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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"

11546 results found.

  1. GRB 241030A: Fermi GBM Observation
  2. GRB 241030B : GIT optical upper limits
  3. GRB 241030B: LCOGT Optical Upper Limits
  4. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  5. Fermi trigger No 752006065: Global MASTER-Net observations report
  6. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  7. GRB 241030B: SVOM/GRM observation
  8. GRB 241030B : MITSuME Akeno optical upper limits
  9. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  10. GRB 241030B: SVOM/VT optical afterglow observations
  11. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  12. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  13. GRB241030B: Fermi GBM Observation
  14. GRB 241030B: BTA observations
  15. GRB 241029A: SVOM/VT optical afterglow observations
  16. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  17. GRB 241030B: optical observations from the INAF Asiago Observatory
  18. GRB 241030B: SAO RAS optical observations
  19. GRB 241030B: AKO Optical Afterglow Detection
  20. GRB 241030B: Nanshan/HMT optical afterglow detection
  21. GRB 241030B: SVOM/ECLAIRs detection of a burst
  22. Konus-Wind detection of GRB 241030A
  23. GRB 241030B: Fermi GBM Final Real-time Localization
  24. GRB 241030A: Fermi-LAT detection
  25. GRB 240912A: radio detection with the VLA
  26. Fermi GRB 241030A: Global MASTER-Net observations report
  27. GRB 241030A: AKO Optical Afterglow Detection
  28. GRB 241030A: Swift/UVOT Detection
  29. GRB 241030A: SVOM/GRM observation
  30. GRB 241030A: SVOM/C-GFT optical observations
  31. GRB 241030A: Multiband optical detection with Mephisto
  32. GRB 241030A: SVOM/VT optical afterglow observations
  33. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  34. GRB 241030A : MITSuME Akeno optical afterglow detection
  35. GRB 241029A: GROWTH-India Telescope optical follow up
  36. GRB 241030A: TRT optical observations
  37. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  38. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  39. GRB 241030A: Fermi GBM Final Real-time Localization
  40. GRB 241029A: SAO RAS optical observations
  41. GRB 241026A: SAO RAS optical observations
  42. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  43. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  44. GRB 241029A: Fermi GBM Observation
  45. GRB 241029A: AKO Optical Afterglow Detection
  46. GRB 241029A: GOTO optical afterglow detection
  47. GRB 241029A: MASTER early optical counterpart detection
  48. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  49. GRB 241029A: Mephisto observations
  50. GRB 241029A: TRT optical afterglow candidate detection
  51. GRB 241029A: SVOM/GRM observation
  52. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  53. Fermi trigger No 751861204: Global MASTER-Net observations report
  54. GRB 241029A: Fermi GBM Final Real-time Localization
  55. GRB 241026A: the 100th GRB detected by GRBAlpha
  56. GRB 241026A: TNOT optical counterpart detection
  57. Konus-Wind detection of GRB 241025A
  58. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  59. GRB 241026A: GECAM detection
  60. GRB 241025A: further SAO RAS optical observations
  61. GRB 241026A: BTA and Zeiss-1000 optical observations
  62. GRB 241026A: SVOM/GRM observation
  63. GRB 241026A: GROWTH-India Telescope optical observations
  64. GRB 241026A Fermi GBM Analysis
  65. GRB 241026A: BTA redshift identification of z = 2.79
  66. GRB 241026A: J-band observations with WINTER
  67. GRB 241026A: Las Cumbres optical detection
  68. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  69. Fermi trigger No 751616906: Global MASTER-Net observations report
  70. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  71. GRB 241026A: SAO RAS observations of possible optical afterglow
  72. Fermi GRB 241026A: Global MASTER-Net observations report
  73. GRB 241026A: Fermi GBM Final Real-time Localization
  74. ​GRB 241025A: optical photometry from Konkoly
  75. GRB 241025A: GROWTH-India Telescope optical observations
  76. GRB 241025A: COLIBRÍ Detection of the Afterglow
  77. GRB 241025C: Fermi GBM Detection
  78. GRB 241025A: Fermi GBM Observation
  79. GRB 241025C: Fermi GBM Final Localization
  80. GRB 241025B: Fermi GBM Final Localization
  81. Fermi trigger No 751563375: Global MASTER-Net observations report
  82. Fermi trigger No 751554401: Global MASTER-Net observations report
  83. Fermi GRB 241025A: Global MASTER-Net observations report
  84. EP241025a (GRB 241025A): EP observations update
  85. GRB 241025A : SVOM/VT optical afterglow observations
  86. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  87. GRB 241025A: DDOTI Afterglow detection
  88. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  89. GRB 241025A: SVOM/GRM observation
  90. GRB 241025A: TRT optical afterglow observation
  91. Fermi GRB 241024B: Global MASTER-Net observations report
  92. GRB 241025A: Fermi GBM Final Real-time Localization
  93. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  94. GRB 241024B: Fermi GBM Final Localization
  95. EP241021a: No Detection in Fermi-GBM Observation
  96. GRB 241024A: Fermi GBM Final Localisation
  97. Fermi trigger No 751449953: Global MASTER-Net observations report
  98. GRB 241018A: REM optical/NIR upper limits
  99. GRB 241016B: Fermi GBM Observations
  100. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst

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