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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"

32496 results found.

  1. GRB 260925A: Swift-BAT refined analysis
  2. Swift Trigger 1513439: consistent with noise and not astrophysical
  3. GRB 260924A: Upper limits from a neutrino search with IceCube
  4. Fermi GRB 260926C: Global MASTER-Net observations report
  5. GRB260914A: MAO/AZT-22 optical observations
  6. Fermi GRB 260926A: Global MASTER-Net observations report
  7. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  8. GRB 260924A: COLIBRÍ optical observations
  9. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  10. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  11. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  12. EP260924a: EP-FXT follow-up observation
  13. GRB 260925A: Swift/UVOT Upper Limits
  14. Konus-Wind detection of GRB 260924A
  15. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  16. GRB 260923A: Glowbug gamma-ray detection
  17. GRB 260924A: Optical follow-up observations with Kinder
  18. GRB 260922A: Glowbug gamma-ray detection
  19. GRB 260925A: COLIBRÍ optical upper limits
  20. GRB 260925A: FRAM-Auger optical limit
  21. GRB 260924A: Ondrejov D50 optical afterglow detection
  22. EP260924a: J-band upper limit with WINTER
  23. GRB 260924A: SVOM/GRM observation
  24. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  25. GRB 260923A: Insight-HXMT/HE detection
  26. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  27. GRB 260924A: Swift/UVOT Detection
  28. GRB 260924A: GROWTH-India Telescope optical observations
  29. GRB 260924A: Swift-BAT refined analysis
  30. GRB 260924A: NuSTAR detection of prompt emission
  31. Konus-Wind detection of GRB 260922A
  32. GRB 260922A: NuSTAR detection of prompt emission
  33. GRB 260921A: NuSTAR detection of prompt emission
  34. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  35. GRB 260921A: SVOM/GRM observation
  36. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  37. GRB 260924A: Fermi GRB Observation
  38. Konus-Wind detection of GRB 260921A (possible merger-origin)
  39. GRB 260924A: Fermi-LAT detection of a bright burst
  40. GRB 260924A: AstroSat CZTI detection
  41. GRB 260920A: SVOM/GRM observation
  42. GRB 260924A: NOT optical counterpart confirmation
  43. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  44. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  45. Fermi GRB 260923A: Global MASTER-Net observations report
  46. Trigger_21914: Swift ToO observations
  47. EP260806a: e-MERLIN detection at 5 GHz
  48. GRB 260922A: Ondrejov D50 optical limit
  49. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  50. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  51. ATCA observations of GRB 260909A
  52. GRB 260922A: Swift-BAT refined analysis
  53. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  54. GRB 260922A: J-band upper limit with WINTER
  55. GRB 260922A: Swift/UVOT Upper Limits
  56. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  57. GRB 260922A: COLIBRÍ optical upper limits
  58. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  59. Konus-Wind detection of GRB 260810A
  60. GRB 260920A: Glowbug gamma-ray detection
  61. GRB 260918A: SVOM/ECLAIRs refined analysis
  62. GRB 260922A: SVOM/C-GFT optical upper limit
  63. GRB 260917C: AstroSat CZTI detection
  64. GRB 260920B/EP260920b: GECAM-B detection of a burst
  65. GRB 260921A: AstroSat CZTI detection
  66. GRB 260921A: Swift-BAT refined analysis
  67. GRB 260921A: Fermi GBM Observation
  68. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  69. GRB 260917B:: SVOM/ECLAIRs refined analysis
  70. EP260920a: VLT/HAWK-I near-infrared candidate
  71. Swift GRB 260921A: Global MASTER-Net observations report
  72. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  73. EP260920b: LCO observations
  74. GRB 260920A: AstroSat CZTI detection
  75. EP260920b: SVOM/VT optical observation
  76. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  77. EP260920b: COLIBRÍ optical observations
  78. EP260920b: LCO optical counterpart detection
  79. EP260920b: Global MASTER-Net observations report
  80. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  81. EP260920a: NOT early time optical upper limits
  82. EP260920a: NOT optical upper limits
  83. EP260920a: SVOM/VT optical upper limits
  84. EP260917a: Global MASTER-Net observations report
  85. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  86. EP260920a: COLIBRÍ optical upper limits
  87. EP260920a: Update of the LCO optical counterpart candidate
  88. EP260917b: EP-FXT non-detection and upper limit
  89. EP260920a: LCO optical counterpart candidate
  90. GRB 260915A: VLT optical and near-infrared upper limits
  91. EP260917a: refined analysis of the EP-FXT observations
  92. IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
  93. EP260806a: Yamaguchi Interferometer radio detections
  94. EP260917a: SVOM/VT optical upper limits
  95. GRB 260918A: SVOM/C-GFT optical upper limits
  96. Fermi GBM Sub-Threshold Detection of GRB 260918A
  97. Konus-Wind detection of GRB 260916B (short/hard)
  98. GRB 260918A: SVOM/VT optical upper limits
  99. GRB 260916B: Glowbug gamma-ray detection of a short burst
  100. GRB 260918A: EP-FXT follow-up observation

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