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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"

3028 results found.

  1. GRB 240118A: Swift-XRT afterglow detection
  2. GRB 240118A: AbAO optical upper limit
  3. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  4. IPN triangulation of GRB 240112A (long)
  5. GRB 240115B: AstroSat CZTI detection
  6. GRB 240107A: VZLUSAT-2 detection
  7. GRB 240115B: Fermi GBM Final Real-time Localization
  8. Fermi trigger No 726774492: Global MASTER-Net observations report
  9. Fermi GRB 240112B: Global MASTER-Net observations report
  10. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  11. GRB 240107A: MAXI/GSC detection
  12. Fermi trigger No 726194053: Global MASTER-Net observations report
  13. GRB 231230A: GOTO optical upper limits
  14. Fermi trigger No 725592555: Global MASTER-Net observations report
  15. LAT GRB231222.31: Global MASTER-Net observations report
  16. GRID detection of GRB 231215A
  17. Fermi trigger No 724781422: Global MASTER-Net observations report
  18. GRB 231215A: GRBAlpha detection
  19. Swift GRB231216.77: Global MASTER-Net observations report
  20. Konus-Wind detection of GRB 231215A
  21. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  22. GRB 231215A: Fermi GBM observation
  23. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  24. GRB 231215A: AGILE detection
  25. GRB 231215A: AstroSat CZTI detection
  26. GRB 231215B: Fermi GBM Final Real-time Localization
  27. GRB 231215A: Swift detection of a burst
  28. Fermi trigger No 724278269: Global MASTER-Net observations report
  29. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  30. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  31. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube-231202A: No candidates from the Zwicky Transient Facility
  33. IPN triangulation of GRB 231129C
  34. GRB 231208A: AstroSat CZTI detection of a faint burst
  35. GRB 231205B: Swift detection of a burst
  36. Fermi trigger No 723435916: Global MASTER-Net observations report
  37. Fermi trigger No 723326169: Global MASTER-Net observations report
  38. Fermi trigger No 723412808: Global MASTER-Net observations report
  39. GRB 231203A: Fermi GBM Final Real-time Localization
  40. GRB 231129A : MITSuME Akeno optical upper limits
  41. GRB 231129C: MAXI/GSC detection
  42. GRB 231117A: MeerKAT 1.3GHz detection
  43. GRB 231125A: GRBAlpha detection
  44. GRB 231125A: CALET Gamma-Ray Burst Monitor detection
  45. GRB 231125A (short): Glowbug gamma-ray detection
  46. GRB 231125A: AstroSat CZTI detection of a short burst
  47. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  48. Fermi trigger No 722462310: Global MASTER-Net observations report
  49. GRB 231115A: JinShan optical upper limits
  50. GRB 231116A: Fermi GBM Final Real-time Localization
  51. GRB 231115A: MASTER optical observations
  52. Integral GRB231115.65: Global MASTER-Net observations report
  53. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  54. Fermi GRB 231115A: Global MASTER-Net observations report
  55. GRB 231104A: VZLUSAT-2 detection
  56. GRB231111A: YAHPT Observations
  57. Swift GRB231110.89: Global MASTER-Net observations report
  58. IceCube-231103A: No candidates from the Zwicky Transient Facility
  59. Fermi GRB 231108A: Global MASTER-Net observations report
  60. GRB 231104A: Swift-BAT refined analysis
  61. Fermi trigger No 721006392: Global MASTER-Net observations report
  62. Fermi GRB 231106A: Global MASTER-Net observations report
  63. GRB 231104A: NuSTAR Observation of the prompt emission
  64. GRB 231104A: Fermi GBM Observation
  65. GRB 231104B: Fermi GBM Final Real-time Localization
  66. Fermi GRB 231103A: Global MASTER-Net observations report
  67. GRB 231104A: AstroSat CZTI detection
  68. GRB 231104A: Fermi-LAT detection
  69. GRB 231104A: Enhanced Swift-XRT position
  70. GRB 231104A: Swift detection of a bright burst
  71. GRB 231104A: Fermi GBM Final Real-time Localization
  72. LIGO/Virgo/KAGRA S231102i: Global MASTER-Net observations report
  73. Fermi GRB 231030B: Global MASTER-Net observations report
  74. IceCube Alert 231027.18: Global MASTER-Net observations report
  75. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  77. Fermi trigger No 719846439: Global MASTER-Net observations report
  78. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  79. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  80. Fermi GRB 231019A: Global MASTER-Net observations report
  81. GRB 231017A: JinShan optical upper limit
  82. GRB 231015A: Glowbug gamma-ray detection
  83. IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility
  84. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  85. GRB 230906A: optical counterpart
  86. Fermi trigger No 716449174: Global MASTER-Net observations report
  87. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  88. GRB 230911A: GOTO optical counterpart candidate
  89. GRB 230906A: Chandra detection of the X-ray afterglow
  90. GRB 230911C: Swift detection of a burst
  91. GRB 230906A: Swift-XRT observations
  92. IPN triangulation of GRB 230906A (short)
  93. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  94. Fermi trigger No 715429986: Global MASTER-Net observations report
  95. Fermi GRB 230904A: Global MASTER-Net observations report
  96. GRB 230828A: AstroSat CZTI detection
  97. Fermi GRB 230827A: Global MASTER-Net observations report
  98. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  99. GRB 230826A: Swift detection of a burst
  100. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations

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