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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').
  1. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  2. EP241021a: Upper limit from Konus-Wind observations
  3. GRB 241101A: Swift-BAT refined analysis
  4. GRB 241030A: further SAO RAS optical observations
  5. GRB 241030A: Optical Observations via Virtual Telescope Project
  6. EP241021a: Liverpool Telescope optical follow-up observations
  7. GRB 241030B: Swift-XRT refined Analysis
  8. GRB 241026A: SAO RAS optical observations
  9. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  10. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  11. GRB 241101A: Swift detection of a burst
  12. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  13. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  14. EP241021a: OHP/T193 optical observations
  15. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  16. GRB 241030B: Montarrenti Observatory optical upper limit
  17. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  18. EP241026b: Liverpool Telescope optical follow-up
  19. Fermi trigger No 752083996: Global MASTER-Net observations report
  20. GRB 241030A: SAO RAS optical observations
  21. GRB 241030A: Fermi GBM Observation
  22. EP241021a: AMI-LA radio detection
  23. GRB 241030B : GIT optical upper limits
  24. GRB 241030B: LCOGT Optical Upper Limits
  25. GRB 241030B: Swift-BAT refined analysis
  26. GRB 241030A: Swift-BAT refined analysis
  27. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  28. GRB 241030B: Swift/UVOT Detection
  29. EP EP241030a: Global MASTER-Net observations report
  30. GRB 241029A: LCO optical detection
  31. Fermi trigger No 752006065: Global MASTER-Net observations report
  32. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  33. Swift GRB241030.77: Global MASTER-Net observations report
  34. GRB 241030B: SVOM/GRM observation
  35. GRB 241030B : MITSuME Akeno optical upper limits
  36. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  37. GRB 241030B: SVOM/VT optical afterglow observations
  38. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  39. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  40. GRB241030B: Fermi GBM Observation
  41. GRB 241030B: BTA observations
  42. GRB 241029A: SVOM/VT optical afterglow observations
  43. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  44. GRB 241030B: Enhanced Swift-XRT position
  45. GRB 241030B: optical observations from the INAF Asiago Observatory
  46. EP241021a: Swift-UVOT detection
  47. GRB241030B: GRANDMA/TAROT Upper Limit
  48. GRB 241030A: Swift-XRT refined Analysis
  49. GRB 241030B: SAO RAS optical observations
  50. GRB 241030B: AKO Optical Afterglow Detection
  51. GRB 241030B: Nanshan/HMT optical afterglow detection
  52. GRB 241030B: SVOM/ECLAIRs detection of a burst
  53. GRB 241030B: Prompt enhanced Swift-XRT position
  54. Konus-Wind detection of GRB 241030A
  55. GRB 241030B: Swift detection of a burst
  56. GRB 241030B: Fermi GBM Final Real-time Localization
  57. GRB 241030A: Fermi-LAT detection
  58. GRB 240912A: radio detection with the VLA
  59. Fermi GRB 241030A: Global MASTER-Net observations report
  60. GRB 241030A: AKO Optical Afterglow Detection
  61. Swift GRB 241030A: Global MASTER-Net observations report
  62. GRB 241030A: Swift/UVOT Detection
  63. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  64. GRB 241030A: SVOM/GRM observation
  65. GRB 241026A: Swift-BAT refined analysis
  66. GRB 241030A: SVOM/C-GFT optical observations
  67. GRB 241026A: LBT optical observations
  68. EP241021a: Optical rebrightening observations with Mephisto
  69. EP241026b: EP-FXT follow-up observation
  70. GRB 241030A: Multiband optical detection with Mephisto
  71. GRB 241030A: SVOM/VT optical afterglow observations
  72. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  73. GRB 241030A : MITSuME Akeno optical afterglow detection
  74. GRB 241030A: Enhanced Swift-XRT position
  75. GRB 241029A: GROWTH-India Telescope optical follow up
  76. GRB 241030A: TRT optical observations
  77. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  78. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  79. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  80. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  81. GRB 241030A: Fermi GBM Final Real-time Localization
  82. GRB 241029A: SAO RAS optical observations
  83. GRB 241026A: SAO RAS optical observations
  84. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  85. EP241021a: SAO RAS observations of rebrightening
  86. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  87. EP241021a: ATCA radio observations
  88. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  89. GRB 241026A: Swift/UVOT Upper Limits
  90. GRB 241029A: Swift-XRT observations
  91. GRB 241029A: Fermi GBM Observation
  92. GRB 241029A: AKO Optical Afterglow Detection
  93. GRB 241029A: GOTO optical afterglow detection
  94. EP241021a: continued SOAR observations confirm optical rebrightening
  95. GRB 241029A: MASTER early optical counterpart detection
  96. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  97. GRB 241029A: Mephisto observations
  98. EP 241026b: LBT possible optical counterpart (brightening source)
  99. GRB 241029A: TRT optical afterglow candidate detection
  100. GRB 241029A: Swift ToO observations

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