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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"

3039 results found.

  1. LIGO/Virgo S230609a: Global MASTER-Net observations report
  2. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  3. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  4. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  5. LIGO/Virgo S230525a: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  7. IceCube Alert 230524.47: Global MASTER-Net observations report
  8. Fermi trigger No 706610076: Global MASTER-Net observations report
  9. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230523A
  10. LIGO/Virgo S230522a: Global MASTER-Net observations report
  11. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  13. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  14. GRB 230520A: MAXI/GSC detection
  15. LIGO/Virgo S230518h: Global MASTER-Net observations report
  16. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  17. GRB 230506C: TSHAO possible afterglow candidate
  18. GRB 230420A: Swift-BAT refined analysis
  19. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  20. GRB 230409B: Mondy optical upper limit
  21. Fermi trigger No 702745263: Global MASTER-Net observations report
  22. GRB 230409B: Swift detection of a burst
  23. Fermi trigger No 701883729: Global MASTER-Net observations report
  24. GRB 230328B: Swift-BAT refined analysis
  25. GRB 230328B: Nanshan/NEXT optical upper limit
  26. Fermi GRB 230328A: Global MASTER-Net observations report
  27. Fermi trigger No 701321709: Global MASTER-Net observations report
  28. Konus-Wind detection of GRB 230309A
  29. GRB 230322A: Fermi GBM Final Real-time Localization
  30. Fermi GRB 230313A: Global MASTER-Net observations report
  31. Further improved IPN localization for GRB 230307A
  32. Fermi GRB 230308A: Global MASTER-Net observations report
  33. Fermi trigger No 699294715: Global MASTER-Net observations report
  34. Fermi trigger No 699311646: Global MASTER-Net observations report
  35. Fermi GRB 230220B: Global MASTER-Net observations report
  36. IceCube-230217A: BOOTES-4/MET Optical Observations
  37. IPN triangulation of GRB 230209B
  38. Fermi trigger No 697926015: Global MASTER-Net observations report
  39. Fermi trigger No 697904388: Global MASTER-Net observations report
  40. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  41. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  42. Fermi trigger No 697098930: Global MASTER-Net observations report
  43. GRB 221216A: Swift-BAT refined analysis
  44. Fermi GRB 230201A: Global MASTER-Net observations report
  45. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
  46. Fermi GRB 230112A: Global MASTER-Net observations report
  47. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  48. Fermi GRB 221226A: Global MASTER-Net observations report
  49. Fermi GRB 221221A: Global MASTER-Net observations report
  50. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  51. Integral GRB221218.34: Global MASTER-Net observations report
  52. Fermi trigger No 692713692: Global MASTER-Net observations report
  53. Swift Trigger 1144538 is not a GRB
  54. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 December 13
  55. Fermi GRB 221211A: Global MASTER-Net observations report
  56. IceCube Alert 221210.36: Global MASTER-Net observations report
  57. IceCube Alert 221124.66: Global MASTER-Net observations report
  58. LAT GRB221119.63: Global MASTER-Net observations report
  59. GRB 221028A: CrAO/ZTSh optical upper limit
  60. GRB 221028B: MAXI/GSC detection
  61. Swift GRB 221027B: Global MASTER-Net observations report
  62. GRB 221022B: Detection by GRBAlpha
  63. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  64. Fermi trigger No 687340841: Global MASTER-Net observations report
  65. Fermi trigger No 687281393: Global MASTER-Net observations report
  66. GRB 221009A: NICER follow-up observations
  67. Fermi trigger No 687190301: Global MASTER-Net observations report
  68. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  69. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  70. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  71. GRB 221008A: MAXI/GSC detection
  72. GRB 221006A: MAXI/GSC detection
  73. Fermi trigger No 686588176: Global MASTER-Net observations report
  74. GRB 220927A: Fermi GBM Final Localization
  75. Fermi GRB 220925A: Global MASTER-Net observations report
  76. Fermi trigger No 685748699: Global MASTER-Net observations report
  77. Fermi trigger No 685452089: Global MASTER-Net observations report
  78. IceCube-220907A: No significant detection in HAWC
  79. Fermi trigger No 684716840: Global MASTER-Net observations report
  80. Fermi GRB 220912A: Global MASTER-Net observations report
  81. IceCube Alert 220907.28: Global MASTER-Net observations report
  82. Fermi GRB 220905A: Global MASTER-Net observations report
  83. Fermi GRB 220902A: Global MASTER-Net observations report
  84. Fermi trigger No 683537972: Global MASTER-Net observations report
  85. Fermi trigger No 683202084: Global MASTER-Net observations report
  86. Fermi trigger No 683183601: Global MASTER-Net observations report
  87. GRB 220825A: Fermi GBM observation
  88. GRB 220825A: Swift/BAT-GUANO detection
  89. GRB 220825A: Fermi GBM Final Localization
  90. Fermi trigger No 682918137: Global MASTER-Net observations report
  91. Fermi trigger No 681719116: Global MASTER-Net observations report
  92. Fermi trigger No 681271717: Global MASTER-Net observations report
  93. Fermi trigger No 680782656: Global MASTER-Net observations report
  94. Fermi GRB 220728A: Global MASTER-Net observations report
  95. GRB 220715B: BOOTES-network optical upper limits
  96. Fermi trigger No 679248723: Global MASTER-Net observations report
  97. Fermi GRB 220711B: Global MASTER-Net observations report
  98. MAXI GRB220706.73: Global MASTER-Net observations report
  99. GRB 200701A: KAIT Optical Upper Limit
  100. Fermi trigger No 678058621: Global MASTER-Net observations report

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