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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"

3674 results found.

  1. Fermi trigger No 724233240: Global MASTER-Net observations report
  2. GRB 231214A: Swift detection of a burst
  3. GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
  4. GRB 231129C: ASIM MXGS observation and localization
  5. Fermi trigger No 723435916: Global MASTER-Net observations report
  6. Fermi trigger No 723326169: Global MASTER-Net observations report
  7. Fermi trigger No 723149952: Global MASTER-Net observations report
  8. GRB 231128A: VZLUSAT-2 detection
  9. GRB 231129C: MAXI/GSC detection
  10. GRB 231128A: Fermi GBM Final Real-time Localization
  11. Fermi trigger No 722507896: Global MASTER-Net observations report
  12. GRB230728A: VIRT optical upper limit
  13. Fermi trigger No 722400249: Global MASTER-Net observations report
  14. GRB 231118A: MeerLICHT afterglow detection
  15. GRB 231115A: optical observations from INAF observatories
  16. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  17. Swift GRB231110.89: Global MASTER-Net observations report
  18. Fermi GRB 231108A: Global MASTER-Net observations report
  19. Fermi trigger No 721006392: Global MASTER-Net observations report
  20. Fermi GRB 231106A: Global MASTER-Net observations report
  21. Fermi GRB 231103A: Global MASTER-Net observations report
  22. GRB 231104A: Fermi-LAT detection
  23. GRB 231104A: Swift detection of a bright burst
  24. GRB 231104A: Fermi GBM Final Real-time Localization
  25. Fermi trigger No 720498201: Global MASTER-Net observations report
  26. GRB 231028B: VZLUSAT-2 detection
  27. Fermi GRB 231030B: Global MASTER-Net observations report
  28. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  30. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  31. GRB 231028A: AstroSat CZTI detection
  32. GRB 231028A: Glowbug gamma-ray detection
  33. GRB 231028A: Fermi GBM Detection
  34. Fermi trigger No 720224759: Global MASTER-Net observations report
  35. Swift GRB 231028A: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
  37. GRB 231028A: Fermi GBM Final Real-time Localization
  38. IceCube Alert 231027.18: Global MASTER-Net observations report
  39. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  41. Fermi trigger No 719846439: Global MASTER-Net observations report
  42. Fermi GRB 231019A: Global MASTER-Net observations report
  43. Konus-Wind detection of GRB 231018A
  44. IPN triangulation of GRB 231018A
  45. GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
  46. IceCube-231004A: No significant detection in HAWC
  47. LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
  48. NuEm-230927A: Swift-XRT follow-up
  49. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  51. IPN triangulation of GRB 230919A (short)
  52. GRB 230916A: NuSTAR Discovery of Prompt Emission from a Potential GRB
  53. Fermi trigger No 716449174: Global MASTER-Net observations report
  54. Fermi trigger No 716145795: Global MASTER-Net observations report
  55. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  56. Fermi GRB 230906A: Global MASTER-Net observations report
  57. GRB 230904C: Fermi GBM Final Localization
  58. Fermi trigger No 715429986: Global MASTER-Net observations report
  59. Fermi GRB 230903A: Global MASTER-Net observations report
  60. GRB 230828A: AstroSat CZTI detection
  61. GRB 230828A: GRBAlpha detection
  62. GRB 230827B / GRB 230827256: Fermi GBM Observation
  63. Fermi GRB 230827A: Global MASTER-Net observations report
  64. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  65. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  66. Integral GRB230824.72: Global MASTER-Net observations report
  67. Swift GRB230821.64: Global MASTER-Net observations report
  68. Swift Triggers 1186280 and 1186291 are not GRBs
  69. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  70. Fermi GRB 230818A: Global MASTER-Net observations report
  71. Swift GRB230818.98: Global MASTER-Net observations report
  72. Swift GRB230818.98: Global MASTER-Net OT detection
  73. Swift GRB230816.80: Global MASTER-Net observations report
  74. LAT GRB230812.79: Global MASTER-Net observations report
  75. Fermi trigger No 713525317: Global MASTER-Net observations report
  76. GRB 230812A: Fermi GBM Final Real-time Localization
  77. GRB 230805B : MITSuME Akeno optical upper limits
  78. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  79. Fermi trigger No 713134237: Global MASTER-Net observations report
  80. GRB 230803A: AstroSat CZTI detection
  81. IceCube-230724A: JCMT/SCUBA-2 submm observations
  82. IceCube-230707A: JCMT/SCUBA-2 submm observations
  83. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  84. Fermi trigger No 712306969: Global MASTER-Net observations report
  85. IceCube-230727A: No candidates from the Zwicky Transient Facility
  86. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  87. GRB 230728A: BOOTES-1 optical upper limit
  88. GRB 230728A: Fermi GBM Observation
  89. GRB 230728A: LCOGT Optical Upper Limit
  90. GRB 230728A: NOT optical observations and possible host galaxy
  91. Swift GRB230728.12: Global MASTER-Net observations report
  92. Fermi GRB 230723A: Global MASTER-Net observations report
  93. IPN triangulation of GRB 230715D
  94. GRB 230709C: Fermi GBM Final Localization
  95. IceCube Alert 230707.71: Global MASTER-Net observations report
  96. LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230701z: one counterpart neutrino candidate from IceCube neutrino searches
  98. IPN triangulation of GRB 230625B (ultra-long)
  99. GRB 230625B: CALET Gamma-Ray Burst Monitor detection
  100. GRB 230625B: AstroSat CZTI detection

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