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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"

152 results found.

  1. GRB 250506A: Swift XRT observations and possible counterpart detection
  2. Integral GRB241215.58: Global MASTER-Net observations report
  3. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  4. GRB 241025A: Swift-XRT refined Analysis
  5. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  6. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  7. Fermi GRB 240407A: Global MASTER-Net observations report
  8. Fermi trigger No 722349867: Global MASTER-Net observations report
  9. GRB 230628E: Swift/UVOT Detection
  10. GRB 230628E: Swift detection of a burst
  11. LIGO/Virgo S230616s: Global MASTER-Net observations report
  12. GRB 220711B: Swift/UVOT Upper Limits
  13. Konus-Wind detection of GRB 220613A
  14. GRB 220610B: AstroSat CZTI detection
  15. Fermi GRB 220514A: Global MASTER-Net observations report
  16. Fermi GRB 220309A: Global MASTER-Net observations report
  17. GRB 211206A: AstroSat CZTI detection
  18. GRB 210709A: AstroSat CZTI detection
  19. MAXI GRB210709.93: Global MASTER-Net observations report
  20. Fermi trigger No 642538568: Global MASTER-Net observations report
  21. GRB 210104A: Swift/UVOT Detection
  22. Swift GRB201024.12: Global MASTER-Net observations report
  23. SGR 1830-0645: Swift/UVOT Upper Limits
  24. GRB 200928B: AstroSat CZTI detection
  25. IceCube-200806A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  26. Fermi GRB 200607B: Global MASTER-Net observations report
  27. Swift GRB200303.11: Global MASTER-Net observations report
  28. Swift GRB200216.56: Global MASTER-Net observations report
  29. Konus-Wind observation of GRB 200120A
  30. GRB 200115A: CALET Gamma-Ray Burst Monitor detection
  31. GRB 190719C: Swift/UVOT Upper Limits
  32. GRB 180418A: TAROT La Silla observatory early optical observations
  33. GRB 180324A: Swift/UVOT Upper Limits
  34. Swift triggered on SAX J1806.5-221
  35. GRB 160409A found in Swift BAT ground analysis
  36. GRB 160327A: Swift/UVOT Upper Limits
  37. GRB 151027B: MASTER-NET early OT detection
  38. Trigger 659734: Swift detection of SAX J1750.8-2900 or other source near Galactic center
  39. Swift detection of SAX J1808.4-3658
  40. GRB 150222A: Swift-XRT refined Analysis
  41. GRB 141031A: Fermi GBM detection
  42. Swift detection of SAX J1712.6-3739
  43. GRB 140506A: Swift/UVOT Detection
  44. Konus-Wind observation of GRB 140213A
  45. GRB 130725B: Swift/UVOT Observations
  46. GRB 130725B: Swift/UVOT Detection of an Optical Counterpart
  47. Swift Trigger 558631: AAO optical observations
  48. GRB 130527A: Suzaku WAM observation of the prompt emission
  49. Swift-BAT trigger 536502 is not astrophysical
  50. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  51. Swift-BAT trigger 535733 is not astrophysical
  52. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  53. GRB 120305A: Swift/UVOT Upper Limits
  54. Swift-BAT refined analysis of outburst from 1E 1841-04.5
  55. GRB 110128A: Swift/UVOT observations
  56. GRB101024A: Swift/UVOT
  57. GRB 081125: Fermi GBM detection
  58. GRB 080506: Enhanced Swift-XRT position
  59. SAX J1818.6-1703: Swift detection (trigger 306379)
  60. UVOT observations of SAXJ1810.8-2609
  61. Swift detection of a outburst from SAX J1810.8-2609
  62. GRB 060717: Swift detection of a burst
  63. Bright short hard GRB 060303: IPN localization and Konus spectrum
  64. GRB050813: SWIFT/UVOT observation
  65. GRB 050714B: refined XRT analysis
  66. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  67. BeppoSAX GRB : GRB020409
  68. GRB020322: Candidate Optical Afterglow
  69. Bepposax GRB020322 The second springtime BSAX GRB
  70. GRB 011211 Optical Observations: Likely Afterglow
  71. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  72. GRB011121: BeppoSAX-WFC refined positions
  73. BEPPOSAX GRB011121
  74. The X-ray Flash 011030 ('GRB 011030')
  75. IPN triangulation of GRB010629
  76. Support extension to the BeppoSAX mission
  77. GRB010222: possible optical counterpart
  78. GRB010222
  79. GRB 010214, Optical Observations
  80. GRB000528, Radio Observations
  81. IPN triangulation of GRB000516
  82. BeppoSAX GRB000424
  83. GRB000419 [IPN Position]
  84. 1SAXJ1715.0-7134 refined position
  85. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  86. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  87. Budget cuts in BeppoSAX operations: impact on GRB observations
  88. GRB000226 [IPN Position]
  89. GRB 000210: BATSE Observations
  90. GRB000210, Radio Observations
  91. SAX_WFC_GRB_NOTICE
  92. SAX_WFC_GRB_NOTICE
  93. GCN resumes full operations
  94. IPN error box for GRB991216
  95. GRB 991217 (SAX J2303.2+0015) Optical observations
  96. GRB991217/SAX J2303.2+0015, optical observations
  97. SAX J2303.2+0015 Optical observations
  98. GRB 991217 (SAX J2303.2+0015) Optical observations
  99. GRB 991217
  100. SAX J2303.2+0015: an x-ray/GRB?

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