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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"

24378 results found.

  1. Swift Trigger 1404295 is not a GRB
  2. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  3. GRB 251017A: Swift detection of a burst with an optical counterpart
  4. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 251016B: CALET Gamma-Ray Burst Monitor detection
  6. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  7. GRB 251016B: Fermi GBM Final Real-time Localization
  8. GRB 251014D: Swift-BAT refined analysis
  9. GRB 251016A: BOOTES-6/DPRT optical upper limit
  10. Fermi GRB 251016A: Global MASTER-Net observations report
  11. GRB 251016A: Fermi GBM Final Localization
  12. GRB 251016A: SVOM detection of a short burst
  13. GRB 251014A: Swift-XRT observations
  14. LIGO/Virgo/KAGRA S251014cn: Updated Sky localization
  15. Upper limits from a search for additional neutrino events in IceCube
  16. IceCube Alert 251014.77: Global MASTER-Net observations report
  17. Swift GRB251015.60: Global MASTER-Net observations report
  18. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  19. Konus-Wind detection of GRB 251007A
  20. GRB 251015A: Fermi GBM Final Real-time Localization
  21. GRB 251013C: SVOM/ECLAIRs refined analysis
  22. GRB 251013D: Swift-XRT observations
  23. GRB 251014B: Swift-XRT observations
  24. GRB 251014B: VLT/FORS2 Optical Observation
  25. GRB 251011B: SVOM/VT optical upper limit
  26. GRB 251013D: Fermi GBM Observation
  27. GRB 251014A: Swift-BAT refined analysis
  28. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
  29. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  30. GRB 251014D: Swift detection of a burst
  31. GRB 251014A: PRIME near-infrared upper limits
  32. GRB 251014C: Fermi GBM Final Localization
  33. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  34. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  35. GRB 251013C: Early and late-time optical counterpart detection by LCO
  36. LIGO/Virgo/KAGRA S251014cn: NED Galaxies in the 3-Initial Localization Volume
  37. GRB 251013C: Fermi GBM Observation
  38. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  39. LIGO/Virgo/KAGRA S251014cn: Identification of a GW compact binary merger candidate
  40. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  41. GRB 251013C: ABObservatory optical observations
  42. GRB 251014A: Fermi GBM Observation
  43. GRB 251013C: EP-FXT counterpart detection
  44. GRB 251013C: AstroSat CZTI detection
  45. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  46. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  47. Swift GRB 251014A: Global MASTER-Net observations report
  48. GRB 251014A: Swift detection of a possibly-short burst
  49. GRB 251014A: Fermi GBM Final Real-time Localization
  50. Fermi trigger No 782044789: Global MASTER-Net observations report
  51. Fermi GRB 251013C: Global MASTER-Net observations report
  52. Fermi GRB 251013B: Global MASTER-Net observations report
  53. Fermi GRB 251013D: Global MASTER-Net observations report
  54. GRB 251013C: LCO optical afterglow detection
  55. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy
  56. GRB 251013C: NOT spectroscopic redshift z = 0.572
  57. GRB 251013C: BOOTES-6 early optical detection
  58. GRB 251013D: Fermi GBM Final Real-time Localization
  59. GRB 251013C: SVOM/VT optical observation
  60. GRB 251013C: SVOM detection of a burst
  61. GRB 251013C: Fermi GBM Final Real-time Localization
  62. LIGO/Virgo/KAGRA S251013x: Updated Sky localization and Source Classification
  63. GRB 251013B: SVOM/GRM observation
  64. GRB 251013A: SVOM/GRM observation
  65. GRB 251013B: Fermi GBM Final Real-time Localization
  66. Fermi GRB 251013A: Global MASTER-Net observations report
  67. GRB 251013A: Fermi GBM Final Real-time Localization
  68. LIGO/Virgo/KAGRA S251013x: Identification of a GW compact binary merger candidate
  69. GRB 251011B inspection: MASTER orphan GRB detection
  70. Fermi GRB 251011A: Global MASTER-Net observations report
  71. GRB 251012A: Fermi GBM Final Real-time Localization
  72. GRB 251011B: SVOM/GRM observation
  73. GRB 251011B: Fermi GBM Observation
  74. GRB 251011C: Fermi GBM Final Real-time Localization
  75. GRB 251011B: Swift detection of a burst
  76. GRB 251011B: Fermi GBM Final Real-time Localization
  77. GRB 251011A: Fermi GBM Final Real-time Localization
  78. GRB 251010A: Fermi GBM Final Real-time Localization
  79. GRB 251009A: GECAM-B detection of a short burst
  80. GRB 251009B (short): Glowbug gamma-ray detection
  81. GRB 251007A: Swift-BAT refined analysis
  82. GRB 251007A: SVOM/GRM observation
  83. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  84. GRB 251007B - SVOM/ECLAIRs refined analysis
  85. SVOM/sb25101004: SVOM detection of a stellar flare
  86. GRB 251009A: Fermi GBM Final Localization
  87. EP251006a: Global MASTER-Net observations report
  88. GRB 251006A: Fermi GBM Observation
  89. GRB 251002A - SVOM/ECLAIRs refined analysis
  90. IceCube alert 141456_888784 retraction
  91. IceCube Alert 251008A: Global MASTER-Net observations report
  92. GRB 251003A: Fermi GBM Observation
  93. GRB 251006B: Fermi GBM Observation
  94. GRB 251006B/EP251006a: EP-FXT afterglow detection
  95. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  96. GRB 251007B: SVOM/VT optical candidate
  97. GRB 251007A: Swift-XRT refined Analysis
  98. GRB 251007A: SVOM/C-GFT optical observations
  99. GRB 251005C: PRIME J-band upper limit
  100. Swift GRB 251007B: Global MASTER-Net observations report

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