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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').
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"

15246 results found.

  1. GRB260914A: MAO/AZT-22 optical observations
  2. GRB 260924A: COLIBRÍ optical observations
  3. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  4. EP260924a: EP-FXT follow-up observation
  5. Swift Trigger 1513439 is probably not a GRB
  6. Konus-Wind detection of GRB 260924A
  7. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  8. GRB 260924A: Optical follow-up observations with Kinder
  9. GRB 260924A: SVOM/GRM observation
  10. GRB 260923A: Insight-HXMT/HE detection
  11. EP260924a: EP-WXT detection of an X-ray transient
  12. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  13. GRB 260924A: GROWTH-India Telescope optical observations
  14. Konus-Wind detection of GRB 260922A
  15. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  16. GRB 260921A: SVOM/GRM observation
  17. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  18. Konus-Wind detection of GRB 260921A (possible merger-origin)
  19. GRB 260924A: Fermi-LAT detection of a bright burst
  20. GRB 260924A: AstroSat CZTI detection
  21. GRB 260920A: SVOM/GRM observation
  22. GRB 260924A: NOT optical counterpart confirmation
  23. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  24. Trigger_21914: Swift ToO observations
  25. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  26. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  27. ATCA observations of GRB 260909A
  28. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  29. GRB 260922A: COLIBRÍ optical upper limits
  30. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  31. Konus-Wind detection of GRB 260810A
  32. GRB 260918A: SVOM/ECLAIRs refined analysis
  33. GRB 260917C: AstroSat CZTI detection
  34. GRB 260920B/EP260920b: GECAM-B detection of a burst
  35. GRB 260921A: AstroSat CZTI detection
  36. GRB 260921A: Fermi GBM Observation
  37. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  38. GRB 260917B:: SVOM/ECLAIRs refined analysis
  39. The EP-WXT trigger 01709319528 is likely a flaring star
  40. EP260920a: VLT/HAWK-I near-infrared candidate
  41. GRB 260920A: AstroSat CZTI detection
  42. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  43. EP260920b: COLIBRÍ optical observations
  44. The EP-WXT trigger 01709318601 is likely a flaring star
  45. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  46. EP-WXT detected a brightening of HMXB LS V +44 17
  47. EP260920a: NOT optical upper limits
  48. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  49. EP260920a: COLIBRÍ optical upper limits
  50. EP260920a: Update of the LCO optical counterpart candidate
  51. EP260917a: refined analysis of the EP-FXT observations
  52. IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
  53. The EP-WXT trigger 01709318491 is likely a flaring star
  54. EP260806a: Yamaguchi Interferometer radio detections
  55. Konus-Wind detection of GRB 260916B (short/hard)
  56. GRB 260917B: Mondy optical upper limit
  57. EP260917b: EP-WXT detection of an X-ray transient
  58. EP260917A: J-band upper limit with WINTER
  59. GRB 260915A: Swift-XRT afterglow detection
  60. GRB 260918A: SVOM detection of a burst
  61. GRB 260917B: FRAM-Auger optical limits
  62. GRB 260916B: Fermi GBM Detection
  63. IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
  64. GRB 260917A: Glowbug gamma-ray detection
  65. GRB 260915A: SVOM/ECLAIRs refined analysis
  66. GRB 260917B: SVOM detection of a faint burst
  67. GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  68. The EP-WXT trigger 01709317235 is likely a flaring star
  69. IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
  70. GRB 260914A: SVOM/GRM observation
  71. GRB 260914A: Mondy and TShAO optical observations
  72. GRB 260914A: SVOM/ECLAIRs refined analysis
  73. GRB 260915A: Swift ToO observations
  74. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  75. GRB 260914A: REM optical/NIR observations
  76. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  77. GRB 260915A: SVOM/VT optical upper limits
  78. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  79. GRB 260915A: 10.4m GTC deep optical limits
  80. GRB 260915A: SVOM detection of a burst
  81. GRB 260914A: LCO optical observation
  82. GRB 260914A: SVOM/VT optical observation from VHF data
  83. GRB 260914A: SVOM detection of a burst
  84. GRB 260913A: SVOM detection of a faint burst
  85. GRB 260907A: SVOM/GRM observation
  86. GRB 260909A: SVOM/ECLAIRs refined analysis
  87. GRB 260910B: GOTO tentative optical counterpart candidates
  88. GRB 260909A: Swift ToO observations
  89. EP260806a: VLA+ALMA radio detections
  90. GRB 260909A: OHP/T193 z-band upper limit
  91. GRB 260909A: VLT optical and near-infrared upper limits
  92. GRB 260909A: SVOM/GRM observation
  93. GRB 260909A: SVOM detection of a burst
  94. GRB 260903A: Swift ToO observations
  95. GRB 260903A: SVOM/ECLAIRs refined analysis
  96. GRB260903A: Liverpool Telescope optical observations
  97. GRB 260830A: GECAM-B detection of a burst
  98. GRB 260830A: Insight-HXMT/HE detection
  99. GRB 260903A: OHP/T193 optical afterglow detection
  100. GRB 260903A: NOT optical observations and afterglow fading

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