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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"

19863 results found.

  1. GRB 090709: Swift detection of a bright burst
  2. GRB 090708: Early RAPTOR Optical Limits
  3. GRB 090708, Swift-BAT refined analysis
  4. GRB 090706: Fermi GBM detection
  5. GRB 090705: PAIRITEL NIR Observations
  6. GRB 090705: Swift detection of a possible burst
  7. XRF 090702 : RTT150 optical observations
  8. GRB 090529: CrAO optical upper limit
  9. GRB 090529: MTM-500 optical observations
  10. GRB 090702: UVOT upper limits
  11. XRF 090702: VLT imaging
  12. XRF 090702: Swift-XRT afterglow position
  13. GRB 090404: Deep optical imaging and possible host association
  14. GRB 090628: Swift XRT refined analysis
  15. GRB 090628: Swift/UVOT Upper Limits
  16. GRB080628: SAO RAS optical observations
  17. GRB 090628: GROND upper limits
  18. GRB 090628: Enhanced Swift-XRT position
  19. GRB 090626: IPN localization
  20. GRB 090423: Spitzer observations of the z~8.3 burst
  21. GRB 090625B: Swift/UVOT Upper Limits
  22. GRB 090625B: GROND upper limits
  23. GRB090618: HCT optical observations
  24. GRB 090618: SARA Second Epoch Observations
  25. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  26. GRB 090618: Correction to GCN 9568
  27. GRB 090618: Suzaku WAM observation of the prompt emission
  28. GRB 090621A: Enhanced Swift-XRT position
  29. GRB 090621B: GRT Optical Observation
  30. GRB 090621A: GRT Optical Observation
  31. GRB 090621B: I-band observations from 1.23m CAHA
  32. GRB 090621B: P60 Observations
  33. GRB 090621: Fermi GBM observation
  34. GRB 090621B: VLA observations
  35. Konus-Wind and Konus-RF observations of GRB 090618
  36. GRB 090621B: Swift/UVOT Upper Limits
  37. GRB 090621B: Swift-XRT refined analysis
  38. GRB 090621B: RTT150 optical observations
  39. GRB 090621B: Swift detection of a short hard burst
  40. GRB 090621: Swift/UVOT Upper Limits
  41. GRB090618: Spectrum and photometry from 6.0m BTA
  42. GRB 090621: Swift detection of a burst
  43. GRB090618: OAA-OAUV Optical observations
  44. GRB 090618: Fermi GBM observation
  45. VLA radio detection of GRB 090618
  46. GRB 090618 15GHz radio detection
  47. GRB090618 - Continued optical monitoring and light curve break
  48. GRB 090618: Swift-BAT refined analysis
  49. GRB 090618: SARA observations
  50. GRB090618: Swift/UVOT bright afterglow detection
  51. GRB 090618: SDSS host detection
  52. Swift XRT observations of GRB 090531A
  53. GRB 090618: AGILE observations
  54. GRB 090618: Enhanced Swift-XRT position
  55. GRB 090618 Faulkes Telescope North observations
  56. GRB090618: P60 Optical Afterglow
  57. GRB 090618: Swift detection of a bright burst with optical afterglow
  58. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  59. GRB 090424: WSRT Radio Observations
  60. RXTE Discovery of Pulsations from SGR 0418+5729
  61. Discovery of a new soft gamma repeater source, SGR 0418+5729
  62. GRB 090607: Swift/UVOT Upper Limits
  63. GRB 090607: GRAS001 optical observations
  64. GRB 090607: Faulkes Telescope North observations
  65. GRB 090607: Swift detection of a burst
  66. GRB 090530: Further NOT optical observations
  67. GRB 090530: RTT150 Optical Observation
  68. GRB 090529A: RTT150 Optical Observations
  69. GMRT observation of GRB 090424 afterglow
  70. GRB090529: Further NOT optical observations
  71. GRB 090531B: GROND observation
  72. GRB 090530: Early RAPTOR Optical Observations
  73. GRB090529B: ROVOR Upper Limits
  74. GRB 090531A: SARA upper limit
  75. GRB 090531B: Swift/BAT spectral lag results
  76. Corrections to GRB 090531B Swift/UVOT Upper Limits
  77. GRB 090531B, RIMOTS optical upper limits
  78. GRB 090531B: Swift/UVOT Upper Limits
  79. GRB 090528B: MASTER-II Kourovka optical limit
  80. GRB 090529: MITSuME optical observation
  81. GRB 090530: GRT Optical Observation
  82. GRB 090531B: Swift-XRT candidate afterglow position
  83. GRB 090531B: ROTSE-III Optical Limits
  84. GRB 090530: break in light curve
  85. GRB 090531: GROND upper limits
  86. GRB 090531: P60 Observations
  87. GRB 090529: NOT optical observations
  88. GRB 090530: NOT optical observations
  89. GRB090530: Swift/UVOT afterglow detection
  90. GRB 090530: Enhanced Swift-XRT position
  91. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  92. GRB 090530: GRAS002 refined OA analysis
  93. GRB 090530: GRAS002 optical observations
  94. GRB 090530: PAIRITEL NIR Detections
  95. GRB 090530: Swift detection of a burst with an optical counterpart
  96. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  97. GRB 090529: Swift-BAT refined analysis
  98. GRB 090529: Enhanced Swift-XRT position
  99. GRB 090529: Preliminary Swift/UVOT Upper Limit
  100. GRB 090529: Swift detection of a burst

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