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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"

37962 results found.

  1. IPN triangulation of GRB 260919A / EP260920a
  2. Fermi GRB 260930B: Global MASTER-Net observations report
  3. GRB 260926C: SVOM/GRM observation
  4. GRB 260930B: Fermi GBM Final Real-time Localization
  5. GRB 260930A: Fermi GBM Final Real-time Localization
  6. IceCube Alert 260930A: Global MASTER-Net observations report
  7. GRB 260926C: AstroSat CZTI detection
  8. GRB 260926C: GECAM-B observation
  9. GRB 260926A: GECAM-B observation
  10. EP260927a: Global MASTER-Net observations report
  11. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  12. GRB 260926A: Glowbug gamma-ray detection
  13. GRB 260924A: VLA detection
  14. GRB 260924A: Swift/UVOT UV grism spectrum results
  15. GRB 260924A: AbAO optical observations
  16. Fermi GRB 260928A: Global MASTER-Net observations report
  17. GRB 260928A: Fermi GBM Final Real-time Localization
  18. EP260924a: Global MASTER-Net observations report
  19. GRB 260925A: Swift-BAT refined analysis
  20. GRB 260924A: Upper limits from a neutrino search with IceCube
  21. Fermi GRB 260926C: Global MASTER-Net observations report
  22. GRB 260926C: Fermi GBM Final Real-time Localization
  23. GRB260914A: MAO/AZT-22 optical observations
  24. GRB 260926B: Fermi GBM Final Real-time Localization
  25. Fermi GRB 260926A: Global MASTER-Net observations report
  26. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  27. GRB 260926A: Fermi GBM Final Real-time Localization
  28. GRB 260924A: COLIBRÍ optical observations
  29. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  30. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  31. GRB 260925A: Swift-XRT refined Analysis
  32. Swift Trigger 1513439 is probably not a GRB
  33. GRB 260925A: Swift/UVOT Upper Limits
  34. Konus-Wind detection of GRB 260924A
  35. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  36. GRB 260923A: Glowbug gamma-ray detection
  37. GRB 260924A: Optical follow-up observations with Kinder
  38. GRB 260922A: Glowbug gamma-ray detection
  39. GRB 260925A: Enhanced Swift-XRT position
  40. GRB 260925A: COLIBRÍ optical upper limits
  41. GRB 260925A: FRAM-Auger optical limit
  42. GRB 260924A: Ondrejov D50 optical afterglow detection
  43. GRB 260924A: SVOM/GRM observation
  44. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  45. GRB 260925A: Swift detection of a burst
  46. GRB 260923A: Insight-HXMT/HE detection
  47. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  48. GRB 260924A: Swift/UVOT Detection
  49. GRB 260924A: GROWTH-India Telescope optical observations
  50. GRB 260924A: Swift-BAT refined analysis
  51. GRB 260924A: NuSTAR detection of prompt emission
  52. GRB 260924A: Swift/UVOT Upper Limits
  53. GRB 260924A: Swift-XRT refined Analysis
  54. Konus-Wind detection of GRB 260922A
  55. GRB 260922A: NuSTAR detection of prompt emission
  56. GRB 260921A: NuSTAR detection of prompt emission
  57. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  58. GRB 260921A: SVOM/GRM observation
  59. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  60. GRB 260924A: Fermi GRB Observation
  61. Konus-Wind detection of GRB 260921A (possible merger-origin)
  62. GRB 260924A: Fermi-LAT detection of a bright burst
  63. GRB 260924A: AstroSat CZTI detection
  64. GRB 260920A: SVOM/GRM observation
  65. GRB 260924A: NOT optical counterpart confirmation
  66. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  67. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  68. GRB 260924A: Enhanced Swift-XRT position
  69. GRB 260924A: Swift detection of a burst
  70. GRB 260924A: Fermi GBM Final Real-time Localization
  71. Fermi GRB 260923A: Global MASTER-Net observations report
  72. GRB 260923A: Fermi GBM Final Real-time Localization
  73. GRB 260922A: Ondrejov D50 optical limit
  74. ATCA observations of GRB 260909A
  75. GRB 260922A: Swift-BAT refined analysis
  76. GRB 260922A: J-band upper limit with WINTER
  77. GRB 260922A: Swift/UVOT Upper Limits
  78. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  79. GRB 260922A: COLIBRÍ optical upper limits
  80. GRB 260922A: Swift-XRT refined Analysis
  81. GRB 260922A: Enhanced Swift-XRT position
  82. Konus-Wind detection of GRB 260810A
  83. GRB 260920A: Glowbug gamma-ray detection
  84. GRB 260918A: SVOM/ECLAIRs refined analysis
  85. GRB 260922A: SVOM/C-GFT optical upper limit
  86. GRB 260922A: Swift detection of a burst
  87. GRB 260917C: AstroSat CZTI detection
  88. GRB 260920B/EP260920b: GECAM-B detection of a burst
  89. GRB 260921A: AstroSat CZTI detection
  90. GRB 260921A: Swift-BAT refined analysis
  91. GRB 260921B: Fermi GBM Final Localization
  92. GRB 260921A: Fermi GBM Observation
  93. EP Alert 260921.58: Global MASTER-Net observations report
  94. GRB 260917B:: SVOM/ECLAIRs refined analysis
  95. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  96. Swift GRB 260921A: Global MASTER-Net observations report
  97. GRB 260921A: Swift detection of a burst
  98. GRB 260921A: Fermi GBM Final Real-time Localization
  99. GRB 260920A: AstroSat CZTI detection
  100. EP Alert 260921.01: Global MASTER-Net observations report

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