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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

5394 results found.

  1. IceCube Alert 220220.60: Global MASTER-Net observations report
  2. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  3. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  4. Fermi trigger No 666489765: Global MASTER-Net observations report
  5. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  6. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 220128A: AstroSat CZTI detection
  9. Konus-Wind detection of GRB 220128A
  10. IPN triangulation of GRB 220128A (long)
  11. Konus-Wind detection of GRB 220124A
  12. IPN triangulation of GRB 220124A
  13. GRB 220124A: AstroSat CZTI detection of a bright long GRB
  14. IPN triangulation of a bright burst from SGR 1935+2154
  15. IPN triangulation of GRB 211226A
  16. GRB 220118A: MITSuME Akeno optical observation
  17. IceCube-220115A: Upper limits from a search for additional neutrino events in IceCube
  18. Fermi trigger No 663966693: Global MASTER-Net observations report
  19. Fermi-GBM Observations of Recent Bursting Activity from SGR J1935+2154
  20. GECAM observations of a series of bursts from SGR J1935+2154
  21. GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow
  22. Fermi trigger No 663658976: Global MASTER-Net observations report
  23. Fermi GRB 220111A: Global MASTER-Net observations report
  24. GRB 220107A: SAO RAS optical observations
  25. GRB 220101A: Additional Liverpool telescope photometry
  26. GRB 220107A: SAO RAS optical observations
  27. Fermi GRB 220107A: Global MASTER-Net observations report
  28. Fermi trigger No 663129379: Global MASTER-Net observations report
  29. GRB 220101A: LCO Continued Optical Observations
  30. Fermi GRB 220103A: Global MASTER-Net observations report
  31. GRB 220103A: Fermi GBM Final Real-time Localization
  32. Alert from the HAWC Burst Monitor HAWC-220103A
  33. GRB 220101A: LCO Optical Observations
  34. GRB 220101A: Asiago spectroscopic and photometric detection
  35. GRB 211229A: Fermi GBM observation
  36. Fermi GRB 211229A: Global MASTER-Net observations report
  37. GRB 211229A: Fermi GBM Final Real-time Localization
  38. Konus-Wind detection of the intermediate flare from SGR 1935+2154
  39. Swift GRB211227.98: Global MASTER-Net observations report
  40. GRB 211225A: MITSuME Akeno optical upper limits
  41. Swift GRB 211225B: Global MASTER-Net observations report
  42. Fermi GRB 211225C: Global MASTER-Net observations report
  43. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  44. AGILE observations of a bright burst from SGR 1935+2154
  45. GRB 211218A: MITSuME Akeno optical upper limits
  46. GRB 211221A: MeerLICHT optical limits
  47. Fermi GRB 211219B: Global MASTER-Net observations report
  48. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  49. MAXI GRB211218.04: Global MASTER-Net observations report
  50. Fermi GRB 211216A: Global MASTER-Net observations report
  51. GRB 211211A: SAO RAS optical observations
  52. Swift GRB 211211A: Global MASTER-Net observations report
  53. GRB 211212A: Fermi GBM Final Real-time Localization
  54. Fermi GRB 211211B: Global MASTER-Net observations report
  55. Fermi trigger No 660868196: Global MASTER-Net observations report
  56. Fermi trigger No 660736561: Global MASTER-Net observations report
  57. Fermi GRB 211204B: Global MASTER-Net observations report
  58. Fermi GRB 211204A: Global MASTER-Net observations report
  59. GRB 211204A: Fermi GBM Final Real-time Localization
  60. Swift GRB 211203A: Global MASTER-Net observations report
  61. GRB 211203A: Swift detection of a burst
  62. Fermi GRB 211130A: Global MASTER-Net observations report
  63. GRB 211120548: Fermi GBM observation
  64. GRB 211118A: Fermi GBM detection
  65. HAWC-211123A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  66. Alert from the HAWC Burst Monitor HAWC-211123A
  67. Fermi trigger No 659106591: Global MASTER-Net observations report
  68. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  69. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  70. Fermi trigger No 658755664: Global MASTER-Net observations report
  71. Fermi GRB 211112A: Global MASTER-Net observations report
  72. GRB 211110A: AstroSat CZTI detection
  73. Fermi trigger No 658214822: Global MASTER-Net observations report
  74. Fermi GRB 211109B: Global MASTER-Net observations report
  75. GRB 211102A: BALROG localization (Fermi Trigger 657533168 / GRB 211102338)
  76. GRB 211102A: Fermi GBM Final Real-time Localization
  77. Fermi GRB 211031A: Global MASTER-Net observations report
  78. GRB 211018A: Swift-XRT observations
  79. GRB 210610B: Sintesz-Newton/CrAO optical observations
  80. GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
  81. Fermi GRB 211024A: Global MASTER-Net observations report
  82. IPN Triangulation of GRB 210927B
  83. Fermi GRB 211019A: Global MASTER-Net observations report
  84. Fermi trigger No 655673024: Global MASTER-Net observations report
  85. Fermi trigger No 655401471: Global MASTER-Net observations report
  86. Fermi trigger No 654854799: Global MASTER-Net observations report
  87. Fermi GRB 210929B: Global MASTER-Net observations report
  88. GRB 210929A: Fermi GBM Final Real-time Localization
  89. IPN triangulation of GRB 210925B
  90. GRB 210919A OSN 1.5m Source Confirmation
  91. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  92. GRB 210919A: NOT upper limits
  93. GRB 210917A: Fermi GBM Final Real-time Localization
  94. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  95. Fermi trigger No 653066776: Global MASTER-Net observations report
  96. Fermi trigger No 653084584: Global MASTER-Net observations report
  97. Fermi trigger No 653083551: Global MASTER-Net observations report
  98. Fermi trigger No 653072474: Global MASTER-Net observations report
  99. Fermi trigger No 653054042: Global MASTER-Net observations report
  100. Fermi trigger No 653049776: Global MASTER-Net observations report

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