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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"

32494 results found.

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

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