  65. GRB 100704A: Fermi GBM observation
  66. GRB 100704A: Swift-BAT refined analysis
  67. GRB100704A: MOA optical upper limit
  68. GRB 100704A: Enhanced Swift-XRT position
  69. GRB 100704A: Swift detection of a burst
  70. GRB 100615A: Additional Gemini/NIRI observations
  71. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  72. GRB 100702A, Swift-BAT refined analysis
  73. Fermi GBM trigger 299767472 (100702531) is not a GRB
  74. GRB 100702A: Swift XRT refined analysis
  75. Swift/UVOT observations of GRB100702A - correction
  76. Swift/UVOT observations of GRB100702A
  77. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  78. GRB 100701B: Fermi GBM detection
  79. GRB 100702A: Magellan near-IR observations
  80. GRB 100702A: VLT optical observations
  81. GRB 100702: ROTSE-III Optical Limits
  82. GRB 100702A: Swift detection of a short burst
  83. GRB 100615A: Chandra X-ray ToO Observation
  84. XRF 100701A : MAXI/GSC detection of a probable XRF
  85. GRB 100213B: Detection of Fading Optical Afterglow
  86. GRB 100625A: Fermi GBM detection
  87. GRB 100628A: Second epoch of Magellan near-IR observations
  88. GRB 100628A: GROND optical/NIR observations of the host candidate
  89. GRB 100628A: Gemini North Observations
  90. GRB 100628A: Coincidence of source "G1" with revised XRT error circle
  91. GRB 100628A: Swift XRT refined position
  92. GRB100625A: GROND confirmation of constant source
  93. GRB 100625A Gemini-South 2nd epoch imaging
  94. GRB100628A : MOA optical upper limit
  95. GRB 090709A: Host galaxy detection
  96. GRB 100628A: Magellan near-IR observations
  97. GRB 100628A: Swift/UVOT Upper Limits
  98. GRB100628A: RTT150 optical observations
  99. GRB 100628A: Swift XRT detection of a possible X-ray afterglow
  100. GRB 100628A: INTEGRAL SPI-ACS light curve

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