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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

2445 results found.

  1. GRB 260706A : GRANDMA Upper limits
  2. GRB 260708A: GECAM-B observation of a burst
  3. IceCube-260708A: One candidate from the Zwicky Transient Facility
  4. GRB 260708A: Fermi-GBM observation
  5. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  6. IceCube Alert 260709A: Global MASTER-Net observations report
  7. GRB 260709A: Fermi GBM Final Real-time Localization
  8. LAT GRB260708.42: Global MASTER-Net observations report
  9. GRB260708B: MAXI/GSC detection
  10. GRB 260708A: Fermi-LAT detection
  11. GRB 260705B: SVOM/GRM observation
  12. GRB 260708A: Fermi-GBM detection
  13. GRB 260706A: Further EP-FXT follow-up observation
  14. GRB 260706A: SVOM/VT optical upper limits
  15. EP260707a (by EP-FXT): NOT optical upper limit
  16. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  17. EP260707a: Einstein Probe detection of an X-ray transient
  18. Nova AT2026oyp (ASASSN-26dt): Pre-outburst Swift UVOT observation
  19. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  20. GRB 260705C: Glowbug gamma-ray detection of a short burst
  21. GRB 260706A: SVOM/ECLAIRs refined analysis
  22. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  23. GRB 260706A: SVOM/GRM observation
  24. GRB 260706A: REM optical/NIR observations
  25. IceCube-260704A: No candidates from the Zwicky Transient Facility
  26. GRB 260706A: LCO optical upper limit
  27. GRB 260706A: EP-FXT follow-up observation
  28. GRB 260707A: Fermi GBM Final Real-time Localization
  29. The EP-WXT trigger 01709274151 is likely a flaring star
  30. The EP-WXT trigger 01709274141 is likely a flaring star
  31. GRB 260706A: Fermi GBM Observation
  32. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  33. GRB 260706A: SVOM detection of a burst
  34. GRB 260706A: Fermi GBM Final Real-time Localization
  35. The EP-WXT trigger 01709274014 is likely a flaring star
  36. IceCube260704A: OHP/T193 optical observations
  37. GRB 260705A: LCO optical upper limits
  38. GRB 260704A: NOT optical upper limits
  39. GRB 260705C: Fermi GBM Final Localization
  40. GRB 260705B: Fermi GBM Final Real-time Localization
  41. Fermi GBM Sub-Threshold Detection of GRB 260705A
  42. GRB 260705A: SVOM detection of a burst
  43. GRB 260704A: EP-FXT follow-up observation
  44. GRB 260629A: SVOM/GRM observation of a short burst
  45. GRB 260629A: GECAM-A observation of a short burst
  46. GRB 260629A: AstroSat CZTI detection
  47. EP260703a: EP-FXT follow-up observation
  48. GRB 260704A: SVOM detection of a possible GRB
  49. GRB 260703B: Fermi GBM Final Localization
  50. EP260703a: EP-WXT detection of a fast X-ray transient
  51. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  52. Fermi trigger No 804738310: Global MASTER-Net observations report
  53. Fermi GRB 260703A: Global MASTER-Net observations report
  54. GRB 260703A: Fermi GBM Final Localization
  55. GRB 260610B: VLA detection
  56. GRB 260623A: Glowbug gamma-ray detection
  57. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  58. Fermi trigger No 804552016: Global MASTER-Net observations report
  59. GRB 260701A: Fermi GBM Final Real-time Localization
  60. Fermi GBM trigger 804552016/260630945 is not a GRB
  61. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  62. EP260628a: EP-FXT follow-up observation
  63. GRB 260629A: Fermi GBM Final Real-time Localization
  64. Fermi GRB 260628A: Global MASTER-Net observations report
  65. EP260628a: EP-WXT detection of a fast X-ray transient
  66. GRB 260628A: Fermi GBM Final Real-time Localization
  67. The EP-WXT trigger 01709272671 is likely a flaring star
  68. EP260626a: further Liverpool Telescope optical upper limits
  69. EP260626a: COLIBRÍ optical upper limit
  70. EP260626a: Liverpool Telescope upper limits
  71. EP260626a: EP-WXT detection of a fast X-ray transient
  72. EP260623a: TNG NIR afterglow detection
  73. GRB 260618A: Fermi GBM Observation
  74. MASS-Cube (GRID 2.0) detection of GRB 260616B
  75. EP260623a: FTW optical and NIR observations
  76. EP260623a: Liverpool Telescope optical observations
  77. Fermi GBM trigger 804010507/260624677 is not a GRB
  78. GRB 260624A: Fermi GBM Final Real-time Localization
  79. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  80. EP260623a: WINTER J-band observations
  81. GRB 260617A: Glowbug gamma-ray detection of a short burst
  82. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  83. EP260623a: Optical follow-up observations with Kinder
  84. GRB 260623A: Fermi GBM Final Real-time Localization
  85. EP260623a: SVOM/VT optical observations
  86. EP260623a: TRT optical observations
  87. EP260623a: REM optical/NIR afterglow detection
  88. EP 260623a: COLIBRÍ optical observations
  89. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  90. EP260623a: OSIRIS+/GTC redshift z = 0.703
  91. EP260623a: Einstein Probe detection of an X-ray transient
  92. GRB 260614B: EP-FXT follow-up observation
  93. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  94. EP260618a: Liverpool Telescope optical observations
  95. GRB 260618B: LCO optical observations
  96. The EP-WXT trigger 01709271197 is likely a flaring star
  97. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  98. GRB 260618B: Fermi GBM Observation
  99. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection

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