Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

28080 results found.

  1. GRB 261005A: Glowbug gamma-ray detection
  2. GRB 261005B: Swift/UVOT Upper Limits
  3. GRB 261005B: J-band upper limit with WINTER
  4. GRB 261001A: GECAM-B observation of a likely long GRB
  5. GRB 261005B: Fermi GBM Observation
  6. GRB 261005B: Enhanced Swift-XRT position
  7. GRB 261005B: Swift detection of a burst
  8. GRB 261003A: Glowbug gamma-ray detection of a likely short burst
  9. EP#01709320865: Swift-XRT observations
  10. GRB 260930B: SVOM/GRM observation
  11. Konus-Wind detection of GRB 260919A / EP 260920a
  12. EP261003a: J-band upper limit with WINTER
  13. EP261003a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  14. GRB 260930B: GECAM-B detection of a burst
  15. EP261003a: COLIBRÍ optical upper limits
  16. Fermi GRB 261003A: Global MASTER-Net observations report
  17. EP261003a: Einstein Probe detection of an X-ray transient
  18. EP Alert 261003.01: Global MASTER-Net observations report
  19. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  20. Fermi GBM Detection of GRB 260919A / EP260920a
  21. IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
  22. Fermi GRB 260930B: Global MASTER-Net observations report
  23. GRB 260926C: SVOM/GRM observation
  24. IceCube Alert 260930A: Global MASTER-Net observations report
  25. EP260927a: SVOM/ECLAIRs Upper Limit
  26. EP260927a: Global MASTER-Net observations report
  27. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  28. GRB 260926A: Glowbug gamma-ray detection
  29. GRB 260924A: AbAO optical observations
  30. Fermi GRB 260928A: Global MASTER-Net observations report
  31. EP260924a: Global MASTER-Net observations report
  32. GRB 260925A: Swift-BAT refined analysis
  33. GRB 260924A: Upper limits from a neutrino search with IceCube
  34. Fermi GRB 260926C: Global MASTER-Net observations report
  35. GRB260914A: MAO/AZT-22 optical observations
  36. Fermi GRB 260926A: Global MASTER-Net observations report
  37. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  38. GRB 260924A: COLIBRÍ optical observations
  39. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  40. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  41. GRB 260925A: Swift-XRT refined Analysis
  42. Swift Trigger 1513439 is probably not a GRB
  43. GRB 260925A: Swift/UVOT Upper Limits
  44. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  45. GRB 260923A: Glowbug gamma-ray detection
  46. GRB 260924A: Optical follow-up observations with Kinder
  47. GRB 260922A: Glowbug gamma-ray detection
  48. GRB 260925A: Enhanced Swift-XRT position
  49. GRB 260925A: COLIBRÍ optical upper limits
  50. GRB 260925A: FRAM-Auger optical limit
  51. GRB 260924A: Ondrejov D50 optical afterglow detection
  52. EP260924a: J-band upper limit with WINTER
  53. GRB 260924A: SVOM/GRM observation
  54. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  55. GRB 260925A: Swift detection of a burst
  56. GRB 260923A: Insight-HXMT/HE detection
  57. EP260924a: EP-WXT detection of an X-ray transient
  58. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  59. GRB 260924A: Swift/UVOT Detection
  60. GRB 260924A: GROWTH-India Telescope optical observations
  61. GRB 260924A: Swift-BAT refined analysis
  62. GRB 260924A: NuSTAR detection of prompt emission
  63. GRB 260924A: Swift-XRT refined Analysis
  64. GRB 260922A: NuSTAR detection of prompt emission
  65. GRB 260921A: NuSTAR detection of prompt emission
  66. GRB 260921A: SVOM/GRM observation
  67. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  68. GRB 260924A: Fermi GRB Observation
  69. GRB 260924A: AstroSat CZTI detection
  70. GRB 260920A: SVOM/GRM observation
  71. GRB 260924A: NOT optical counterpart confirmation
  72. GRB 260924A: Enhanced Swift-XRT position
  73. GRB 260924A: Swift detection of a burst
  74. Fermi GRB 260923A: Global MASTER-Net observations report
  75. EP260806a: e-MERLIN detection at 5 GHz
  76. GRB 260922A: Ondrejov D50 optical limit
  77. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  78. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  79. GRB 260922A: Swift-BAT refined analysis
  80. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  81. GRB 260922A: J-band upper limit with WINTER
  82. GRB 260922A: Swift/UVOT Upper Limits
  83. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  84. GRB 260922A: COLIBRÍ optical upper limits
  85. GRB 260922A: Swift-XRT refined Analysis
  86. GRB 260922A: Enhanced Swift-XRT position
  87. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  88. GRB 260920A: Glowbug gamma-ray detection
  89. GRB 260922A: SVOM/C-GFT optical upper limit
  90. GRB 260922A: Swift detection of a burst
  91. GRB 260921A: AstroSat CZTI detection
  92. GRB 260921A: Swift-BAT refined analysis
  93. GRB 260921A: Fermi GBM Observation
  94. EP Alert 260921.58: Global MASTER-Net observations report
  95. GRB 260917B:: SVOM/ECLAIRs refined analysis
  96. The EP-WXT trigger 01709319528 is likely a flaring star
  97. EP260920a: VLT/HAWK-I near-infrared candidate
  98. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  99. Swift GRB 260921A: Global MASTER-Net observations report
  100. GRB 260921A: Swift detection of a burst

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov