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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"

36790 results found.

  1. GRB 241025A: LBT optical observations
  2. GRB241105A: Gemini-South Optical Afterglow Detection
  3. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  4. GRB 241105A: Swift/UVOT Detection
  5. EP241101a: CrAO ZTSH optical observations
  6. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  7. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  8. GRB 241105A: BOOTES-7 optical detection
  9. GRB 241030A: Mondy optical observations
  10. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  11. Konus-Wind detection of GRB 241105A (short with extended emission)
  12. Konus-Wind detection of GRB 241021A
  13. GRB 241105A: SVOM/VT optical afterglow observations
  14. GRB 241105A: Swift-XRT afterglow detection
  15. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  16. GRB 241104A: Swift-XRT observations
  17. GRB 240511A: LCO upper limits
  18. GRB 241104A: Fermi GBM Observation
  19. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  20. GRB 241105A: Swift ToO observations
  21. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  22. GRB 241104A: Swift ToO observations
  23. GRB 241104A: NOT optical non-detection
  24. GRB 241105A: GOTO tentative optical counterpart candidate
  25. Fermi GRB 241105A: Global MASTER-Net observations report
  26. GRB 241104A: SVOM/VT optical candidate
  27. GRB 241105A: Fermi GBM Final Real-time Localization
  28. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  29. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  30. GRB 241104A: SVOM/GRM observation
  31. EP241104a: EP detection of GRB 241104A X-ray emission
  32. GRB 241010A: host galaxy redshift z = 0.977
  33. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  34. GRB 240821A: further radio observations with the VLA
  35. Fermi GRB 241104A: Global MASTER-Net observations report
  36. GRB 241104A: Fermi GBM Final Real-time Localization
  37. GRB 241030A: GRBAlpha detection
  38. Fermi trigger No 752365806: Global MASTER-Net observations report
  39. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  40. GRB 241030A: Rapid release of TESS data.
  41. GRB 241029A: GRBAlpha detection
  42. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  43. GRB241030A: OHP/T193 optical observations
  44. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  45. Swift GRB 241101A: Global MASTER-Net observations report
  46. GRB 241101A: FRAM-ORM optical limit
  47. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  48. EP241021a: Upper limit from Konus-Wind observations
  49. GRB 241101A: Swift-BAT refined analysis
  50. GRB 241030A: further SAO RAS optical observations
  51. GRB 241030A: Optical Observations via Virtual Telescope Project
  52. GRB 241030B: Swift-XRT refined Analysis
  53. GRB 241026A: SAO RAS optical observations
  54. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  55. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  56. GRB 241101A: Swift detection of a burst
  57. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  58. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  59. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  60. GRB 241030B: Montarrenti Observatory optical upper limit
  61. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  62. Fermi trigger No 752083996: Global MASTER-Net observations report
  63. GRB 241030A: SAO RAS optical observations
  64. GRB 241030A: Fermi GBM Observation
  65. GRB 241030B : GIT optical upper limits
  66. GRB 241030B: LCOGT Optical Upper Limits
  67. GRB 241030B: Swift-BAT refined analysis
  68. GRB 241030A: Swift-BAT refined analysis
  69. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  70. GRB 241030B: Swift/UVOT Detection
  71. GRB 241029A: LCO optical detection
  72. Fermi trigger No 752006065: Global MASTER-Net observations report
  73. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  74. GRB 241030B: SVOM/GRM observation
  75. GRB 241030B : MITSuME Akeno optical upper limits
  76. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  77. GRB 241030B: SVOM/VT optical afterglow observations
  78. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  79. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  80. GRB241030B: Fermi GBM Observation
  81. GRB 241030B: BTA observations
  82. GRB 241029A: SVOM/VT optical afterglow observations
  83. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  84. GRB 241030B: Enhanced Swift-XRT position
  85. GRB 241030B: optical observations from the INAF Asiago Observatory
  86. GRB241030B: GRANDMA/TAROT Upper Limit
  87. GRB 241030A: Swift-XRT refined Analysis
  88. GRB 241030B: SAO RAS optical observations
  89. GRB 241030B: AKO Optical Afterglow Detection
  90. GRB 241030B: Nanshan/HMT optical afterglow detection
  91. GRB 241030B: SVOM/ECLAIRs detection of a burst
  92. GRB 241030B: Prompt enhanced Swift-XRT position
  93. Konus-Wind detection of GRB 241030A
  94. GRB 241030B: Swift detection of a burst
  95. GRB 241030B: Fermi GBM Final Real-time Localization
  96. GRB 241030A: Fermi-LAT detection
  97. GRB 240912A: radio detection with the VLA
  98. Fermi GRB 241030A: Global MASTER-Net observations report
  99. GRB 241030A: AKO Optical Afterglow Detection
  100. Swift GRB 241030A: Global MASTER-Net observations report

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