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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 210704A: Zeiss-1000/SAO-RAS optical observations
  2. GRB 210715B: DDOTI Upper Limits on the Afterglow
  3. Fermi trigger No 648033323: Global MASTER-Net observations report
  4. Fermi trigger No 648024201: Global MASTER-Net observations report
  5. Fermi trigger No 647942198: Global MASTER-Net observations report
  6. GRB 210712A: Swift-BAT refined analysis
  7. GECAM detection of a short burst from SGR J1935+2154
  8. Recent activity of SGR 1935+2154 as observed by CGBM
  9. GRB 210712A: Swift-XRT refined Analysis
  10. GRB 210712A: Swift/UVOT Upper Limits
  11. GRB 210712A: BOOTES-3/YA optical upper limit
  12. Fermi trigger No 647805873: Global MASTER-Net observations report
  13. GRB 210712A: Enhanced Swift-XRT position
  14. GRB 210704A: classification as long GRB and redshift estimating
  15. GRB 210704A: Lowell Discovery Telescope Optical Observations
  16. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  17. GECAM detection of a short burst from SGR J1935+2154
  18. Fermi trigger No 647775795: Global MASTER-Net observations report
  19. GRB 210712A: Swift detection of a burst
  20. GRB 210709A: AstroSat CZTI detection
  21. GRB 210704A: Continued Gemini-North NIR K-band Detections
  22. GRB 210704A: INTEGRAL observations
  23. GRB 210704A: NOT optical observations and color change
  24. GRB210704A: Gemini near-infrared upper limits
  25. Fermi trigger No 647653174: Global MASTER-Net observations report
  26. GRB 210704A: Assy optical afterglow upper limit
  27. Fermi trigger No 647641569: Global MASTER-Net observations report
  28. Fermi trigger No 647624281: Global MASTER-Net observations report
  29. GECAM detection of a short burst from SGR J1935+2154
  30. GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy
  31. MAXI GRB210709.93: Global MASTER-Net observations report
  32. Fermi trigger No 647522278: Global MASTER-Net observations report
  33. GRB 210704A: Gemini-North Infrared Source Detection
  34. GRB 210704A: further TNG optical observations
  35. GRB 210706A: Swift/XRT afterglow confirmation
  36. GECAM detection of a short burst from SGR 1935+2154
  37. GRB 210708B: Swift-BAT refined analysis
  38. Fermi GRB 210709A: Global MASTER-Net observations report
  39. GRB 210709A: Fermi GBM Final Real-time Localization
  40. Swift GRB 210708B: Global MASTER-Net observations report
  41. GRB 210708A: Swift/UVOT Upper Limits
  42. GRB 210702A: ATCA detection
  43. GRB 210702A: ALMA detection
  44. GRB 210708A: Swift-BAT refined analysis
  45. Fermi GBM Sub-Threshold Detection of GRB 210708A
  46. Fermi GBM Sub-Threshold Detection of GRB 210707A
  47. IceCube-210629A - Spectroscopic observation of AT2021osi
  48. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  49. GRB 210708B: Swift detection of a possible burst
  50. GRB 210708A: Swift-XRT refined Analysis
  51. GECAM detection of a short burst from SGR 1935+2154
  52. GRB 210707A: A long GRB detected by INTEGRAL
  53. GRB 210708A: Swift detection of a burst
  54. Swift GRB210708.10: Global MASTER-Net observations report
  55. GRB 210704A: CAHA 2.2m telescope optical limit
  56. Fermi trigger No 647365516: Global MASTER-Net observations report
  57. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 6
  58. Fermi trigger No 647271699: Global MASTER-Net observations report
  59. Fermi GBM Observations of SGR J1935+2154
  60. Swift-BAT detection of a burst from SGR 1935+2154
  61. GRB 210706A: Fermi GBM observation
  62. GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
  63. Konus-Wind detection of GRB 210706A
  64. GRB 210706A: GIT optical upper limits
  65. GRB 210704A: OAJ T80 multi-color detections
  66. GECAM detection of a bright short burst from SGR 1935+2154
  67. GRB 210706A: Swift-XRT afterglow detection
  68. Integral GRB210707.02: Global MASTER-Net observations report
  69. GRB 210706A: Swift ToO observations
  70. Fermi trigger No 647252274: Global MASTER-Net observations report
  71. INTEGRAL detection of a burst from SGR 1935+2154
  72. Integral GRB210706.72: Global MASTER-Net observations report
  73. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  74. GRB 210704A: OSIRIS/GTC spectroscopy
  75. GRB 210704A: CAHA 2.2m Afterglow Detection
  76. GRB 210704A: RATIR optical upper limits
  77. GRB 210704A: Swift/UVOT Upper Limits
  78. Konus-Wind detection of GRB 210704A
  79. GRB 210704B: AstroSat CZTI detection
  80. GRB 210619B: ALMA detection
  81. GRB 210704A: TNG detection of the optical afterglow candidate
  82. GRB 210704A: Assy optical afterglow candidate
  83. GRB 210704A: DDOTI upper limit
  84. GRB 210704B: Fermi GBM detection
  85. GRB 210704A: possible local hosts
  86. GRB 210704A: Fermi GBM detection
  87. GRB 210704A: Swift-XRT afterglow detection
  88. GRB 210704A: AstroSat CZTI detection
  89. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  90. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  91. GRB 210704A: Fermi-LAT detection
  92. GRB 210704A: Swift ToO observations
  93. GRB 210705A: AGILE/MCAL detection of a burst
  94. GRB 210704A: AGILE/MCAL detection
  95. Fermi trigger No 647108723: Global MASTER-Net observations report
  96. Fermi trigger No 647120009: Global MASTER-Net observations report
  97. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  98. GRB 210702A, Swift-BAT refined analysis
  99. GRB 210702A: BOOTES-3/YA optical counterpart observations
  100. Konus-Wind detection of GRB 210702A

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