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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"

3038 results found.

  1. Fermi trigger No 737523389: Global MASTER-Net observations report
  2. MAXI GRB240514.78: Global MASTER-Net observations report
  3. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  4. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  5. GRB 240514A: Fermi GBM Final Real-time Localization
  6. LAT GRB240513.31: Global MASTER-Net observations report
  7. Fermi GRB 240513B: Global MASTER-Net observations report
  8. GRB 240513B: Fermi GBM Final Real-time Localization
  9. Fermi trigger No 737247400: Global MASTER-Net observations report
  10. Fermi trigger No 737196587: Global MASTER-Net observations report
  11. Fermi trigger No 737168073: Global MASTER-Net observations report
  12. Fermi trigger No 737105243: Global MASTER-Net observations report
  13. GRB 240511A: Fermi GBM Final Real-time Localization
  14. Fermi trigger No 737111207: Global MASTER-Net observations report
  15. IPN triangulation of GRB 240504A
  16. Fermi trigger No 736564880: Global MASTER-Net observations report
  17. GRB 240503A: AstroSat CZTI detection
  18. Fermi trigger No 736387941: Global MASTER-Net observations report
  19. Fermi GRB 240501A: Global MASTER-Net observations report
  20. Fermi trigger No 736197684: Global MASTER-Net observations report
  21. GRB 240501B: AstroSat CZTI detection
  22. GRB 240426A: AstroSat CZTI detection
  23. EP240426a: YAHPT optical upper limit
  24. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  25. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  26. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  27. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  28. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  29. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  30. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  31. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  32. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  33. Fermi GRB 240422A: Global MASTER-Net observations report
  34. Fermi GRB 240421B: Global MASTER-Net observations report
  35. Fermi trigger No 735280430: Global MASTER-Net observations report
  36. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  37. Fermi GRB 240417A: Global MASTER-Net observations report
  38. Improved IPN triangulation of GRB 240411A
  39. EP240416A: MASTER optical observations
  40. Fermi GRB 240415A: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  42. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  43. GRB 240411B: CrAO/ZTSh optical observations
  44. IceCube Alert 240412.23: Global MASTER-Net observations report
  45. Swift Trigger 1220736: detection of 4U 1543-62.
  46. Fermi GRB 240407A: Global MASTER-Net observations report
  47. GRB 240405B: Fermi GBM Final Real-time Localization
  48. GRB 240405A: Fermi GBM Final Real-time Localization
  49. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  50. Konus-Wind detection of LXT 240402A/GRB 240402B
  51. LXT 240402A: MASTER optical observations with AGN in error-box
  52. GRB 240402B: GECAM-C detection
  53. X-ray transient LXT 240402A: LEIA detection
  54. EP240331A: MASTER optical observations
  55. Fermi trigger No 733366352: Global MASTER-Net observations report
  56. Fermi GRB 240329A: Global MASTER-Net observations report
  57. GRB 240329A: Fermi GBM Final Real-time Localization
  58. Fermi GRB 240328B: Global MASTER-Net observations report
  59. Fermi GRB 240328A: Global MASTER-Net observations report
  60. IceCube-240327B: No candidates from the Zwicky Transient Facility
  61. GRB 240328A: Fermi GBM Final Real-time Localization
  62. IceCube Alert 240327.68: Global MASTER-Net observations report
  63. Fermi trigger No 733097506: Global MASTER-Net observations report
  64. Fermi trigger No 733092476: Global MASTER-Net observations report
  65. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  66. GRB 240320A: Fermi GBM Final Real-time Localization
  67. Fermi GRB 240318A: Global MASTER-Net observations report
  68. GRB 240317A: AstroSat CZTI detection
  69. Fermi GRB 240317B: Global MASTER-Net observations report
  70. Fermi trigger No 732299243: Global MASTER-Net observations report
  71. Fermi trigger No 731839490: Global MASTER-Net observations report
  72. Fermi GRB 240310A: Global MASTER-Net observations report
  73. Fermi GRB 240306A: Global MASTER-Net observations report
  74. Fermi GRB 240305A: Global MASTER-Net observations report
  75. GRB 240218A: ALMA detection
  76. IPN triangulation of GRB 240229A
  77. GRB240218A: ATCA observation of the radio counterpart
  78. Swift Trigger 1218645: Another detection of Swift J151857.0-572147
  79. Konus-Wind detection of GRB 240225B (long)
  80. Fermi GRB 240227A: Global MASTER-Net observations report
  81. GRB 240218A: CMO SAI NIR upper limit
  82. Fermi trigger No 730618809: Global MASTER-Net observations report
  83. GRB 240218A: VLA detection
  84. Transient EPW20240219aa: 7DT Optical Upper Limits
  85. GRB 240215B: GRBAlpha detection
  86. Fermi trigger No 729914426: Global MASTER-Net observations report
  87. GRB 240218A: REM detection of a NIR afterglow candidate
  88. Swift GRB240218.08: Global MASTER-Net observations report
  89. Fermi trigger No 729703985: Global MASTER-Net observations report
  90. GRB 240214A/1H 0451-560: MAXI/GSC detection
  91. Fermi GRB 240213A: Global MASTER-Net observations report
  92. GRB 240209A: GOTO optical counterpart candidate
  93. Fermi trigger No 729152364: Global MASTER-Net observations report
  94. Fermi trigger No 729012023: Global MASTER-Net observations report
  95. GRB 240205B: Fermi GBM Observation
  96. Fermi trigger No 728749569: Global MASTER-Net observations report
  97. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  98. Swift GRB240205.93: Global MASTER-Net observations report
  99. Fermi Gamma-ray Burst Monitor trigger 728740048/240204491 is not a GRB
  100. Fermi trigger No 728796365: Global MASTER-Net observations report

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