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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"

23436 results found.

  1. SGR 1900+14: Swift detection of an outburst
  2. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  3. GRB060403: optical observations
  4. GRB 060403 Optical observations
  5. GRB 060403: MITSuME optical observation
  6. GRB060403: Optical Limit
  7. GRB 060403: Swift/UVOT upper limits
  8. SGR 1900+14: BAT observations
  9. GRB 060403: Refined analysis of the Swift-BAT burst
  10. GRB 060403: Swift detection of a burst
  11. HETE trigger H4044: RTT150 optical observations
  12. GRB060331: Swift/UVOT upper limits
  13. Swift XRT observations of the HETE transient H4043
  14. H4043, an unusual high-energy transient observed by HETE
  15. GRB 060322: LNA optical limit
  16. INTEGRAL and XMM ToO observations of SGR1900+14
  17. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  18. SGR 1900+14: Swift-BAT detection of a bright outburst
  19. GRB 060323 : WIDGET simultaneous optical observations
  20. GRB 060323: Early optical observation at Xinglong
  21. GRB 060322: Confirmation of Swift XRT afterglow
  22. SGR 1900+14: Swift detection of renewed activity
  23. GRB060323: NOT optical observations
  24. GRB 060322: IAC80 optical observations
  25. GRB 060322: Swift XRT afterglow candidate
  26. GRB060323: P60 Observations
  27. GRB 060323: Swift/UVOT Observations
  28. GRB 060323: optical afterglow confirmed
  29. GRB060323: NOT observations
  30. GRB 060323: Optical Observations
  31. GRB 060323: optical observations at TNG
  32. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  33. GRB060323, optical observation
  34. GRB060323 - SDSS Pre-Burst Observations
  35. GRB 060323: Swift detection of a burst with a possible optical afterglow
  36. GRB 060322: Swift-BAT detection of a 200-sec burst
  37. GRB 060218/SN 2006aj, LNA optical observation
  38. GRB060218: Refined photometric calibration of comparison stars
  39. GRB 060319: WHT K-band candidate afterglow
  40. GRB060319: Swift/UVOT upper limits
  41. GRB060319: MASTER limit
  42. GRB 060319 optical observations at TNG
  43. GRB060319 : Liverpool Telescope optical limit
  44. GRB060319: MASTER optical observation
  45. GRB060319 - SDSS Pre-burst Observations
  46. GRB 060319: Swift detection of a burst
  47. GRB060313: Radio Observations
  48. GRB 060313: early afterglow NIR upper limits with REM
  49. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  50. GRB 060313: Swift/UVOT Observations
  51. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  52. GRB 060313, SMARTS optical/IR observations
  53. GRB060313: optical and near infrared observations with REM
  54. GRB 060313: Swift-BAT detection of a bright short hard burst
  55. GRB060218: SARA Observations of SN2006aj
  56. GRB060312: Swift UVOT observation
  57. GRB 060312: Refined analysis of the Swift-BAT burst
  58. GRB 060218/SN 2006aj, high resolution spectra
  59. GRB 060312: Swift XRT team refined analysis
  60. GRB060306: APO Ks-band Imaging Observations
  61. GRB 060312: ROTSE-III Optical Limits
  62. GRB 060312: Swift detection of a burst
  63. GRB 060306: SOAR Ks Observations
  64. Bright short hard GRB 060303: IPN localization and Konus spectrum
  65. GRB060219: Liverpool Telescope observations
  66. GRB 060306: MAGNUM observations
  67. GRB060218: analysis of the XMM-Newton observation
  68. Swift/UVOT observations of GRB060306
  69. GRB 060306: Swift-XRT team refined analysis
  70. GRB 060306: PROMPT Observations
  71. GRB 060306: Swift detection of a bright burst
  72. GRB 060218: RTT150 optical observations
  73. GRB060223b: optical limit
  74. GRB 060218 : GMRT observation [Correction and Improvement]
  75. GRB 060223b: Swift/UVOT Upper Limits
  76. GRB 060218/SN 2006aj: K-380 optical observations
  77. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  78. GRB200618: optical polarimetry and photometry
  79. GRB 060223B: Swift XRT possible afterglow
  80. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  81. GRB 060218 : Radio upper limits from GMRT
  82. GRB 060204B: GETS early limit
  83. GRB 060223A:Xinglong optical limits
  84. GRB 060223B: ART optical limits
  85. GRB 060223a: Swift/UVOT refined analysis
  86. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  87. GRB 060223B: Swift detection of a bright burst
  88. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  89. GRB 060223: Swift detection of a burst
  90. Spectral properties of GRB060218/SN2006aj
  91. GRB 060218: Decline in r-band flux
  92. GRB 060218: Likely an underluminous GRB
  93. GRB060219: SARA Observations
  94. GRB 060219: Swift/UVOT Upper Limits
  95. GRB 051221B: Swift-XRT Team Refined Analysis
  96. GRB060218: Radio Afterglow Discovery
  97. GRB060219: SDSS pre-burst observations
  98. GRB 060219: Swift-BAT detection of a weak burst
  99. Oddball GRB 060218, transient or GRB?
  100. GRB060218: Swift/XRT Team preliminary analysis of the possible burst

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