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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 648024201: Global MASTER-Net observations report
  2. Fermi trigger No 647942198: Global MASTER-Net observations report
  3. GRB 210712A: Swift-BAT refined analysis
  4. GECAM detection of a short burst from SGR J1935+2154
  5. Recent activity of SGR 1935+2154 as observed by CGBM
  6. GRB 210712A: Swift-XRT refined Analysis
  7. GRB 210712A: Swift/UVOT Upper Limits
  8. GRB 210712A: BOOTES-3/YA optical upper limit
  9. Fermi trigger No 647805873: Global MASTER-Net observations report
  10. GRB 210712A: Enhanced Swift-XRT position
  11. GRB 210704A: classification as long GRB and redshift estimating
  12. GRB 210704A: Lowell Discovery Telescope Optical Observations
  13. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  14. GECAM detection of a short burst from SGR J1935+2154
  15. Fermi trigger No 647775795: Global MASTER-Net observations report
  16. GRB 210712A: Swift detection of a burst
  17. GRB 210709A: AstroSat CZTI detection
  18. GRB 210704A: Continued Gemini-North NIR K-band Detections
  19. GRB 210704A: INTEGRAL observations
  20. GRB 210704A: NOT optical observations and color change
  21. GRB210704A: Gemini near-infrared upper limits
  22. Fermi trigger No 647653174: Global MASTER-Net observations report
  23. GRB 210704A: Assy optical afterglow upper limit
  24. Fermi trigger No 647641569: Global MASTER-Net observations report
  25. Fermi trigger No 647624281: Global MASTER-Net observations report
  26. GECAM detection of a short burst from SGR J1935+2154
  27. GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy
  28. MAXI GRB210709.93: Global MASTER-Net observations report
  29. Fermi trigger No 647522278: Global MASTER-Net observations report
  30. GRB 210704A: Gemini-North Infrared Source Detection
  31. GRB 210704A: further TNG optical observations
  32. GRB 210706A: Swift/XRT afterglow confirmation
  33. GECAM detection of a short burst from SGR 1935+2154
  34. GRB 210708B: Swift-BAT refined analysis
  35. Fermi GRB 210709A: Global MASTER-Net observations report
  36. GRB 210709A: Fermi GBM Final Real-time Localization
  37. Swift GRB 210708B: Global MASTER-Net observations report
  38. GRB 210708A: Swift/UVOT Upper Limits
  39. GRB 210702A: ATCA detection
  40. GRB 210702A: ALMA detection
  41. GRB 210708A: Swift-BAT refined analysis
  42. Fermi GBM Sub-Threshold Detection of GRB 210708A
  43. Fermi GBM Sub-Threshold Detection of GRB 210707A
  44. IceCube-210629A - Spectroscopic observation of AT2021osi
  45. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  46. GRB 210708B: Swift detection of a possible burst
  47. GRB 210708A: Swift-XRT refined Analysis
  48. GECAM detection of a short burst from SGR 1935+2154
  49. GRB 210707A: A long GRB detected by INTEGRAL
  50. GRB 210708A: Swift detection of a burst
  51. Swift GRB210708.10: Global MASTER-Net observations report
  52. GRB 210704A: CAHA 2.2m telescope optical limit
  53. Fermi trigger No 647365516: Global MASTER-Net observations report
  54. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 6
  55. Fermi trigger No 647271699: Global MASTER-Net observations report
  56. Fermi GBM Observations of SGR J1935+2154
  57. Swift-BAT detection of a burst from SGR 1935+2154
  58. GRB 210706A: Fermi GBM observation
  59. GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
  60. Konus-Wind detection of GRB 210706A
  61. GRB 210706A: GIT optical upper limits
  62. GRB 210704A: OAJ T80 multi-color detections
  63. GECAM detection of a bright short burst from SGR 1935+2154
  64. GRB 210706A: Swift-XRT afterglow detection
  65. Integral GRB210707.02: Global MASTER-Net observations report
  66. GRB 210706A: Swift ToO observations
  67. Fermi trigger No 647252274: Global MASTER-Net observations report
  68. INTEGRAL detection of a burst from SGR 1935+2154
  69. Integral GRB210706.72: Global MASTER-Net observations report
  70. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  71. GRB 210704A: OSIRIS/GTC spectroscopy
  72. GRB 210704A: CAHA 2.2m Afterglow Detection
  73. GRB 210704A: RATIR optical upper limits
  74. GRB 210704A: Swift/UVOT Upper Limits
  75. Konus-Wind detection of GRB 210704A
  76. GRB 210704B: AstroSat CZTI detection
  77. GRB 210619B: ALMA detection
  78. GRB 210704A: TNG detection of the optical afterglow candidate
  79. GRB 210704A: Assy optical afterglow candidate
  80. GRB 210704A: DDOTI upper limit
  81. GRB 210704B: Fermi GBM detection
  82. GRB 210704A: possible local hosts
  83. GRB 210704A: Fermi GBM detection
  84. GRB 210704A: Swift-XRT afterglow detection
  85. GRB 210704A: AstroSat CZTI detection
  86. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  87. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  88. GRB 210704A: Fermi-LAT detection
  89. GRB 210704A: Swift ToO observations
  90. GRB 210705A: AGILE/MCAL detection of a burst
  91. GRB 210704A: AGILE/MCAL detection
  92. Fermi trigger No 647108723: Global MASTER-Net observations report
  93. Fermi trigger No 647120009: Global MASTER-Net observations report
  94. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  95. GRB 210702A, Swift-BAT refined analysis
  96. GRB 210702A: BOOTES-3/YA optical counterpart observations
  97. Konus-Wind detection of GRB 210702A
  98. GRB 210702A: Chilescope optical observations
  99. GRB 210702A: iTelescope optical afterglow observations
  100. GRB 210702A: AGILE detection

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