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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"

3039 results found.

  1. Fermi trigger No 728796365: Global MASTER-Net observations report
  2. IceCube Alert 240204.38: Global MASTER-Net observations report
  3. GRB 240127A: Fermi GBM Final Real-time Localization
  4. GRB 240123A: GRBAlpha detection
  5. GRB 240118A: Mondy optical observations
  6. GRB 240118A: Swift-XRT afterglow detection
  7. GRB 240118A: AbAO optical upper limit
  8. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  9. IPN triangulation of GRB 240112A (long)
  10. GRB 240115B: AstroSat CZTI detection
  11. GRB 240107A: VZLUSAT-2 detection
  12. GRB 240115B: Fermi GBM Final Real-time Localization
  13. Fermi trigger No 726774492: Global MASTER-Net observations report
  14. Fermi GRB 240112B: Global MASTER-Net observations report
  15. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  16. GRB 240107A: MAXI/GSC detection
  17. Fermi trigger No 726194053: Global MASTER-Net observations report
  18. GRB 231230A: GOTO optical upper limits
  19. Fermi trigger No 725592555: Global MASTER-Net observations report
  20. LAT GRB231222.31: Global MASTER-Net observations report
  21. GRID detection of GRB 231215A
  22. Fermi trigger No 724781422: Global MASTER-Net observations report
  23. GRB 231215A: GRBAlpha detection
  24. Swift GRB231216.77: Global MASTER-Net observations report
  25. Konus-Wind detection of GRB 231215A
  26. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  27. GRB 231215A: Fermi GBM observation
  28. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  29. GRB 231215A: AGILE detection
  30. GRB 231215A: AstroSat CZTI detection
  31. GRB 231215B: Fermi GBM Final Real-time Localization
  32. GRB 231215A: Swift detection of a burst
  33. Fermi trigger No 724278269: Global MASTER-Net observations report
  34. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  35. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  36. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  37. IceCube-231202A: No candidates from the Zwicky Transient Facility
  38. IPN triangulation of GRB 231129C
  39. GRB 231208A: AstroSat CZTI detection of a faint burst
  40. GRB 231205B: Swift detection of a burst
  41. Fermi trigger No 723435916: Global MASTER-Net observations report
  42. Fermi trigger No 723326169: Global MASTER-Net observations report
  43. Fermi trigger No 723412808: Global MASTER-Net observations report
  44. GRB 231203A: Fermi GBM Final Real-time Localization
  45. GRB 231129A : MITSuME Akeno optical upper limits
  46. GRB 231129C: MAXI/GSC detection
  47. GRB 231117A: MeerKAT 1.3GHz detection
  48. GRB 231125A: GRBAlpha detection
  49. GRB 231125A: CALET Gamma-Ray Burst Monitor detection
  50. GRB 231125A (short): Glowbug gamma-ray detection
  51. GRB 231125A: AstroSat CZTI detection of a short burst
  52. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  53. Fermi trigger No 722462310: Global MASTER-Net observations report
  54. GRB 231115A: JinShan optical upper limits
  55. GRB 231116A: Fermi GBM Final Real-time Localization
  56. GRB 231115A: MASTER optical observations
  57. Integral GRB231115.65: Global MASTER-Net observations report
  58. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  59. Fermi GRB 231115A: Global MASTER-Net observations report
  60. GRB 231104A: VZLUSAT-2 detection
  61. GRB231111A: YAHPT Observations
  62. Swift GRB231110.89: Global MASTER-Net observations report
  63. IceCube-231103A: No candidates from the Zwicky Transient Facility
  64. Fermi GRB 231108A: Global MASTER-Net observations report
  65. GRB 231104A: Swift-BAT refined analysis
  66. Fermi trigger No 721006392: Global MASTER-Net observations report
  67. Fermi GRB 231106A: Global MASTER-Net observations report
  68. GRB 231104A: NuSTAR Observation of the prompt emission
  69. GRB 231104A: Fermi GBM Observation
  70. GRB 231104B: Fermi GBM Final Real-time Localization
  71. Fermi GRB 231103A: Global MASTER-Net observations report
  72. GRB 231104A: AstroSat CZTI detection
  73. GRB 231104A: Fermi-LAT detection
  74. GRB 231104A: Enhanced Swift-XRT position
  75. GRB 231104A: Swift detection of a bright burst
  76. GRB 231104A: Fermi GBM Final Real-time Localization
  77. LIGO/Virgo/KAGRA S231102i: Global MASTER-Net observations report
  78. Fermi GRB 231030B: Global MASTER-Net observations report
  79. IceCube Alert 231027.18: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  82. Fermi trigger No 719846439: Global MASTER-Net observations report
  83. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  84. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  85. Fermi GRB 231019A: Global MASTER-Net observations report
  86. GRB 231017A: JinShan optical upper limit
  87. GRB 231015A: Glowbug gamma-ray detection
  88. IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility
  89. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  90. GRB 230906A: optical counterpart
  91. Fermi trigger No 716449174: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  93. GRB 230911A: GOTO optical counterpart candidate
  94. GRB 230906A: Chandra detection of the X-ray afterglow
  95. GRB 230911C: Swift detection of a burst
  96. GRB 230906A: Swift-XRT observations
  97. IPN triangulation of GRB 230906A (short)
  98. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  99. Fermi trigger No 715429986: Global MASTER-Net observations report
  100. Fermi GRB 230904A: Global MASTER-Net observations report

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