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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"

3043 results found.

  1. LIGO/Virgo S230617aq: Global MASTER-Net observations report
  2. LIGO/Virgo S230617aj: Global MASTER-Net observations report
  3. LIGO/Virgo S230616s: Global MASTER-Net observations report
  4. LIGO/Virgo S230608as: Global MASTER-Net observations report
  5. LIGO/Virgo S230609a: Global MASTER-Net observations report
  6. LIGO/Virgo S230608ah: Global MASTER-Net observations report
  7. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  8. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  9. LIGO/Virgo S230525a: Global MASTER-Net observations report
  10. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  11. IceCube Alert 230524.47: Global MASTER-Net observations report
  12. Fermi trigger No 706610076: Global MASTER-Net observations report
  13. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230523A
  14. LIGO/Virgo S230522a: Global MASTER-Net observations report
  15. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  17. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  18. GRB 230520A: MAXI/GSC detection
  19. LIGO/Virgo S230518h: Global MASTER-Net observations report
  20. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  21. GRB 230506C: TSHAO possible afterglow candidate
  22. GRB 230420A: Swift-BAT refined analysis
  23. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  24. GRB 230409B: Mondy optical upper limit
  25. Fermi trigger No 702745263: Global MASTER-Net observations report
  26. GRB 230409B: Swift detection of a burst
  27. Fermi trigger No 701883729: Global MASTER-Net observations report
  28. GRB 230328B: Swift-BAT refined analysis
  29. GRB 230328B: Nanshan/NEXT optical upper limit
  30. Fermi GRB 230328A: Global MASTER-Net observations report
  31. Fermi trigger No 701321709: Global MASTER-Net observations report
  32. Konus-Wind detection of GRB 230309A
  33. GRB 230322A: Fermi GBM Final Real-time Localization
  34. Fermi GRB 230313A: Global MASTER-Net observations report
  35. Further improved IPN localization for GRB 230307A
  36. Fermi GRB 230308A: Global MASTER-Net observations report
  37. Fermi trigger No 699294715: Global MASTER-Net observations report
  38. Fermi trigger No 699311646: Global MASTER-Net observations report
  39. Fermi GRB 230220B: Global MASTER-Net observations report
  40. IceCube-230217A: BOOTES-4/MET Optical Observations
  41. IPN triangulation of GRB 230209B
  42. Fermi trigger No 697926015: Global MASTER-Net observations report
  43. Fermi trigger No 697904388: Global MASTER-Net observations report
  44. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  45. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  46. Fermi trigger No 697098930: Global MASTER-Net observations report
  47. GRB 221216A: Swift-BAT refined analysis
  48. Fermi GRB 230201A: Global MASTER-Net observations report
  49. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
  50. Fermi GRB 230112A: Global MASTER-Net observations report
  51. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  52. Fermi GRB 221226A: Global MASTER-Net observations report
  53. Fermi GRB 221221A: Global MASTER-Net observations report
  54. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  55. Integral GRB221218.34: Global MASTER-Net observations report
  56. Fermi trigger No 692713692: Global MASTER-Net observations report
  57. Swift Trigger 1144538 is not a GRB
  58. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 December 13
  59. Fermi GRB 221211A: Global MASTER-Net observations report
  60. IceCube Alert 221210.36: Global MASTER-Net observations report
  61. IceCube Alert 221124.66: Global MASTER-Net observations report
  62. LAT GRB221119.63: Global MASTER-Net observations report
  63. GRB 221028A: CrAO/ZTSh optical upper limit
  64. GRB 221028B: MAXI/GSC detection
  65. Swift GRB 221027B: Global MASTER-Net observations report
  66. GRB 221022B: Detection by GRBAlpha
  67. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  68. Fermi trigger No 687340841: Global MASTER-Net observations report
  69. Fermi trigger No 687281393: Global MASTER-Net observations report
  70. GRB 221009A: NICER follow-up observations
  71. Fermi trigger No 687190301: Global MASTER-Net observations report
  72. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  73. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  74. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  75. GRB 221008A: MAXI/GSC detection
  76. GRB 221006A: MAXI/GSC detection
  77. Fermi trigger No 686588176: Global MASTER-Net observations report
  78. GRB 220927A: Fermi GBM Final Localization
  79. Fermi GRB 220925A: Global MASTER-Net observations report
  80. Fermi trigger No 685748699: Global MASTER-Net observations report
  81. Fermi trigger No 685452089: Global MASTER-Net observations report
  82. IceCube-220907A: No significant detection in HAWC
  83. Fermi trigger No 684716840: Global MASTER-Net observations report
  84. Fermi GRB 220912A: Global MASTER-Net observations report
  85. IceCube Alert 220907.28: Global MASTER-Net observations report
  86. Fermi GRB 220905A: Global MASTER-Net observations report
  87. Fermi GRB 220902A: Global MASTER-Net observations report
  88. Fermi trigger No 683537972: Global MASTER-Net observations report
  89. Fermi trigger No 683202084: Global MASTER-Net observations report
  90. Fermi trigger No 683183601: Global MASTER-Net observations report
  91. GRB 220825A: Fermi GBM observation
  92. GRB 220825A: Swift/BAT-GUANO detection
  93. GRB 220825A: Fermi GBM Final Localization
  94. Fermi trigger No 682918137: Global MASTER-Net observations report
  95. Fermi trigger No 681719116: Global MASTER-Net observations report
  96. Fermi trigger No 681271717: Global MASTER-Net observations report
  97. Fermi trigger No 680782656: Global MASTER-Net observations report
  98. Fermi GRB 220728A: Global MASTER-Net observations report
  99. GRB 220715B: BOOTES-network optical upper limits
  100. Fermi trigger No 679248723: Global MASTER-Net observations report

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