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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"

32507 results found.

  1. GRB 260926C: GECAM-B observation
  2. GRB 260926A: GECAM-B observation
  3. EP260927a: Global MASTER-Net observations report
  4. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  5. GRB 260926A: Glowbug gamma-ray detection
  6. GRB 260924A: VLA detection
  7. GRB 260924A: Swift/UVOT UV grism spectrum results
  8. GRB 260924A: AbAO optical observations
  9. Fermi GRB 260928A: Global MASTER-Net observations report
  10. EP260924a: Global MASTER-Net observations report
  11. GRB 260925A: Swift-BAT refined analysis
  12. Swift Trigger 1513439: consistent with noise and not astrophysical
  13. GRB 260924A: Upper limits from a neutrino search with IceCube
  14. Fermi GRB 260926C: Global MASTER-Net observations report
  15. GRB260914A: MAO/AZT-22 optical observations
  16. Fermi GRB 260926A: Global MASTER-Net observations report
  17. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  18. GRB 260924A: COLIBRÍ optical observations
  19. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  20. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  21. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  22. EP260924a: EP-FXT follow-up observation
  23. GRB 260925A: Swift/UVOT Upper Limits
  24. Konus-Wind detection of GRB 260924A
  25. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  26. GRB 260923A: Glowbug gamma-ray detection
  27. GRB 260924A: Optical follow-up observations with Kinder
  28. GRB 260922A: Glowbug gamma-ray detection
  29. GRB 260925A: COLIBRÍ optical upper limits
  30. GRB 260925A: FRAM-Auger optical limit
  31. GRB 260924A: Ondrejov D50 optical afterglow detection
  32. EP260924a: J-band upper limit with WINTER
  33. GRB 260924A: SVOM/GRM observation
  34. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  35. GRB 260923A: Insight-HXMT/HE detection
  36. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  37. GRB 260924A: Swift/UVOT Detection
  38. GRB 260924A: GROWTH-India Telescope optical observations
  39. GRB 260924A: Swift-BAT refined analysis
  40. GRB 260924A: NuSTAR detection of prompt emission
  41. Konus-Wind detection of GRB 260922A
  42. GRB 260922A: NuSTAR detection of prompt emission
  43. GRB 260921A: NuSTAR detection of prompt emission
  44. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  45. GRB 260921A: SVOM/GRM observation
  46. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  47. GRB 260924A: Fermi GRB Observation
  48. Konus-Wind detection of GRB 260921A (possible merger-origin)
  49. GRB 260924A: Fermi-LAT detection of a bright burst
  50. GRB 260924A: AstroSat CZTI detection
  51. GRB 260920A: SVOM/GRM observation
  52. GRB 260924A: NOT optical counterpart confirmation
  53. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  54. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  55. Fermi GRB 260923A: Global MASTER-Net observations report
  56. Trigger_21914: Swift ToO observations
  57. EP260806a: e-MERLIN detection at 5 GHz
  58. GRB 260922A: Ondrejov D50 optical limit
  59. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  60. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  61. ATCA observations of GRB 260909A
  62. GRB 260922A: Swift-BAT refined analysis
  63. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  64. GRB 260922A: J-band upper limit with WINTER
  65. GRB 260922A: Swift/UVOT Upper Limits
  66. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  67. GRB 260922A: COLIBRÍ optical upper limits
  68. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  69. Konus-Wind detection of GRB 260810A
  70. GRB 260920A: Glowbug gamma-ray detection
  71. GRB 260918A: SVOM/ECLAIRs refined analysis
  72. GRB 260922A: SVOM/C-GFT optical upper limit
  73. GRB 260917C: AstroSat CZTI detection
  74. GRB 260920B/EP260920b: GECAM-B detection of a burst
  75. GRB 260921A: AstroSat CZTI detection
  76. GRB 260921A: Swift-BAT refined analysis
  77. GRB 260921A: Fermi GBM Observation
  78. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  79. GRB 260917B:: SVOM/ECLAIRs refined analysis
  80. EP260920a: VLT/HAWK-I near-infrared candidate
  81. Swift GRB 260921A: Global MASTER-Net observations report
  82. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  83. EP260920b: LCO observations
  84. GRB 260920A: AstroSat CZTI detection
  85. EP260920b: SVOM/VT optical observation
  86. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  87. EP260920b: COLIBRÍ optical observations
  88. EP260920b: LCO optical counterpart detection
  89. EP260920b: Global MASTER-Net observations report
  90. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  91. EP260920a: NOT early time optical upper limits
  92. EP260920a: NOT optical upper limits
  93. EP260920a: SVOM/VT optical upper limits
  94. EP260917a: Global MASTER-Net observations report
  95. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  96. EP260920a: COLIBRÍ optical upper limits
  97. EP260920a: Update of the LCO optical counterpart candidate
  98. EP260917b: EP-FXT non-detection and upper limit
  99. EP260920a: LCO optical counterpart candidate
  100. GRB 260915A: VLT optical and near-infrared upper limits

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