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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  2. EP240408a: GSP optical upper limit
  3. GRB 240411B: CrAO/ZTSh optical observations
  4. GRB 240411B: Kinder observations with Lulin observatory
  5. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  6. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  7. GRB 240411B: HiPERCAM/GTC observation
  8. IceCube Alert 240412.23: Global MASTER-Net observations report
  9. GRB 240411B: Swift-BAT refined analysis
  10. GRB 240411B: Swift-XRT refined Analysis
  11. IceCube-240412A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 240411B: 1.3m DFOT Optical observations
  13. GRB 240411A: GRBAlpha detection
  14. GRB 240411B: OHP/T193 optical observations
  15. GRB 240405A: Glowbug gamma-ray detection
  16. GRB 240411B: Enhanced Swift-XRT position
  17. GRB 240411B: LCO optical afterglow detection
  18. GRB 240411B: Swift detection of a burst
  19. GRB 240408B: GRBAlpha detection
  20. GRB 240411A: Fermi GBM Final Real-time Localization
  21. EP240408A: MASTER optical observations
  22. EP240408a: GROND detection of a candidate counterpart
  23. EP240408a: Upper limits from GECAM-B Observation
  24. EP240408a: Swift follow-up observation
  25. EP240408a: BOOTES-6/DPRT optical upper limit
  26. X-ray transient EP240315a: second epoch e-MERLIN radio observations
  27. GRB 240405A: GRBAlpha detection
  28. EP240408a: EP-WXT detection of a fast X-ray transient
  29. Swift Trigger 1220736: detection of 4U 1543-62.
  30. GRB 240408B: AstroSat CZTI detection
  31. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  32. Fermi GRB 240408A: Global MASTER-Net observations report
  33. GRB 240408A: Fermi GBM Final Real-time Localization
  34. GRB 240407A: BALROG localization (Fermi Trigger 734144396 / GRB 240407042)
  35. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  36. Fermi GRB 240407A: Global MASTER-Net observations report
  37. GRB 240407A: Fermi GBM Final Real-time Localization
  38. Fermi-LAT gamma-ray observations of IceCube-240327B
  39. Fermi-LAT gamma-ray observations of IceCube-240327A
  40. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  41. Fermi GRB 240405B: Global MASTER-Net observations report
  42. GRB 240405B: Fermi GBM Final Real-time Localization
  43. GRB 240402C: Glowbug gamma-ray detection
  44. GRB 240405A: Fermi GBM Final Real-time Localization
  45. GRB 240402C: GRBAlpha detection
  46. GRB 240331A: GRBAlpha detection
  47. LXT 240402A/GRB 240402B: GECAM-C refined analysis
  48. Swift satellite resumes pointed science observations
  49. GRB 240403B: Glowbug gamma-ray detection
  50. GRB 240403A: Glowbug gamma-ray detection
  51. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  52. X-ray transient LXT 240402A: WFST optical upper limits​
  53. Konus-Wind detection of LXT 240402A/GRB 240402B
  54. GRB/FXT 240402B: Kinder optical counterpart candidate
  55. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  56. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  57. GRB 240403A: Fermi GBM Detection
  58. X-ray transient LXT240402A: AST3-3 optical upper limits
  59. LXT 240402A: EP-FXT detection of the X-ray afterglow
  60. Fermi GRB 240404A: Global MASTER-Net observations report
  61. GRB 240404A: Fermi GBM Final Real-time Localization
  62. LXT 240402A: MASTER optical observations with AGN in error-box
  63. GRB 240402B: GWAC-F50A optical upper limit
  64. GRB 240402B: GECAM-C detection
  65. X-ray transient LXT 240402A: LEIA detection
  66. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  67. Fermi trigger No 733808041: Global MASTER-Net observations report
  68. Fermi GRB 240402A: Global MASTER-Net observations report
  69. GRB 240402A: Fermi GBM Final Real-time Localization
  70. X-ray transient EP240331a: Kinder optical upper limits
  71. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  72. EP240331A: MASTER optical observations
  73. Transient EP240315a: J-band observations of AT2024eju with WIRC
  74. X-ray transient EP20240331a: MeerLICHT optical upper limits
  75. IBAS Alert n.10651 not a GRB
  76. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  77. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  78. Integral GRB240401.69: Global MASTER-Net observations report
  79. GRB 240329A: Glowbug gamma-ray detection
  80. GRB 240324A: AstroSat CZTI detection of a short burst
  81. GRB 240331A: AstroSat CZTI detection
  82. GRB 240329A: AstroSat CZTI detection
  83. GRB 240331A: Fermi GBM Final Real-time Localization
  84. GRB 240329A: GRBAlpha detection
  85. Fermi trigger No 733366352: Global MASTER-Net observations report
  86. Fermi GRB 240329A: Global MASTER-Net observations report
  87. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  88. GRB 240329A: Fermi GBM Final Real-time Localization
  89. Fermi GRB 240328B: Global MASTER-Net observations report
  90. Fermi GRB 240328A: Global MASTER-Net observations report
  91. X-ray transient EP240315a: continued ATCA monitoring
  92. IceCube-240327B: No candidates from the Zwicky Transient Facility
  93. GRB 240328C: Glowbug gamma-ray detection
  94. GRB 240328B: Fermi GBM Final Real-time Localization
  95. GRB 240328A: Fermi GBM Final Real-time Localization
  96. IceCube Alert 240327.68: Global MASTER-Net observations report
  97. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  98. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  99. X-ray transient EP 240315a: Second epoch Chandra observations
  100. Fermi trigger No 733097506: Global MASTER-Net observations report

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