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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"

32506 results found.

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

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