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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3139 results found.

  1. EP260924a: Global MASTER-Net observations report
  2. Fermi GRB 260926C: Global MASTER-Net observations report
  3. Swift Trigger 1513439 is probably not a GRB
  4. GRB 260924A: Optical follow-up observations with Kinder
  5. GRB 260924A: AstroSat CZTI detection
  6. Fermi GRB 260923A: Global MASTER-Net observations report
  7. GRB 260917C: AstroSat CZTI detection
  8. GRB 260921A: AstroSat CZTI detection
  9. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  10. GRB 260920A: AstroSat CZTI detection
  11. EP260920b: LCO optical counterpart detection
  12. EP Alert 260921.01: Global MASTER-Net observations report
  13. EP260917a: Global MASTER-Net observations report
  14. EP Alert 260918.24: Global MASTER-Net observations report
  15. SVOM GRB260918.16: Global MASTER-Net observations report
  16. Konus-Wind detection of GRB 260916B (short/hard)
  17. IPN triangulation of GRB 260916B (short)
  18. IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
  19. GRB 260915A: SVOM/ECLAIRs refined analysis
  20. MAXI GRB260916.37: Global MASTER-Net observations report
  21. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  22. GRB 260915A: LCO optical upper limits
  23. EP Alert 260914.53: Global MASTER-Net observations report
  24. GRB 260915A: SVOM detection of a burst
  25. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  26. SVOM GRB260914.47: Global MASTER-Net observations report
  27. GRB 260910B: GOTO tentative optical counterpart candidates
  28. GRB 260910B: Fermi GBM Final Real-time Localization
  29. EP Alert 260909.53: Global MASTER-Net observations report
  30. Fermi GRB 260907A: Global MASTER-Net observations report
  31. GRB260903A: Liverpool Telescope optical observations
  32. GRB 260903A: SVOM/VT optical candidate
  33. EP260901a: Global MASTER-Net observations report
  34. GRB 260829A: AstroSat CZTI detection
  35. GRB 260827A: Glowbug gamma-ray detection
  36. GRB 260825A: AstroSat CZTI detection
  37. GRB 260827A: Fermi GBM Final Real-time Localization
  38. IceCube Alert 260825A: Global MASTER-Net observations report
  39. The EP-WXT trigger 01709287395 is likely a flaring star
  40. EP260806a: SVOM/ECLAIRs detection through targeted search
  41. EP260806a: NUTTELA-TAO optical observations
  42. GRB 260810A: AstroSat CZTI detection of a long burst
  43. GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
  44. GRB 260808A: Fermi GBM Final Real-time Localization
  45. SN 2026stf / GRB 260708A: ATLAS forced photometry
  46. GRB 260803A: Fermi GBM Final Real-time Localization
  47. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  48. GRB 260731A: AstroSat CZTI detection of a long burst
  49. GRB 260730B: AstroSat CZTI detection
  50. GRB 260727A: AstroSat CZTI detection
  51. Fermi GRB 260726A: Global MASTER-Net observations report
  52. GRB 260723A: Fermi GBM Final Localization
  53. GRB 260718A: SVOM/VT optical upper limits
  54. SVOM sb26071506: Global MASTER-Net observations report
  55. GRB 260710A: AstroSat CZTI detection
  56. GRB 260709A: AstroSat CZTI detection
  57. GRB 260714B: AstroSat CZTI detection
  58. GRB 260714B: Fermi GBM Final Real-time Localization
  59. GRB 260708A: GRANDMA Optical Observations
  60. GRB 260705C: AstroSat CZTI detection
  61. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  62. LAT GRB260708.42: Global MASTER-Net observations report
  63. GRB 260706A: SVOM/VT optical upper limits
  64. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  65. GRB 260707A: Fermi GBM Final Real-time Localization
  66. IPN triangulation of GRB 260627A
  67. GRB 260629A: AstroSat CZTI detection
  68. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  69. Fermi trigger No 804552016: Global MASTER-Net observations report
  70. GRB 260616B: AstroSat CZTI detection
  71. GRB 260616A: AstroSat CZTI detection
  72. GRB 260506B: cubesat Avion detection
  73. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  74. GRB260616C: MAXI/GSC detection
  75. GRB 260614A: AstroSat CZTI detection
  76. GRB 260603C: AstroSat CZTI detection
  77. EP260605a: COLIBRÍ optical upper limits
  78. GRB 260604C: AstroSat CZTI detection
  79. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  80. GRB 260607B: AstroSat CZTI detection
  81. The EP-WXT trigger 01709267001 is likely a flaring star
  82. GRB 260601B / EP260601a: AstroSat CZTI detection
  83. EP260603a: Global MASTER-Net observations report
  84. Fermi GRB 260602B: Global MASTER-Net observations report
  85. Fermi GRB 260602B: Global MASTER-Net observations report
  86. GRB 260602A: Fermi GBM Final Real-time Localization
  87. Fermi trigger No 801900520: Global MASTER-Net observations report
  88. GRB 260531A: MAXI/GSC detection
  89. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  90. GRB 260526A: GECAM-B observation
  91. GRB 260525A: AstroSat CZTI detection
  92. Fermi GRB 260526A: Global MASTER-Net observations report
  93. GRB 260525A: Fermi GBM Final Real-time Localization
  94. GRB 260523B: AstroSat CZTI detection
  95. GRB 260511A: iTelescope T-75 optical detection
  96. GRB 260518A: AstroSat CZTI detection of a long burst
  97. GRB 260515A: further Liverpool Telescope observations
  98. Fermi GRB 260516C: Global MASTER-Net observations report
  99. GRB 260515A: Liverpool Telescope optical detection
  100. GRB 260515A: LCO optical observations

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