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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"

32509 results found.

  1. LXT 240402A: MASTER optical observations with AGN in error-box
  2. GRB 240402B: GWAC-F50A optical upper limit
  3. GRB 240402B: GECAM-C detection
  4. Fermi GRB 240402A: Global MASTER-Net observations report
  5. X-ray transient EP240331a: Kinder optical upper limits
  6. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  7. EP240331A: MASTER optical observations
  8. Transient EP240315a: J-band observations of AT2024eju with WIRC
  9. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 240329A: Glowbug gamma-ray detection
  12. GRB 240331A: AstroSat CZTI detection
  13. GRB 240329A: AstroSat CZTI detection
  14. GRB 240329A: GRBAlpha detection
  15. Fermi GRB 240329A: Global MASTER-Net observations report
  16. Fermi GRB 240328B: Global MASTER-Net observations report
  17. Fermi GRB 240328A: Global MASTER-Net observations report
  18. X-ray transient EP240315a: continued ATCA monitoring
  19. IceCube-240327B: No candidates from the Zwicky Transient Facility
  20. X-ray transient EP 240315a: Second epoch Chandra observations
  21. X-ray transient EP240315a: e-MERLIN radio observations
  22. X-ray transient EP240315a: Ondrejov D50 optical limit
  23. Transient EPW20240219aa: REM optical/NIR further observations
  24. GRB 240320A: Glowbug gamma-ray detection
  25. GRB 240318A: Fermi GBM Observation
  26. Fermi GRB 240320A: Global MASTER-Net observations report
  27. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  28. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  29. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
  30. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  31. X-ray transient EP 240315a: Chandra observations
  32. X-ray transient EP240315a: GTC/HiPERCAM photometry
  33. X-ray transient EP240315a: MeerKAT radio detection
  34. X-ray transient EP240315a: GTC/OSIRIS spectroscopic redshift confirmation
  35. GRB 240318A: Glowbug gamma-ray detection
  36. X-ray transient EP240315a: PRIME near infrared detection
  37. GRB 240317B: Fermi GBM Observation
  38. X-ray transient EP240315a: 3.6 m TNG NIR detection
  39. Swift satellite in safe mode
  40. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  41. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  42. Fermi GRB 240318A: Global MASTER-Net observations report
  43. GRB 240317A: AstroSat CZTI detection
  44. X-ray transient EP240315a: Kitab observatory optical upper limitns
  45. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  46. Fermi GRB 240317B: Global MASTER-Net observations report
  47. Fermi GRB 240317A: Global MASTER-Net observations report
  48. X-ray transient EP240315a: orphan FXT?
  49. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  50. X-ray transient EP240315a: GROND J-band detection
  51. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  52. X-ray transient EP240315a: Nanshan/HMT optical upper limit
  53. AT2024eju: followup observations with Liverpool Telescope suggest a fading transient
  54. X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
  55. GRID detection of GRB 240306A
  56. Changes to the Fermi-GBM Triggering Thresholds
  57. Fermi GRB 240314A: Global MASTER-Net observations report
  58. GRB240204A: VIRT optical upper limit
  59. GRB 240312A: Glowbug gamma-ray detection
  60. GRB 240310A: MASTER OT J200702.72-263928.7 inside 3sigma
  61. Fermi-LAT gamma-ray observations of IceCube-240307A
  62. Fermi GRB 240310A: Global MASTER-Net observations report
  63. IceCube-240307A: Upper limits from a search for additional neutrino events in IceCube
  64. GRID detection of GRB 240229A (Updated Report)
  65. GRID detection of GRB 240229A
  66. GRB 231215A: further radio observations with the VLA
  67. GRB 240306A: Fermi GBM observation
  68. GRB 240229A: Glowbug gamma-ray detection
  69. GRB 240227A (short): Glowbug gamma-ray detection
  70. GRB 240229A: GRBAlpha detection
  71. Konus-Wind detection of GRB 231118A
  72. GRB 240306A: AstroSat CZTI detection
  73. Fermi GRB 240306A: Global MASTER-Net observations report
  74. Fermi GRB 240305A: Global MASTER-Net observations report
  75. GRB 240305A: Fermi GBM observation
  76. Fermi-LAT gamma-ray observations of IceCube-240229A
  77. GRB 240305C: AstroSat CZTI detection of a short burst
  78. Fermi GRB 240305C: Global MASTER-Net observations report
  79. GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
  80. GRB 240218A: ALMA detection
  81. GRB 240218A: Chandra Detection and Jet Break Confirmation
  82. Konus-Wind detection of GRB 240227A (short/hard)
  83. GRB 240303B: VZLUSAT-2 detection
  84. GRB 240229A: VZLUSAT-2 detection
  85. Improved IPN triangulation of GRB 240227A (short)
  86. IPN triangulation of GRB 240229A
  87. GRB240218A: ATCA observation of the radio counterpart
  88. Transient EPW20240219aa: Optical observations with LDT
  89. Konus-Wind detection of GRB 240303B
  90. Swift Trigger 1218645: Another detection of Swift J151857.0-572147
  91. IPN triangulation of GRB 240303B
  92. Swift J151857.0-572147: Swift-BAT refined analysis
  93. GRB 240303B: Fermi GBM Detection
  94. GRB 240225B: Swift-XRT afterglow detection
  95. Swift detection of Swift J151857.0-572147
  96. GRB 240303B: CALET Gamma-Ray Burst Monitor detection
  97. Swift GRB 240303A: Global MASTER-Net observations report
  98. Swift J151857.0-572147: Confirmation of a new galactic transient
  99. GRB 240225B: Glowbug gamma-ray detection
  100. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube

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