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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"

36701 results found.

  1. GRB 241030B: Nanshan/HMT optical afterglow detection
  2. GRB 241030B: SVOM/ECLAIRs detection of a burst
  3. GRB 241030B: Prompt enhanced Swift-XRT position
  4. Konus-Wind detection of GRB 241030A
  5. GRB 241030B: Swift detection of a burst
  6. GRB 241030B: Fermi GBM Final Real-time Localization
  7. GRB 241030A: Fermi-LAT detection
  8. GRB 240912A: radio detection with the VLA
  9. Fermi GRB 241030A: Global MASTER-Net observations report
  10. GRB 241030A: AKO Optical Afterglow Detection
  11. Swift GRB 241030A: Global MASTER-Net observations report
  12. GRB 241030A: Swift/UVOT Detection
  13. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  14. GRB 241030A: SVOM/GRM observation
  15. GRB 241026A: Swift-BAT refined analysis
  16. GRB 241030A: SVOM/C-GFT optical observations
  17. GRB 241026A: LBT optical observations
  18. GRB 241030A: Multiband optical detection with Mephisto
  19. GRB 241030A: SVOM/VT optical afterglow observations
  20. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  21. GRB 241030A : MITSuME Akeno optical afterglow detection
  22. GRB 241030A: Enhanced Swift-XRT position
  23. GRB 241029A: GROWTH-India Telescope optical follow up
  24. GRB 241030A: TRT optical observations
  25. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  26. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  27. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  28. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  29. GRB 241030A: Fermi GBM Final Real-time Localization
  30. GRB 241029A: SAO RAS optical observations
  31. GRB 241026A: SAO RAS optical observations
  32. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  33. EP241021a: SAO RAS observations of rebrightening
  34. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  35. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  36. GRB 241026A: Swift/UVOT Upper Limits
  37. GRB 241029A: Swift-XRT observations
  38. GRB 241029A: Fermi GBM Observation
  39. GRB 241029A: AKO Optical Afterglow Detection
  40. GRB 241029A: GOTO optical afterglow detection
  41. GRB 241029A: MASTER early optical counterpart detection
  42. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  43. GRB 241029A: Mephisto observations
  44. EP 241026b: LBT possible optical counterpart (brightening source)
  45. GRB 241029A: TRT optical afterglow candidate detection
  46. GRB 241029A: Swift ToO observations
  47. GRB 241029A: SVOM/GRM observation
  48. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  49. Fermi trigger No 751861204: Global MASTER-Net observations report
  50. GRB 241029A: Fermi GBM Final Real-time Localization
  51. GRB 240821A: Keck/LRIS spectroscopic observations
  52. GRB 241026A: the 100th GRB detected by GRBAlpha
  53. GRB 241026A: TNOT optical counterpart detection
  54. Konus-Wind detection of GRB 241025A
  55. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  56. GRB 241026A: LBT redshift confirmation
  57. GRB 241026A: GECAM detection
  58. GRB 241025A: further SAO RAS optical observations
  59. GRB 241026A: BTA and Zeiss-1000 optical observations
  60. GRB 241026A: SVOM/GRM observation
  61. GRB 241025A: Swift/UVOT Detection
  62. GRB 241026A: GROWTH-India Telescope optical observations
  63. GRB 241026A Fermi GBM Analysis
  64. GRB 241026A: BTA redshift identification of z = 2.79
  65. GRB 241026A: J-band observations with WINTER
  66. GRB 241025A: SAO RAS optical observations
  67. GRB 241026A: Las Cumbres optical detection
  68. GRB 241025A: Mondy optical observations
  69. EP241021a: further SAO RAS optical observations
  70. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  71. GRB 241026A: Swift-XRT refined Analysis
  72. GRB 241026A: Enhanced Swift-XRT position
  73. GRB 241026A: KAIT optical observations
  74. Fermi trigger No 751616906: Global MASTER-Net observations report
  75. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  76. GRB 241026A: SAO RAS observations of possible optical afterglow
  77. Fermi GRB 241026A: Global MASTER-Net observations report
  78. GRB 241026A: Prompt enhanced Swift-XRT position
  79. GRB 241026A: Swift detection of a burst
  80. GRB 241026A: Fermi GBM Final Real-time Localization
  81. GRB241025A: 1.3m DFOT optical afterglow detection
  82. ​GRB 241025A: optical photometry from Konkoly
  83. GRB 241025A: GROWTH-India Telescope optical observations
  84. GRB 241025A: COLIBRÍ Detection of the Afterglow
  85. GRB 241025A: Swift-XRT refined Analysis
  86. GRB 241025C: Fermi GBM Detection
  87. GRB 241025A: Fermi GBM Observation
  88. IPN triangulation of GRB 241022A (short/hard)
  89. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  90. GRB 241025C: Fermi GBM Final Localization
  91. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  92. GRB 241025B: Fermi GBM Final Localization
  93. Fermi trigger No 751563375: Global MASTER-Net observations report
  94. Fermi trigger No 751554401: Global MASTER-Net observations report
  95. EP 241021a: Swift-XRT observations
  96. Fermi GRB 241025A: Global MASTER-Net observations report
  97. Swift GRB 241025A: Global MASTER-Net observations report
  98. EP241025a (GRB 241025A): EP observations update
  99. GRB 241025A : SVOM/VT optical afterglow observations
  100. GRB 241025A: Enhanced Swift-XRT position

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