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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"

24600 results found.

  1. GRB 240123A: Swift detection of a burst with a possible optical counterpart
  2. GRB 240122A: Swift-XRT afterglow detection
  3. GRB 240122A: GOTO optical counterpart candidate
  4. IPN triangulation of GRB 240119A (short)
  5. GRB 240119A: GECAM detection of a short burst
  6. GRB 240118C: GECAM-B detection of a long burst
  7. GRB 240119A: AstroSat CZTI detection of a short burst
  8. GRB 240118A: Mondy optical observations
  9. GRB 240118A: Swift-XRT afterglow detection
  10. GRB 240118C: Fermi GBM Observation
  11. IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
  12. GRB 240118C: Swift/BAT-GUANO detection of a burst
  13. GRB 240118D: AstroSat CZTI detection
  14. GRB 240118A: AbAO optical upper limit
  15. GRB 240118A: NuSTAR Offline Analysis of the GRB
  16. GRB 240117A: Glowbug gamma-ray detection
  17. GRB 240118A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  18. GRB 240118C: BALROG localization (Fermi Trigger 727291408 / GRB 240118725)
  19. GRB 240118A: Fermi GBM Observation
  20. GRID detection of GRB 231230A
  21. GRB 240115A: Swift/BAT-GUANO detection of a short burst
  22. Swift Triggers 1209369 and 1209370 are not astrophysical events
  23. GRB 240115B: AstroSat CZTI detection
  24. LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO
  25. GRB 240115B: Fermi GBM Detection
  26. GRB 240112D: Glowbug gamma-ray detection
  27. GRB 240112C: Glowbug gamma-ray detection
  28. GRB 240112C: VZLUSAT-2 detection
  29. GRB 240114A: MAXI/GSC detection
  30. GRB 240112C: Swift/UVOT Detection
  31. GRB 240112C: Fermi GBM Detection
  32. Fermi trigger No 726773850: Global MASTER-Net observations report
  33. GRB 240112C: Swift-XRT refined Analysis
  34. GRB 240112C: SAO RAS optical observations
  35. GRB 240109A: Swift-BAT refined analysis
  36. GRB 240112C: Swift detection of a burst with an optical counterpart
  37. GRB 240112A: GECAM detection of a burst
  38. GRB 240109A: Fermi GBM Observation
  39. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  40. GRB 240108A: Glowbug gamma-ray detection
  41. GRB 240106B: Glowbug gamma-ray detection
  42. GRB 240106A: Glowbug gamma-ray detection
  43. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  44. LIGO/Virgo/KAGRA S240109a: Updated Sky localization
  45. GRB 231215A: radio detection with the VLA
  46. GRB 230818A: further radio observations with the VLA
  47. GRB 230812B: further radio observations with the VLA
  48. Swift GRB240109.17: Global MASTER-Net observations report
  49. LIGO/Virgo/KAGRA S240109a: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240107b: Updated Sky localization and Source Classification
  52. GRB 240107A: MAXI/GSC detection
  53. LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate
  54. IPN triangulation of GRB 240101C (short)
  55. GRB 240101A: 1.3m DFOT optical observations
  56. GRB 240102A: 1.3m DFOT optical upper limit
  57. GRB 240101B: 1.3m DFOT optical upper limit
  58. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  59. LIGO/Virgo/KAGRA S240104bl: Updated Sky localization
  60. LIGO/Virgo/KAGRA S240104bl: Identification of a GW compact binary merger candidate
  61. GRB 240102A: Swift-BAT refined analysis
  62. GRB 240102A: Swift/UVOT Upper Limits
  63. GRB 231230A: Swift-BAT refined analysis
  64. GRB 240101A: Swift-BAT refined analysis
  65. GRB 240101B: Swift-BAT refined analysis
  66. GRB 240102A: Enhanced Swift-XRT position
  67. GRB 240101B: Swift-XRT refined Analysis
  68. GRB 240102A: Swift-XRT refined Analysis
  69. GRB 240102A: LCOGT Optical Upper Limits
  70. GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  71. IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
  72. GRB 240102A: Swift detection of a burst
  73. GRB 240101C: GRBAlpha detection
  74. GRB 240101B: Swift/UVOT Upper Limits
  75. GRB 240101A: Swift/UVOT Upper Limits
  76. GRB 240101A: Swift-XRT refined Analysis
  77. GRB 240101B: Enhanced Swift-XRT position
  78. GRB 240101A: Enhanced Swift-XRT position
  79. GRB 240101B: Swift detection of a burst
  80. LIGO/Virgo/KAGRA S231231ag: Updated Sky localization and Source Classification
  81. LIGO/Virgo/KAGRA S231231ag: Identification of a GW compact binary merger candidate
  82. GRB231230A: Fermi GBM Observation
  83. GRB 231230A: Swift-XRT refined Analysis
  84. GRB 231230A: Enhanced Swift-XRT position
  85. GRB 231230A: Swift/UVOT Upper Limits
  86. GRB 231230A: NOT optical upper limits
  87. GRB 231230A: Swift detection of a burst
  88. LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
  89. LIGO/Virgo/KAGRA S231226av: Updated Sky localization
  90. LIGO/Virgo/KAGRA S231226av: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo/KAGRA S231224e: Updated Sky localization and Source Classification
  92. LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo/KAGRA S231223j: Updated Sky localization
  94. GRB 231222B: Swift-XRT afterglow detection
  95. LIGO/Virgo/KAGRA S231223j: Identification of a GW compact binary merger candidate
  96. GRB 231222B: Fermi GBM Detection
  97. IceCube-231211A: GRANDMA observations of PKS2047+098
  98. GRID detection of GRB 231215A
  99. GRB 231220A: Swift-XRT follow-up observations
  100. GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst

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