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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 080916B: Enhanced Swift-XRT position
  2. GRB 080916C: Fermi LAT observation
  3. GRB 080916C: Fermi GBM Detection
  4. GRB 080916A: Swift XRT refined analysis
  5. GRB 080916A, Swift-BAT refined analysis
  6. GRB 080916B: Swift-XRT afterglow detection
  7. GRB 080916A: Enhanced Swift-XRT position
  8. GRB 080916B: Swift detection of a burst
  9. GRB 080916: REM detection of the NIR afterglow
  10. GRB 080916: REM candidate afterglow
  11. GRB 080916: Swift detection of a burst with optical afterglow
  12. GRB 080915B, Swift-BAT refined analysis
  13. GRB 080912 : Fermi GBM detection
  14. GRB 080915B: Swift detection of a burst
  15. GRB 080915: REM NIR early observations
  16. GRB 080915: Swift/UVOT Upper Limits
  17. GRB 080915: Swift-XRT afterglow detection and analysis
  18. GRB 080915, Swift-BAT refined analysis
  19. SGR 0501+4516 : P200 i-band observations
  20. GRB 080915: ROTSE-III Optical Limits
  21. GRB 080915: Swift detection of a burst
  22. GRB 080913: Swift-XRT refined analysis
  23. GRB 080913: VLT/FORS spectrum
  24. GRB080913: Swift/UVOT Upper Limits
  25. GRB 080913: GROND photo-z
  26. GRB 080913, Swift-BAT refined analysis
  27. GRB 080913: VLT/FORS2 observations
  28. GRB 080913: REM NIR early observations
  29. GRB 080913: Enhanced Swift-XRT position
  30. GRB 080913: GROND observation of a high-z optical/NIR afterglow candidate
  31. GRB 080913: Swift detection of a burst
  32. GRB 080906: Watcher observations
  33. Swift-BAT/-XRT refined analysis on trigger 324362 (LS I +61 303)
  34. GRB 080906B: Fermi GBM detection
  35. GRB 080905C: Fermi GBM detection
  36. SGR J0501+4516: radio pulsar searches with GBT and WSRT
  37. Swift trigger 324362 (LS I +61 303 ?): XRT
  38. GRB 080905B: Photometric Redshift for the 2MASS Galaxy
  39. Swift trigger 324362 (LS I +61 303 ?)
  40. GRB080905A: Swift/UVOT Upper Limits
  41. GRB 080905B: Watcher optical detection
  42. GRB 080904: Fermi Gamma-ray Burst Monitor detection
  43. GRB 080905B: Fermi Gamma-ray Burst Monitor detection
  44. GRB 080905A: Fermi Gamma-ray Burst Monitor detection
  45. GRB 080905A: Enhanced Swift-XRT position
  46. GRB 080905A: MITSuME Akeno optical upper limits
  47. Swift Trigger 324122 is again known source Swift J1842.5-1124
  48. Swift Trigger 324116 is known source again
  49. Swift Trigger 324112 is known source Swift J1842.5-1124
  50. GRB 080906: Refined Swift/UVOT Observations
  51. GRB 080906: Swift-XRT Refined Analysis
  52. GRB 080906, Swift-BAT refined analysis
  53. GRB 080905A: optical afterglow
  54. GRB 080906: GROND observations of the optical/NIR afterglow
  55. GRB 080905B: Swift-XRT Refined Analysis
  56. GRB 080905B: Refined UVOT Analysis
  57. GRB 080905B: VLT redshift
  58. GRB 080905A: NOT and VLT observations
  59. GRB 080905B: Enhanced Swift-XRT position
  60. GRB 080905B, Swift-BAT refined analysis
  61. GRB 080905A, Swift-BAT refined analysis
  62. GRB 080906: Swift detection of a burst with optical afterglow
  63. GRB 080905A: Swift-XRT Refined Analysis
  64. GRB 080825C: Fermi GBM Spectral Analysis
  65. GRB080825C: Fermi-LAT observations
  66. GRB 080905B: Swift detection of a burst with possible optical counterpart
  67. GRB 080905: R & I-band optical observations
  68. GRB 080905: Swift detection of a probably-short burst
  69. GRB 080903: Swift/UVOT Observations
  70. GRB 080903: Swift-XRT Refined Analysis
  71. GRB 080903: Enhanced Swift-XRT position
  72. GRB 080903, Swift-BAT refined analysis
  73. GRB 080903: optical observations
  74. GRB 080903: Liverpool Telescope observations
  75. GRB 080903: Astrotel-Caucasus optical observations
  76. GRB 080903: Optical afterglow candidate
  77. GRB 080903: TAROT Calern observatory optical observations
  78. GRB 080903: ROTSE-III Optical Limits
  79. GRB 080903: Swift detection of a burst
  80. Recent VLA non-detection of SGR 0501+4516
  81. GRB 080830: Fermi Gamma-ray Burst Monitor detection
  82. SGR 0501+4516: Spin Down Rate and Inferred Dipole Magnetic Field
  83. SGR 0501+4516: preliminary results of the first XMM-Newton observation
  84. nIR observations of SGR 0501+4516
  85. INTEGRAL ToO observation of SGR0501+4516
  86. SGR 0501+4516: Confirmation of the NIR counterpart
  87. GRB080828: Swift/UVOT Upper Limits
  88. SGR 0501+4516: Detection of possible optical counterpart
  89. SGR 0501+4516: WHT observations of the possible near-infrared counterpart
  90. GRB080825B: Swift/UVOT Upper Limits
  91. GRB 080828: Swift-XRT detection of a possible X-ray afterglow
  92. Swift-BAT trigger 322590 is not a GRB
  93. VLA non-detection of SGR 0501+4516
  94. Radio Detection of SGR 0501+4516: Retraction
  95. Swift trigger 322590: BAT detection of a possible burst
  96. SGR 0501+4516: XMM-Newton monitoring schedule
  97. GRB 080828: SuperAGILE GRB Localization
  98. SGR 0501+4516: Decline in Activity
  99. SGR 0501+4516: Proximity to supernova remnant HB9
  100. Enhanced Swift-XRT position of SGR 0501+4516

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