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

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