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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 100724A: X-shooter redshift
  2. GRB 100724A: fading afterglow seen with GROND
  3. GRB 100724A, GROND detection of an afterglow candidate
  4. GRB 100724A: Swift detection of a burst
  5. GRB 100614A: 10.4-m GTC deep-optical limit
  6. GRB 100722A: Fermi GBM detection
  7. GRB 100718A: MASTER-Net optical prompt and alert observations
  8. GRB 100719A: Swift-BAT refined analysis
  9. GRB 100719A: Swift detection of a burst
  10. GRB 100713A: optical observation in Maidanak
  11. GRB 100713A: further inspection of TNG images
  12. GRB 100713A: Swift XRT refined analysis
  13. GRB 100713A : IRSF/SIRIUS NIR upper limits
  14. Fermi GBM trigger 300794561 (100714419) is not a GRB
  15. GRB100713A: Swift/UVOT observations
  16. GRB 100713A: GROND upper limits
  17. GRB 100713A: optical upper limit
  18. GRB 100713A: TNG optical observations
  19. GRB 100713A: TELMA and 1.5m OSN optical observations
  20. GRB100713A: Swift X-ray afterglow detection
  21. GRB 100713A: a long GRB detected by INTEGRAL
  22. GRB 100707A: Suzaku WAM observation of the prompt emission
  23. Fermi GBM trigger 300370702 (100709513) is not a GRB
  24. Konus-Wind observation of GRB 100707A
  25. IPN triangulation of GRB 100707A
  26. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  27. GRB 100707A: Fermi LAT detection
  28. GRB 100707A: Fermi GBM detection
  29. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  30. GRB 100628A: Chandra observations
  31. GRB 100628A: Swift XRT/UVOT refined analysis
  32. Tentative redshift of GRB100704A from Swift-XRT data
  33. Konus-Wind observation of GRB 100701B
  34. IPN triangulation of GRB 100701B
  35. Konus-Wind observation of GRB 100704A
  36. GRB 100703A: a short GRB detected by INTEGRAL
  37. GRB 100704A: Swift XRT refined analysis
  38. GRB 100704: Swift/UVOT Upper Limits
  39. GRB 100704A: Fermi GBM observation
  40. GRB 100704A: Swift-BAT refined analysis
  41. GRB100704A: MOA optical upper limit
  42. GRB 100704A: Enhanced Swift-XRT position
  43. GRB 100704A: Swift detection of a burst
  44. GRB 100615A: Additional Gemini/NIRI observations
  45. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  46. GRB 100702A, Swift-BAT refined analysis
  47. Fermi GBM trigger 299767472 (100702531) is not a GRB
  48. GRB 100702A: Swift XRT refined analysis
  49. Swift/UVOT observations of GRB100702A - correction
  50. Swift/UVOT observations of GRB100702A
  51. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  52. GRB 100701B: Fermi GBM detection
  53. GRB 100702A: Magellan near-IR observations
  54. GRB 100702A: VLT optical observations
  55. GRB 100702: ROTSE-III Optical Limits
  56. GRB 100702A: Swift detection of a short burst
  57. GRB 100615A: Chandra X-ray ToO Observation
  58. XRF 100701A : MAXI/GSC detection of a probable XRF
  59. GRB 100213B: Detection of Fading Optical Afterglow
  60. GRB 100625A: Fermi GBM detection
  61. GRB 100628A: Second epoch of Magellan near-IR observations
  62. GRB 100628A: GROND optical/NIR observations of the host candidate
  63. GRB 100628A: Gemini North Observations
  64. GRB 100628A: Coincidence of source "G1" with revised XRT error circle
  65. GRB 100628A: Swift XRT refined position
  66. GRB100625A: GROND confirmation of constant source
  67. GRB 100625A Gemini-South 2nd epoch imaging
  68. GRB100628A : MOA optical upper limit
  69. GRB 090709A: Host galaxy detection
  70. GRB 100628A: Magellan near-IR observations
  71. GRB 100628A: Swift/UVOT Upper Limits
  72. GRB100628A: RTT150 optical observations
  73. GRB 100628A: Swift XRT detection of a possible X-ray afterglow
  74. GRB 100628A: INTEGRAL SPI-ACS light curve
  75. GRB 100625A: Magellan near-IR Observations
  76. GRB 100628A: Swift-BAT refined analysis
  77. GRB 100628A: Swift detection of a short hard burst
  78. Swift-BAT trigger 426048 is not a burst
  79. GRB 100614A: CrAO optical limit
  80. GRB 100625A: Swift/UVOT Upper Limits
  81. GRB 100625A: Swift-BAT refined analysis
  82. Konus-Wind observation of GRB 100625A
  83. GRB 100625A : IRSF/SIRIUS NIR upper limit
  84. GRB 100625A: Swift-XRT Team refined analysis
  85. GRB 100625A: Gemini candidate afterglow
  86. GRB 100625A: Enhanced Swift-XRT position
  87. GRB100625A : MOA optical upper limit
  88. GRB 100625A: Swift detection of a short hard burst
  89. GRB 100418A: late time optical observations
  90. Konus-Wind observation of GRB 100621A
  91. GRB 100621A: IRSF/SIRIUS NIR Observation
  92. GRB 100621A MOA-II optical limit
  93. GRB 100619A: Correction to the Fermi GBM trigger time
  94. GRB 100621A: Swift/UVOT observations
  95. GRB 100621A: Swift XRT refined analysis
  96. GRB 100621A: VLT/X-shooter redshift
  97. GRB 100621A: Swift-BAT refined analysis
  98. GRB 100621A: GROND observation of bright NIR afterglow
  99. GRB 100621A: Enhanced Swift-XRT position
  100. GRB 100621A: Prompt enhanced Swift-XRT position

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