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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"

21795 results found.

  1. GRB060403: Optical Limit
  2. GRB 060403: Swift/UVOT upper limits
  3. SGR 1900+14: BAT observations
  4. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  5. GRB 060403: Swift detection of a burst
  6. HETE trigger H4044: RTT150 optical observations
  7. GRB060331: Swift/UVOT upper limits
  8. Swift XRT observations of the HETE transient H4043
  9. HETE Trigger 4043: ROTSE-III Optical Limits
  10. H4043, an unusual high-energy transient observed by HETE
  11. GRB 060322: LNA optical limit
  12. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  13. GRB 060323 : WIDGET simultaneous optical observations
  14. GRB 060323: Early optical observation at Xinglong
  15. GRB 060322: Confirmation of Swift XRT afterglow
  16. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  17. GRB060323: NOT optical observations
  18. GRB 060322: IAC80 optical observations
  19. GRB 060322: Swift XRT afterglow candidate
  20. GRB060323: P60 Observations
  21. GRB 060323: Swift/UVOT Observations
  22. GRB 060323: optical afterglow confirmed
  23. GRB060323: NOT observations
  24. GRB 060323: Optical Observations
  25. GRB 060323: Refined analysis of the Swift-BAT burst
  26. GRB 060323: optical observations at TNG
  27. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  28. GRB 060322: Refined analysis of the Swift-BAT burst
  29. GRB060323, optical observation
  30. GRB060323 - SDSS Pre-Burst Observations
  31. GRB 060323: Swift detection of a burst with a possible optical afterglow
  32. GRB 060218/SN 2006aj, LNA optical observation
  33. GRB060218: Refined photometric calibration of comparison stars
  34. GRB 060319: WHT K-band candidate afterglow
  35. GRB060319: Swift/UVOT upper limits
  36. GRB 060319 optical observations at TNG
  37. GRB060319 : Liverpool Telescope optical limit
  38. GRB060319 - SDSS Pre-burst Observations
  39. GRB060319: Swift/XRT position
  40. GRB060313: Radio Observations
  41. GRB 060313: early afterglow NIR upper limits with REM
  42. Konus-Wind observation of GRB 060313
  43. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  44. GRB 060313: Swift/UVOT Observations
  45. GRB 060313, SMARTS optical/IR observations
  46. GRB060313: optical and near infrared observations with REM
  47. GRB 060313: Swift-BAT detection of a bright short hard burst
  48. GRB060218: SARA Observations of SN2006aj
  49. GRB 060312: Swift XRT team refined analysis
  50. GRB060306: APO Ks-band Imaging Observations
  51. GRB 060312: ROTSE-III Optical Limits
  52. Bright short hard GRB 060303: IPN localization and Konus spectrum
  53. GRB 060306: MAGNUM observations
  54. GRB060218: analysis of the XMM-Newton observation
  55. Swift/UVOT observations of GRB060306
  56. GRB 060306: Swift-XRT team refined analysis
  57. GRB 060306: Swift detection of a bright burst
  58. GRB060218: Ep,i - Eiso correlation
  59. GRB060223b: optical limit
  60. GRB 060223b: Swift/UVOT Upper Limits
  61. GRB 060218/SN 2006aj: K-380 optical observations
  62. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  63. GRB200618: optical polarimetry and photometry
  64. GRB 060223B: Swift XRT possible afterglow
  65. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  66. GRB 060218 : Radio upper limits from GMRT
  67. GRB 060223A:Xinglong optical limits
  68. GRB 060223a: Swift/UVOT refined analysis
  69. GRB 060223B: Swift detection of a bright burst
  70. GRB 060218: rebrightening
  71. GRB 060219: Swift-BAT refined analysis
  72. GRB 060218: Decline in r-band flux
  73. GRB060219: SARA Observations
  74. GRB 060219: Swift/UVOT Upper Limits
  75. GRB 051221B: Swift-XRT Team Refined Analysis
  76. GRB060218: Radio Afterglow Discovery
  77. GRB060219: SDSS pre-burst observations
  78. GRB 060219: Swift-BAT detection of a weak burst
  79. Oddball GRB 060218, transient or GRB?
  80. Brightening of the Optical Counterpart of the Possible GRB 060218
  81. GRB 060218: Pre-burst detection of a possible host galaxy
  82. GRB 060218A: ROTSE-III Possible Optical Flare
  83. GRB 060211B: Swift/UVOT Upper Limits
  84. GRB060218 : SDSS pre-burst observations
  85. GRB 060218: Swift XRT Position
  86. GRB 060213: optical afterglow not confirmed
  87. Swift UVOT observations of GRB060213
  88. GRB060213: Swift XRT observations and possible afterglow candidate
  89. Konus-Wind observation of bright hard GRB 060213
  90. GRB 060213: IPN localization
  91. GRB060211B: REM optical and NIR observations
  92. GRB 060211A: Further refined analysis of the Swift burst
  93. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  94. GRB 060211b: P60 Observations
  95. GRB 060211B: Swift/BAT refined analysis
  96. GRB060210: Swift/UVOT Upper Limits
  97. GRB 060210: Optical Observations
  98. GRB 060211: ROTSE-III Optical Limits
  99. GRB 060211: Swift detection of a long burst
  100. GRB060210: Optical Observations

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