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"

42192 results found.

  1. GRB 260924A: Swift/UVOT UV grism spectrum results
  2. GRB 260924A: AbAO optical observations
  3. Fermi GRB 260928A: Global MASTER-Net observations report
  4. GRB 260928A: Fermi GBM Final Real-time Localization
  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. GRB 260926C: Fermi GBM Final Real-time Localization
  11. GRB260914A: MAO/AZT-22 optical observations
  12. GRB 260926B: Fermi GBM Final Real-time Localization
  13. Fermi GRB 260926A: Global MASTER-Net observations report
  14. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  15. GRB 260926A: Fermi GBM Final Real-time Localization
  16. The EP-WXT trigger 01709320726 is likely a flaring star
  17. GRB 260924A: COLIBRÍ optical observations
  18. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  19. GRB 260925A: Swift-XRT refined Analysis
  20. EP260924a: EP-FXT follow-up observation
  21. Swift Trigger 1513439 is probably not a GRB
  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: Enhanced Swift-XRT position
  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 260925A: Swift detection of a burst
  36. GRB 260923A: Insight-HXMT/HE detection
  37. EP260924a: EP-WXT detection of an X-ray transient
  38. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  39. GRB 260924A: Swift/UVOT Detection
  40. GRB 260924A: GROWTH-India Telescope optical observations
  41. GRB 260924A: Swift-BAT refined analysis
  42. GRB 260924A: NuSTAR detection of prompt emission
  43. GRB 260924A: Swift/UVOT Upper Limits
  44. GRB 260924A: Swift-XRT refined Analysis
  45. Konus-Wind detection of GRB 260922A
  46. GRB 260922A: NuSTAR detection of prompt emission
  47. GRB 260921A: NuSTAR detection of prompt emission
  48. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  49. GRB 260921A: SVOM/GRM observation
  50. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  51. GRB 260924A: Fermi GRB Observation
  52. Konus-Wind detection of GRB 260921A (possible merger-origin)
  53. GRB 260924A: Fermi-LAT detection of a bright burst
  54. GRB 260924A: AstroSat CZTI detection
  55. GRB 260920A: SVOM/GRM observation
  56. GRB 260924A: NOT optical counterpart confirmation
  57. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  58. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  59. GRB 260924A: Enhanced Swift-XRT position
  60. The EP-WXT trigger 01709319842 is likely a flaring star
  61. GRB 260924A: Swift detection of a burst
  62. GRB 260924A: Fermi GBM Final Real-time Localization
  63. Fermi GRB 260923A: Global MASTER-Net observations report
  64. GRB 260923A: Fermi GBM Final Real-time Localization
  65. Trigger_21914: Swift ToO observations
  66. EP260806a: e-MERLIN detection at 5 GHz
  67. GRB 260922A: Ondrejov D50 optical limit
  68. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  69. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  70. ATCA observations of GRB 260909A
  71. GRB 260922A: Swift-BAT refined analysis
  72. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  73. GRB 260922A: J-band upper limit with WINTER
  74. GRB 260922A: Swift/UVOT Upper Limits
  75. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  76. GRB 260922A: COLIBRÍ optical upper limits
  77. GRB 260922A: Swift-XRT refined Analysis
  78. GRB 260922A: Enhanced Swift-XRT position
  79. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  80. Konus-Wind detection of GRB 260810A
  81. GRB 260920A: Glowbug gamma-ray detection
  82. GRB 260918A: SVOM/ECLAIRs refined analysis
  83. GRB 260922A: SVOM/C-GFT optical upper limit
  84. GRB 260922A: Swift detection of a burst
  85. GRB 260917C: AstroSat CZTI detection
  86. GRB 260920B/EP260920b: GECAM-B detection of a burst
  87. GRB 260921A: AstroSat CZTI detection
  88. GRB 260921A: Swift-BAT refined analysis
  89. GRB 260921B: Fermi GBM Final Localization
  90. GRB 260921A: Fermi GBM Observation
  91. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  92. EP Alert 260921.58: Global MASTER-Net observations report
  93. GRB 260917B:: SVOM/ECLAIRs refined analysis
  94. The EP-WXT trigger 01709319528 is likely a flaring star
  95. EP260920a: VLT/HAWK-I near-infrared candidate
  96. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  97. Swift GRB 260921A: Global MASTER-Net observations report
  98. GRB 260921A: Swift detection of a burst
  99. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  100. GRB 260921A: Fermi GBM Final Real-time Localization

Advanced

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