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"

28044 results found.

  1. GRB 260924A: COLIBRÍ optical observations
  2. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  3. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  4. GRB 260925A: Swift-XRT refined Analysis
  5. Swift Trigger 1513439 is probably not a GRB
  6. GRB 260925A: Swift/UVOT Upper Limits
  7. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  8. GRB 260923A: Glowbug gamma-ray detection
  9. GRB 260924A: Optical follow-up observations with Kinder
  10. GRB 260922A: Glowbug gamma-ray detection
  11. GRB 260925A: Enhanced Swift-XRT position
  12. GRB 260925A: COLIBRÍ optical upper limits
  13. GRB 260925A: FRAM-Auger optical limit
  14. GRB 260924A: Ondrejov D50 optical afterglow detection
  15. EP260924a: J-band upper limit with WINTER
  16. GRB 260924A: SVOM/GRM observation
  17. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  18. GRB 260925A: Swift detection of a burst
  19. GRB 260923A: Insight-HXMT/HE detection
  20. EP260924a: EP-WXT detection of an X-ray transient
  21. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  22. GRB 260924A: Swift/UVOT Detection
  23. GRB 260924A: GROWTH-India Telescope optical observations
  24. GRB 260924A: Swift-BAT refined analysis
  25. GRB 260924A: NuSTAR detection of prompt emission
  26. GRB 260924A: Swift-XRT refined Analysis
  27. GRB 260922A: NuSTAR detection of prompt emission
  28. GRB 260921A: NuSTAR detection of prompt emission
  29. GRB 260921A: SVOM/GRM observation
  30. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  31. GRB 260924A: Fermi GRB Observation
  32. GRB 260924A: AstroSat CZTI detection
  33. GRB 260920A: SVOM/GRM observation
  34. GRB 260924A: NOT optical counterpart confirmation
  35. GRB 260924A: Enhanced Swift-XRT position
  36. GRB 260924A: Swift detection of a burst
  37. Fermi GRB 260923A: Global MASTER-Net observations report
  38. EP260806a: e-MERLIN detection at 5 GHz
  39. GRB 260922A: Ondrejov D50 optical limit
  40. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  41. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  42. GRB 260922A: Swift-BAT refined analysis
  43. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  44. GRB 260922A: J-band upper limit with WINTER
  45. GRB 260922A: Swift/UVOT Upper Limits
  46. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  47. GRB 260922A: COLIBRÍ optical upper limits
  48. GRB 260922A: Swift-XRT refined Analysis
  49. GRB 260922A: Enhanced Swift-XRT position
  50. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  51. GRB 260920A: Glowbug gamma-ray detection
  52. GRB 260922A: SVOM/C-GFT optical upper limit
  53. GRB 260922A: Swift detection of a burst
  54. GRB 260921A: AstroSat CZTI detection
  55. GRB 260921A: Swift-BAT refined analysis
  56. GRB 260921A: Fermi GBM Observation
  57. EP Alert 260921.58: Global MASTER-Net observations report
  58. GRB 260917B:: SVOM/ECLAIRs refined analysis
  59. The EP-WXT trigger 01709319528 is likely a flaring star
  60. EP260920a: VLT/HAWK-I near-infrared candidate
  61. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  62. Swift GRB 260921A: Global MASTER-Net observations report
  63. GRB 260921A: Swift detection of a burst
  64. EP260920b: LCO observations
  65. EP260920b: SVOM/VT optical observation
  66. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  67. EP260920b: COLIBRÍ optical observations
  68. EP260920b: LCO optical counterpart detection
  69. EP Alert 260921.01: Global MASTER-Net observations report
  70. EP260920b: Global MASTER-Net observations report
  71. EP260920b: Einstein Probe detection of an X-ray transient
  72. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  73. EP Alert 260920.66: Global MASTER-Net observations report
  74. EP-WXT detected a brightening of HMXB LS V +44 17
  75. EP260920a: NOT early time optical upper limits
  76. EP260920a: NOT optical upper limits
  77. EP260920a: SVOM/VT optical upper limits
  78. EP260917a: Global MASTER-Net observations report
  79. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  80. EP260920a: COLIBRÍ optical upper limits
  81. EP260917b: EP-FXT non-detection and upper limit
  82. IceCube Alert 260919A: Global MASTER-Net observations report
  83. EP260920a: LCO optical counterpart candidate
  84. EP260920a: Einstein Probe detection of an X-ray transient
  85. EP Alert 260919.40: Global MASTER-Net observations report
  86. GRB 260915A: VLT optical and near-infrared upper limits
  87. EP260917a: SVOM/VT optical upper limits
  88. GRB 260918A: SVOM/C-GFT optical upper limits
  89. EP Alert 260918.62: Global MASTER-Net observations report
  90. Fermi GBM Sub-Threshold Detection of GRB 260918A
  91. EP Alert 260918.24: Global MASTER-Net observations report
  92. SVOM GRB260918.16: Global MASTER-Net observations report
  93. GRB 260916B: Glowbug gamma-ray detection of a short burst
  94. GRB 260918A: EP-FXT follow-up observation
  95. GRB 260917B: Mondy optical upper limit
  96. EP260917b: EP-WXT detection of an X-ray transient
  97. EP260917A: J-band upper limit with WINTER
  98. EP Alert 260917.32: Global MASTER-Net observations report
  99. GRB 260917B: EP-FXT follow-up observation
  100. EP260917a: COLIBRÍ optical upper limits

Advanced

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