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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"

3867 results found.

  1. GRB071020, optical upper limit
  2. GRB 071017: a SHORT GRB detected by INTEGRAL
  3. GRB071010B: Swift/XRT detection
  4. GRB 070911, SMARTS optical/IR afterglow observations
  5. GRB 070920B: ROTSE-III Early Optical Limits
  6. INTEGRAL ToO observations of SGR1806-20
  7. GRB 070920b, SMARTS optical observation
  8. SGR1806-20: Swift-BAT detection of enhanced activity
  9. GRB 070911: Swift XRT refined analysis
  10. GRB 070911, Swift-BAT refined analysis
  11. Intense burst from SGR 1806-20 detected on September 7
  12. GRB 070810: ROTSE-III Detection of Optical Counterpart
  13. GRB 070809: ROTSE-III Optical Limits
  14. GRB 070808: Xinglong TNT optical Upper Limit
  15. GRB070808: Optical observations with KANATA
  16. GRB 070808: Swift detection of a burst
  17. Swift detection of a outburst from SAX J1810.8-2609
  18. VLA non-detection of GRB 070721B
  19. AGILE-ACS position for the SGR 1806-20 July 27 burst
  20. Intense burst from SGR 1806-20 detected on July 27
  21. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  22. GRB 070714: Swift detection of a bright burst, possibly short
  23. GRB 070628: Watcher Observations
  24. OT20050728 was not an optical GRB afterglow
  25. GRB 070616: Swift detection of a burst
  26. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  27. GRB 070611: Swift/UVOT Observations
  28. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  29. GRB 070611; Swift-XRT position
  30. Swift trigger 280447 is probably a Galactic transient
  31. GRB 070518: MARGE Observations
  32. GRB070521: P200 Observations
  33. GRB 070508: Suzaku/WAM observation of the prompt emission
  34. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  35. GRB070429B: VLT observations
  36. GRB070429B: possible host galaxy detection
  37. Konus-Wind observation of GRB 070420
  38. GRB 070420 Swift-BAT Refined Analysis
  39. Suzaku ToO observation of SGR 1806-20
  40. INTEGRAL ToO Observation of SGR1806-20
  41. long burst from SGR 1806-20 detected on March 26
  42. Short-Hard GRB 070209: PROMPT Observations
  43. GRB 070318: Swift detection of a burst with an optical afterglow
  44. GRB 070224: SARA upper limit
  45. GRB 070224: MASTER-Net refind analysis
  46. GRB 070224: MASTER-VWF-Kislovodsk observations
  47. GRB 070201: clarification on localization and Konus-Wind spectra
  48. IPN localization of very intense short GRB 070201
  49. GRB 070208: Swift detection of a burst
  50. GRB 070125: further AAVSO optical observations
  51. GRB 070125: Continued P60 Observations
  52. GRB 070110: Continued Detection and Request for Ground Followup
  53. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  54. Retractions of previous Swift-BAT triggers
  55. GRB061222a: optical observations
  56. GRB 061222B: MITSuME Akeno optical upper limits
  57. GRB 061222A: Prompt ROTSE-III Optical Limits
  58. GRB 061201: Magellan Redshift of nearby Abell cluster
  59. Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
  60. GRB061121, optical observation
  61. GRB 061121: Swift detection of a bright burst with an optical counterpart
  62. GRB061019: second epoch CrAO observations
  63. GRB 061028: Swift/XRT Astrometry Correction
  64. GRB 061028: Optical R passband observations
  65. GRB 061028: Futher P200 Observations
  66. GRB 061028: Swift/UVOT Observations
  67. GRB 061028: Swift detection of a burst
  68. GRB 061027: Swift detection of a possible burst
  69. GRB061019: optical observations
  70. GRB 061019: SMARTS afterglow confirmation
  71. GRB 061019: REM K-band candidate afterglow
  72. GRB061019: Swift/XRT position
  73. GRB 061007: Suzaku/WAM observation of the prompt emission
  74. GRB 061007: Swift-BAT refined analysis
  75. GRB 061007: Swift detection of a burst with an optical counterpart
  76. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  77. GRB 061002: Swift detection of a burst
  78. GRB 060929: TNG K-band observations
  79. GRB060929: Optical limit
  80. GRB 060729: An update on the late-time Swift observations
  81. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  82. GRB 060926: Swift detection of a burst
  83. GRB 060923C: Keck Observations
  84. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  85. GRB 060919, Swift-BAT refined analysis
  86. GRB060904b optical detections (delayed report due to internet outage)
  87. GRB 060904B: RTT150 optical observations
  88. Two bright bursts from SGR 1806-20 detected with IBAS
  89. GRB 060825: VLA observations
  90. GRB060729: analysis of XMM-Newton observation
  91. GRB 060813: Swift XRT refined analysis
  92. Image of the dust-scattering halo around SGR 1806-20
  93. Second VLA limit on new radio point source in SGR 1806-20
  94. A dust-scattering halo detected around SGR 1806-20
  95. GRB060714: optical observations
  96. GRB060807: Optical limiting magnitudes
  97. VLA Upper Limit on Outburst of SGR 1806-20
  98. GRB060806 is similar to previous activity of SGR1806-20
  99. GRB 060728: Upper limits of the X-ray emission
  100. GRB 060729: Swift/UVOT Detections

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