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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. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  2. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  3. GRB241030A: OHP/T193 optical observations
  4. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  5. EP241101a: EP-WXT detection of a fast X-ray transient
  6. Swift GRB 241101A: Global MASTER-Net observations report
  7. GRB 241101A: FRAM-ORM optical limit
  8. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  9. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  10. EP241021a: Upper limit from Konus-Wind observations
  11. GRB 241101A: Swift-BAT refined analysis
  12. GRB 241030A: further SAO RAS optical observations
  13. GRB 241030A: Optical Observations via Virtual Telescope Project
  14. EP241021a: Liverpool Telescope optical follow-up observations
  15. GRB 241030B: Swift-XRT refined Analysis
  16. GRB 241026A: SAO RAS optical observations
  17. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  18. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  19. GRB 241101A: Swift detection of a burst
  20. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  21. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  22. EP241021a: OHP/T193 optical observations
  23. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  24. GRB 241030B: Montarrenti Observatory optical upper limit
  25. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  26. EP241026b: Liverpool Telescope optical follow-up
  27. Fermi trigger No 752083996: Global MASTER-Net observations report
  28. GRB 241030A: SAO RAS optical observations
  29. GRB 241030A: Fermi GBM Observation
  30. EP241021a: AMI-LA radio detection
  31. GRB 241030B : GIT optical upper limits
  32. GRB 241030B: LCOGT Optical Upper Limits
  33. GRB 241030B: Swift-BAT refined analysis
  34. GRB 241030A: Swift-BAT refined analysis
  35. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  36. GRB 241030B: Swift/UVOT Detection
  37. EP EP241030a: Global MASTER-Net observations report
  38. GRB 241029A: LCO optical detection
  39. Fermi trigger No 752006065: Global MASTER-Net observations report
  40. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  41. Swift GRB241030.77: Global MASTER-Net observations report
  42. GRB 241030B: SVOM/GRM observation
  43. GRB 241030B : MITSuME Akeno optical upper limits
  44. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  45. GRB 241030B: SVOM/VT optical afterglow observations
  46. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  47. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  48. GRB241030B: Fermi GBM Observation
  49. GRB 241030B: BTA observations
  50. GRB 241029A: SVOM/VT optical afterglow observations
  51. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  52. GRB 241030B: Enhanced Swift-XRT position
  53. GRB 241030B: optical observations from the INAF Asiago Observatory
  54. EP241021a: Swift-UVOT detection
  55. GRB241030B: GRANDMA/TAROT Upper Limit
  56. GRB 241030A: Swift-XRT refined Analysis
  57. GRB 241030B: SAO RAS optical observations
  58. GRB 241030B: AKO Optical Afterglow Detection
  59. GRB 241030B: Nanshan/HMT optical afterglow detection
  60. GRB 241030B: SVOM/ECLAIRs detection of a burst
  61. GRB 241030B: Prompt enhanced Swift-XRT position
  62. Konus-Wind detection of GRB 241030A
  63. GRB 241030B: Swift detection of a burst
  64. GRB 241030B: Fermi GBM Final Real-time Localization
  65. GRB 241030A: Fermi-LAT detection
  66. GRB 240912A: radio detection with the VLA
  67. Fermi GRB 241030A: Global MASTER-Net observations report
  68. GRB 241030A: AKO Optical Afterglow Detection
  69. Swift GRB 241030A: Global MASTER-Net observations report
  70. GRB 241030A: Swift/UVOT Detection
  71. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  72. GRB 241030A: SVOM/GRM observation
  73. GRB 241026A: Swift-BAT refined analysis
  74. GRB 241030A: SVOM/C-GFT optical observations
  75. GRB 241026A: LBT optical observations
  76. EP241021a: Optical rebrightening observations with Mephisto
  77. EP241026b: EP-FXT follow-up observation
  78. GRB 241030A: Multiband optical detection with Mephisto
  79. GRB 241030A: SVOM/VT optical afterglow observations
  80. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  81. GRB 241030A : MITSuME Akeno optical afterglow detection
  82. GRB 241030A: Enhanced Swift-XRT position
  83. GRB 241029A: GROWTH-India Telescope optical follow up
  84. GRB 241030A: TRT optical observations
  85. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  86. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  87. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  88. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  89. GRB 241030A: Fermi GBM Final Real-time Localization
  90. GRB 241029A: SAO RAS optical observations
  91. GRB 241026A: SAO RAS optical observations
  92. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  93. EP241021a: SAO RAS observations of rebrightening
  94. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  95. EP241021a: ATCA radio observations
  96. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  97. GRB 241026A: Swift/UVOT Upper Limits
  98. GRB 241029A: Swift-XRT observations
  99. GRB 241029A: Fermi GBM Observation
  100. GRB 241029A: AKO Optical Afterglow Detection

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