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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"

3106 results found.

  1. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  2. GRB 231215A: AGILE detection
  3. GRB 231215A: AstroSat CZTI detection
  4. GRB 231215B: Fermi GBM Final Real-time Localization
  5. GRB 231215A: Swift detection of a burst
  6. Fermi trigger No 724278269: Global MASTER-Net observations report
  7. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  8. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  9. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  10. IceCube-231202A: No candidates from the Zwicky Transient Facility
  11. IPN triangulation of GRB 231129C
  12. GRB 231208A: AstroSat CZTI detection of a faint burst
  13. GRB 231205B: Swift detection of a burst
  14. Fermi trigger No 723435916: Global MASTER-Net observations report
  15. Fermi trigger No 723326169: Global MASTER-Net observations report
  16. Fermi trigger No 723412808: Global MASTER-Net observations report
  17. GRB 231203A: Fermi GBM Final Real-time Localization
  18. GRB 231129A : MITSuME Akeno optical upper limits
  19. GRB 231129C: MAXI/GSC detection
  20. GRB 231117A: MeerKAT 1.3GHz detection
  21. GRB 231125A: GRBAlpha detection
  22. GRB 231125A: CALET Gamma-Ray Burst Monitor detection
  23. GRB 231125A (short): Glowbug gamma-ray detection
  24. GRB 231125A: AstroSat CZTI detection of a short burst
  25. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  26. Fermi trigger No 722462310: Global MASTER-Net observations report
  27. GRB 231115A: JinShan optical upper limits
  28. GRB 231116A: Fermi GBM Final Real-time Localization
  29. GRB 231115A: MASTER optical observations
  30. Integral GRB231115.65: Global MASTER-Net observations report
  31. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  32. Fermi GRB 231115A: Global MASTER-Net observations report
  33. GRB 231104A: VZLUSAT-2 detection
  34. GRB231111A: YAHPT Observations
  35. Swift GRB231110.89: Global MASTER-Net observations report
  36. IceCube-231103A: No candidates from the Zwicky Transient Facility
  37. Fermi GRB 231108A: Global MASTER-Net observations report
  38. GRB 231104A: Swift-BAT refined analysis
  39. Fermi trigger No 721006392: Global MASTER-Net observations report
  40. Fermi GRB 231106A: Global MASTER-Net observations report
  41. GRB 231104A: NuSTAR Observation of the prompt emission
  42. GRB 231104A: Fermi GBM Observation
  43. GRB 231104B: Fermi GBM Final Real-time Localization
  44. Fermi GRB 231103A: Global MASTER-Net observations report
  45. GRB 231104A: AstroSat CZTI detection
  46. GRB 231104A: Fermi-LAT detection
  47. GRB 231104A: Enhanced Swift-XRT position
  48. GRB 231104A: Swift detection of a bright burst
  49. GRB 231104A: Fermi GBM Final Real-time Localization
  50. LIGO/Virgo/KAGRA S231102i: Global MASTER-Net observations report
  51. Fermi GRB 231030B: Global MASTER-Net observations report
  52. IceCube Alert 231027.18: Global MASTER-Net observations report
  53. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  55. Fermi trigger No 719846439: Global MASTER-Net observations report
  56. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  57. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  58. Fermi GRB 231019A: Global MASTER-Net observations report
  59. GRB 231017A: JinShan optical upper limit
  60. GRB 231015A: Glowbug gamma-ray detection
  61. IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility
  62. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  63. GRB 230906A: optical counterpart
  64. Fermi trigger No 716449174: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  66. GRB 230911A: GOTO optical counterpart candidate
  67. GRB 230906A: Chandra detection of the X-ray afterglow
  68. GRB 230911C: Swift detection of a burst
  69. GRB 230906A: Swift-XRT observations
  70. IPN triangulation of GRB 230906A (short)
  71. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  72. Fermi trigger No 715429986: Global MASTER-Net observations report
  73. Fermi GRB 230904A: Global MASTER-Net observations report
  74. GRB 230828A: AstroSat CZTI detection
  75. Fermi GRB 230827A: Global MASTER-Net observations report
  76. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  77. GRB 230826A: Swift detection of a burst
  78. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  79. Swift GRB230825.75: Global MASTER-Net observations report
  80. GRB 230812B: radio detection with the VLA
  81. Fermi trigger No 714618399: Global MASTER-Net observations report
  82. GRB 230812B: Assy optical observations, possible SN rise
  83. Swift GRB230820.81: Global MASTER-Net observations report
  84. Fermi GRB 230818A: Global MASTER-Net observations report
  85. Swift GRB230818.98: Global MASTER-Net observations report
  86. IPN triangulation of GRB 230815B
  87. Fermi GRB 230814A: Global MASTER-Net observations report
  88. GRB 230812B: continued AbAO optical afterglow observations
  89. GRB 230812B: Optical observaions from Rozhen Observatory
  90. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  91. GRB 230812B: CrAO ZTSh optical observations
  92. GRB 230812B: Koshka Zeiss-1000 optical observations
  93. GRB 230812B: Leavitt Observatory optical observations
  94. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  95. GRB 230812B: AbAO optical observations
  96. GRB 230812B: Montarrenti Observatory optical observations
  97. GRB 230812B: Detected Optical Afterglow Candidate
  98. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  99. Fermi GRB 230812B: MASTER optical counterpart
  100. GRB 230812B: KAIT Optical Afterglow Candidate

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