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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"

20357 results found.

  1. XRF 090702 : RTT150 optical observations
  2. GRB 090529: CrAO optical upper limit
  3. GRB 090529: MTM-500 optical observations
  4. GRB 090702: UVOT upper limits
  5. XRF 090702: VLT imaging
  6. XRF 090702: Swift-XRT afterglow position
  7. GRB 090404: Deep optical imaging and possible host association
  8. GRB 090628: Swift XRT refined analysis
  9. GRB 090628: Swift/UVOT Upper Limits
  10. GRB080628: SAO RAS optical observations
  11. GRB 090628: GROND upper limits
  12. GRB 090628: Enhanced Swift-XRT position
  13. GRB 090626: IPN localization
  14. GRB 090423: Spitzer observations of the z~8.3 burst
  15. GRB 090625B: Swift/UVOT Upper Limits
  16. GRB 090625B: GROND upper limits
  17. GRB090618: HCT optical observations
  18. GRB 090618: SARA Second Epoch Observations
  19. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  20. GRB 090618: Correction to GCN 9568
  21. GRB 090618: Suzaku WAM observation of the prompt emission
  22. GRB 090621A: Enhanced Swift-XRT position
  23. GRB 090621B: GRT Optical Observation
  24. GRB 090621A: GRT Optical Observation
  25. GRB 090621B: I-band observations from 1.23m CAHA
  26. GRB 090621B: P60 Observations
  27. GRB 090621: Fermi GBM observation
  28. GRB 090621B: VLA observations
  29. Konus-Wind and Konus-RF observations of GRB 090618
  30. GRB 090621B: Swift/UVOT Upper Limits
  31. GRB 090621B: Swift-XRT refined analysis
  32. GRB 090621B: RTT150 optical observations
  33. GRB 090621B: Swift detection of a short hard burst
  34. GRB 090621: Swift/UVOT Upper Limits
  35. GRB090618: Spectrum and photometry from 6.0m BTA
  36. GRB 090621: Swift detection of a burst
  37. GRB090618: OAA-OAUV Optical observations
  38. GRB 090618: Fermi GBM observation
  39. VLA radio detection of GRB 090618
  40. GRB 090618 15GHz radio detection
  41. GRB090618 - Continued optical monitoring and light curve break
  42. GRB 090618: Swift-BAT refined analysis
  43. GRB 090618: SARA observations
  44. GRB090618: Swift/UVOT bright afterglow detection
  45. GRB 090618: SDSS host detection
  46. Swift XRT observations of GRB 090531A
  47. GRB 090618: AGILE observations
  48. GRB 090618: Enhanced Swift-XRT position
  49. GRB 090618 Faulkes Telescope North observations
  50. GRB090618: P60 Optical Afterglow
  51. GRB 090618: Swift detection of a bright burst with optical afterglow
  52. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  53. GRB 090424: WSRT Radio Observations
  54. RXTE Discovery of Pulsations from SGR 0418+5729
  55. Discovery of a new soft gamma repeater source, SGR 0418+5729
  56. GRB 090607: Swift/UVOT Upper Limits
  57. GRB 090607: GRAS001 optical observations
  58. GRB 090607: Faulkes Telescope North observations
  59. GRB 090607: Swift detection of a burst
  60. GRB 090530: Further NOT optical observations
  61. GRB 090530: RTT150 Optical Observation
  62. GRB 090529A: RTT150 Optical Observations
  63. GMRT observation of GRB 090424 afterglow
  64. GRB090529: Further NOT optical observations
  65. GRB 090531B: GROND observation
  66. GRB 090530: Early RAPTOR Optical Observations
  67. GRB090529B: ROVOR Upper Limits
  68. GRB 090531A: SARA upper limit
  69. GRB 090531B: Swift/BAT spectral lag results
  70. Corrections to GRB 090531B Swift/UVOT Upper Limits
  71. GRB 090531B, RIMOTS optical upper limits
  72. GRB 090531B: Swift/UVOT Upper Limits
  73. GRB 090528B: MASTER-II Kourovka optical limit
  74. GRB 090529: MITSuME optical observation
  75. GRB 090530: GRT Optical Observation
  76. GRB 090531B: Swift-XRT candidate afterglow position
  77. GRB 090531B: ROTSE-III Optical Limits
  78. GRB 090530: break in light curve
  79. GRB 090531: GROND upper limits
  80. GRB 090531: P60 Observations
  81. GRB 090529: NOT optical observations
  82. GRB 090530: NOT optical observations
  83. GRB090530: Swift/UVOT afterglow detection
  84. GRB 090530: Enhanced Swift-XRT position
  85. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  86. GRB 090530: GRAS002 refined OA analysis
  87. GRB 090530: GRAS002 optical observations
  88. GRB 090530: PAIRITEL NIR Detections
  89. GRB 090530: Swift detection of a burst with an optical counterpart
  90. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  91. GRB 090529: Swift-BAT refined analysis
  92. GRB 090529: Enhanced Swift-XRT position
  93. GRB 090529: Preliminary Swift/UVOT Upper Limit
  94. GRB 090529: Swift detection of a burst
  95. GRB 090518 - NOT upper limit
  96. GRB 090520: GROND upper limits
  97. GRB 090519B: Fermi GBM detection
  98. GRB 090519: Swift-XRT refined analysis
  99. GRB 090519: NOT refined analysis
  100. GRB 090519: VLT spectroscopic redshift

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