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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"

32501 results found.

  1. GRB 260924A: VLA detection
  2. GRB 260924A: Swift/UVOT UV grism spectrum results
  3. GRB 260924A: AbAO optical observations
  4. Fermi GRB 260928A: Global MASTER-Net observations report
  5. EP260924a: Global MASTER-Net observations report
  6. GRB 260925A: Swift-BAT refined analysis
  7. Swift Trigger 1513439: consistent with noise and not astrophysical
  8. GRB 260924A: Upper limits from a neutrino search with IceCube
  9. Fermi GRB 260926C: Global MASTER-Net observations report
  10. GRB260914A: MAO/AZT-22 optical observations
  11. Fermi GRB 260926A: Global MASTER-Net observations report
  12. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  13. GRB 260924A: COLIBRÍ optical observations
  14. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  15. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  16. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  17. EP260924a: EP-FXT follow-up observation
  18. GRB 260925A: Swift/UVOT Upper Limits
  19. Konus-Wind detection of GRB 260924A
  20. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  21. GRB 260923A: Glowbug gamma-ray detection
  22. GRB 260924A: Optical follow-up observations with Kinder
  23. GRB 260922A: Glowbug gamma-ray detection
  24. GRB 260925A: COLIBRÍ optical upper limits
  25. GRB 260925A: FRAM-Auger optical limit
  26. GRB 260924A: Ondrejov D50 optical afterglow detection
  27. EP260924a: J-band upper limit with WINTER
  28. GRB 260924A: SVOM/GRM observation
  29. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  30. GRB 260923A: Insight-HXMT/HE detection
  31. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  32. GRB 260924A: Swift/UVOT Detection
  33. GRB 260924A: GROWTH-India Telescope optical observations
  34. GRB 260924A: Swift-BAT refined analysis
  35. GRB 260924A: NuSTAR detection of prompt emission
  36. Konus-Wind detection of GRB 260922A
  37. GRB 260922A: NuSTAR detection of prompt emission
  38. GRB 260921A: NuSTAR detection of prompt emission
  39. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  40. GRB 260921A: SVOM/GRM observation
  41. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  42. GRB 260924A: Fermi GRB Observation
  43. Konus-Wind detection of GRB 260921A (possible merger-origin)
  44. GRB 260924A: Fermi-LAT detection of a bright burst
  45. GRB 260924A: AstroSat CZTI detection
  46. GRB 260920A: SVOM/GRM observation
  47. GRB 260924A: NOT optical counterpart confirmation
  48. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  49. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  50. Fermi GRB 260923A: Global MASTER-Net observations report
  51. Trigger_21914: Swift ToO observations
  52. EP260806a: e-MERLIN detection at 5 GHz
  53. GRB 260922A: Ondrejov D50 optical limit
  54. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  55. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  56. ATCA observations of GRB 260909A
  57. GRB 260922A: Swift-BAT refined analysis
  58. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  59. GRB 260922A: J-band upper limit with WINTER
  60. GRB 260922A: Swift/UVOT Upper Limits
  61. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  62. GRB 260922A: COLIBRÍ optical upper limits
  63. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  64. Konus-Wind detection of GRB 260810A
  65. GRB 260920A: Glowbug gamma-ray detection
  66. GRB 260918A: SVOM/ECLAIRs refined analysis
  67. GRB 260922A: SVOM/C-GFT optical upper limit
  68. GRB 260917C: AstroSat CZTI detection
  69. GRB 260920B/EP260920b: GECAM-B detection of a burst
  70. GRB 260921A: AstroSat CZTI detection
  71. GRB 260921A: Swift-BAT refined analysis
  72. GRB 260921A: Fermi GBM Observation
  73. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  74. GRB 260917B:: SVOM/ECLAIRs refined analysis
  75. EP260920a: VLT/HAWK-I near-infrared candidate
  76. Swift GRB 260921A: Global MASTER-Net observations report
  77. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  78. EP260920b: LCO observations
  79. GRB 260920A: AstroSat CZTI detection
  80. EP260920b: SVOM/VT optical observation
  81. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  82. EP260920b: COLIBRÍ optical observations
  83. EP260920b: LCO optical counterpart detection
  84. EP260920b: Global MASTER-Net observations report
  85. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  86. EP260920a: NOT early time optical upper limits
  87. EP260920a: NOT optical upper limits
  88. EP260920a: SVOM/VT optical upper limits
  89. EP260917a: Global MASTER-Net observations report
  90. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  91. EP260920a: COLIBRÍ optical upper limits
  92. EP260920a: Update of the LCO optical counterpart candidate
  93. EP260917b: EP-FXT non-detection and upper limit
  94. EP260920a: LCO optical counterpart candidate
  95. GRB 260915A: VLT optical and near-infrared upper limits
  96. EP260917a: refined analysis of the EP-FXT observations
  97. IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
  98. EP260806a: Yamaguchi Interferometer radio detections
  99. EP260917a: SVOM/VT optical upper limits
  100. GRB 260918A: SVOM/C-GFT optical upper limits

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