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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"

22077 results found.

  1. GRB 240225B: Liverpool Telescope optical afterglow observations
  2. GRB 240225B: NOT optical observations
  3. GRB 240218A: CMO SAI NIR upper limit
  4. Fermi GRB 240226A: Global MASTER-Net observations report
  5. GRB 240225B: Swift-XRT observations
  6. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  7. Transient EPW20240219aa: J-band upper limits from WINTER
  8. GRB 240225B: GOTO detection of a candidate optical afterglow
  9. Transient EPW20240219aa: REM optical/NIR upper limits
  10. GRB 240222A: ATCA radio observations
  11. Fermi trigger No 730618809: Global MASTER-Net observations report
  12. GRB 240225B: Tiled Swift observations
  13. GRB 240218A: VLA detection
  14. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  15. Transient EPW20240219aa: 7DT Optical Upper Limits
  16. VLA X-band observation of EPW20240219aa
  17. Transient EPW20240219aa: Mondy optical observations
  18. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  19. GRB 240222A: Swift/UVOT Upper Limits
  20. Swift GRB 240222A: Global MASTER-Net observations report
  21. Fermi GRB 240222A: Global MASTER-Net observations report
  22. GRB 240222A: REM optical and NIR early-time observations
  23. Swift GRB240221.92: Global MASTER-Net observations report
  24. GRB 240218A: MeerLICHT upper limits
  25. GRB 240218A: LBT H-band detection
  26. Fermi GRB 240220A: Global MASTER-Net observations report
  27. Konus-Wind detection of GRB 240218A
  28. Fermi trigger No 729914426: Global MASTER-Net observations report
  29. GRB 240218A: VLT/FORS2 z-band detection
  30. GRB 240218A: REM detection of a NIR afterglow candidate
  31. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  32. Swift GRB240218.08: Global MASTER-Net observations report
  33. GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  34. Fermi GRB 240216A: Global MASTER-Net observations report
  35. Fermi trigger No 729719508: Global MASTER-Net observations report
  36. GRB 240215A: Tiled Swift observations
  37. GRB 240215A: Swift/BAT-GUANO localization of a burst
  38. Fermi trigger No 729703985: Global MASTER-Net observations report
  39. Fermi trigger No 729650855: Global MASTER-Net observations report
  40. GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
  41. GRB 240209A: Fermi GBM observation
  42. The AGILE satellite ceased operations and re-entered today into the atmosphere
  43. The AGILE satellite ceased operations and re-entered today into the atmosphere
  44. GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
  45. GRB 240209A: Wendelstein Optical Observations
  46. GRB 240128A: Further Swift-XRT observations
  47. GRB 240214A: Tiled Swift observations
  48. GRB 240214A/1H 0451-560: MAXI/GSC detection
  49. Fermi GRB 240213A: Global MASTER-Net observations report
  50. GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
  51. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  52. GRB 240209A: GOTO optical counterpart candidate
  53. Konus-Wind detection of GRB 240205A (short)
  54. Fermi trigger No 729152364: Global MASTER-Net observations report
  55. Fermi-LAT gamma-ray observations of IceCube-240204A
  56. GRB 240205B: PRIME near infrared detection
  57. GRB240204A: Swift/UVOT Upper Limits
  58. Fermi trigger No 729012023: Global MASTER-Net observations report
  59. Konus-Wind detection of GRB 240205B (long / very soft)
  60. GRB 240205B: VLT/X-shooter redshift
  61. GRB 240205B: BOOTES-6 optical afterglow follow-up
  62. GRB 240205B: ATCA detection of radio counterpart
  63. GRB 240205B: REM detection of the optical/NIR afterglow
  64. GRB 240204A: Mondy optical afterglow observations
  65. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  66. GRB 240205B: Skynet Optical Afterglow Observations
  67. GRB 240205B: BOOTES-7 optical afterglow follow-up
  68. Fermi trigger No 728749569: Global MASTER-Net observations report
  69. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  70. GRB 240205B: Swift detection of a burst
  71. Swift GRB240205.93: Global MASTER-Net observations report
  72. GRB 240204a: Liverpool Telescope optical afterglow detection
  73. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  74. Fermi trigger No 728796365: Global MASTER-Net observations report
  75. GRB 240204A: Montarrenti Observatory optical observations
  76. Fermi GRB 240204A: Global MASTER-Net observations report
  77. Fermi trigger No 728706420: Global MASTER-Net observations report
  78. IceCube Alert 240204.38: Global MASTER-Net observations report
  79. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  80. GRB 240128A: Swift-XRT observations
  81. GRB 240128A: Tiled Swift observations
  82. Fermi GRB 240127A: Global MASTER-Net observations report
  83. GRB 240122A: ATCA detection of radio counterpart
  84. GRB240122A: PRIME near infrared detection
  85. GRB 240123B: Swift/BAT-GUANO detection of a long burst
  86. Fermi-LAT gamma-ray observations of IceCube-240123A
  87. GRB 240123A: further SAO RAS optical observations
  88. IceCube Alert 240123.48: Global MASTER-Net observations report
  89. GRB 240123A: Mondy continued optical observations and the PL decay index
  90. GRB 240123A: SAO RAS optical observations
  91. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  92. Fermi GRB 240123B: Global MASTER-Net observations report
  93. GRB 240122A: Swift/UVOT Upper Limits
  94. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  95. GRB 240123A: Mondy continued optical observations + correction of the GRB name in GCN 35605
  96. GRB 240118A: Swift/UVOT Upper Limits
  97. GRB 240123A: Mondy optical afterglow observations
  98. Swift GRB240123.46: Global MASTER-Net observations report
  99. GRB 240122A: Swift-XRT afterglow detection
  100. GRB 240122A: VLT/X-shooter redshift confirmation

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