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

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