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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"

100 results found.

  1. Fermi GRB 241209A: Global MASTER-Net observations report
  2. Swift triggered on SAX J1806.5-221
  3. GRB 160409A found in Swift BAT ground analysis
  4. Trigger 659734: Swift detection of SAX J1750.8-2900 or other source near Galactic center
  5. Swift detection of SAX J1808.4-3658
  6. Swift detection of SAX J1712.6-3739
  7. Swift-BAT trigger 536502 is not astrophysical
  8. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  9. Swift-BAT trigger 535733 is not astrophysical
  10. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  11. GRB 110422A: Swift/UVOT Detection of optical afterglow
  12. SAX J1818.6-1703: Swift detection (trigger 306379)
  13. UVOT observations of SAXJ1810.8-2609
  14. Swift detection of a outburst from SAX J1810.8-2609
  15. GRB 060111B: Swift UVOT Refined Magnitudes
  16. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  17. SN 2003jd (SN/GRB?) -- X-ray Observations
  18. BeppoSAX GRB : GRB020409
  19. GRB020322: Candidate Optical Afterglow
  20. Bepposax GRB020322 The second springtime BSAX GRB
  21. GRB 011211 Optical Observations: Likely Afterglow
  22. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  23. GRB011121: BeppoSAX-WFC refined positions
  24. BEPPOSAX GRB011121
  25. The X-ray Flash 011030 ('GRB 011030')
  26. IPN triangulation of GRB010629
  27. Support extension to the BeppoSAX mission
  28. GRB010222: possible optical counterpart
  29. GRB010222
  30. GRB 010214, Optical Observations
  31. GRB000528, Radio Observations
  32. IPN triangulation of GRB000516
  33. BeppoSAX GRB000424
  34. GRB000419 [IPN Position]
  35. 1SAXJ1715.0-7134 refined position
  36. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  37. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  38. Budget cuts in BeppoSAX operations: impact on GRB observations
  39. GRB000226 [IPN Position]
  40. GRB 000210: BATSE Observations
  41. GRB000210, Radio Observations
  42. SAX_WFC_GRB_NOTICE
  43. SAX_WFC_GRB_NOTICE
  44. GCN resumes full operations
  45. IPN error box for GRB991216
  46. GRB 991217 (SAX J2303.2+0015) Optical observations
  47. GRB991217/SAX J2303.2+0015, optical observations
  48. SAX J2303.2+0015 Optical observations
  49. GRB 991217 (SAX J2303.2+0015) Optical observations
  50. GRB 991217
  51. SAX J2303.2+0015: an x-ray/GRB?
  52. BeppoSAX NFI Observation of GRB991106
  53. GRB 991105: BATSE Observations
  54. BeppoSAX refined position for GRB991106
  55. GRB991105: SAX-GRBM/-WFC detection
  56. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  57. GRB ALERT: GRB991105
  58. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  59. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  60. GRB990806 BeppoSAX follow up
  61. GRB 990712
  62. Infrared and Optical Observations of GRB990705
  63. GRB990704: SAX-NFI results summary
  64. GRB 990704 X-ray Observations
  65. GRB990705: Intriguing Positional Coincidences
  66. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  67. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  68. Optical report on X-ray/GRB transient
  69. BeppoSAX: A new fast X-ray transient
  70. GRB990123, Probability of gravitational lensing
  71. GRB990123 IPN annulus
  72. GRB990123, refined SAX-WFC position
  73. GRB 981226 Optical Observations
  74. GRB981226 BeppoSAX follow up
  75. GRB980425: X-ray revised positions
  76. GRB980519, Optical Observations
  77. GRB980703, Host galaxy multicolor photometry
  78. GRB 980703 (NFI observations)
  79. BeppoSAX NFI observations of GRB 980703
  80. GRB980703
  81. GRB980613, optical observations
  82. GRB 980613 Optical Observations
  83. GRB980613 BeppoSAX-NFI follow up
  84. GRB980613, BeppoSAX WFC positions
  85. GRB980519 IPN POSITION
  86. GRB980515: SAX-WFC updated position
  87. BSAX Observations of GRB980425 field
  88. GRB980425 BATSE observations
  89. SAX J0840.7+2248 Optical Observations
  90. report on BSAX observations of GRB980425
  91. GRB980329 IPN annulus
  92. GRB980329 near-IR observations
  93. GRB980329 near-IR observations
  94. GRB980329 near IR observations
  95. GRB980329 optical observations
  96. Optical Observations for GRB 971227
  97. GRB 971227: Optical observations
  98. GRB971214: Optical Observations and Calibrations
  99. Optical Observations of GRB 971214 at Keck
  100. GRB 971214: USNOFS Observations Summary

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