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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').
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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"

109 results found.

  1. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  2. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  3. Fermi GRB 210324B: Global MASTER-Net observations report
  4. GRB 201216C: Swift/UVOT Upper Limits
  5. Fermi GRB190425.09 Global MASTER-Net observations report
  6. Swift triggered on SAX J1806.5-221
  7. GRB 160409A found in Swift BAT ground analysis
  8. GRB 160119A: Swift/UVOT Upper Limits
  9. Trigger 659734: Swift detection of SAX J1750.8-2900 or other source near Galactic center
  10. Swift detection of SAX J1808.4-3658
  11. GRB 150110B: Enhanced Swift-XRT position
  12. Swift detection of SAX J1712.6-3739
  13. Swift-BAT trigger 536502 is not astrophysical
  14. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  15. Swift-BAT trigger 535733 is not astrophysical
  16. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  17. SAX J1818.6-1703: Swift detection (trigger 306379)
  18. UVOT observations of SAXJ1810.8-2609
  19. Swift detection of a outburst from SAX J1810.8-2609
  20. GRB050802: TNG optical observations
  21. GRB 050802.422: Fading of the afterglow and detection of the host
  22. GRB050802: Tentative absorption redshift
  23. GRB 050802: Swift/UVOT optical and UV detections
  24. GRB050802: CrAO optical observations
  25. GRB 050802: early Swift XRT analysis results
  26. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  27. BeppoSAX GRB : GRB020409
  28. GRB020322: Candidate Optical Afterglow
  29. Bepposax GRB020322 The second springtime BSAX GRB
  30. GRB 011211 Optical Observations: Likely Afterglow
  31. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  32. GRB011121: BeppoSAX-WFC refined positions
  33. BEPPOSAX GRB011121
  34. The X-ray Flash 011030 ('GRB 011030')
  35. IPN triangulation of GRB010629
  36. Support extension to the BeppoSAX mission
  37. GRB010222: possible optical counterpart
  38. GRB010222
  39. GRB 010214, Optical Observations
  40. GRB000528, Radio Observations
  41. IPN triangulation of GRB000516
  42. BeppoSAX GRB000424
  43. GRB000419 [IPN Position]
  44. 1SAXJ1715.0-7134 refined position
  45. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  46. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  47. Budget cuts in BeppoSAX operations: impact on GRB observations
  48. GRB000226 [IPN Position]
  49. GRB 000210: BATSE Observations
  50. GRB000210, Radio Observations
  51. SAX_WFC_GRB_NOTICE
  52. SAX_WFC_GRB_NOTICE
  53. GCN resumes full operations
  54. IPN error box for GRB991216
  55. GRB 991217 (SAX J2303.2+0015) Optical observations
  56. GRB991217/SAX J2303.2+0015, optical observations
  57. SAX J2303.2+0015 Optical observations
  58. GRB 991217 (SAX J2303.2+0015) Optical observations
  59. GRB 991217
  60. SAX J2303.2+0015: an x-ray/GRB?
  61. BeppoSAX NFI Observation of GRB991106
  62. GRB 991105: BATSE Observations
  63. BeppoSAX refined position for GRB991106
  64. GRB991105: SAX-GRBM/-WFC detection
  65. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  66. GRB ALERT: GRB991105
  67. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  68. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  69. GRB990806 BeppoSAX follow up
  70. GRB 990712
  71. Infrared and Optical Observations of GRB990705
  72. GRB990704: SAX-NFI results summary
  73. GRB 990704 X-ray Observations
  74. GRB990705: Intriguing Positional Coincidences
  75. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  76. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  77. Optical report on X-ray/GRB transient
  78. BeppoSAX: A new fast X-ray transient
  79. GRB990123, Probability of gravitational lensing
  80. GRB990123 IPN annulus
  81. GRB990123, refined SAX-WFC position
  82. GRB 981226 Optical Observations
  83. GRB981226 BeppoSAX follow up
  84. GRB980425: X-ray revised positions
  85. GRB980519, Optical Observations
  86. GRB980703, Host galaxy multicolor photometry
  87. GRB 980703 (NFI observations)
  88. BeppoSAX NFI observations of GRB 980703
  89. GRB980703
  90. GRB980613, optical observations
  91. GRB 980613 Optical Observations
  92. GRB980613 BeppoSAX-NFI follow up
  93. GRB980613, BeppoSAX WFC positions
  94. GRB980519 IPN POSITION
  95. GRB980515: SAX-WFC updated position
  96. BSAX Observations of GRB980425 field
  97. GRB980425 BATSE observations
  98. SAX J0840.7+2248 Optical Observations
  99. report on BSAX observations of GRB980425
  100. GRB980329 IPN annulus

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