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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. Fermi trigger No 647942198: Global MASTER-Net observations report
  2. GRB 210712A: Swift-BAT refined analysis
  3. GECAM detection of a short burst from SGR J1935+2154
  4. Recent activity of SGR 1935+2154 as observed by CGBM
  5. GRB 210712A: Swift-XRT refined Analysis
  6. GRB 210712A: Swift/UVOT Upper Limits
  7. GRB 210712A: BOOTES-3/YA optical upper limit
  8. Fermi trigger No 647805873: Global MASTER-Net observations report
  9. GRB 210712A: Enhanced Swift-XRT position
  10. GRB 210704A: classification as long GRB and redshift estimating
  11. GRB 210704A: Lowell Discovery Telescope Optical Observations
  12. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  13. GECAM detection of a short burst from SGR J1935+2154
  14. Fermi trigger No 647775795: Global MASTER-Net observations report
  15. GRB 210712A: Swift detection of a burst
  16. GRB 210709A: AstroSat CZTI detection
  17. GRB 210704A: Continued Gemini-North NIR K-band Detections
  18. GRB 210704A: INTEGRAL observations
  19. GRB 210704A: NOT optical observations and color change
  20. GRB210704A: Gemini near-infrared upper limits
  21. Fermi trigger No 647653174: Global MASTER-Net observations report
  22. GRB 210704A: Assy optical afterglow upper limit
  23. Fermi trigger No 647641569: Global MASTER-Net observations report
  24. Fermi trigger No 647624281: Global MASTER-Net observations report
  25. GECAM detection of a short burst from SGR J1935+2154
  26. GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy
  27. MAXI GRB210709.93: Global MASTER-Net observations report
  28. Fermi trigger No 647522278: Global MASTER-Net observations report
  29. GRB 210704A: Gemini-North Infrared Source Detection
  30. GRB 210704A: further TNG optical observations
  31. GRB 210706A: Swift/XRT afterglow confirmation
  32. GECAM detection of a short burst from SGR 1935+2154
  33. GRB 210708B: Swift-BAT refined analysis
  34. Fermi GRB 210709A: Global MASTER-Net observations report
  35. GRB 210709A: Fermi GBM Final Real-time Localization
  36. Swift GRB 210708B: Global MASTER-Net observations report
  37. GRB 210708A: Swift/UVOT Upper Limits
  38. GRB 210702A: ATCA detection
  39. GRB 210702A: ALMA detection
  40. GRB 210708A: Swift-BAT refined analysis
  41. Fermi GBM Sub-Threshold Detection of GRB 210708A
  42. Fermi GBM Sub-Threshold Detection of GRB 210707A
  43. IceCube-210629A - Spectroscopic observation of AT2021osi
  44. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  45. GRB 210708B: Swift detection of a possible burst
  46. GRB 210708A: Swift-XRT refined Analysis
  47. GECAM detection of a short burst from SGR 1935+2154
  48. GRB 210707A: A long GRB detected by INTEGRAL
  49. GRB 210708A: Swift detection of a burst
  50. Swift GRB210708.10: Global MASTER-Net observations report
  51. GRB 210704A: CAHA 2.2m telescope optical limit
  52. Fermi trigger No 647365516: Global MASTER-Net observations report
  53. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 6
  54. Fermi trigger No 647271699: Global MASTER-Net observations report
  55. Fermi GBM Observations of SGR J1935+2154
  56. Swift-BAT detection of a burst from SGR 1935+2154
  57. GRB 210706A: Fermi GBM observation
  58. GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
  59. Konus-Wind detection of GRB 210706A
  60. GRB 210706A: GIT optical upper limits
  61. GRB 210704A: OAJ T80 multi-color detections
  62. GECAM detection of a bright short burst from SGR 1935+2154
  63. GRB 210706A: Swift-XRT afterglow detection
  64. Integral GRB210707.02: Global MASTER-Net observations report
  65. GRB 210706A: Swift ToO observations
  66. Fermi trigger No 647252274: Global MASTER-Net observations report
  67. INTEGRAL detection of a burst from SGR 1935+2154
  68. Integral GRB210706.72: Global MASTER-Net observations report
  69. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  70. GRB 210704A: OSIRIS/GTC spectroscopy
  71. GRB 210704A: CAHA 2.2m Afterglow Detection
  72. GRB 210704A: RATIR optical upper limits
  73. GRB 210704A: Swift/UVOT Upper Limits
  74. Konus-Wind detection of GRB 210704A
  75. GRB 210704B: AstroSat CZTI detection
  76. GRB 210619B: ALMA detection
  77. GRB 210704A: TNG detection of the optical afterglow candidate
  78. GRB 210704A: Assy optical afterglow candidate
  79. GRB 210704A: DDOTI upper limit
  80. GRB 210704B: Fermi GBM detection
  81. GRB 210704A: possible local hosts
  82. GRB 210704A: Fermi GBM detection
  83. GRB 210704A: Swift-XRT afterglow detection
  84. GRB 210704A: AstroSat CZTI detection
  85. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  86. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  87. GRB 210704A: Fermi-LAT detection
  88. GRB 210704A: Swift ToO observations
  89. GRB 210705A: AGILE/MCAL detection of a burst
  90. GRB 210704A: AGILE/MCAL detection
  91. Fermi trigger No 647108723: Global MASTER-Net observations report
  92. Fermi trigger No 647120009: Global MASTER-Net observations report
  93. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  94. GRB 210702A, Swift-BAT refined analysis
  95. GRB 210702A: BOOTES-3/YA optical counterpart observations
  96. Konus-Wind detection of GRB 210702A
  97. GRB 210702A: Chilescope optical observations
  98. GRB 210702A: iTelescope optical afterglow observations
  99. GRB 210702A: AGILE detection
  100. GRB 210702A: CALET Gamma-Ray Burst Monitor detection

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